Author:
Harbut Piotr,Campoccia Jalde Francesca,Dahlberg Martin,Forsgren Anders,Andersson Elisabeth,Lundholm Andreas,Janc Jaroslaw,Lesnik Patrycja,Suchanski Michal,Zatorski Pawel,Trzebicki Janusz,Skalec Tomasz,Günther Mattias
Abstract
Abstract
Background
Prone position is used in acute respiratory distress syndrome and in coronavirus disease 2019 (Covid-19) acute respiratory distress syndrome (ARDS). However, physiological mechanisms remain unclear. The aim of this study was to determine whether improved oxygenation was related to pulmonary shunt fraction (Q’s/Q’t), alveolar dead space (Vd/Vtalv) and ventilation/perfusion mismatch (V’A/Q’).
Methods
This was an international, prospective, observational, multicenter, cohort study, including six intensive care units in Sweden and Poland and 71 mechanically ventilated adult patients.
Results
Prone position increased PaO2:FiO2 after 30 min, by 78% (83–148 mm Hg). The effect persisted 120 min after return to supine (p < 0.001). The oxygenation index decreased 30 min after prone positioning by 43% (21–12 units). Q’s/Q’t decreased already after 30 min in the prone position by 17% (0.41–0.34). The effect persisted 120 min after return to supine (p < 0.005). Q’s/Q’t and PaO2:FiO2 were correlated both in prone (Beta -137) (p < 0.001) and in the supine position (Beta -270) (p < 0.001). V’A/Q’ was unaffected and did not correlate to PaO2:FiO2 (p = 0.8). Vd/Vtalv increased at 120 min by 11% (0.55–0.61) (p < 0.05) and did not correlate to PaO2:FiO2 (p = 0.3). The ventilatory ratio increased after 30 min in the prone position by 58% (1.9–3.0) (p < 0.001). PaO2:FiO2 at baseline predicted PaO2:FiO2 at 30 min after proning (Beta 1.3) (p < 0.001).
Conclusions
Improved oxygenation by prone positioning in COVID-19 ARDS patients was primarily associated with a decrease in pulmonary shunt fraction. Dead space remained high and the global V’A/Q’ measure could not explain the differences in gas exchange.
Publisher
Springer Science and Business Media LLC
Cited by
1 articles.
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1. Prone positioning;Intensive Care Medicine;2024-04-24