1629 LOWEST VENTILATOR FLOW RATE DECREASES BAROTRAUMA

Abstract

Barotrauma from artificial ventilation may be one of the causes of bronchopulmonary dysplasia (BPD). We measured non-elastic work of ventilation (NEWV) as an index of barotrauma. Four infants on time-cycled pressure limited ventilators were studied after insertion of a pneumotach and esophageal balloon. We varied flow rate and adjusted peak airway pressure to keep tidal volume (VT) constant. Rate, inspiratory time and PEEP were maintained at prestudy values. NEWV was determined for each flow rate from the area of the hysteresis loop of the pressure-volume curve. NEWV and mean airway pressure (MAP) were both lowest at the minimum flow rate (MFR) required to maintain VT. The linear regression of NEWV or MAP with flow rate was highly significant (p ≤ .005). There were no significant changes in PO2 or PCO2. Since the use of the lowest flow rate to deliver a given tidal volume at a given rate causes the lowest NEWV and the lowest MAP, the use of a minimum flow rate setting may decrease barotrauma and the incidence of BPD in ventilated newborns.