Physiologic Effects of the Awake Prone Position Combined With High-Flow Nasal Oxygen on Gas Exchange and Work of Breathing in Patients With Severe COVID-19 Pneumonia: A Randomized Crossover Trial

Samuel Lehingue; Jérôme Allardet-Servent; Anne Ferdani; Sami Hraeich; Jean-Marie Forel; Jean-Michel Arnal; Eloi Prud'homme; Guillaume Penaranda; Jeremy Bourenne; Olivier Monnet; Marc Gainnier; Emmanuel Cantais

doi:10.1097/CCE.0000000000000805

Physiologic Effects of the Awake Prone Position Combined With High-Flow Nasal Oxygen on Gas Exchange and Work of Breathing in Patients With Severe COVID-19 Pneumonia: A Randomized Crossover Trial

Crit Care Explor. 2022 Dec 14;4(12):e0805. doi: 10.1097/CCE.0000000000000805. eCollection 2022 Dec.

Authors

Affiliations

¹ Department of Intensive Care, Hôpital Saint Joseph, Marseille, France.
² Department of Intensive Care, Hôpital Européen Marseille, Marseille, France.
³ Department of Intensive Care, Centre Hospitalier d'Aix-en-Provence, Aix-en-Provence, France.
⁴ Médecine Intensive Réanimation, Assistance Publique-Hôpitaux de Marseille, Hôpital Nord, Marseille, France.
⁵ Multipurpose Intensive Care Service, Hôpital Sainte Musse, Toulon, France.
⁶ Service des Maladies Respiratoires, Centre Hospitalier d'Aix-en-Provence, Aix-en-Provence, France.
⁷ Biostastistic, Laboratoire Européen Alphabio, Marseille, France.
⁸ Emergency and Critical Care Medicine, Assistance Publique-Hôpitaux de Marseille, CHU Timone, Marseille, France.
⁹ Department of Radiology, Hôpital Saint Joseph, Marseille, France.

Abstract

To determine the effect of the awake prone position (APP) on gas exchange and the work of breathing in spontaneously breathing patients with COVID-19-associated acute hypoxemic respiratory failure (AHRF) supported by high-flow nasal oxygen.

Design: Prospective randomized physiologic crossover multicenter trial.

Settings: Four ICUs in Marseille, France.

Patients: Seventeen patients with laboratory-confirmed COVID-19 pneumonia and Pao₂/Fio₂ less than or equal to 300 mm Hg while treated with high-flow nasal cannula oxygen therapy.

Interventions: Periods of APP and semirecumbent position (SRP) were randomly applied for 2 hours and separated by a 2-hour washout period.

Measurements and main results: Arterial blood gases, end-tidal CO₂. and esophageal pressure were recorded prior to and at the end of each period. Inspiratory muscle effort was assessed by measuring the esophageal pressure swing (∆P_ES) and the simplified esophageal pressure-time product (sPTP_ES). The other endpoints included physiologic dead space to tidal volume ratio (V_D/V_T) and the transpulmonary pressure swing. The APP increased the Pao₂/Fio₂ from 84 Torr (61-137 Torr) to 208 Torr (114-226 Torr) (p = 0.0007) and decreased both the V_D/V_T and the respiratory rate from 0.54 (0.47-0.57) to 0.49 (0.45-0.53) (p = 0.012) and from 26 breaths/min (21-30 breaths/min) to 21 breaths/min (19-22 breaths/min), respectively (p = 0.002). These variables remained unchanged during the SRP. The ∆P_ES and sPTP_ES per breath were unaffected by the position. However, the APP reduced the sPTP_ES per minute from 225 cm H₂O.s.m^-1 (176-332 cm H₂O.s.m^-1) to 174 cm H₂O.s.m^-1 (161-254 cm H₂O.s.m^-1) (p = 0.049).

Conclusions: In spontaneously breathing patients with COVID-19-associated AHRF supported by high-flow nasal oxygen, the APP improves oxygenation and reduces the physiologic dead space, respiratory rate, and work of breathing per minute.

Keywords: COVID-19; prone position; respiratory distress syndrome; respiratory insufficiency; work of breathing.