Prone positioning improves oxygenation in spontaneously breathing nonintubated patients with hypoxemic acute respiratory failure: a retrospective study

Purpose: Prone positioning (PP) improves oxygenation and outcome of patients with acute respiratory distress syndrome undergoing invasive ventilation. We evaluated feasibility and efficacy of PP in awake, non-intubated, spontaneously breathing patients with hypoxemic acute respiratory failure (ARF). Material and Methods: We retrospectively studied non-intubated subjects with hypoxemic ARF treated with PP from January 2009 to December 2014. Data were extracted from medical records. Arterial blood gas analyses, respiratory rate, and hemodynamics were retrieved 1 to 2 hours before pronation (step PRE), during PP (step PRONE), and 6 to 8 hours after resupination (step POST). Results: Fifteen non-intubated ARF patients underwent 43 PP procedures. Nine subjects were immunocompromised. Twelve subjects were discharged from hospital, while 3 died. Only 2 maneuvers were interrupted, owing to patient intolerance. No complications were documented. PP did not alter respiratory rate or hemodynamics. In the subset of procedures during which the same positive end expiratory pressure and Fio2 were utilized throughout the pronation cycle (n = 18), PP improved oxygenation (Pao2/Fio2 124 ± 50 mmHg, 187 ± 72 mmHg, and 140 ± 61 mmHg, during PRE, PRONE, and POST steps, respectively, P < .001), while pH and Paco2 were unchanged. Conclusions: PP was feasible and improved oxygenation in non-intubated, spontaneously breathing patients with ARF.