Public Defence: Sigurd Aarrestad Sigurd Aarrestad at Institute of Clinical Medicine will be defending the thesis "Monitoring long-term nocturnal non-invasive ventilation for chronic hypercapnic respiratory failure: What are the basic tools?" for the degree of PhD (Philosophiae Doctor).

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Foto: Paula Aarrestad

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Adjudication committee

  • First opponent: Associate Professor Bengt Midgren, Lund University, Sweden
  • Second opponent: Associate Professor Sverre Lehmann, Department of Clinical Science, University of Bergen
  • Third member and chair of the evaluation committee: Professor II Harriet Akre, Institute of Clinical Medicine, University of Oslo

Chair of defence

Associate Professor Are Martin Holm, Institute of Clinical Medicine, University of Oslo 

Principal Supervisor

Professor II Ole Henning Skjønsberg, Institute of Clinical Medicine, University of Oslo


Monitoring long-term nocturnal non-invasive ventilation for chronic hypercapnic respiratory failure: What are the basic tools?

Neuromuscular disorders, obesity and chest wall disorders can lead to chronic hypercapnic respiratory failure. Non-invasive ventilation (NIV) is increasingly used for long-term treatment of these patients. During NIV-treatment sleep related respiratory events like obstructive or central apnea and hypopnea, patient-ventilator asynchrony, mask leaks, and sleep hypoventilation may compromise the efficacy of NIV.

The aim of this thesis was to evaluate the accuracy of a test panel for detecting sleep related respiratory events, suggested in a European consensus report. They have proposed that a combination of clinical evaluation, daytime arterial blood gases, nocturnal pulse oximetry (SpO2), and a synthesis report from the ventilator software should be used as the first step during follow-up of these patients.

We have shown that it is feasible and important to evaluate the presence of undesired nocturnal respiratory events during NIV. Transcutaneous CO2 (PtcCO2) is an accurate tool for monitoring PaCO2 and can be used to detect sleep hypoventilation. Respiratory polygraphy during NIV can be used to detect apnea/hypopnea and patient-ventilator asynchrony. We found that sleep hypoventilation, hypopnea and patient-ventilator asynchrony were frequent, often without generating symptoms. The suggested test panel proved to have insufficient accuracy in detecting these events. Also, we have confirmed that daytime arterial blood gases and nocturnal SpO2 are insufficient tests to detect sleep hypoventilation. Obstructive hypopnea was the most frequent event and could be accurately detected by the built-in sensor in the ventilator (AHIventilator). Therefore, PtcCO2 and evaluation of AHIventilator should be implemented in the routine follow-up of these patients.

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Published Feb. 28, 2020 1:54 PM - Last modified Mar. 4, 2020 10:39 AM