Physiologic effects of prone positioning on gas exchange and ventilation-perfusion matching in awake patients with AHRF

• Published in: BMC pulmonary medicine 2024-12, Vol.24 (1), p.600-8
• Main Authors: Chao, Yali, Yuan, Xueyan, Zhao, Zhanqi, Frerichs, Inéz, Li, Zhe, Sun, Qin, Chen, Dongyu, Zhang, Rui, Qiu, Haibo, Liu, Ling
• Format: Article
• Language: English
• Subjects: Acute hypoxemic respiratory failure; Aged; Analysis; Awake prone positioning; Care and treatment; Dead space; Female; Hemodynamics; Humans; Hypoxia - physiopathology; Hypoxia - therapy; Influence; Lung - diagnostic imaging; Lung - physiopathology; Male; Middle Aged; Patient Positioning - methods; Posture; Prone Position; Prospective Studies; Pulmonary Gas Exchange; Respiratory insufficiency; Respiratory Insufficiency - physiopathology; Respiratory Insufficiency - therapy; Shunt; Tomography, X-Ray Computed; Ventilation-perfusion matching; Ventilation-Perfusion Ratio; Wakefulness
• ISSN: 1471-2466; 1471-2466
• DOI: 10.1186/s12890-024-03411-0

Prone positioning (PP) improves oxygenation in awake patients with acute hypoxemic respiratory failure (AHRF). However, the underlying mechanisms remain unclear in patients with diverse lung morphology. We aimed to determine the short-term effects of awake prone positioning (APP) in AHRF patients with focal and non-focal lung morphology. This is a prospective physiological study. Twenty-four non-intubated patients with PaO /FiO  ≤ 300 mm Hg were included. Gas exchange, ventilation and perfusion distribution, and hemodynamics variables were recorded in the supine position (SP1), 2 h after PP, and 1 h after re-supine (SP2). Lung morphology was classified as focal and non-focal patterns using computed tomography. Twelve of the included patients were classified to the focal group and 12 to the non-focal group. PaO /FiO improved after PP in all patients (161 [137, 227] mmHg vs. 236 [202, 275] mmHg, p