Residual volume in the cuff of the endotracheal tube when the pilot balloon is torn off instead of deflated using a syringe.

BACKGROUND: In recent years, there has been a shift in airway management with the use of cuffed endotracheal tubes (ETT) in pediatric patients. While the use of a syringe to deflate the cuff is generally recommended, anecdotal observations suggest that some healthcare practitioners tear off the pilot balloon from ETT to deflate the cuff. This study was conducted to estimate the residual volume in the cuff when the pilot balloon is torn off for deflation.

METHOD: The in vitro study was conducted in three phases. In phases 1 and 2, various sized cuffed ETTs (3.0, 4.0, and 5.0 mm) were inflated to achieve an intracuff pressure of 20-30 cmH2O in open atmosphere (phase 1) or inside a tube to simulate external pressure from the tracheal wall (phase 2). The pilot balloons were ripped off and the residual volume in the cuff was measured. The process was repeated using 10 ETTs of each of the 3 sizes. In phase 3, the same process was repeated using ten, size 7.0 cuffed ETTs inflated in an intubating mannequin.

RESULTS: In phase 1, the percentage of the remaining residual volume was 60.7, 72.8, and 69.5% in 3.0, 4.0, and 5.0 mm ETTs respectively. Although the percentage of residual volume in phases 2 and 3 was less than phase 1, the residual volume in phases 2 and 3 still averaged approximately 60-70% of the volume required for cuff inflation. In one case, the pilot balloon tube was completely occluded and the residual volume in the cuff could not be expelled even with external pressure.

CONCLUSION: Since significant percentage of the volume remained in the cuff after tearing off the pilot balloon tube with one being completely occluded, we would not recommend this method for cuff deflation.