Fridtjof Heyerdahl

• Busken, W. J. van den; Dines, Alison M.; Eyer, Florian; Heyerdahl, Fridtjof; Hovda, Knut Erik & Liechti, Matthias E. [Show all 13 contributors for this article] (2026). Cardiovascular effects associated with acute recreational drug toxicity presentations to the emergency department: a European drug emergencies network (Euro-DEN plus) study. Clinical Toxicology. ISSN 1556-3650. doi: 10.1080/15563650.2026.2669671. Full text in Research Archive
• Simensen, Randi; Smalberget, Live & Heyerdahl, Fridtjof (2026). MetoksyKval: the extent of pre-hospital methoxyflurane administration for acute traumatic pain: focus on economic impact and rationale for use. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine. 34(1), p. 1–10. doi: 10.1186/s13049-026-01546-z. Full text in Research Archive Show summary

  Background Effective pain management is critical in pre-hospital care, yet many patients still receive suboptimal treatment. Methoxyflurane, a handheld self-administered analgesic, is increasingly used in European ambulance services. Its effectiveness and safety are established, but the reasons for its use in acute pre-hospital settings have received limited attention. This study aimed to explore patterns of use, effectiveness, and economic implications of methoxyflurane in traumatic pain, with particular focus on decision-making and patient satisfaction. Methods This prospective observational study in a Norwegian ground ambulance service, conducted from January 15 to July 15, 2024, involved adult patients (aged ≥ 18 years) with moderate to severe traumatic pain treated by the ground ambulance service of Innlandet Hospital Trust. Methoxyflurane was administered at the discretion of the ambulance personnel. Pain intensity scores, demographic characteristics, treatment satisfaction levels, and rationale behind choosing methoxyflurane were recorded. Results A total of 48 patients were included (median age 69 years, 58% male), most with fall-related injuries (77%) and fractures (65%). In the corresponding 2022 period, only 41% of patients with an Numeric rating Scale (NRS) pain score ≥ 4 received any analgesia. In this study, methoxyflurane accounted for 7% of such cases but increased overall analgesic costs three-fold. It was selected in 15/48 (31%) cases due to difficult intravenous access, in 15/48 (31%) as a preferred non-opioid option despite NRS ≥ 4, and in 13/48 (27%) to reduce on-scene time. Pain measured on NRS decreased from a median of 8 at baseline to 5 within ten minutes, with 52% achieving sufficient relief without rescue medication. Satisfaction was good or better in 61%, 67% would choose methoxyflurane again, and 90% of personnel reported a strong preference for future use. Adverse events were mild and comparable to earlier studies. Conclusions Methoxyflurane was viewed as a useful non-intravenous option in settings where rapid analgesia is essential. Although used in only 7% of patients with moderate to severe pain and associated with higher costs, it provided fast pain relief in patients with difficult venous access and when minimising on-scene time was critical. These results support its role as a bridge to longer-acting intravenous analgesia and may help decision-makers identify patient groups most likely to benefit, enabling more targeted and cost-effective implementation. Trial registration Approved by the Regional Ethics Committee, South East; https://rekportalen.no , ref no. 658708/ 255159 and Data Protection Officer at Innlandet Hospital Trust ref.no 28028904).

• Bekkevold, Marit; Solvik-Olsen, TONE; Lang, Astri Maria; Heyerdahl, Fridtjof; Hagemo, Jostein Skjalg & Rehn, Marius (2025). Data variables reported during neonatal transport: a systematic literature review. Journal of Perinatology. ISSN 0743-8346. 46(1), p. 6–11. doi: 10.1038/s41372-025-02483-y. Full text in Research Archive Show summary

  Neonatal transports are essential for providing access to advanced intensive care treatment for sick and premature neonates. There is a lack of consensus of which core physiological variables, clinical parameters and quality metrics to report for clinical guidance during transport and clinical governance of transport systems. We performed a systematic literature review to identify which data variables are reported during neonatal transports and assess whether these variables are uniform and transferable across studies. In the final data extraction and quality appraisal, 108 studies were included. The studies were heterogenous, presented a large variation of registered variables and frequently lacked uniform definitions. Reaching consensus on a set of defined variables for registration and implementation internationally will enhance the opportunity to improve the safety, effectiveness and quality of care for these vulnerable neonates.

• Solvik-Olsen, TONE; Bekkevold, Marit; Heyerdahl, Fridtjof; Lang, Astri Maria; Hagemo, Jostein Skjalg & Rehn, Marius (2025). Environmental factors and clinical markers of stress during neonatal transport: A systematic literature review. BMJ Paediatrics Open. 9(1). doi: 10.1136/bmjpo-2025-003568. Full text in Research Archive Show summary

  Background Neonatal transport is an essential component of modern neonatal intensive care globally, providing access to advanced treatment while exposing vulnerable neonates to environmental conditions that may increase the risk of physiological instability. Objective To systematically review studies measuring environmental exposures, specifically vibration, sound and temperature fluctuations during neonatal transport and to evaluate their impact on clinical parameters in neonates. Methods A systematic literature review identified studies reporting environmental factors or clinical data during transport via ground, rotor or fixed-wing air ambulances. The medical databases searched included MEDLINE/PubMed, Embase, the Cochrane database of systematic reviews, Nursing Reference Center Plus, UpToDate and SveMed covering the period from November 2020 to January 2025. Results 15 observational studies, 13 prospective and 2 retrospective covering publications from 1992 to 2025 were included. The studies included data on vibration, sound, ambient temperature and a wide range of clinical parameters such as heart rate and heart rate variability, change in clinical behaviour scales and cortisol in saliva reflecting the neonatal condition. Only four articles reported the effect of environmental factors on neonatal physiology. Conclusions This review highlights the presence of environmental factors, particularly noise and vibration, during transport and raises concerns about their impact on neonates. Although diverse clinical parameters were documented, the small sample sizes and variability in measurement methods across studies limit the ability to draw definitive conclusions. These observations emphasise the need

• Berling, Ingrid; Yates, Christopher; Hoffman, Robert S.; Hatten, Benjamin W.; Roberts, Darren M. & Wong, Anselm [Show all 18 contributors for this article] (2025). QT interval prolongation in acute antipsychotic poisoning: systematic review and recommendations. Clinical Toxicology. ISSN 1556-3650. 63(11), p. 810–837. doi: 10.1080/15563650.2025.2554950. Full text in Research Archive Show summary

  Introduction Antipsychotic medications are often associated with QT interval prolongation, which can lead to ventricular dysrhythmias, including torsade de pointes. However, unstable or significant dysrhythmic events are rare. Evidence-based recommendations on the assessment and management of poisoned patients at risk for QT interval prolongation are lacking. Current practice often involves costly and lengthy cardiac monitoring, leading to delayed disposition of the patient from emergency departments or prolonged monitoring times in other hospital units. To address this issue, the QT Interval Prolongation in Clinical Toxicology Workgroup was formed by the Clinical Toxicology Recommendations Collaborative to develop evidence-based recommendations for the management and treatment of QT interval prolongation in acute overdose patients. This article reports our findings on patients with antipsychotic poisoning. Methods A systematic review of the literature regarding QT interval prolongation in all acute overdoses was undertaken, and the evidence was summarized for antipsychotic medication overdose. Voting statements were drafted using a predetermined format for monitoring the QT interval and use of continuous cardiac monitoring. A two-round modified Delphi method was used to reach a consensus. The strength of consensus was measured using the disagreement index as defined by the RAND/UCLA Appropriateness Method. Results From the 327 articles that were included in the systematic review of QT interval prolongation in all acute overdoses, a total of 55 articles were relevant to antipsychotic medication-induced QT prolongation in acute overdose. Medications with more than three articles were reviewed individually for recommendations, whilst medications with less than three were grouped together for discussion as miscellaneous. Individual medication recommendations were made for amisulpride (15 articles), thioridazine (11 articles), ziprasidone (eight articles) and quetiapine (13 articles), whilst consensus statements based on limited data were made for acute ingestions of clozapine, haloperidol, iloperidone, pimozide, pipamperone, olanzapine and risperidone (14 articles in total). The electrocardiogram is suggested as a risk assessment tool for ingestion of all antipsychotic medication. We recommend continuous cardiac monitoring for patients ingesting more than amisulpride 2 g, thioridazine 1 g, and ziprasidone 3 g. We suggest continuous cardiac monitoring for the above-mentioned medications for lower dose ingestions as well as for ingestions of haloperidol, iloperidone, pimozide and pipamperone. We do not suggest continuous cardiac monitoring for acute clozapine and risperidone poisoning, and do not recommend continuous cardiac monitoring for the QT interval in acute olanzapine or quetiapine poisoning. The need for ongoing cardiac monitoring should be guided by an individual risk assessment considering the medication and dose ingested, the time since ingestion, as well as other factors such as heart rate or co-ingestions. Discussion The quality of evidence for the risk of QT interval prolongation and torsade de pointes is heterogeneous among different antipsychotics and inherently constrains the recommendations. Available data suggest that amisulpride, thioridazine and ziprasidone are associated with QT interval prolongation and torsade de pointes, while the risk is likely overstated for quetiapine, olanzapine and risperidone. Ongoing research is needed to improve management strategies for acute antipsychotic overdose-induced QT interval prolongation and dysrhythmias. Conclusions The QT Interval Prolongation in Clinical Toxicology Workgroup recommends the use of screening electrocardiograms in all patients with acute antipsychotic medication overdose and cardiac monitoring in patients with at-risk overdoses from thioridazine, amisulpride, and ziprasidone. The QT Interval Prolongation in Clinical Toxicology Workgroup suggests the same approach for patients with overdoses of haloperidol, iloperidone, pipamperone and pimozide. The risk of torsade de pointes is likely overstated for acute antipsychotic medication overdose as a general class group, and concern should rather focus on a few specific medications.

• Ouwerkerk, Joep J.J.; Wood, David M.; Dines, Alison M.; Yates, Christopher; Eyer, Florian & Heyerdahl, Fridtjof [Show all 14 contributors for this article] (2025). Differences in the clinical presentation of acute 3,4-methylenedioxymetamfetamine intoxication by co-intoxication and patient sex to European emergency departments. Clinical Toxicology. ISSN 1556-3650. 63(3), p. 183–192. doi: 10.1080/15563650.2025.2453052. Full text in Research Archive
• Lyphout, Cathelijne; Paepe, Peter De; Dines, Alison M.; Eyer, Florian; Giraudon, Isabelle & Heyerdahl, Fridtjof [Show all 14 contributors for this article] (2025). Emergency Department Presentations Related to the Abuse of Illicit and Prescription Opioids Through a European Sentinel-centres–Based Registry. Journal of addiction medicine. ISSN 1932-0620. doi: 10.1097/adm.0000000000001632. Full text in Research Archive Show summary

  Objectives: Opioid use, both prescribed and illicit, has caused considerable harm and fatalities. This study aims at characterising patterns of emergency department (ED) presentations related to opioid abuse across Europe. Methods: Data on demographics, clinical features, and epidemiology were extracted from the Euro-DEN Plus data set for presentations involving acute opioid toxicity between October 2013 and December 2021. Results: Of 62,545 presentations, 3888 (6.2%) involved prescription opioids, 11,252 (18.0%) illicit opioids, and 587 (0.9%) both. Heroin accounted for 99.8% of illicit opioid cases. The most commonly reported prescription opioids were methadone (51.3%), buprenorphine (13.9%), morphine (9.3%), fentanyl (6.8%), and tramadol (6.7%). Co-use of benzodiazepines and Z-drugs (35.6%) and pregabalin (6.6%) was significantly higher in prescription opioid cases compared with illicit (20.6% and 1.5%, respectively; P < 0.001). Mortality was greater with prescription opioids (1.2%) than illicit opioids (0.4%, P < 0.001). Conclusions: Heroin remains the predominant opioid; though the relative contribution of prescription opioids varies significantly across centres and countries. Methadone and buprenorphine predominate among prescribed opioids, while fentanyl and oxycodone account for a small proportion, contrasting with North American patterns.

• Simensen, Randi; Fjose, Lars Olav; Thorsen, Kjetil; Olsen, Inge Christoffer; Rehn, Marius & Hagemo, Jostein Skjalg [Show all 8 contributors for this article] (2025). Comparison of inhalational methoxyflurane, intranasal fentanyl, and intravenous morphine for treatment of prehospital acute pain in Norway (PreMeFen): a randomised, non-inferiority, three-arm, phase 3 trial. The Lancet. ISSN 0140-6736. p. 1–10. doi: 10.1016/s0140-6736(25)01575-2. Full text in Research Archive Show summary

  Background: Adequate pain control is essential; however, acute pain is often undertreated in prehospital care. This study aimed to evaluate three analgesic regimens for treating acute pain in an ambulance setting. Methods: PreMeFen is a randomised, open-label, non-inferiority, three-arm, phase 3 trial conducted in the working areas of the ground ambulance service of the Innlandet Hospital Trust, Norway. Patients aged 18-69 years and 70 years and older with traumatic or medical acute pain scoring 4 or higher on the Numeric Rating Scale (NRS) were randomly assigned (1:1:1) to receive in titration doses 3 mL inhalational methoxyflurane, 50 μg or 100 μg intranasal fentanyl, or 0·05 mg/kg or 0·1 mg/kg intravenous morphine, respectively, depending on the age group. The primary endpoint was change in pain NRS score from baseline to 10 min after treatment start and was analysed per protocol. The non-inferiority margin was 1·3. This trial is registered with ClinicalTrials.gov (NCT05137184) and is completed. Findings: Between Nov 12, 2021, and April 22, 2023, 632 patients were assessed for eligibility, and 338 were randomly assigned to methoxyflurane (n=112), fentanyl (n=115), or morphine (n=111). 281 patients were included in the per-protocol population. 145 (52%) of 281 patients were female and 136 (48%) were male. Median age was 61 years (IQR 47-75). The baseline NRS score was 7·6 (SD 1·8). Mean NRS score changes after 10 min were -3·31 (SD 2·67) for methoxyflurane, -1·98 (2·28) for fentanyl, and -2·74 (2·12) for morphine. Comparing changes in mean NRS score while adjusting for baseline showed that methoxyflurane was non-inferior to fentanyl (-1·33 [95% CI -2·01 to -0·64]) and morphine (-0·36 [-1·03 to 0·31]). Intranasal fentanyl was not non-inferior to morphine at 10 min (0·91 [0·27 to 1·55]). Adverse events occurred in 26 (24%) of 109 patients in the morphine group, 27 (24%) of 112 in the fentanyl group, and 24 (22%) of 111 in the methoxyflurane group. Two serious adverse events, respiratory depression (grade 2) and loss of consciousness (grade 3), occurred in the same patient in the methoxyflurane group. There were no treatment-related deaths. Interpretation: Inhalational methoxyflurane is non-inferior to intranasal fentanyl and intravenous morphine for acute pain management in the prehospital environment, assessed 10 min after administration. Inhalational methoxyflurane serves as a valuable non-intravenous alternative in the early phase of treatment and might bridge the gap to longer-acting analgesics.

• Miró, Òscar; Galicia, Miguel; Dargan, Paul I.; Wood, David M.; Dines, Alison M. & Heyerdahl, Fridtjof [Show all 13 contributors for this article] (2025). Changes in clinical features and severity in patients presenting to European emergency departments with acute cannabis toxicity over the 10‐year period from 2013 to 2022. Addiction. ISSN 0965-2140. doi: 10.1111/add.70233. Full text in Research Archive Show summary

  Abstract Background and aims In recent years, the potency of natural cannabis products (herb and resin) has increased with a higher delta‐ 9‐tetrahydrocannabinol (Δ9‐THC) content, but there are limited data on trends on clinical presentation and severity of toxicity in cannabis users consulting the emergency department (ED) for acute intoxication. This study aimed to analyse the evolution over time of clinical findings and severity of presentations in a large series of patients presenting to European EDs with acute toxicity after lone cannabis use. Design Secondary analysis of data included in the Euro‐DEN Registry from 1 October 2013 to 31 December 2022. Setting 40 EDs in 25 European countries. Participants/cases ED presentations reporting lone cannabis use. Presentations reporting concomitant use of, or having positive toxicological tests for, ethanol or other drugs were excluded. 3839 ED presentations reporting lone cannabis use were analysed (median age 25 years, interquartile range= 20–33; 71% male). Measurements Temporal trends of 14 pre‐defined clinical signs/symptoms and 4 markers of severity, which included the need for ambulance transfer to the ED, hospitalisation, intensive care unit admission (ICU) and death. Findings The most frequent clinical features were anxiety (35%), agitation (22%), decreased alertness (drowsiness or coma, 21%) and vomiting (20%), while seizures, arrythmias and hyperthermia were observed in <3% of cases. Statistically significant changes over time were only found in the frequency of hypotension [adjusted odds ratio (OR) = 1.239 per every subsequent year, 95% confidence interval (CI) = 1.107–1.386], hypertensive crisis (OR = 1.168, 95% CI = 1.070–1.274) and palpitations (OR = 0.922, 95% CI = 0.883–0.962). Nonlinear analyses detected statistically significant mid‐period increases for anxiety, agitation and arrhythmias that subsided by the end of the study, and showed increases in chest pain and decreases in seizures that became statistically significant in the latter half of the period. Regarding episode severity, 76% of cases were brought to the ED by ambulance, 13% required hospitalisation, 1% were admitted to the ICU and 0.1% died. No statistically significant changes were observed over time in either the linear or the nonlinear models. Conclusion Very few changes in the clinical features of patients presenting to European emergency departments with lone acute cannabis toxicity were identified over 2013 to 2022, suggesting that despite the increase in potency of cannabis in Europe over this period, the severity of acute intoxication has remained unchanged.

• Ouwerkerk, Joep JJ; Wood, David M.; Dines, Alison M.; Yates, Christopher; Eyer, Florian & Heyerdahl, Fridtjof [Show all 13 contributors for this article] (2025). Differences in the clinical presentation of acute 3,4-methylenedioxymetamfetamine intoxication by co-intoxication and patient sex to European emergency departments. Clinical Toxicology. ISSN 1556-3650. 63, p. 183–192. doi: 10.1080/15563650.2025.2453052. Full text in Research Archive Show summary

  Introduction This study hypothesized that 3,4-methylenedioxymetamfetamine intoxication presents with distinct clinical features and outcomes when combined with other substances of misuse, compared to mono-3,4-methylenedioxymetamfetamine intoxication. This study investigated the clinical presentation of acute mono-3,4-methylenedioxymetamfetamine intoxication, 3,4-methylenedioxymetamfetamine intoxication with exclusive co-usage of ethanol, and 3,4-methylenedioxymetamfetamine-co-intoxication with co-usage of other substances with or without ethanol, with a focus on patient sex differences. Methods A retrospective analysis was conducted using the Euro-DEN Plus database (2013–2022), which collects data on emergency department presentations with acute drug intoxication from 28 sentinel centres in 18 European countries. Odds ratios for clinical features were calculated for the three study groups with mono-3,4-methylenedioxymetamfetamine intoxication as the reference group. A sub-analysis explored patient sex differences in clinical features. Results Among 4,102 presentations, 3,4-methylenedioxymetamfetamine-ethanol intoxication (n = 1,376) was associated with increased odds of agitation (OR: 1.34), drowsiness (OR: 2.30), and vomiting (OR: 1.85) compared to mono-3,4-methylenedioxymetamfetamine intoxication (n = 359). 3,4-Methylenedioxymetamfetamine-co-intoxication (n = 2,367) was associated with higher odds of bradycardia (OR: 3.14), psychosis (OR: 1.91), and coma (OR: 1.72). Mortality rates did not significantly differ across groups. Females reported a lower incidence of chest pain (OR 0.78) while reporting higher rates of vomiting (OR: 1.64), headache (OR: 1.61), and hypotension (OR: 1.89) compared to males. Discussion The variation in clinical manifestation of acute 3,4-methylenedioxymetamfetamine intoxication is associated with co-intoxication and patient sex. Co-intoxication with ethanol or other substances was associated with an increased incidence of more severe symptoms, such as agitation and psychosis, necessitating tailored management. These variations suggest the need for physicians to consider the type of co-intoxication and patient sex to optimize treatment strategies. Although co-intoxication affected the clinical trajectory, the mortality risk remains low. Conclusions Ethanol co-intoxication, co-intoxication with other substances of misuse, and patient sex were associated with varying clinical presentations in the emergency department, necessitating tailored treatment approaches.

• Miró, Òscar; Galicia, Miguel; Dargan, Paul I.; Wood, David M.; Dines, Alison M. & Heyerdahl, Fridtjof [Show all 11 contributors for this article] (2025). Age and sex related differences in clinical manifestations and severity of acute cocaine toxicity presentations to European emergency departments. American Journal of Emergency Medicine. ISSN 0735-6757. 96, p. 151–160. doi: 10.1016/j.ajem.2025.06.035. Full text in Research Archive
• Solvik-Olsen, Tone; Kåsin, Jan Ivar; Hagemo, Jostein Skjalg & Heyerdahl, Fridtjof (2024). Manikin study showed that neonates are exposed to high sound and vibration levels during helicopter incubator transports. Acta Paediatrica. ISSN 0803-5253. 113(11), p. 2327–2492. doi: 10.1111/apa.17326. Full text in Research Archive Show summary

  Aim This initial Norwegian study aimed to quantify the vibrations and sounds experienced by neonates when they were transported by helicopter in an incubator. Methods Two neonatal manikins weighing 500 and 2000 g were placed in a transport incubator and transported in an Airbus H145 D3 helicopter during standard flight profiles. The vibrations were measured on the mattress inside the incubator and the sound levels were measured inside and outside the incubator. Results The highest vibration levels were recorded during standard flight profiles when the lighter manikin was used. These ranged 0.27–0.94 m/s2, compared to 0.27–0.76 m/s2 for the heavier manikin. The measurements exceeded the action levels set by the European Union Vibration Directive for adult work environments. The sound levels inside the incubator ranged 84.6–86.3 A-weighted decibels, with a C-weighted peak level of 122 decibels. The sound levels inside the incubator were approximately 10 decibels lower than outside, but amplification was observed in the incubator at frequencies below 160 Hz. Conclusion Vibrations were highest for the lighter manikin. The sound levels during helicopter transport were higher than recommended for neonatal environments and sounds were amplified within the incubator at lower frequencies.

• Eide, Desiree; Gjersing, Linn; Danielsen, Aksel Wüsthoff; Skulberg, Arne Kristian; Dale, Ola & Braarud, Anne-Cathrine [Show all 8 contributors for this article] (2024). Heightened mortality risk after a non‐fatal opioid overdose: Risk factors for mortality in the week following emergency treatment. Addiction. ISSN 0965-2140. 119(12), p. 2131–2138. doi: 10.1111/add.16632. Full text in Research Archive Show summary

  Aims To measure all-cause mortality risk after an ambulance-attended non-fatal opioid overdose and associations with number of days following attendance, and individual and clinical characteristics. Design A prospective observational study. Setting Oslo, Norway. Participants Patients treated with naloxone for opioid overdose by Oslo Emergency Services between 1 June 2014 and 31 December 2018. Measurements Medical records were linked to the national Cause of Death Registry (1 June 2014–31 December 2019). Crude mortality rates (CMR) and incidence risk ratios (IRR) with 95% confidence intervals (CI) were estimated for the time periods (0–7 days, 8–31 days, 32–91 days, 92–183 days, >183 days) using multivariate Poisson regression analysis. IRR were estimated for sex, age, Glasgow Coma Scale (GCS), respiration rate, place of attendance and non-transportation following treatment. Robust variance estimates applied due to multiple risk periods. Standardized Mortality Rates (SMR) were estimated. Findings Overall, 890 patients treated for 1764 overdoses contributed to a total time at risk of 3142 person-years (PY). Median number of attendances was 1 (range 1–27). The majority were male (75.5%) and the mean age was 37.7 years. In total, 112 (12.6%) died; 5.2% within 183 days and 2.2% between 184 and 365 days. Acute poisoning was the most common single cause of death (52.7%). The CMR was 3.6 (95% CI = 3.0–4.2) per 100-PY. The women had a SMR of 32 (95% CI = 15.8–57.9) and the men 24.9 (95% CI = 17.7–34.2). The CMR (22.2, 95% CI = 10.6–46.8) was particularly high in the first 7 days, and significantly higher than in the following periods. However, this finding was only valid for those with severe overdose symptoms (GCS score = 3/15 and/or respiratory rate ≤6/min). Except for increasing age, no other indicators were associated with the mortality risk. Conclusion Patients treated by Oslo Emergency Services between June 2014 and December 2018 for a non-fatal opioid overdose with severe overdose symptoms at attendance had an overall high mortality risk compared with the general population, but particularly during the first 7 days after attendance.

• Waters, Mitchell L; Dargan, Paul I.; Yates, Christopher; Dines, Alison M.; Eyer, Florian & Giraudon, Isabelle [Show all 62 contributors for this article] (2024). Clinical effects of cannabis compared to synthetic cannabinoid receptor agonists (SCRAs): a retrospective cohort study of presentations with acute toxicity to European hospitals between 2013 and 2020. Clinical Toxicology. ISSN 1556-3650. 62(6), p. 378–384. doi: 10.1080/15563650.2024.2346125. Full text in Research Archive Show summary

  Introduction: Cannabis is the most common recreational drug worldwide and synthetic cannabinoid receptor agonists are currently the largest group of new psychoactive substances. The aim of this study was to compare the clinical features and outcomes of lone acute cannabis toxicity with lone acute synthetic cannabinoid receptor agonist toxicity in a large series of presentations to European emergency departments between 2013-2020. Methods: Self-reported drug exposure, clinical, and outcome data were extracted from the European Drug Emergencies Network Plus which is a surveillance network that records data on drug-related emergency department presentations to 36 centres in 24 European countries. Cannabis exposure was considered the control in all analyses. To compare the lone cannabis and lone synthetic cannabinoid receptor agonist groups, univariate analysis using chi squared testing was used for categorical variables and non-parametric Mann-Whitney U- testing for continuous variables. Statistical significanc

• Bekkevold, Marit; Solvik-Olsen, Tone; Heyerdahl, Fridtjof; Lang, Astri Maria; Hagemo, Jostein Skjalg & Rehn, Marius (2024). Reporting interhospital neonatal intensive care transport: international five-step Delphi-based template. BMJ Paediatrics Open. 8(1), p. 1–7. doi: 10.1136/bmjpo-2023-002374. Full text in Research Archive Show summary

  Objective To develop a general and internationally applicable template of data variables for reporting interhospital neonatal intensive care transports. Design A five-step Delphi method. Setting A group of experts was guided through a formal consensus process using email. Subjects 12 experts in neonatal intensive care transports from Canada, Denmark, Norway, the UK and the USA. Four women and eight men. The experts were neonatologists, anaesthesiologists, intensive care nurse, anaesthetic nurse, medical leaders, researchers and a parent representative. Main outcome measures 37 data variables were included in the final template. Results Consensus was achieved on a template of 37 data variables with definitions. 30 variables to be registered for each transport and 7 for annual registration of the system of the transport service. 11 data variables under the category structure, 20 under process and 6 under outcome. Conclusions We developed a template with a set of data variables to be registered for neonatal intensive care transports. To register the same data will enable larger datasets and comparing services.

• Noseda, Roberta; Franchi, Matteo; Pagnamenta, Alberto; Müller, Laura; Dines, Alison M. & Giraudon, Isabelle [Show all 16 contributors for this article] (2023). Determinants of Admission to Critical Care Following Acute Recreational Drug Toxicity: A Euro-DEN Plus Study. Journal of Clinical Medicine. 12(18). doi: 10.3390/jcm12185970. Full text in Research Archive Show summary

  This study aimed to characterize patients admitted to critical care following Emergency Department (ED) presentation with acute recreational drug toxicity and to identify determinants of admission to critical care. A retrospective multicenter matched case-control study was conducted by the European Drug Emergency Network Plus (Euro-DEN Plus) over the period 2014–2021. The cases were ED presentations with acute recreational drug toxicity admitted to critical care, the controls consisted of ED presentations with acute recreational drug toxicity medically discharged directly from the ED. The potential determinants of admission to critical care were assessed through multivariable conditional stepwise logistic regression analysis and multiple imputation was used to account for the missing data. From 2014 to 2021, 3448 Euro-DEN Plus presentations involved patients admitted to critical care (76.9% males; mean age 33.2 years; SD 10.9 years). Patient age ≥35 years (as compared to ≤18 years) was a determinant of admission to critical care following acute recreational drug toxicity (adjusted odds ratio, aOR, 1.51, 95% confidence interval, CI, 1.15–1.99), along with polydrug use (aOR 1.39, 95% CI 1.22–1.59), ethanol co-ingestion (aOR 1.44, 95% CI 1.26–1.64), and the use of gamma-hydroxybutyrate/gamma-butyrolactone (GHB/GBL, aOR 3.08, 95% CI 2.66–3.57). Conversely, lower odds of admission to critical care were associated with the use of cocaine (aOR 0.85, 95% CI 0.74–0.99), cannabis (aOR 0.44, 95% CI 0.37–0.52), heroin (aOR 0.80, 95% CI 0.69–0.93), and amphetamine (aOR 0.65, 95% CI 0.54–0.78), as was the arrival to the ED during the night (8 p.m.–8 a.m., aOR 0.88, 95% CI 0.79–0.98). These findings, which deserve confirmation and further investigation, could contribute to a more complete understanding of the decision-making process underlying the admission to critical care of patients with acute recreational drug toxicity.

• Vallersnes, Odd Martin; Dines, Alison M.; Wood, David M.; Heyerdahl, Fridtjof; Hovda, Knut Erik & Yates, Christopher [Show all 20 contributors for this article] (2023). Self-discharge during treatment for acute recreational drug toxicity: an observational study from emergency departments in seven European countries. International Journal of Emergency Medicine. ISSN 1865-1372. 16(1). doi: 10.1186/s12245-023-00566-1. Full text in Research Archive Show summary

  Background Self-discharge is a risk factor for readmission and excess mortality. We assess the rate of self-discharge from the emergency department (ED) among presentations for acute recreational drug toxicity and identify factors associated with self-discharge. Methods From the Euro-DEN Plus database of presentations to the ED with acute recreational drug toxicity, we extracted data from 11 centres in seven European countries from 2014 to 2017. Self-discharge was defined as taking one’s own discharge or escaping from the ED before being medically cleared. We used multiple logistic regression analyses to look for factors associated with self-discharge. Results Among 15,135 included presentations, 1807 (11.9%) self-discharged. Self-discharge rates varied from 1.7 to 17.1% between centres. Synthetic cannabinoids were associated with self-discharge, adjusted odds ratio 1.44 (95% confidence interval 1.10–1.89), as were heroin, 1.44 (1.26–1.64), agitation, 1.27 (1.10–1.46), and naloxone treatment, 1.27 (1.07–1.51), while sedation protected from self-discharge, 0.38 (0.30–0.48). Conclusion One in eight presentations self-discharged. There was a large variation in self-discharge rates across the participating centres, possibly partly reflecting different discharge procedures and practices. Measures to improve the management of agitation and cautious administration of naloxone to avoid opioid withdrawal symptoms may be approaches worth exploring to reduce self-discharge.

• Rydlöv, Hanna Sofia; Fjose, Lars Olav & Heyerdahl, Fridtjof (2023). Pain Management with Inhalation of Methoxyflurane Administrated by Non-Medical Ski Patrol: A Quality Assessment Study. Pain and Therapy. ISSN 2193-8237. 12(6). doi: 10.1007/s40122-023-00547-5. Full text in Research Archive Show summary

  Introduction: Pain management can be challenging, especially in remote locations where first responders are not certified health care personnel. In these settings, traditional intravenous administration of analgesics is not feasible. In this study, we explore the feasibility of using methoxyflurane as a first-line analgesic in ski-related traumas, administered by the ski patrol, acting as the municipality physician's aiding personnel. Methods: This is a quality assessment of a project aimed at improving pain management in trauma patients at the largest ski resort in Norway. Members of the ski patrol were trained and delegated administration of methoxyflurane on behalf of the municipality physician. Patients > 18 years with ski-related trauma and pain Numeric Rating Scale (NRS) of 6 or more were included. The patients received inhalational methoxyflurane on site, with continued administration during transport. Data were collected by the ski patrol and entered into a quality register. Results: In total, 53 patients (18 to 76 years, 32 (60%) males) accepted to be registered. The injuries were fractures in 35 (66%), joint luxation in seven (13%), combination of fracture and luxation in seven (13%), and blunt soft tissue damage in four (8%) cases. Median NRS before administration of methoxyflurane was 8 decreasing to median NRS 5 after 5-10 min. The median NRS reduction of 3 (25-75% percentiles 2-5) was significant, p < 0.001. Patients rated the perceived effect as good in 40 (80%) moderate in nine (18%) and no effect in 1 (2%). Side effects were mild: Six patients (11%) experienced dizziness, one patient (2%) was considered drowsy. Conclusions: Methoxyflurane is feasible as a first-line analgesic administered by a non-medical ski patrol in a responsibly organized system. Early pain management with inhalation of methoxyflurane provides good perceived effect with mild adverse events and can be of great value in settings where few alternatives for pain management are available.

• Rehn, Marius; Heyerdahl, Fridtjof; Osbakk, Svein Are; Andresen, Åke Erling Lappen & Hagemo, Jostein Skjalg (2023). Challenges and Risks in Out-of-Hospital Transport of Patients During the Coronavirus Disease 2019 Pandemic. Air Medical Journal. ISSN 1067-991X. 42(3), p. 191–195. doi: 10.1016/j.amj.2023.02.002. Full text in Research Archive Show summary

  Objective: Norwegian critical care resources are regionalized making air ambulances transport of suspected or confirmed coronavirus disease 2019 (COVID-19)-positive patients a necessity. We prospectively observed pre- and interhospital transportation of patients with suspected or confirmed COVID-19 in our physician-manned emergency medical services. Methods: This was a prospective, observational quality assurance study of primary and secondary missions conducted by 2 Norwegian air ambulances during the COVID-19 pandemic. Results: Forty-one (24.1%) were primary missions, whereas 129 (75.9%) were interhospital transports. Most patients (158 [92.9%]) were transported with ground-based vehicles, and 12 (7.1%) were transported by rotor wing aircrafts. One hundred thirty-four of 170 patients (78.8%) were COVID-19 positive at the time of transportation. The median (interquartile range) fraction of inspired oxygen concentration was 0.60 (0.50-0.80), the positive end-expiratory pressure was 11 cm H2O (8-13.5 cm H2O), and the peak inspiratory pressure was 26 cm H2O (22-30 cm H2O). Some degree of elevated treatment challenge was reported in 157 (87.7%) transports, and in 139 (77.7%), the patient risk was considered elevated. The physician stated that some degree of elevated risk for the provider was elevated in 131 (73.2%) of the transports. Conclusion: The capacity of the physician-manned emergency medical services to safely transfer patients remains essential to maintain resilient critical care capacity, and the perceived elevated risks should be considered in capacity planning.

• Engelsen, Peder Christian Grendstad; Heyerdahl, Fridtjof; Maddali, Dharani Dhar; Akhavi, Medhi Sadat; Undseth, Ragnhild Marie & Elle, Ole Jakob [Show all 7 contributors for this article] (2023). Ascending with ultrasound: telementored eFAST in flight—a feasibility study. Emergency Radiology. ISSN 1070-3004. 31, p. 25–31. doi: 10.1007/s10140-023-02186-x. Full text in Research Archive Show summary

  Abstract Purpose Teleultrasound uses telecommunication technologies to transmit ultrasound images from a remote location to an expert who guides the acquisition of images and interprets them in real time. Multiple studies have demonstrated the feasibility of teleultrasound. However, its application during helicopter flight using long-term evolution (LTE) for streaming has not been studied. Therefore, we conducted a study to examine the feasibility of teleultrasound in an Airbus H145 helicopter. Methods Four anesthesiologists and one military physician were recruited to perform telementored extended Focused Assessment with Sonography in Trauma (eFAST) during nine helicopter flights, each with a unique healthy volunteer. A radiologist was recruited as a remote expert, guiding the physicians in their examinations. The examining physicians reported the user experience of telementored eFAST on a questionnaire, while the remote expert rated the diagnostic quality of the images on a 1–5 Likert scale. In addition, we measured the duration of the examinations and key LTE network parameters including signal strength, quality, and continuity. Results The images were rated to an average of 4.9 by the remote expert, corresponding to good diagnostic quality. The average duration of telementored eFAST was 05:54 min. LTE coverage was negatively affected by proximity to urban areas and ceased above 2000 ft altitude. Occasional audio problems were addressed by using the Voice over LTE network for communication. The examining physicians unanimously reported on the questionnaire that they would use telementored eFAST on patients. Conclusion Telementored eFAST is feasible in ambulance helicopters and can produce images of good diagnostic quality. However, it relies on stable LTE coverage, which is influenced by many factors, including the helicopter’s altitude and flight path. Furthermore, its benefit on patient outcomes remains to be proven. Graphical abstract

• Miró, Òscar; Burillo-Putze, Guillermo; Schmid, Yasmin; Salgado, Emilio; Liechti, Matthias E & Dines, Alison M. [Show all 14 contributors for this article] (2022). Severity of emergency department presentations due to acute drug toxicity in Europe: a longitudinal analysis over a 6-year period (2014–2019) stratified by sex. European journal of emergency medicine. ISSN 0969-9546. doi: 10.1097/MEJ.0000000000000978. Full text in Research Archive
• Ingebrigtsen, Erlend; Persett, Per Sverre; Brekke, Mette; Heyerdahl, Fridtjof; Hovda, Knut Erik & Vallersnes, Odd Martin (2022). Poisoning with central stimulant drugs: an observational study from Oslo, Norway. International Journal of Emergency Medicine. ISSN 1865-1372. 15(1). doi: 10.1186/s12245-022-00457-x. Full text in Research Archive Show summary

  Background The use of central stimulant drugs causes significant morbidity. We describe poisonings with central stimulant drugs and compare the different central stimulants concerning combinations with other drugs, treatment, and clinical course.  Methods Patients presenting from 1 October 2013 to 31 March 2016 with poisoning related to the recreational use of central stimulant drugs were retrospectively included at a primary care emergency outpatient clinic and at a hospital emergency department in Oslo, Norway. Diagnosis of toxic agents was mainly based on the clinical assessment of the doctor treating the patient. Amphetamine and methamphetamine were co-categorized as amphetamine. Results Among the 1131 cases of acute poisoning with central stimulant drugs at the outpatient clinic, amphetamine was involved in 808 (71.4%), cocaine in 252 (22.3%) methylenedioxymethamphetamine (MDMA) in 104 (9.2%), and methylphenidate in 13 (1.1%). Among the 211 cases at the hospital, amphetamine was involved in 167 (79.1%), cocaine in 60 (28.4%), and MDMA in 38 (18.0%). Amphetamine was frequently combined with opioids (40.1% at the outpatient clinic and 41.9% at the hospital) and benzodiazepines (28.3% and 45.5%), while MDMA often was combined with ethanol (64.4% and 71.1%), as was cocaine (62.7% and 61.7%). Sedation was given in 5.2% and 38.4% of cases, naloxone in 9.4% and 37.0%, and flumazenil in 0.1% and 28.0%. In total, 16.5% of the cases at the outpatient clinic were transferred to a hospital for medical review and 8.5% to a psychiatric hospital. Among the hospital patients, 92.9% were admitted to intensive care. Conclusion Amphetamine was the most common central stimulant drug involved in acute poisoning in Oslo, often combined with opioids and benzodiazepines.

• Lao, Yvonne Elisabeth; Heyerdahl, Fridtjof; Jacobsen, Dag & Hovda, Knut Erik (2022). An enzymatic assay with formate oxidase for point-of-care diagnosis of methanol poisoning. Basic & Clinical Pharmacology & Toxicology. ISSN 1742-7835. 131(6), p. 547–554. doi: 10.1111/bcpt.13789. Full text in Research Archive Show summary

  Gas chromatographic analysis for quantification of plasma methanol requires laboratory equipment and personnel, and it is typically unavailable in short time notice, especially in low- and middle-income countries. Detection of formate with the enzyme formate oxidase (FOX) is a promising method that can make the diagnosis of methanol poisoning simple and fast. The aims of this study were to test the sensitivity and specificity of a modified FOX-enzyme and to test the specificity of a point-of-care (POC)-model containing FOX-enzyme with samples from patients with metabolic acidosis. The sensitivity and specificity of FOX-enzyme in aqueous solution were evaluated with a spectrometer and by visual detection for colour change. Formate concentrations between 1 and 20 mmol/L were used to test sensitivity, and 18 potentially interfering substances were tested for specificity. The sensitivity of the FOX-enzyme was 100% and the specificity 97%. When specificity of the POC-model was tested, no false positives were detected. As such, the sensitivity and specificity of this modified FOX-enzyme for detection of formate were high. The results with this enzyme confirm the potential for its use in formate analysis as a fast diagnosis of methanol poisoning.

• Crulli, Benjamin; Dines, Alison M.; Blanco, Georgina; Giraudon, Isabelle; Eyer, Florian & Liechti, Matthias E [Show all 13 contributors for this article] (2022). Novel psychoactive substances-related presentations to the emergency departments of the European drug emergencies network plus (Euro-DEN plus) over the six-year period 2014–2019. Clinical Toxicology. ISSN 1556-3650. doi: 10.1080/15563650.2022.2137524. Full text in Research Archive Show summary

  Introduction Novel psychoactive substances (NPS) have been increasingly reported in the last 15–20 years. We aimed to describe presentations to the emergency department (ED) with acute recreational drug toxicity involving NPS. Methods Data were extracted from the European Drug Emergencies Network (Euro-DEN) Plus database for all presentations to ED (36 EDs in 24 European countries) with acute toxicity between January 2014 and December 2019. Patient demographics, agents involved, and clinical outcomes were described and the subgroup of presentations involving NPS was compared with the rest of the cohort. Results Out of 43,633 Euro-DEN Plus presentations, 3304 (7.6%) involved at least one NPS. Agents were identified mainly based on self-report or clinical presentation, with analytical confirmation being performed only in 17.9% of NPS presentations. The proportion of NPS presentations varied by centre (0–48.8%). For centres where data were available for all 6 years, NPS-related presentations peaked in 2015 (11.9%). In 2014, 78.4% of NPS agents reported were cathinones, while only 3.4% were synthetic cannabinoids (SCs); conversely, in 2019 only 11.6% of NPS agents reported were cathinones, while 72.2% were SCs. NPS-related presentations involved younger patients (median 30 (23–37) vs. 32 (25–40) years, p < 0.001) and more males (84.8 vs. 75.8%, p < 0.001) compared with the rest of the cohort. Patients presenting to ED after using NPS were more likely to self-discharge (22.8 vs. 15.1%), less likely to be admitted to critical care (3.6 vs. 6.1%) but had a longer length of stay in hospital (median 5.1 (2.7–18.7) vs. 4.7 (2.5–9.2) h, p < 0.001). Death occurred in 0.5% of all presentations involving NPS and in 0.4% of non-NPS presentations. Conclusions This large multicentre series of NPS presentations to European EDs showed marked geographical variation and changes over time in the proportion of presentations to ED involving NPS, as well as the proportion of NPS subgroups.

• Skulberg, Arne Kristian; Tylleskär, Ida; Valberg, Morten; Braarud, Anne-Cathrine; Dale, Jostein & Heyerdahl, Fridtjof [Show all 10 contributors for this article] (2022). Comparison of intranasal and intramuscular naloxone in opioid overdoses managed by ambulance staff: a double-dummy, randomised, controlled trial. Addiction. ISSN 0965-2140. 117(6), p. 1658–1667. doi: 10.1111/add.15806. Full text in Research Archive
• Schmid, Yasmin; Galicia, Miguel; Vogt, Severin B.; Liechti, Matthias E.; Burillo-Putze, Guillermo & Dargan, Paul I. [Show all 13 contributors for this article] (2022). Differences in clinical features associated with cannabis intoxication in presentations to European emergency departments according to patient age and sex. Clinical Toxicology. ISSN 1556-3650. 60(8), p. 912–919. doi: 10.1080/15563650.2022.2060116. Full text in Research Archive
• Heier, Eva-Carina; Eyer, Florian; Rabe, Christian; Geith, Stefanie; Dargan, Paul I & Wood, David M. [Show all 15 contributors for this article] (2022). Clinical effect of ethanol co-use in patients with acute drug toxicity involving the use of central nervous system depressant recreational drugs. European journal of emergency medicine. ISSN 0969-9546. 29(4), p. 291–300. doi: 10.1097/MEJ.0000000000000932. Full text in Research Archive
• Bailey, Claire; Makison-Booth, Catherine; Farrant, Jayne; Beswick, Alan; Chewins, John & Eimstad, Michael [Show all 8 contributors for this article] (2021). Validation of the decontamination of a specialist transport system for patients with high consequence infectious diseases. Microorganisms. 9:2575(12), p. 1–11. doi: 10.3390/microorganisms9122575. Full text in Research Archive Show summary

  When transferring highly infective patients to specialist hospitals, safe systems of work minimise the risk to healthcare staff. The EpiShuttle is a patient transport system that was developed to fit into an air ambulance. A validated decontamination procedure is required before the system can be adopted in the UK. Hydrogen peroxide (H2O2) vapour fumigation may offer better penetration of the inaccessible parts than the liquid disinfectant wiping that is currently suggested. To validate this, an EpiShuttle was fumigated in a sealed test chamber. Commercial bacterial spore indicators (BIs), alongside organic liquid suspensions and dried surface samples of MS2 bacteriophage (a safe virus surrogate), were placed in and around the EpiShuttle, for the purpose of evaluation. The complete kill of all of the BIs in the five test runs demonstrated the efficacy of the fumigation cycle. The log reduction of the MS2 that was dried on the coupons ranged from 2.66 to 4.50, but the log reduction of the MS2 that was in the organic liquids only ranged from 0.07 to 1.90, confirming the results of previous work. Fumigation with H2O2 alone may offer insufficient inactivation of viruses in liquid droplets, therefore a combination of fumigation and disinfectant surface wiping was proposed. Initial fumigation reducing contamination with minimal intervention allows disinfectant wipe cleaning to be completed more safely, with a second fumigation step inactivating the residual pathogens.

• Eiding, Helge; Kongsgaard, Ulf; Olasveengen, Theresa M. & Heyerdahl, Fridtjof (2021). Interhospital transport of critically ill patients: A prospective observational study of patient and transport characteristics. Acta Anaesthesiologica Scandinavica. ISSN 0001-5172. p. 1–8. doi: 10.1111/aas.14005. Full text in Research Archive
• Noseda, Roberta; Schmid, Yasmin; Scholz, Irene; Liakoni, Evangelia; Liechti, Matthias E. & Dargan, Paul I. [Show all 36 contributors for this article] (2021). MDMA-related presentations to the emergency departments of the European Drug Emergencies Network plus (Euro-DEN Plus) over the four-year period 2014-2017. Clinical Toxicology. ISSN 1556-3650. 59(2), p. 131–137. doi: 10.1080/15563650.2020.1784914. Full text in Research Archive
• Waldman, Wojciech; Kabata, Pm; Dines, Alison M.; Wood, David M.; Yates, Christopher & Heyerdahl, Fridtjof [Show all 10 contributors for this article] (2021). Rhabdomyolysis related to acute recreational drug toxicity—A Euro-DEN study. PLOS ONE. 16(3), p. 1–11. doi: 10.1371/journal.pone.0246297. Full text in Research Archive
• Leaper, Craig; Dines, Alison M.; Dargan, Paul I.; Yates, Christopher; Hovda, Knut Erik & Heyerdahl, Fridtjof [Show all 8 contributors for this article] (2021). Impact of pregabalin co-use in patients presenting with acute heroin toxicity to the European Drug Emergencies Network plus project. European journal of emergency medicine. ISSN 0969-9546. 28(2), p. 144–146. doi: 10.1097/MEJ.0000000000000738. Full text in Research Archive
• Miro, Oscar; Waring, W. Stephen; Dargan, Paul I.; Wood, David M.; Dines, Alison M. & Yates, Christopher [Show all 25 contributors for this article] (2021). Variation of drugs involved in acute drug toxicity presentations based on age and sex: an epidemiological approach based on European emergency departments. Clinical Toxicology. ISSN 1556-3650. doi: 10.1080/15563650.2021.1884693. Full text in Research Archive
• Tylleskär, Ida; Gjersing, Linn; Bjørnsen, Lars Petter Bache-Wiig; Braarud, Anne-Cathrine; Heyerdahl, Fridtjof & Dale, Ola [Show all 7 contributors for this article] (2020). Prehospital naloxone administration – what influences choice of dose and route of administration? BMC Emergency Medicine. 20. doi: 10.1186/s12873-020-00366-3. Full text in Research Archive Show summary

  Background Amidst the ongoing opioid crisis there are debates regarding the optimal route of administration and dosages of naloxone. This applies both for lay people administration and emergency medical services, and in the development of new naloxone products. We examined the characteristics of naloxone administration, including predictors of dosages and multiple doses during patient treatment by emergency medical service staff in order to enlighten this debate. Methods This was a prospective observational study of patients administered naloxone by the Oslo City Center emergency medical service, Norway (2014–2018). Cases were linked to The National Cause of Death Registry. We investigated the route of administration and dosage of naloxone, clinical and demographic variables relating to initial naloxone dose and use of multiple naloxone doses and one-week mortality. Results Overall, 2215 cases were included, and the majority (91.9%) were administered intramuscular naloxone. Initial doses were 0.4 or 0.8 mg, and 15% of patients received multiple dosages. Unconscious patients or those in respiratory arrest were more likely to be treated with 0.8 mg naloxone and to receive multiple doses. The one-week mortality from drug-related deaths was 4.1 per 1000 episodes, with no deaths due to rebound opioid toxicity. Conclusions Intramuscular naloxone doses of 0.4 and 0.8 mg were effective and safe in the treatment of opioid overdose in the prehospital setting. Emergency medical staff appear to titrate naloxone based on clinical presentation.

• Layne, Kerry A.; Dargan, Paul I.; Dines, Alison M.; Leaper, Craig; Yates, Christopher & Hovda, Knut Erik [Show all 10 contributors for this article] (2020). Acute toxicity related to misuse (nonmedical use) of tramadol: Experience of the European Drug Emergencies Network Plus. British Journal of Clinical Pharmacology. ISSN 0306-5251. p. 1–8. doi: 10.1111/bcp.14408. Full text in Research Archive
• Skulberg, Arne Kristian; Tylleskär, Ida; Næss, Anne-Cathrine Braarud; Dale, Jostein; Heyerdahl, Fridtjof & Mellesmo, Sindre [Show all 8 contributors for this article] (2020). NTNU intranasal naloxone trial (NINA-1) study protocol for a double-blind, double-dummy, non-inferiority randomised controlled trial comparing intranasal 1.4 mg to intramuscular 0.8 mg naloxone for prehospital use. BMJ Open. 10:e041556(11), p. 1–8. doi: 10.1136/bmjopen-2020-041556. Full text in Research Archive Show summary

  Abstract Introduction Intranasal naloxone is widely used to treat opioid overdoses. The advantage of nasal administration compared to injection lies in its suitability for administration by lay people as it is needless. Approved formulations of nasal naloxone with bioavailability of approximately 50% have only undergone trials in healthy volunteers, while off-label nasal sprays with low bioavailability have been studied in patients. Randomised clinical trials are needed to investigate efficacy and safety of approved intranasal naloxone in patients suffering overdose. This study investigates whether the administration of 1.4 mg naloxone in 0.1 millilitres per dose is non- inferior to 0.8 mg intramuscular injection in patients treated for opioid overdose. Methods and analysis Sponsor is the Norwegian University of Science and Technology. The study has been developed in collaboration with user representatives. The primary endpoint is the restoration of spontaneous respiration ≥10 breaths/minute based on a sample of 200 opioid overdose cases. Double-dummy design ensures blinding, which will be maintained until the database is locked. Ethics and dissemination The study was approved by the Norwegian Medicines Agency and Regional Ethics Committees (REC: 2016/2000). It adheres to the Good Clinical Practice guidelines as set out by The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use. Informed consent will be sought through a differentiated model. This allows for deferred consent after inclusion for patients who have regained the ability to consent. Patients who are unable to consent prior to discharge by emergency services are given written information and can withdraw at a later date in line with user recommendations. Metadata will be published in the NTNU Open repository. De-identified individual participant data will be made available to recipients conditional of data processor agreement being entered. Trial registrations: EudraCT number: 2016-004072-22 and Clinicaltrials.gov NCT03518021

• Tollisen, Karen Synnøve Hunting; Lund, Cathrine; Bjerva, Marianne; Dahl, Gry Torsæter; Högvall, Lisa Maria & Sandvik, Leiv [Show all 9 contributors for this article] (2020). Clinical impact of chronic substance abuse in a Norwegian ICU-population. Acta Anaesthesiologica Scandinavica. ISSN 0001-5172. p. 1–10. doi: 10.1111/aas.13766. Full text in Research Archive Show summary

  Background The clinical impact of chronic substance abuse of alcohol and drugs—referred to as substance use disorders (SUD)—is often overlooked in the intensive care (ICU) setting. The aims of the present study were to identify patients with SUD—regardless of cause of admission—in a mixed Norwegian ICU‐population, and to compare patients with and without SUD with regard to clinical characteristics and mortality. Methods Cross‐sectional prospective study of a mixed medical and surgical ICU‐population aged ≥18 years in Oslo, Norway. Data were collected consecutively, using a questionnaire including the AUDIT‐C test, medical records and toxicology results. Patients classified with SUD were divided into the subgroups alcohol use disorders (AUD) and drug use disorders (DUD). Results Overall, 222 (26%) of the 861 patients included were classified with SUD; 137 (16%) with AUD and 85 (10%) with DUD. 130/222 (59%) of the SUD‐patients had substance abuse‐related cause of ICU‐admission. Compared to non‐SUD patients, DUD‐patients were younger (median age 42 vs 65 years) and had lower SAPS II scores (41 vs 46), while AUD‐patients had higher SOFA scores (8.0 vs 7.3). Overall, age‐adjusted logistic regression analysis showed similar hospital mortality for SUD‐patients and non‐SUD patients, but AUD was associated with increased mortality among medical patients and in patients with sepsis (OR 1.7 (95% CI 1.0‐2.8), and OR 2.6 (95% CI 1.1‐6.2)). Conclusion One in four ICU‐patients had SUD regardless of cause of admission. Alcohol use disorder was associated with increased mortality in medical patients and in patients with sepsis.

• Miro, Oscar; Dargan, Paul I; Wood, David M.; Dines, Alison M.; Yates, Christopher & Heyerdahl, Fridtjof [Show all 9 contributors for this article] (2019). Epidemiology, clinical features and management of patients presenting to European emergency departments with acute cocaine toxicity: comparison between powder cocaine and crack cocaine cases. Clinical Toxicology. ISSN 1556-3650. 57(8), p. 718–726. doi: 10.1080/15563650.2018.1549735. Full text in Research Archive
• Tollisen, Karen Synnøve Hunting; Bjerva, Marianne; Dahl, Gry Torsæter; Meidell, Nina Knutrud; Sandvik, Leiv & Heyerdahl, Fridtjof [Show all 7 contributors for this article] (2019). Acute illness, Co-morbidity and Mortality in a Norwegian Intensive Care Population. International Journal of Anesthetics and Anesthesiology. ISSN 2377-4630. 6(1). doi: 10.23937/2377-4630/1410084. Full text in Research Archive Show summary

  Background The need for intensive care beds is high and expected to increase. Descriptive studies of the intensive care population may reveal differences in predisposing factors and outcome within subgroups and help identify areas in need of increased prevention efforts. Objective To describe preadmission and clinical characteristics of an intensive care population in Oslo, and to compare the characteristics and outcomes of selected subgroups of this ICU-population. Method Prospective observational cohort study of intensive care patients aged ≥ 18, admitted to two hospitals in Oslo during a one-year period. Acute illness characteristics, comorbidity, limitations of life-sustaining treatment and hospital mortality were studied for the overall population and stratified for a) Gender and b) Medical and surgical patients within the age groups 18-59 years and 60 and above. Results We included 861 patients, 567 (66%) males; median age 63 years (range 18-95); 537 (62%) medical admissions and 324 (38%) surgical admissions. 632 (73%) received mechanical ventilation. Trauma (n = 191, 21%) and cardiovascular disease (n = 180, 20%) were the most common causes of admission. In patients aged 18-59, poisoning caused 56/217 (26%) of the medical admissions and medical patients had a higher prevalence of pre-existing chronic disease (157/217, 72% vs. 69/160, 43%) and Charlson comorbidity index (mean 2.0 vs. 0.7, p < 0.001) than surgical patients. In patients aged 60 and above, comorbidity was similar, but medical patients had a higher hospital mortality (143/320, 45% vs. 58/164, 34%, p < 0.05). 205 (24%) died in the ICU, and limitations of life-sustaining treatment were made in 183 (89%) cases 279(32%) died during the hospital stay. Of the 582 surviving patients 455 (78%) were discharged to home or rehabilitation, 88 (15%) to nursing homes and 39 (7%) to other institutions. Conclusion In patients younger than 60 years, trauma and poisoning were the most common causes of admission. Within this age group, medical patients had much higher prevalence of preexisting chronic disease than surgical patients, suggesting differences in predisposing factors. The majority of the surviving patients were discharged to home or to rehabilitation, indicating a low prevalence of futile intensive care.

• Wolfe, Caitlin E; Wood, David M.; Dines, Alison; Whatley, Benjamin P; Yates, Christopher & Heyerdahl, Fridtjof [Show all 9 contributors for this article] (2019). Seizures as a complication of recreational drug use: Analysis of the Euro-DEN Plus data-set. Neurotoxicology. ISSN 0161-813X. 73, p. 183–187. doi: 10.1016/j.neuro.2019.04.003. Full text in Research Archive
• Wood, David M.; Rue, Luke De La; Hosin, Ali A; Jurgens, Gesche; Liakoni, Evangelia & Heyerdahl, Fridtjof [Show all 11 contributors for this article] (2019). Poor Identification of Emergency Department Acute Recreational Drug Toxicity Presentations Using Routine Hospital Coding Systems: the Experience in Denmark, Switzerland and the UK. Journal of Medical Toxicology. ISSN 1556-9039. 15(2), p. 112–120. doi: 10.1007/s13181-018-0687-z. Full text in Research Archive
• Galicia, Miguel; Dargan, Paul I.; Dines, Alison M.; Yates, Christopher; Heyerdahl, Fridtjof & Hovda, Knut Erik [Show all 9 contributors for this article] (2019). Clinical relevance of ethanol coingestion in patients with GHB/GBL intoxication. Toxicology Letters. ISSN 0378-4274. 314, p. 37–42. doi: 10.1016/j.toxlet.2019.07.001. Full text in Research Archive
• Tollisen, Karen Synnøve Hunting; Bjerva, Marianne; Lund, Cathrine; Dahl, Gry Torsæter; Högvall, Lisa Maria & Sandvik, Leiv [Show all 8 contributors for this article] (2019). Substance Abuse-Related Admissions in a mixed Norwegian Intensive Care Population. Acta Anaesthesiologica Scandinavica. ISSN 0001-5172. doi: 10.1111/aas.13506. Full text in Research Archive Show summary

  Background Alcohol and drug abuse are potentially modifiable risk factors for critical illness. The aims of this study were to describe patients with substance abuse‐related admissions (abbreviated SARA) in a mixed intensive care (ICU) population in Oslo, and to compare these patients with patients with non‐SARA. Methods Cross‐sectional prospective study of a mixed medical and surgical ICU‐population in Oslo, Norway. Data were collected consecutively using a questionnaire, medical records, and toxicology results. SARA included admissions due to acute or chronic complications of alcohol or drug abuse, as well as substance abuse‐related injuries. Results Of the 852 patients included, 168 (20%) had SARA; 102 (12%) alcohol‐related and 66 (8%) drug‐related. Male patients aged 18‐39 had the highest proportion of SARA (47/97, 49%). Among the trauma patients, 69/182 (38%) were influenced by alcohol and drugs at the time of injury. Patients with SARA were significantly younger (median age 48 vs 66), had lower Charlson comorbidity index (mean 1.4 vs 2.5) and shorter length of stay (median days 2.4 vs 4.9), than non‐SARA patients. Hospital mortality was similar when adjusting for age (OR 0.8, P = .27, non‐SARA as reference). Conclusion Overall, one in five ICU admissions was associated with substance abuse. For male patients aged 18‐39 this ratio was nearly half. More than one third of the trauma patients were influenced by alcohol or drugs at time of injury.

• Syse, Victoria Lykke; Brekke, Mette; Grimsrud, Marit Mæhle; Persett, Per Sverre; Heyerdahl, Fridtjof & Hovda, Knut Erik [Show all 7 contributors for this article] (2019). Gender differences in acute recreational drug toxicity: a case series from Oslo, Norway. BMC Emergency Medicine. 19(1). doi: 10.1186/s12873-019-0244-3. Full text in Research Archive Show summary

  Background Female drug users report poorer physical and mental health than male drug users. We describe female and male patients treated for acute recreational drug toxicity, and look for gender differences in clinical state, treatment, and toxic agents taken. Methods Retrospective case series from a primary care emergency outpatient clinic and a hospital emergency department in Oslo, Norway. All patients treated for acute recreational drug toxicity from October 2013 through March 2015 were included, except patients with lone alcohol intoxication. Patients were grouped according to whether they had taken opioids or not, as a proxy differentiation between heavy drug users and party drug users. Data from the two clinical settings were analysed separately. Results In total, 2495 cases were included, 567 (22.7%) were women. Female patients were younger than males, median 31 vs 34 years (p < 0.001). On most comparisons of clinical variables there were no significant differences between genders. A larger proportion of females in the outpatient opioid group were hypotensive, 10.9% vs 3.9% (p < 0.001). Fewer females were intubated, none vs 21.1% (p = 0.019) in the hospital opioid group, and 6.4% vs 21.0% (p = 0.039) in the hospital non-opioid group. The proportion of gamma-hydroxybutyrate (GHB) poisoning was larger among females both at the outpatient clinic (14.4% vs 8.6%, p < 0.001) and at the hospital (60.3% vs 36.4%, p = 0.001), while the proportion of heroin poisoning was smaller among females at the outpatient clinic (37.1% vs 47.0%, p < 0.001). Conclusion One in four patients treated for acute recreational drug toxicity were women. Female patients were younger, had more frequently taken GHB and were less frequently intubated. Otherwise, the gender differences regarding clinical state and treatment were small. Although female drug users are known to report poorer health than males, we did not find that women had a more severe clinical course than men when presenting with overdose.

• Yamamoto, Takahiro; Dargan, Paul Ivor; Dines, Alison M.; Yates, Christopher B.; Heyerdahl, Fridtjof & Hovda, Knut Erik [Show all 31 contributors for this article] (2018). Concurrent Use of Benzodiazepine by Heroin Users—What Are the Prevalence and the Risks Associated with This Pattern of Use? Journal of Medical Toxicology. ISSN 1556-9039. 15(1), p. 4–11. doi: 10.1007/s13181-018-0674-4. Full text in Research Archive
• Madah-Amiri, Desiree; Skulberg, Arne Kristian; Næss, Anne-Cathrine Braarud; Dale, Ola; Heyerdahl, Fridtjof & Lobmaier, Philipp Paul [Show all 7 contributors for this article] (2018). Ambulance-attended opioid overdoses: An examination into overdose locations and the role of a safe injection facility. Substance Abuse. ISSN 0889-7077. doi: 10.1080/08897077.2018.1485130. Full text in Research Archive Show summary

  Background: Although the United States and numerous other countries are amidst an opioid overdose crisis, access to safe injection facilities remains limited. Methods: We used prospective data from ambulance journals in Oslo, Norway, to describe the patterns, severity, and outcomes of opioid overdoses and compared these characteristics among various overdose locations. We also examined what role a safe injection facility may have had on these overdoses. Results: Based on 48,825 ambulance calls, 1054 were for opioid overdoses from 465 individuals during 2014 and 2015. The rate of calls for overdoses was 1 out of 48 of the total ambulance calls. Males made up the majority of the sample (n = 368, 79%), and the median age was 35 (range: 18–96). Overdoses occurred in public locations (n = 530, 50.3%), the safe injection facility (n = 353, 33.5%), in private homes (n = 83, 7.9%), and other locations (n = 88, 8.3%). Patients from the safe injection facility and private homes had similarly severe initial clinical symptoms (Glasgow Coma Scale median =3 and respiratory frequency median =4 breaths per minute) when compared with other locations, yet the majority from the safe injection facility did not require further ambulance transport to the hospital (n = 302, 85.6%). Those overdosed in public locations (odds ratio [OR] = 1.66, 95% confidence interval [CI] = 1.17–2.35), and when the safe injection facility was closed (OR =1.4, 95% CI =1.04–1.89), were more likely to receive transport for further treatment. Conclusions: Our findings suggest that the opening hours at the safe injection facility and the overdose location may impact the likelihood of ambulance transport for further treatment.

• Miro, Oscar; Yates, Christopher; Dines, Alison M.; Wood, David M.; Dargan, Paul I. & Galan, Itxaso [Show all 26 contributors for this article] (2018). Emergencies related to recreational drug abuse in Spain compared to emergencies attended in 3 European areas. Emergencias. ISSN 1137-6821. 30, p. 385–394. Full text in Research Archive
• Liakoni, Evangelia; Yates, Christopher; Dines, Alison M.; Dargan, Paul I; Heyerdahl, Fridtjof & Hovda, Knut Erik [Show all 9 contributors for this article] (2018). Acute recreational drug toxicity: Comparison of self-reports and results of immunoassay and additional analytical methods in a multicenter European case series. Medicine. ISSN 0025-7974. 97(5), p. 1–7. doi: 10.1097/MD.0000000000009784. Full text in Research Archive
• Lyphout, Cathelijne; Yates, Christopher B.; Margolin, Zachary R.; Dargan, Paul Ivor; Dines, Alison M. & Heyerdahl, Fridtjof [Show all 11 contributors for this article] (2018). Presentations to the emergency department with non-medical use of benzodiazepines and Z-drugs: profiling and relation to sales data. European Journal of Clinical Pharmacology. ISSN 0031-6970. 75(1), p. 77–85. doi: 10.1007/s00228-018-2550-1. Full text in Research Archive
• Miro, Oscar; Galicia, Miguel; Dargan, Paul; Dines, Alison M.; Giraudon, Isabelle & Heyerdahl, Fridtjof [Show all 9 contributors for this article] (2017). Intoxication by gamma hydroxybutyrate and related analogues: Clinical characteristics and comparison between pure intoxication and that combined with other substances of abuse. Toxicology Letters. ISSN 0378-4274. 277, p. 84–91. doi: 10.1016/j.toxlet.2017.05.030. Full text in Research Archive
• Nakstad, Espen Rostrup; Aass, Hans Christian; Opdahl, Helge; Witsø, Anne; Borchsenius, Fredrik & Heyerdahl, Fridtjof [Show all 7 contributors for this article] (2017). Bronchial wheezing predicts inflammation and respiratory failure in fire smoke victims. Acta Anaesthesiologica Scandinavica. ISSN 0001-5172. 61(9), p. 1142–1154. doi: 10.1111/aas.12962. Full text in Research Archive Show summary

  BackgroundAcute fire smoke inhalation injury involves inflammatory mediators whose roles are poorly understood. We carried out a prospective observational study of fire smoke victims to identify clinical and biochemical markers that may predict pulmonary dysfunction and investigated possible correlations between dysfunction and cytokines in bronchoalveolar lavage (BAL) fluid and blood. MethodsForty patients with respiratory and/or neurological symptoms following acute fire smoke inhalation had pulmonary function tests and blood gas analyses performed on admission, at discharge, and after 3 months. Cytokines were measured using BioPlex/XMap technology. ResultsOn admission, 30 (75%) patients had dyspnea. Patients presenting with bronchial wheezing (n = 14) had significantly lower PEF (201 l/min, 82-360) than non-wheezing patients (406 l/min, 100-683) (n = 16, P = 0.03). Bronchial wheezing predicted need for ICU treatment with OR = 93.3 at 95% CI (P < 0.001) and was associated with gas exchange impairment, with mean p(a)O(2)/FiO(2) ratio 34.4 (11.8-49.8) kPa on admission and 21.3 (8.3-44.5) kPa 48 h later. Blood HbCO also predicted ICU treatment, with OR = 1.58 at 95% CI (P < 0.001). Serum CRP, IL-6, IL-8, and MCP-1 were significantly higher in wheezing patients after 12-24 h compared with non-wheezing patients and study controls. Cytokine levels were still elevated after 3 months. BAL fluid had significantly higher levels of IL-8, MCP-1, IL-1, and G-CSF compared with healthy controls. ConclusionIn victims of fire smoke inhalation, pulmonary wheezing predicts inflammation, pulmonary dysfunction, respiratory failure, and need for intensive care.

• Vallersnes, Odd Martin; Persett, Per Sverre; Øiestad, Elisabeth Leere; Karinen, Ritva Anneli; Heyerdahl, Fridtjof & Hovda, Knut Erik (2017). Underestimated impact of novel psychoactive substances: laboratory confirmation of recreational drug toxicity in Oslo, Norway. Clinical Toxicology. ISSN 1556-3650. 55(7), p. 636–644. doi: 10.1080/15563650.2017.1312002. Full text in Research Archive Show summary

  Context: Recreational drug toxicity is frequent. Availability of new psychoactive substances is steadily increasing. However, data with verified analyses from clinical settings are limited. To evaluate the impact of novel psychoactive substances (NPS) on recreational drug toxicity in Oslo, Norway, we analysed samples from a selection of patients. Methods: All the patients presenting with recreational drug toxicity at the Oslo Accident and Emergency Outpatient Clinic (OAEOC) and at the Oslo University Hospital (OUH) were registered from April through September 2014. Oral fluid samples were collected at the OAEOC. Blood samples were collected at the OUH. The samples were screened using ultra-high performance liquid chromatography – tandem mass spectrometry (UHPLC-MS/MS). Results: Nine hundred and sixty-four cases were included, 841 (87.2%) at the OAEOC and 123 (12.8%) at the OUH. A total of 55 oral fluid samples (OAEOC) and 103 blood samples (OUH) could be analysed. NPS were not clinically suspected in any of the screened cases. At the outpatient clinic, the most commonly found substances were clonazepam in 42/55 (76.4%) cases, amfetamines in 40/55 (72.7%) and heroin in 39/55 (70.9%). In seven (12.7%) cases NPS were detected: 4-methylamfetamine in three cases, dimethyltryptamine in two, methylone in one, and N,N-dimethyl-3,4-methylenedioxyamfetamine in one. Among the hospital patients, the most commonly found substances were clonazepam in 51/103 (49.5%) cases, amfetamines in 48/103 (46.6%), heroin in 31/103 (30.1%), and diazepam in 30/103 (29.1%). In five (4.9%) cases NPS were detected: JWH-210 in two cases, AM-2201 in two, and 5-EAPB in one. Conclusion: NPS were clinically not suspected, though found in eight percent of cases. Still, the vast majority of patients treated for recreational drug toxicity in Oslo have taken classical drugs. Management of these patients should be based on their clinical condition. However, it is highly important to be alert to atypical presentations possibly resulting from unsuspected drugs. This is an Accepted Manuscript of an article published by Taylor & Francis Group in Clinical Toxicology on 13/04/2017, available online: http://www.tandfonline.com/10.1080/15563650.2017.1312002

• Gjelsvik, Bergljot; Heyerdahl, Fridtjof; Holmes, Jane; Lunn, Daniel & Hawton, Keith (2017). Is There a Relationship between Suicidal Intent and Lethality in Deliberate Self-Poisoning? Suicide and Life-Threatening Behaviour. ISSN 0363-0234. 47(2), p. 205–216. doi: 10.1111/sltb.12277. Full text in Research Archive
• Nakstad, Espen Rostrup; Opdahl, Helge; Heyerdahl, Fridtjof; Borchsenius, Fredrik & Skjønsberg, Ole Henning (2017). Manual ventilation and open suction procedures contribute to negative pressures in a mechanical lung model. BMJ Open Respiratory Research. 4:e000176, p. 1–7. doi: 10.1136/bmjresp-2016-000176. Full text in Research Archive
• Gjelsvik, Bergljot; Heyerdahl, Fridtjof; Holmes, Jane; Lunn, Daniel & Hawton, Keith (2017). Looking Back on Self-Poisoning: The Relationship between Depressed Mood and Reporting of Suicidal Intent in People Who Deliberately Self-Poison. Suicide and Life-Threatening Behaviour. ISSN 0363-0234. 47(2), p. 228–241. doi: 10.1111/sltb.12278. Full text in Research Archive
• Wood, David M.; Dines, Alison M.; Heyerdahl, Fridtjof; Yates, Christopher; Giraudon, Isabelle & Paasma, Raido [Show all 8 contributors for this article] (2016). Review of European-Drug Emergencies Network (Euro-DEN) training package for non-specialist workers to assess acute recreational drug and new psychoactive substance toxicity in night-time economy environments. Drugs: education prevention and policy. ISSN 0968-7637. 23(1), p. 73–77. doi: 10.3109/09687637.2015.1081379. Full text in Research Archive
• Nakstad, Espen Rostrup; Opdahl, Helge; Heyerdahl, Fridtjof; Borchsenius, Fredrik & Skjønsberg, Ole Henning (2016). Can ventilator settings reduce the negative effects of endotracheal suctioning? Investigations in a mechanical lung model. BMC Anesthesiology. 16:30. doi: 10.1186/s12871-016-0196-z. Full text in Research Archive
• Vallersnes, Odd Martin; Dines, Alison M.; Wood, David M.; Yates, Christopher; Heyerdahl, Fridtjof & Hovda, Knut Erik [Show all 8 contributors for this article] (2016). Psychosis associated with acute recreational drug toxicity: a European case series. BMC Psychiatry. 16:293, p. 1–8. doi: 10.1186/s12888-016-1002-7. Full text in Research Archive Show summary

  Background Psychosis can be associated with acute recreational drug and novel psychoactive substance (NPS) toxicity. However, there is limited data available on how common this is and which drugs are most frequently implicated. We describe a European case series of psychosis associated with acute recreational drug toxicity, and estimate the frequency of psychosis for different recreational drugs. Methods The European Drug Emergencies Network (Euro-DEN) collects data on presentations to Emergency Departments (EDs) with acute recreational drug and NPS toxicity at 16 centres in ten countries. Euro-DEN data from October 2013 through September 2014 was retrospectively searched, and cases with psychosis were included. The proportion of cases with psychosis per drug was calculated in the searched Euro-DEN dataset. Results Psychosis was present in 348 (6.3 %) of 5529 cases. The median (interquartile range) age was 29 (24-38) years, 276 (79.3 %) were male and 114 (32.8 %) were admitted to psychiatric ward. The drugs most commonly reported were cannabis in 90 (25.9 %) cases, amphetamine in 87 (25.0 %) and cocaine in 56 (16.1 %). More than one drug was taken in 189 (54.3 %) cases. Psychosis was frequent in those ED presentations involving tryptamines (4/7; 57.1 %), methylenedioxypyrovalerone (MDPV) (6/22; 27.3 %), methylphenidate (6/26; 23.1 %), lysergic acid diethylamide (LSD) (18/86; 20.9 %), psilocybe mushrooms (3/16; 18.8 %), synthetic cannabinoid receptor agonists (4/26; 15.4 %) and amphetamine (87/593; 14.7 %), but less common in those involving mephedrone (14/245; 5.7 %), methylenedioxymethamphetamine (MDMA) (20/461; 4.3 %) and methedrone (3/92; 3.3 %). Amphetamine was the most frequent drug associated with psychosis when only one agent was reported, with psychosis occurring in 32.4 % of these presentations. Conclusion The frequency of psychosis in acute recreational drug toxicity varies considerably between drugs, but is a major problem in amphetamine poisoning. In rapidly changing drug markets and patterns of use, the Euro-DEN sentinel network contributes to measuring the scale of drug-related harms in Europe beyond other more established indicators.

• Dines, Alison M.; Woods, David; Galicia, Miguel; Yates, Christopher; Heyerdahl, Fridtjof & Hovda, Knut Erik [Show all 9 contributors for this article] (2015). Presentations to the emergency department following cannabis use - a multi-centre case series from ten European countries. Journal of Medical Toxicology. ISSN 1556-9039. 11(4), p. 415–421. doi: 10.1007/s13181-014-0460-x. Full text in Research Archive
• Dines, Alison M.; Wood, David M.; Yates, Christopher; Heyerdahl, Fridtjof; Hovda, Knut Erik & Giraudon, Isabelle [Show all 8 contributors for this article] (2015). Acute recreational drug and new psychoactive substance toxicity in Europe: 12 months data collection from the European Drug Emergencies Network (Euro-DEN). Clinical Toxicology. ISSN 1556-3650. 53(9), p. 893–900. doi: 10.3109/15563650.2015.1088157. Full text in Research Archive
• Gjelsvik, Bergljot; Heyerdahl, Fridtjof; Lunn, Daniel & Hawton, Keith (2014). Change in Access to Prescribed Medication following an Episode of Deliberate Self-Poisoning: A Multilevel Approach. PLOS ONE. 9(5). doi: 10.1371/journal.pone.0098086. Full text in Research Archive Show summary

  Objective: Patients with a history of deliberate self-poisoning (DSP) are prescribed a greater amount of medication than the general public. DSP is the most robust risk factor for repeat episodes of DSP and subsequent death by suicide, and one might therefore expect that access to prescribed medication would be reduced following an episode of DSP. However, it is unclear whether access to prescribed medication changes after an episode of DSP. The objectives of this study were to investigate changes in 1) overall, psychotropic, non-psychotropic and the psychotropic subgroup antidepressant prescribed medication availability in DSP patients following an episode of DSP, 2) prescribing of the medication ingested in the episode, and 3) potential effects of gender, age and repeater status on such change. Methods: The design was longitudinal. We included 171 patients admitted for DSP between January 2006 and March 2007. Data on patients' prescriptions prior to admission were retrieved from The Norwegian Prescription Database. The outcome measure was the difference between medication load in the year following compared to the year prior to the DSP episode. Results: There was a significant increase in total medication load following DSP, including both psychotropic and non-psychotropic medication. Antidepressant medication load remained stable. There was a tendency for access to drugs ingested in the episode to increase following the episode, albeit not significantly. Medication load increased with age across all medication groups irrespective of time period and gender. Conclusions: The findings show that physicians do not curb prescribing to patients who have recently deliberately self-poisoned. Moreover, they highlight the need for cautious and judicious prescribing for these patients, in combination with psychological and social interventions.

• Heyerdahl, Fridtjof; Hovda, Knut Erik; Giraudon, Isabelle; Yates, Christopher; Dines, Alison M. & Sedefov, Roumen [Show all 8 contributors for this article] (2014). Current European data collection on emergency department presentations with acute recreational drug toxicity: Gaps and national variations. Clinical Toxicology. ISSN 1556-3650. 52(10), p. 1005–1012. doi: 10.3109/15563650.2014.976792. Full text in Research Archive
• Gjelsvik, Bergljot; Heyerdahl, Fridtjof & Hawton, Keith (2012). Prescribed medication availability and deliberate self-poisoning: A longitudinal study. Journal of Clinical Psychiatry. ISSN 0160-6689. 73(4), p. e548–e554. doi: 10.4088/JCP.11m07209. Full text in Research Archive
• Lenz, Harald; Ræder, Johan; Drægni, Tomas; Heyerdahl, Fridtjof; Schmelz, Martin & Stubhaug, Audun (2011). Effects of COX inhibition on experimental pain and hyperalgesia during and after remifentanil infusion in humans. Pain. ISSN 0304-3959. 152(6), p. 1289–1297. doi: 10.1016/j.pain.2011.02.007. Full text in Research Archive
• Kolvik, Hallgeir; Bjørnaas, Mari Asphjell; Hovda, Knut Erik; Jacobsen, Dag; Ekeberg, Øivind & Heyerdahl, Fridtjof (2011). Levekår og forgiftningsmønster i Oslos bydeler. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 131, p. 1424–1428. doi: 10.4045/tidsskr.10.0531. Full text in Research Archive
• Bjørnaas, Mari Asphjell; Teige, Brita; Hovda, Knut Erik; Ekeberg, Øivind; Heyerdahl, Fridtjof & Jacobsen, Dag (2010). Fatal poisonings in Oslo: A one-year observational study. BMC Emergency Medicine. 10(6), p. 10–13. doi: 10.1186/1471-227X-10-13. Full text in Research Archive Show summary

  Background Acute poisonings are common and are treated at different levels of the health care system. Since most fatal poisonings occur outside hospital, these must be included when studying characteristics of such deaths. The pattern of toxic agents differs between fatal and non-fatal poisonings. By including all poisoning episodes, cause-fatality rates can be calculated. Methods Fatal and non-fatal acute poisonings in subjects aged ≥16 years in Oslo (428 198 inhabitants) were included consecutively in an observational multi-centre study including the ambulance services, the Oslo Emergency Ward (outpatient clinic), and hospitals, as well as medico-legal autopsies from 1st April 2003 to 31st March 2004. Characteristics of fatal poisonings were examined, and a comparison of toxic agents was made between fatal and non-fatal acute poisoning. Results In Oslo, during the one-year period studied, 103 subjects aged ≥16 years died of acute poisoning. The annual mortality rate was 24 per 100 000. The male-female ratio was 2:1, and the mean age was 44 years (range 19-86 years). In 92 cases (89%), death occurred outside hospital. The main toxic agents were opiates or opioids (65% of cases), followed by ethanol (9%), tricyclic anti-depressants (TCAs) (4%), benzodiazepines (4%), and zopiclone (4%). Seventy-one (69%) were evaluated as accidental deaths and 32 (31%) as suicides. In 70% of all cases, and in 34% of suicides, the deceased was classified as drug or alcohol dependent. When compared with the 2981 non-fatal acute poisonings registered during the study period, the case fatality rate was 3% (95% C.I., 0.03-0.04). Methanol, TCAs, and antihistamines had the highest case fatality rates; 33% (95% C.I., 0.008-0.91), 14% (95% C.I., 0.04-0.33), and 10% (95% C.I., 0.02-0.27), respectively. Conclusions Three per cent of all acute poisonings were fatal, and nine out of ten deaths by acute poisonings occurred outside hospital. Two-thirds were evaluated as accidental deaths. Although case fatality rates were highest for methanol, TCAs, and antihistamines, most deaths were caused by opiates or opioids.

• Muan, Berit; Heyerdahl, Fridtjof; Lindås, Roald; Prestmo, Anders; Skjønsberg, Helge & Berg, Knut Joachim (2010). Kodepraksis ved forgiftningsdødsfall. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 130(16), p. 1601–1605. doi: 10.4045/tidsskr.09.0571. Full text in Research Archive
• Bjørnaas, Mari Asphjell; Hovda, Knut Erik; Heyerdahl, Fridtjof; Skog, Karina; Drottning, Per & Opdahl, Anders [Show all 8 contributors for this article] (2010). Suicidal intention, psychosocial factors and referral to further treatment: A one-year cross-sectional study of self-poisoning. BMC Psychiatry. 10. doi: 10.1186/1471-244X-10-58. Full text in Research Archive Show summary

  Background Patients treated for self-poisoning have an increased risk of death, both by natural and unnatural causes. The follow-up of these patients is therefore of great importance. The aim of this study was to explore the differences in psychosocial factors and referrals to follow-up among self-poisoning patients according to their evaluated intention. Methods A cross-sectional multicenter study of all 908 admissions to hospital because of self-poisoning in Oslo during one year was completed. Fifty-four percent were females, and the median age was 36 years. The patients were grouped according to evaluated intention: suicide attempts (moderate to high suicide intent), appeals (low suicide intent) and substance-use related poisonings. Multinomial regression analyses compared patients based on their evaluated intention; suicide attempts were used as the reference. Results Of all self-poisoning incidents, 37% were suicide attempts, 26% were appeals and 38% were related to substance use. Fifty-five percent of the patients reported previous suicide attempts, 58% reported previous or current psychiatric treatment and 32% reported daily substance use. Overall, patients treated for self-poisoning showed a lack of social integration. Only 33% were employed, 34% were married or cohabiting and 53% were living alone. Those in the suicide attempt and appeal groups had more previous suicide attempts and reported more psychiatric treatment than those with poisoning related to substance use. One third of all patients with substance use-related poisoning reported previous suicide attempts, and one third of suicide attempt patients reported daily substance use. Gender distribution was the only statistically significant difference between the appeal patients and suicide attempt patients. Almost one in every five patients was discharged without any plans for follow-up: 36% of patients with substance use-related poisoning and 5% of suicide attempt patients. Thirty-eight percent of all suicide attempt patients were admitted to a psychiatric ward. Only 10% of patients with substance use-related poisoning were referred to substance abuse treatment. Conclusions All patients had several risk factors for suicidal behavior. There were only minor differences between suicide attempt patients and appeal patients. If the self-poisoning was evaluated as related to substance use, the patient was often discharged without plans for follow-up.

• Heyerdahl, Fridtjof; Bjørnaas, Mari Asphjell; Dahl, Rune; Hovda, Knut Erik; Nore, AK & Ekeberg, Øivind [Show all 7 contributors for this article] (2009). Repetition of acute poisoning in Oslo: 1-year prospective study. British Journal of Psychiatry. ISSN 0007-1250. 194(1), p. 73–79. doi: 10.1192/bjp.bp.107.048322. Full text in Research Archive

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• Simensen, Randi; Rehn, Marius; Hagemo, Jostein Skjalg; Fjose, Lars Olav & Heyerdahl, Fridtjof (2026). Methoxyflurane: analgesic benefit and environmental impact – Authors' reply. The Lancet. ISSN 0140-6736. 407, p. 1427–1428. doi: 10.1016/s0140-6736(26)00495-2. Full text in Research Archive
• Wærp, Cora Mjeldheim; Hauge, Jostein Wågen; Heyerdahl, Fridtjof; Lilleby, Henrik Lied; Møinichen, Marie Mørck & Abedini, Sadollah (2025). Akutt nyresvikt som følge av vitamin D-forgiftning. doi: 10.4045/tidsskr.25.0157. Full text in Research Archive
• Engelsen, Peder Christian Grendstad; Heyerdahl, Fridtjof; Maddali, Dharani Dhar; Akhavi, Mehdi Sadat; Undseth, Ragnhild Marie & Elle, Ole Jakob [Show all 7 contributors for this article] (2024). Correction to: Ascending with ultrasound: telementored eFAST in flight—a feasibility study (Emergency Radiology, (2023), 31, 1, (25-31), 10.1007/s10140-023-02186-x). Emergency Radiology. ISSN 1070-3004. 31(4), p. 629–629. doi: 10.1007/s10140-024-02265-7. Full text in Research Archive
• Lyphout, Cathelijne; Dargan, Paul I.; Wood, David M.; Dines, Alison M.; Giraudon, Isabelle & Heyerdahl, Fridtjof [Show all 14 contributors for this article] (2024). Profiling emergency department presentations related to recreational illicit and prescription opioid use through a European Sentinel-Centre Based Registry. Full text in Research Archive
• Skulberg, Arne Kristian; Heyerdahl, Fridtjof; Dale, Ola & Eide, Desiree (2024). Vi trenger sanntidsovervåkning av overdoser. 144(8). doi: 10.4045/tidsskr.24.0202. Full text in Research Archive
• Brantsæter, Arne Broch; Hansen, Ernst Andreas; Gustavsen, Andreas Gisholt; Stensvåg, Vidar; Aastrøm, Hege Anita & Heyerdahl, Fridtjof [Show all 8 contributors for this article] (2024). Transport of Patients With High-Consequence Infectious Diseases: Development of European Capacity in Norway. Health Security. ISSN 2326-5094. doi: 10.1089/hs.2023.0153. Full text in Research Archive Show summary

  Infection of Western aid workers with Ebola virus disease during the 2014-2016 West African outbreak demonstrated the need for medical evacuation to high-level isolation units in Europe and the United States. In Norway, an ad hoc preparedness team was established for aeromedical evacuation in case of need. In October 2014, this team transported an infected aid worker from the military section of Oslo Airport to Oslo University Hospital. To maintain and strengthen the capacity for domestic ambulance transport on the ground and in the air, the Norwegian Medical Emergency Response Team for High Consequence Infectious Diseases (in Norway known as “Nasjonalt medisinsk utrykningsteam for høyrisikosmitte”), or NORTH, was established as a permanent service in 2017. Recognizing the expertise of this domestic team, Norway was subsequently entrusted with the task of enhancing the European aeromedical transport capacity for high-consequence infectious diseases and establishing the Norwegian rescEU Jet Air Ambulance for Transport of Highly Infectious Patients, or NOJAHIP, in 2022. In this case study, we present experiences and lessons learned from these 2 services and discuss how they can be further developed.

• Solvik-Olsen, Tone; Kåsin, Jan Ivar; Hagemo, Jostein Skjalg & Heyerdahl, Fridtjof (2024). Response to the letter: ‘Vibrations during helicopter neonatal transport’. Acta Paediatrica. ISSN 0803-5253. doi: 10.1111/apa.17374. Full text in Research Archive
• Wood, David M.; Dines, Alison M.; Liechti, Matthias E.; Giraudon, Isabelle; Heyerdahl, Fridtjof & hovda, knut erik [Show all 10 contributors for this article] (2023). Diphenidine, methoxyphenidine and related 1,2-diarylethylamine acute toxicity reported to the Euro-DEN Plus project. Full text in Research Archive
• Haakonsen, Helene Brenna; Jortveit, Jarle & Heyerdahl, Fridtjof (2023). Mann i 60-årene med akutte brystsmerter. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 143(12). doi: 10.4045/tidsskr.23.0113. Full text in Research Archive
• Simensen, Randi; Fjose, Lars Olav; Rehn, Marius; Hagemo, Jostein Skjalg; Thorsen, Kjetil & Heyerdahl, Fridtjof (2023). Comparison of three regimens with inhalational methoxyflurane versus intranasal fentanyl versus intravenous morphine in pre-hospital acute pain management: study protocol for a randomized controlled trial (PreMeFen). Trials. 24(1). doi: 10.1186/s13063-023-07590-9. Full text in Research Archive Show summary

  Background Pre-hospital pain management has traditionally been performed with intravenous (IV) morphine, but oligoanalgesia remain a recognized problem. Pain reduction is essential for patient satisfaction and is regarded as a measure of successful treatment. We aim to establish whether non-invasive methods such as inhalation of methoxyflurane is non-inferior to intranasal fentanyl or non-inferior to the well-known IV morphine in the pre-hospital treatment of acute pain. Method/design The PreMeFen study is a phase three, three-armed, randomized, controlled, non-inferiority trial to compare three regimens of analgesics: inhalation of methoxyflurane and intranasal (IN) fentanyl versus IV morphine. It is an open-label trial with a 1:1:1 randomization to the three treatment groups. The primary endpoint is the change in pain numeric rating scale (NRS) (0–10) from baseline to 10 min after start of investigational medicinal product administration (IMP). The non-inferiority margin was set to 1.3, and a sample size of 270 patients per protocol (90 in each treatment arm) will detect this difference with 90% power. Discussion We chose a study design with comparison of analgesic regimens rather than fixed doses because of the substantial differences in drug characteristics and for the results to be relevant to inform policymakers in the pre-hospital setting. We recognize that easier administration of analgesics will lead to better pain management for many patients if the regimens are as good as the existing, and hence, we chose a non-inferiority design. The primary endpoint, the change in pain (NRS) after 10 min, is set to address the immediate need of pain reduction for patients with acute prehospital pain. On a later stage, more analgesic methods are often available. Summary PreMeFen is a non-inferiority randomized controlled trial comparing three analgesic regimens aiming to establish whether inhalation of methoxyflurane or intranasal fentanyl is as good as IV morphine for fast reduction of acute pain in the prehospital setting.

• Gustavsen, Ingebjørg G. & Heyerdahl, Fridtjof (2023). Senskader etter kullosforgiftning. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 143(13). doi: 10.4045/tidsskr.23.0482. Full text in Research Archive
• Waters, Mitchell; Wood, David M.; Yates, Christopher; Dines, Alison M.; Giraudon, Isabelle & Liechti, Matthias E. [Show all 11 contributors for this article] (2022). Clinical effects of cannabis compared to synthetic cannabinoids (SCs): a retrospective cohort study. Full text in Research Archive
• Hagemo, Jostein Skjalg; Skulberg, Arne Kristian; Rehn, Marius; Valberg, Morten; Pesonen, Maiju & Heimdal, Hans Julius [Show all 7 contributors for this article] (2022). Inhaled nitric oxide as temporary respiratory stabilization in patients with COVID-19 related respiratory failure (INOCOV): Study protocol for a randomized controlled trial. PLOS ONE. 17(5). doi: 10.1371/journal.pone.0268822. Full text in Research Archive Show summary

  Background In March 2020, WHO announced the COVID-19 a pandemic and a major global public health emergency. Mortality from COVID-19 is rapidly increasing globally, with acute respiratory failure as the predominant cause of death. Many patients experience severe hypoxia and life-threatening respiratory failure often requiring mechanical ventilation. To increase safety margins during emergency anaesthesia and rapid sequence intubation (RSI), patients are preoxygenated with a closed facemask with high-flow oxygen and positive end-expiratory pressure (PEEP). Due to the high shunt fraction of deoxygenated blood through the lungs frequently described in COVID-19 however, these measures may be insufficient to avoid harmful hypoxemia. Preoxygenation with inhaled nitric oxide (iNO) potentially reduces the shunt fraction and may thus allow for the necessary margins of safety during RSI. Methods and design The INOCOV protocol describes a phase II pharmacological trial of inhaled nitric oxide (iNO) as an adjunct to standard of care with medical oxygen in initial airway and ventilation management of patients with known or suspected COVID-19 in acute respiratory failure. The trial is parallel two-arm, randomized, controlled, blinded trial. The primary outcome measure is the change in oxygen saturation (SpO2), and the null hypothesis is that there is no difference in the change in SpO2 following initiation of iNO. Trial registration EudraCT number 2020-001656-18; WHO UTN: U1111-1250-1698. Protocol version: 2.0 (June 25th, 2021).

• Heyerdahl, Fridtjof (2022). Ny redningshelikopter og ny ige virksomhetsdata. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 142(18). doi: 10.4045/tidsskr.22.0732. Full text in Research Archive
• Slørdahl, Johannes Thomassen; Persett, Per Sverre; Brekke, Mette; Heyerdahl, Fridtjof; Hovda, Knut Erik & Vallersnes, Odd Martin (2021). Acute poisoning from concurrent use of opioids and amphetamine. Full text in Research Archive
• Vallersnes, Odd Martin; Dines, Alison M.; Wood, David M.; Heyerdahl, Fridtjof; Hovda, Knut Erik & Yates, Christopher [Show all 8 contributors for this article] (2020). Self-discharge during treatment for acute recreational drug toxicity: an analysis of four-years of Euro-DEN Plus presentations. Full text in Research Archive
• Syse, Victoria Lykke; Brekke, Mette; Grimsrud, Marit Mæhle; Persett, Per Sverre; Heyerdahl, Fridtjof & Hovda, Knut Erik [Show all 7 contributors for this article] (2019). Acute recreational drug toxicity in women: a case series from Oslo, Norway. Full text in Research Archive
• Tylleskär, Ida; Braarud, Anne-Cathrine; Heyerdahl, Fridtjof; Dale, Ola & Skulberg, Arne Kristian (2019). Dosing of naloxone in opioid overdose outside of hospital. Observational data 2014-2018 in Oslo, Norway. Full text in Research Archive
• Tylleskär, Ida; Braarud, Anne-Cathrine; Heyerdahl, Fridtjof; Dale, Ola & Skulberg, Arne Kristian (2019). Dosering av nalokson ved opioidoverdoser utenfor sykehus. Full text in Research Archive
• Lorentzen, Helga Ruus; Seljetun, Kristin Opdal; Rønning, Tarjei Skeide; Dale, Ane Cecilie & Heyerdahl, Fridtjof (2018). A case of copper acetoarsenite poisoning. Clinical Toxicology. ISSN 1556-3650. 56(6), p. 540–540. doi: 10.1080/15563650.2018.1457818. Full text in Research Archive
• Vallersnes, Odd Martin; Dines, Alison M.; Wood, David M.; Yates, Christopher; Heyerdahl, Fridtjof & hovda, knut erik [Show all 8 contributors for this article] (2016). Erratum to: Psychosis associated with acute recreational drug toxicity: A European case series [BMC Psychiatry, 16 (2016), (293)], DOI:10.1186/s12888-016-1002-7. BMC Psychiatry. 16(1). doi: 10.1186/s12888-016-1066-4. Full text in Research Archive
• Vallersnes, Odd Martin; Dines, Alison M.; Wood, David M.; Yates, Christopher; Heyerdahl, Fridtjof & Hovda, Knut Erik [Show all 9 contributors for this article] (2015). Psychosis associated with acute poisoning by recreational drugs: a European case series. Full text in Research Archive
• Persett, Per Sverre; Vallersnes, Odd Martin; Øiestad, Elisabeth Leere; Karinen, Ritva Anneli; Bogstrand, Stig Tore & Heyerdahl, Fridtjof [Show all 7 contributors for this article] (2015). Laboratory confirmation of recreational drugs in Oslo, Norway. Full text in Research Archive
• Gjelsvik, Bergljot; Heyerdahl, Fridtjof & Hawton, Keith (2013). Deliberate self-poisoning with prescribed drugs is not related to medical severity of acts. Journal of Clinical Psychiatry. ISSN 0160-6689. 74(6), p. 630–630. doi: 10.4088/JCP.12l08298. Full text in Research Archive
• Heyerdahl, Fridtjof; Bjørnaas, Mari Asphjell; Lund, Cathrine; Jacobsen, Dag & Ekeberg, Øivind (2013). Long-term follow-up of three cohorts of self-poisoning. Clinical Toxicology. ISSN 1556-3650. 51(4), p. 254–254. Full text in Research Archive
• Heyerdahl, Fridtjof; Opdahl, Helge & Jacobsen, Dag (2012). The Role of the Norwegian Competence Centre for NBC Medicine during the Non-CBRN Terrorist Attacks in Norway on 22 July 2011. Clinical Toxicology. ISSN 1556-3650. 50(4), p. 276–276. Full text in Research Archive
• Heyerdahl, Fridtjof; Haavind, Anniken & Jacobsen, Dag (2012). A Fatal Case of Suicidal Injection and Ingestion of Self-Extracted Ricin. Clinical Toxicology. ISSN 1556-3650. 50(4), p. 290–290. Full text in Research Archive
• Bjornaas, MA; Bjørnaas, Mari Asphjell; Teige, Brita; Hovda, KE; Heyerdahl, F & Ekeberg, O [Show all 7 contributors for this article] (2009). Deaths by self-poisoning in Oslo and the surrounding area during one year. Clinical Toxicology. ISSN 1556-3650. 47(5), p. 504–505. Full text in Research Archive
• Heyerdahl, Fridtjof (2009). Antidepressant Prescribing to Deliberate Self-Poisoning Patients the Last Year Prior to the Deliberate Self-Poisoning Episode. Clinical Toxicology. ISSN 1556-3650. 47(5), p. 506–506. Full text in Research Archive
• Grimholt, Tine; Bjørnaas, Mari Asphjell; Dieserud, Gudrun; Heyerdahl, Fridtjof; Hovda, Knut Erik & Jacobsen, Dag [Show all 7 contributors for this article] (2009). Psykiske symptomer og tilbud om oppfølging tre måneder etter selvpåført forgiftning. Full text in Research Archive
• Lenz, Harald; Ræder, Johan; Drægni, Tomas; Heyerdahl, Fridtjof & Stubhaug, Audun (2009). Modulering av remifentanilindusert hyperalgesi med parecoxib eller ketorolac på friske, frivillige forsøkspersoner. Full text in Research Archive

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