tetano
Editor, Senior Moderator
Eur J Med Res
. 2023 Dec 16;28(1):597.
doi: 10.1186/s40001-023-01559-9. Improved oxygenation in prone positioning of mechanically ventilated patients with COVID-19 acute respiratory distress syndrome is associated with decreased pulmonary shunt fraction: a prospective multicenter study
Piotr Harbut[SUP] 1 [/SUP], Francesca Campoccia Jalde[SUP] 2 3 [/SUP], Martin Dahlberg[SUP] 4 [/SUP], Anders Forsgren[SUP] 5 [/SUP], Elisabeth Andersson[SUP] 5 [/SUP], Andreas Lundholm[SUP] 1 [/SUP], Jaroslaw Janc[SUP] 6 [/SUP], Patrycja Lesnik[SUP] 6 [/SUP], Michal Suchanski[SUP] 6 [/SUP], Pawel Zatorski[SUP] 7 [/SUP], Janusz Trzebicki[SUP] 7 [/SUP], Tomasz Skalec[SUP] 8 [/SUP], Mattias Günther[SUP] 9 [/SUP]
Affiliations
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'[SUB]A[/SUB]/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 PaO[SUB]2[/SUB]:FiO[SUB]2[/SUB] 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 PaO[SUB]2[/SUB]:FiO[SUB]2[/SUB] were correlated both in prone (Beta -137) (p < 0.001) and in the supine position (Beta -270) (p < 0.001). V'[SUB]A[/SUB]/Q' was unaffected and did not correlate to PaO[SUB]2[/SUB]:FiO[SUB]2[/SUB] (p = 0.8). Vd/Vtalv increased at 120 min by 11% (0.55-0.61) (p < 0.05) and did not correlate to PaO[SUB]2[/SUB]:FiO[SUB]2[/SUB] (p = 0.3). The ventilatory ratio increased after 30 min in the prone position by 58% (1.9-3.0) (p < 0.001). PaO[SUB]2[/SUB]:FiO[SUB]2[/SUB] at baseline predicted PaO[SUB]2[/SUB]:FiO[SUB]2[/SUB] 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'[SUB]A[/SUB]/Q' measure could not explain the differences in gas exchange.
Keywords: Acute respiratory distress syndrome; COVID-19; Intensive care; Prone position; Pulmonary shunt fraction.
. 2023 Dec 16;28(1):597.
doi: 10.1186/s40001-023-01559-9. Improved oxygenation in prone positioning of mechanically ventilated patients with COVID-19 acute respiratory distress syndrome is associated with decreased pulmonary shunt fraction: a prospective multicenter study
Piotr Harbut[SUP] 1 [/SUP], Francesca Campoccia Jalde[SUP] 2 3 [/SUP], Martin Dahlberg[SUP] 4 [/SUP], Anders Forsgren[SUP] 5 [/SUP], Elisabeth Andersson[SUP] 5 [/SUP], Andreas Lundholm[SUP] 1 [/SUP], Jaroslaw Janc[SUP] 6 [/SUP], Patrycja Lesnik[SUP] 6 [/SUP], Michal Suchanski[SUP] 6 [/SUP], Pawel Zatorski[SUP] 7 [/SUP], Janusz Trzebicki[SUP] 7 [/SUP], Tomasz Skalec[SUP] 8 [/SUP], Mattias Günther[SUP] 9 [/SUP]
Affiliations
- PMID: 38102699
- PMCID: PMC10725003
- DOI: 10.1186/s40001-023-01559-9
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'[SUB]A[/SUB]/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 PaO[SUB]2[/SUB]:FiO[SUB]2[/SUB] 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 PaO[SUB]2[/SUB]:FiO[SUB]2[/SUB] were correlated both in prone (Beta -137) (p < 0.001) and in the supine position (Beta -270) (p < 0.001). V'[SUB]A[/SUB]/Q' was unaffected and did not correlate to PaO[SUB]2[/SUB]:FiO[SUB]2[/SUB] (p = 0.8). Vd/Vtalv increased at 120 min by 11% (0.55-0.61) (p < 0.05) and did not correlate to PaO[SUB]2[/SUB]:FiO[SUB]2[/SUB] (p = 0.3). The ventilatory ratio increased after 30 min in the prone position by 58% (1.9-3.0) (p < 0.001). PaO[SUB]2[/SUB]:FiO[SUB]2[/SUB] at baseline predicted PaO[SUB]2[/SUB]:FiO[SUB]2[/SUB] 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'[SUB]A[/SUB]/Q' measure could not explain the differences in gas exchange.
Keywords: Acute respiratory distress syndrome; COVID-19; Intensive care; Prone position; Pulmonary shunt fraction.