Assessment Of Positive End-expiratory Pressure Induced Lung Volume Change By Ultrasound In Mechanically Ventilated Patient

ObjectiveOur goal was to compare pressure-volume (P-V) curve method with Lung ultrasound for assessing positive end-expiratory pressure (PEEP)-induced lung volume change in mechanically ventilated patients with Acute Lung Injury(ALI) or acute respiratory distress syndrome (ARDS).Methods:18patients with ALI or ARDS were prospectively studied. P-V curves and lung ultrasound were performed in PEEP12,8,4and0cmH2O. PEEP-induced lung volume change was measured using the P-V curve method.Measurements and main results:Four lung ultrasound entities were defined:Consolidation,multiple irregularly spaced B lines, multiple abutting B lines and normal aeration.For each of the12lung regions examined, PEEP-induced ultrasound changes were measured and an lung ultrasound score(LUS)was calculated. A highly significant correlation was found between PEEP-induced lung volume change measured by P-V curves and LUS change (rho=0.82,p<0.01). A statistically significant correlation was found between LUS change and PEEP-induced increase in PaO2(rho=0.66, p<0.01).Conclusion:PEEP-induced lung volume change can be adequately estimated with bedside lung ultrasound. Since lung ultrasound cannot assess PEEP-induced lung hyperinflation, it should not be the sole method for PEEP titration.