Continuous Negative Abdominal Pressure Reduces Ventilator-induced Lung Injury in a Porcine Model.

<zdoi;10.1097/ALN.0000000000002236> Anesthesiology, V 129 • No 1 163 July 2018 T HE lungs of patients with adult respiratory distress syndrome are often compartmentalized into two regions, aerated versus atelectatic.1 In the supine position, the aerated region is usually in nondependent lung and receives most of the tidal volume(VT). The weight of the edematous lung and an increased pleural pressure gradient explain the propensity for atelectasis to develop in dependent regions2–4; this is accentuated by sedation and neuromuscular blockade, lowering diaphragm tone and permitting the abdominal contents to shift the diaphragm cephalad.5,6 The conventional approaches to recruitment of atelectasis are prone positioning and increasing airway pressure. Prone positioning in adult respiratory distress syndrome can successfully recruit dependent atelectasis and improve survival, but recent comprehensive data (459 intensive care units, 50 countries) make it clear that clinicians seldom use this (used in less than 20% of cases).7 Elevated airway pressure (e.g., positive end-expiratory pressure [PEEP] or high frequency oscillatory ventilation] are commonly used to recruit atelectasis but have failed to improve outcome in clinical trials.8–11 One reason may be that increased airway pressure tends to recruit atelectasis only after overinflating (and potentially injuring) already aerated lung.12 What We Already Know about This Topic