The use of cuffed tracheal tubes in children younger than 8 yr of age has recently increased, although cuff hyperinflation may cause tracheal mucosal damage. In this study, we sought to measure the cuff pressure (P(cuff)) after initial free air inflation (iP(cuff)) and to follow its evolution throughout the duration of 50% nitrous oxide (N(2)O) anesthesia. One-hundred-seventy-four children, aged 0 to 9 yr, fulfilling the following criteria, were studied: 1). weight of 3-35 kg; 2). ASA physical status I or II; 3). elective surgery; 4). anesthesia with tracheal intubation using a cuffed tube and lasting at least 45 min; and 5). gas mixture containing 50% N(2)O. Free air inflation results in variable iP(cuff), with hyperinflation in 39% of cases. Numerous gas removals were required to maintain P(cuff) less than 25 cm H(2)O in 85% of the patients. The number of deflations decreased with the duration of mechanical ventilation and was small after 105 min. No difference was observed among the different cuffed tube sizes. We conclude that iP(cuff) is unpredictable after free air inflation and that numerous gas removals are required to maintain P(cuff) less than 25 cm H(2)O during N(2)O anesthesia in children.
Implications: Free inflation of the tracheal tube cuff, controlled only by the palpation of the pilot balloon, is not reliable and results in extremely variable (and sometimes very high) initial cuff pressures in children. In addition, nitrous oxide anesthesia may result in cuff hyperinflation requiring numerous gas removals.