Non-toxic alveolar oxygen concentration without hypoxemia during apnoeic oxygenation: an experimental study
2011 (English)In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 55, no 9, 1078-1084 p.Article in journal (Refereed) Published
Background: Oxygenation without tidal breathing, i.e. apnoeic oxygenation in combination with extracorporeal carbon dioxide removal, might be an option in the treatment of acute respiratory failure. However, ventilation with 100% O(2), which is potentially toxic, is considered a prerequisite to ensure acceptable oxygenation. We hypothesized that trapping nitrogen (N(2)) in the lungs before the start of apnoeic oxygenation would keep the alveolar O(2) at a non-toxic level and still maintain normoxaemia. The aim was to test whether a predicted N(2) concentration would agree with a measured concentration at the end of an apnoeic period. Methods: Seven anaesthetized, muscle relaxed, endotracheally intubated pigs (22-27 kg) were ventilated in a randomized order with an inspired fraction of O(2) 0.6 and 0.8 at two positive end-expiratory pressure levels (5 cm and 10 cm H(2)O) before being connected to continuous positive airway pressure using 100% O(2) for apnoeic oxygenation. N(2) was measured before the start of and at the end of the 10-min apnoeic period. The predicted N(2) concentration was calculated from the initial N(2) concentration, the end-expiratory lung volume, and the anatomical dead space. Results: The mean difference and standard deviation between measured and predicted N(2) concentration was -0.5 +/- 2%, P = 0.587. No significant difference in the agreement between measured and predicted N(2) concentrations was seen in the four settings. Conclusions: This study indicates that it is possible to predict and keep alveolar N(2) concentration at a desired level and, thus, alveolar O(2) concentration at a non-toxic level during apnoeic oxygenation.
Place, publisher, year, edition, pages
2011. Vol. 55, no 9, 1078-1084 p.
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:uu:diva-160124DOI: 10.1111/j.1399-6576.2011.02499.xISI: 000295102500006OAI: oai:DiVA.org:uu-160124DiVA: diva2:448635