The changes of endotracheal tube cuff pressure by the position changes from supine to prone and the flexion and extension of head / 대한마취과학회지

BACKGROUND: The proper cuff pressure is important to prevent complications related to the endotracheal tube (ETT). We evaluated the change in ETT cuff pressure by changing the position from supine to prone without head movement. METHODS: Fifty-five patients were enrolled and scheduled for lumbar spine surgery. Neutral angle, which was the angle on the mandibular angle between the neck midline and mandibular inferior border, was measured. The initial neutral pressure of the ETT cuff was measured, and the cuff pressure was subsequently adjusted to 26 cmH2O. Flexed or extended angles and cuff pressure were measured in both supine and prone positions, when the patient's head was flexed or extended. Initial neutral pressure in prone was compared with adjusted neutral pressure (26 cmH2O) in supine. Flexed and extended pressure were compared with adjusted neutral pressure in supine or prone, respectively. RESULTS: There were no differences between supine and prone position for neutral, flexed, and extended angles. The initial neutral pressure increased after changing position from supine to prone (26.0 vs. 31.5 +/- 5.9 cmH2O, P < 0.001). Flexed and extended pressure in supine were increased to 38.7 +/- 6.7 (P < 0.001) and 26.7 +/- 4.7 cmH2O (not statistically significant) than the adjusted neutral pressure. Flexed and extended pressure in prone were increased to 40.5 +/- 8.8 (P < 0.001) and 29.9 +/- 8.7 cmH2O (P = 0.002) than the adjusted neutral pressure. CONCLUSIONS: The position change from supine to prone without head movement can cause a change in ETT cuff pressure.

Head and Neck Positional Change Causes the Alteration in Endotracheal Cuff Pressure / 대한마취과학회지

BACKGROUND: Endotracheal tube movement due to changes in the position of the head and neck can affect the intracuff pressure and volume. The alteration in the endotracheal cuff pressure after positional changes of the head and neck were examined and compared to that in the neutral position. METHODS: 20 adult male patients undergoing orotracheal intubation for endoscopic sinus surgery under general anesthesia were studied. A reinforced tube (internal diameter 8.0 mm) was used for endotracheal intubation. If the initial intracuff pressure exceeded 22 mmHg, it was set to the adjusted intracuff pressure, defined as an intracuff pressure ranging from 15 to 20 mmHg. After recording the adjusted intracuff pressure in the neutral position, repeated measurements after positional changes to 45 degrees flexed, 45 degrees extended and fully rotated positions of the head and neck were taken. The sealing intracuff pressure and volume required for the elimination of audible air-leaks were re-measured in the neutral position, and the changes in the sealing pressure after positional changes of the head and neck were then repeatedly measured. Lastly, the genuine sealing pressure and volume were measured in the flexed, extended and rotated positions. RESULTS: The adjusted intracuff and sealing pressures were higher in the flexed, extended and rotated positions than in the neutral position (P<0.01). The genuine sealing pressure in flexion and rotation were lower than that in the neutral position (P<0.05). The genuine sealing volumes were smaller in the other positions than in the neutral position (P<0.01). CONCLUSIONS: It is recommended to make genuine sealing pressure of intracuff pressure under direct pressure monitoring after positional changes of the head and neck.