Nikolai Ravn Aarskog

• Aarskog, Nikolai Ravn; Bjørsrud, Hanna Othilie Lindvig; Holten, Aleksander Rygh; Watne, Leiv Otto; Neerland, Bjørn Erik & Rostrup, Morten (2025). Ventilatory response and delirium risk in hospitalised patients with acute hypoxia due to COVID-19. Scientific Reports. 15. doi: 10.1038/s41598-025-13016-0. Full text in Research Archive Show summary

  Mountaineers with a high ventilatory response to hypoxia experience greater cognitive impairment at high altitude, possibly because hyperventilation causes hypocapnia, cerebral vasoconstriction and ultimately cerebral ischaemia. We hypothesised that a high ventilatory response, and consequently a lower arterial partial pressure of carbon dioxide (PaCO2), could increase the risk of delirium in hospitalised patients with acute hypoxia. To test our hypothesis, we conducted a cohort study in which PaCO2 and arterial oxygen saturation were measured upon hospital admission in 126 patients with COVID-19. After adjusting for oxygen saturation, we found that a lower PaCO2 was associated with a higher risk of delirium during hospital admission (risk ratio 1.67 [95% confidence interval 1.09–2.54] per 1 kilopascal reduction, P = 0.017). The association remained statistically significant after adjusting for other well-established risk factors for delirium. This finding supports our hypothesis that a high hypoxic ventilatory response increases the risk of delirium in patients with acute hypoxia.

• Aarskog, Nikolai Ravn; Hallem, Ronja; Godhavn, Jakob Strand & Rostrup, Morten (2024). Time-Dependent Changes in Pulmonary Turnover of Thrombocytes during Critical COVID-19. Critical Care Explorations. 6(7), p. e1128–e1128. doi: 10.1097/CCE.0000000000001128. Full text in Research Archive
• Halvorsen, Lene Vernås; Søraas, Camilla Lund; Larstorp, Anne Cecilie Kjeldsen; Hjørnholm, Ulla; Kjær, Vibeke Norheim & Liestøl, Knut [Show all 21 contributors for this article] (2024). Effect of Therapeutic Drug Monitoring on Adherence and Blood Pressure: A Multicenter Randomized Clinical Trial. American Journal of Hypertension. ISSN 0895-7061. 37(10), p. 826–836. doi: 10.1093/ajh/hpae059. Full text in Research Archive Show summary

  BACKGROUND Drug concentration in blood or urine is an acknowledged method to detect nonadherence. Observational studies suggest that informing patients about low or absent serum drug levels improves blood pressure (BP). We performed a multicenter randomized clinical trial to test the hypothesis that therapeutic drug monitoring (TDM) could improve drug adherence and BP in patients with uncontrolled hypertension (HT). METHODS Patients were ≥18 years on stable treatment with at least 2 antihypertensive agents. We planned to randomize 80 nonadherent patients with a systolic daytime ambulatory BP ≥135 mm Hg to TDM intervention or not. The control group and the study personnel who measured BP remained uninformed about serum drug measurements throughout. All patients and physicians were blinded for BPs. Lifestyle advice and detailed information on the disease process and the importance of BP treatment were given to both groups. RESULTS From 2017 to 2022, we randomized 46 diagnosed nonadherent from a total of 606 patients with uncontrolled HT. The TDM group had a 6.7 (±14.5) mm Hg reduction from 147.9 (±10.3) to 141.1 (±14.1) mm Hg, and the control group experienced a 7.3 (±13.2) mm Hg reduction from 147.1 (±9.2) to 139.1 (±17.4) mm Hg, P = 0.9 between groups. Adherence improved in both groups, 73% in the TDM group and 59% in the control group became adherent at 3 months, P = 0.51. CONCLUSIONS In our prospective multicenter clinical trial of uncontrolled and nonadherent hypertensive patients, we found no additional effect of TDM on BP and drug adherence compared with standard care.

• Aarskog, Nikolai Ravn; Aass, Hans Christian Dalsbotten; Holter, Jan Cato; Rostrup, Morten & Holten, Aleksander Rygh (2021). Interleukin-6 in Critical Coronavirus Disease 2019, a Driver of Lung Inflammation of Systemic Origin? Critical Care Explorations. 3(10). doi: 10.1097/cce.0000000000000542. Full text in Research Archive Show summary

  OBJECTIVES: To examine whether interleukin-6 in critical coronavirus disease 2019 is higher in arterial than in central venous blood, as a sign of predominantly local pulmonal rather than systemic interleukin-6 production. DESIGN: Prospective cohort pilot study with repeated weekly measurements of interleukin-6 in arterial and central venous blood. Respiratory function, assessed with Pao2/Fio2 ratio, was measured at the time of blood sampling. SETTING: ICU at a university hospital. SUBJECTS: Nine adult patients with critical coronavirus disease 2019, actively treated and receiving mechanical ventilation. MEASUREMENTS AND MAIN RESULTS: No difference between arterial and central venous interleukin-6 was found. There was a significant negative relationship between interleukin-6 concentration and P/F ratio in both arterial (p = 0.04) and central venous (p = 0.03) blood. CONCLUSIONS: The absence of an arteriovenous interleukin-6 difference implies that interleukin-6 in critical coronavirus disease 2019 is mainly produced outside the lungs as part of a systemic inflammatory response syndrome and act as a driver of local inflammation and damage in the lungs.

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• Aarskog, Nikolai Ravn (2025). Pest eller sjolera? Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 145(3). doi: 10.4045/tidsskr.24.0214. Full text in Research Archive
• Aarskog, Nikolai Ravn; Iuell, Ragnhild Skari; Dunlop, Oona Borghild; Sevre, Knut; Bendz, Bjørn & Rostrup, Morten (2023). Neuropsychological function is associated with hypocapnia at simulated high altitude. Acta Physiologica. ISSN 1748-1708. doi: 10.1111/apha.13949. Full text in Research Archive

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