A randomized, crossover comparison of various ventilation devices in a swine pneumothorax model

Bag-valve-mask devices (BVMs), manually triggered ventilators (MTVs), and automatic transport ventilators (ATVs) are three available options for out-of-hospital artificial ventilation. Use of the MTV and the ATVs has been limited by concern for causing or worsening a pneumothorax (PTX). The purpose of this study was to compare the effects of ventilation with a BVM, ATV, and MTV in a swine PTX model.

This was a randomized, crossover study. Six fasted swine (21.2-24.5 kg, mean = 23.5 kg) were sedated and paralyzed. The swine were intubated with a cuffed endotracheal tube. A lung injury was created with a hemostat under direct visualization after the pleural cavity was entered by sharp dissection. A 16-Fr Foley catheter was inserted and sealed in the pleural space at the injury site. Prior to each trial, a PTX was created by instilling 300 mL of air through the Foley catheter. Each swine underwent 10-minute ventilation trials, at a rate of 12-14 breaths/min, with BVM, MTV, and ATV by the same investigator following each trial; PTX size was determined by withdrawing air through the Foley catheter. Analysis of variance for repeated measures (alpha = 0.05) was used for statistical analysis.

There was no difference in the extent of PTX expansion produced by ventilation with BVM (339.8 +/- 35.9 mL), MTV 327.8 +/- 28.9 mL), or ATV (321.8 +/- 22.2 ml).

BVMs, MTVs, and ATVs do not differ in their effects on PTX volumes. Concern for excessive expansion of PTX by MTVs and ATVs is not supported. Prospective evaluation is warranted to determine the efficacy of these ventilation techniques.