Changes in the Cuff Pressure in Infants in the Absence of Nitrous Oxide

Introduction:

During perioperative period some factors may change the endotracheal tube (ETT) cuff pressure. They include time (1), changes in core temperature (2), neuromuscular blockade (3), sedation (4), altitude (5), use of nitrous oxide (6,7), changes in tracheal muscle tone and respiratory system impedance (8), different body, head and neck positions (9), mechanical ventilation and transoesophageal echocardiography probe insertion (10).

Some have chosen to avoid the use of nitrous oxide (N2O) during surgery because of the theoretical risk of multiple deleterious effects on the neurologic, cardiovascular, hematologic and immune systems. In addition, N2O diffuses into all gas-filled cavities increasing their sizes and pressures including ETT cuffs (11). ETT cuff pressure increases after exposure to nitrous oxide (12).

However, the changes in the cuff pressure in the absence of nitrous oxide are less clear. Kako et al. (13) investigated the relationship between head and neck position and ETT cuff pressure in children in the absence of N2O in the supine position. In this study, 1000 intracuff readings were evaluated in 200 children based on position of the head and neck. They found that cuff pressure increased in two-thirds of the measurements 545 out of 1000 when compared with the neutral position. Most frequently change was noted with neck flexion. The mean increase in cuff pressure was 7.2±8.3 cmH2O from the neutral position (p<0.05).

In the current study, we aim to determine the changes in cuff pressure over time in infants undergoing myelomeningocele repair in prone position under general anesthesia in the absence of N2O.