Comparison of delivered volumes and airway pressures when ventilating through an endotracheal tube with bag-valve versus demand-valve.

INTRODUCTION

Use of an oxygen-powered demand-valve to ventilate through an endotracheal tube is considered inappropriate due to concern regarding excessive airway pressures.

HYPOTHESIS

It was hypothesized that ventilation through an endotracheal tube using bag-valve (BV) device and the recently modified demand-valve (DV) would produce similar tidal volumes (Vt), minute ventilation (MV), and peak airway pressures (PAP).

METHODS

This is a prospective, randomized in vitro experimental model. Subjects were blinded to volume and pressure gauges. Thirty-nine EMTs (mean age 27 years with mean experience five years) volunteered to ventilate a mechanical test lung through an endotracheal tube for 10 minutes. Each subject was randomized to BV or DV and to either normal (0.1 L/cm H 2O) or poor (0.04 L/cm H 2O) lung compliance. This DV delivers set flow of 40 L/min at maximum 50+/-5 cm H 2O. Subjects were instructed to use their "usual" technique for an average size adult in respiratory arrest with normal heart rate and blood pressure. The Vt and PAP were recorded for each breath; the MV and maximum PAP (PAP-max) for each minute was noted. Data were analyzed using repeated measures ANOVA and Tukey multiple comparisons with alpha set at 0.05.

RESULTS

Overall average tidal volumes and minute ventilations were acceptable with both ventilatory devices at both normal and poor compliance for the first, fifth, and 10th minute of continuous ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)