Impact of Chest Wall Modifications and Lung Injury on the Correspondence Between Airway and Transpulmonary Driving Pressures.

Abstract Recent interest has arisen in airway driving pressure (DP(AW)), the quotient of tidal volume (V(T)), and respiratory system compliance (C(RS)), which could serve as a direct and easily measured marker for ventilator-induced lung injury risk. We aimed to test the correspondence between DP(AW) and transpulmonary driving pressure (DP(TP))-the quotient of V(T) and lung compliance (C(L)), in response to intra-abdominal hypertension and changes in positive end-expiratory pressure during different models of lung pathology. Well-controlled experimental setting that allowed reversible modification of chest wall compliance (C(CW)) in a variety of models of lung pathology. Large animal laboratory of a university-affiliated hospital. Ten deeply anesthetized swine. Application of intra-abdominal pressures of 0 and 20 cm H2O at positive end-expiratory pressure of 1 and 10 cm H2O, under volume-controlled mechanical ventilation in the settings of normal lungs (baseline), unilateral whole-lung atelectasis, and unilateral and bilateral lung injuries caused by saline lavage. Pulmonary mechanics including esophageal pressure and calculations of DP(AW), DP(TP), C(RS), C(L), and C(CW). When compared with normal intra-abdominal pressures, intra-abdominal hypertension increased DP(AW), during both "normal lung conditions" (p