Simple on-line endotracheal cuff pressure relief valve.

Ischemic injury of the tracheal mucosa in the endotracheally intubated patient is directly proportional to the tracheal tube cuff pressure. At a cuff pressure of 30 cm H2O, the tracheal mucosal blood flow becomes partially obstructed, and at a pressure of 45 cm H2O, the obstruction to the tracheal mucosal blood becomes total, leading to tracheal mucosal damage and subsequent complications. In our institute, we have developed a simple and very inexpensive method to gauge the cuff pressure. We use a regular 20-mL syringe attached in line with the connector of the endotracheal tube cuff. In this manner, we monitored the intracuff pressure in 120 patients who underwent ear or neck surgery. The syringe was connected to the tube cuff and inflated with 15 mL of air. The syringe was left constantly connected to the cuff. In addition, the cuff pressure was measured with the Mallinckrodt Hi-Lo aneroid pressure gauge at the beginning of surgery and hourly thereafter for the duration of surgery. At the same time, a check for leakage around the cuff was made by auscultation with a stethoscope above the sternal notch. Multiple comparisons between the repetitive intracuff pressure measurements revealed that there were no significant differences in the intracuff pressure values measured at the different times of surgery. These results indicate that there was an adequate venting of the excess intracuff pressure and also that there was no leakage around the cuff.