Behavior of Endotracheal Tube Cuff Pressure During a Routine Control Maneuver With Different Manometers

Background: The main functions of the endotracheal tube (ETT) cuff are to prevent aspiration and to allow pressurization of the respiratory system. For this purpose, it is essential to maintain adequate pressure inside the cuff, thus reducing the risks for the patient. It is regularly checked using a manometer and is considered the best alternative. The objective of this study was to evaluate the cuff pressure behavior of different ETTs during the simulation of an inflation maneuver using different manometers.

Methods: A bench study was performed. Four brands of 8-mm internal diameter single lumen with a Murphy eye ETT with cuff and 3 different brands of manometers were used. In addition, a pulmonary mechanics monitor was connected to the inside of the cuff through the body of the distal end of the ETT.

Results: A total of 528 measurements were made on the 4 ETTs. During the complete procedure (connection and disconnection), there was a significant pressure drop of 7 ± 1.4 cm H₂O from the initial pressure (P_initial) (P < .001), of which 6 ± 1.4 cm H₂O was lost during connection (difference between P_initial and P_connection). The P_reconnection value was 19.1 ± 1.6 cm H₂O, showing a significant total pressure drop of 11 ± 1.6 cm H₂O (difference between P_initial and P_reconnection) (P < .001). The P_final mean was 29.6 ± 1.3 cm H₂O. Significant differences were found between manometers according to the time of measurement. A similar phenomenon was evidenced when analyzing different ETTs.

Conclusions: Significant pressure changes occur secondary to ETT cuff measurement, which has important implications for patient safety.