Impact of Supine Versus Semirecumbent Body Posture on the Distribution of Ventilation in Acute Respiratory Distress Syndrome - PubMed (original) (raw)

Impact of Supine Versus Semirecumbent Body Posture on the Distribution of Ventilation in Acute Respiratory Distress Syndrome

Alex K Pearce et al. Crit Care Explor. 2023.

Abstract

In some patients with acute respiratory distress syndrome (ARDS), a paradoxical improvement in respiratory system compliance (CRS) has been observed when assuming a supine (head of bed [HOB] 0°) compared with semirecumbent (HOB 35-40°) posture. We sought to test the hypothesis that mechanically ventilated patients with ARDS would have improved CRS, due to changes in ventilation distribution, when moving from the semirecumbent to supine position. We conducted a prospective, observational ICU study including 14 mechanically ventilated patients with ARDS. For each patient, ventilation distribution (assessed by electrical impedance tomography) and pulmonary mechanics were compared in supine versus semirecumbent postures. Compared with semirecumbent, in the supine posture CRS increased (33 ± 21 vs. 26 ± 14 mL/cm H2O, p = 0.005), driving pressure was reduced (14 ± 6 vs. 17 ± 7 cm H2O, p < 0.001), and dorsal fraction of ventilation was decreased (48.5 ± 14.1% vs. 54.5 ± 12.0%, p = 0.003). Posture change from semirecumbent to supine resulted in a favorable physiologic response in terms of improved CRS and reduced driving pressure-with a corresponding increase in ventral ventilation, possibly related to reduced ventral overdistension.

Keywords: acute respiratory distress syndrome; electrical impedance tomography; mechanical ventilation; respiratory system compliance.

Copyright © 2023 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the Society of Critical Care Medicine.

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Conflict of interest statement

Drs. Pearce and McGuire received funding from the National Institutes of Health- National Heart Lung and Blood Institute (NIH-NHLBI) T32. Dr. Malhotra has received funding from the National Institutes of Health (NIH). Dr. Malhotra also reports income related to medical education from Livanova, Jazz, Zoll, and Eli Lilly. ResMed gave a philanthropic donation to University of California San Diego (UCSD). Dr. Malhotra is a co-founder of Healcisio which is a startup related to predictive analytics in sepsis. The remaining authors have disclosed that they do not have any conflicts of interest related to this work.

Figures

Figure 1.

Figure 1.

Impact of posture on respiratory system compliance, driving pressure, and dorsal fraction of ventilation. A, Respiratory system compliance. B, Driving pressure. C, Dorsal fraction of ventilation. Individual patient data are identified by unique symbols and connected with solid lines. *p < 0.05 semirecumbent (35–40°) versus supine (0°).

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