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KEY POINTS
Prone positioning, when started early in the management of severe acute respiratory distress syndrome (ARDS), is an effective modality to improve oxygenation and survival and warrants widespread adoption.
Prone position ventilation (PPV) is readily implemented, including in under-resourced care environments, without specialized equipment and with a moderate amount of team-based expertise and experience, including the care of patients with COVID-19-related ARDS.
PPV reduces ventilator-induced lung injury by reducing the strain associated with both volutrauma and atelectrauma. The observed improvement in survival appears to be mechanistically dissociated from other salutary effects, including reducing intrapulmonary shunting and improved oxygenation.
PPV is safe and broadly effective when initiated for the management of ARDS in patients with a P/F ratio <150 as a result of medical and surgical causes of disease. Morbidly obese and pregnant patients appear to derive similar if not greater degrees of improvement.
Major complications are infrequent even when PPV is continued in an uninterrupted fashion for several days and include skin breakdown on the ventral body surface, facial, conjunctival, and upper airway edema at rates higher than ARDS patients managed in the supine position. Very rarely, brachial plexus injuries, other mononeuritides, and retinal ischemia with blindness may occur.
Patient-directed self-proning appears to be beneficial for improving oxygenation in nonintubated patients with hypoxemic respiratory failure but the impact on progression to need for intubation and mechanical ventilation and associated mortality is unknown.
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Prone position ventilation (PPV) while frequently deployed as rescue therapy for patients with severe and often intractable severe acute hypoxemic respiratory failure (AHRF) from acute respiratory distress syndrome (ARDS) is, fundamentally a lung recruitment strategy to optimize lung protective mechanical ventilation and to mitigate effects of cyclic volutrauma on the injured lung. Indeed, the attributable survival benefits of PPV appear to accrue in large part independent of the effects on enhancing oxygenation. Rather, the evidence points to the primary mechanism of PPV to alleviate regional overdistention and cyclic volutrauma, including biotrauma, and thus reducing the potential for the injured ARDS lung to become an engine of systemic inflammation and injury, leading to MODS and death.
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PPV has been applied in the care of critically ill patients with ARDS for more than 40 years;1 however, adoption has remained infrequent even at large referral centers despite the aggregation of a compelling preclinical and clinical evidence base, including the publication of the landmark Prone Positioning in Severe Acute Respiratory Distress Syndrome (PROSEVA) trial in 2013, demonstrating improved ARDS survival.2 In subsequent point prevalence studies, PPV was still only used in ∼15% of patients with severe ARDS3,4 and on average for just 18 hours each day.
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PPV has been extensively prescribed in the care of critically ill mechanically ventilated patients with ARDS from COVID-19 infections. Indeed, the COVID-19 pandemic has been highly impactful in accelerating the adoption of PPV for patients with AHRF ...