The reasons for the excessive intracuff pressure requirements were not clear.
Recently we had occasion to review two cases in which patients with ARDS sustained ischemic tracheal complications following a prolonged period of mechanical ventilation with high PIP above 50 cm H20. One of these patients developed a tracheoesophageal fistula requiring tracheal reconstruction and prolonged hospitalization. The other patient suffered massive tracheal dilation before succumbing to multiple organ failure. In both cases, ETTs with high-volume, low-pressure cuffs had been continuously employed. Proper cuff inflation (minimal leak) techniques had been utilized, together with appropriate humidification, tidal volume and minute ventilation. As in the report of Stauffer et al, we were unable to explain the extensive tracheal damage associated with the use of high-volume, low-pressure ETT cuffs and created a laboratory model to examine intracuff pressure and volume characteristics.
We studied the effects of airway pressure on the performance of current ETT cuff designs by using a laboratory model to simulate the extremes of clinically employed positive pressure mechanical ventilation, iey under conditions of high Cl with low PIP vs markedly reduced Cl with high PIP. Three ETT cuff designs, LO, MED and HI were evaluated using 7.0- and 8.0-mm ID ETTs (Fig 1).
Figure 1. Tbp, Schematic of testing apparatus and picture of the three endotracheal tube cuff designs studied: Bottom left, LO; bottom center, MED; and bottom right, HI.