Changes in the cuff pressure in neonates in the absence of nitrous oxide

Background
Changes in the pressure of cuffed neonatal size tracheal tubes (TT) during anaesthesia without nitrous oxide are not well described. We determined whether the cuff pressure changes over time in neonates under general anaesthesia without nitrous oxide.

Methods
The airways of thirty neonates were secured with a high volume low pressure cuffed TT for meningocele surgery. The cuff was manually inflated until there was no audible leak and maintained at 10–15 cm H2O throughout by monitoring the pressure continuously with both a manometer and a pressure transducer. At baseline, the cuff pressure was assessed in the supine and then prone positions. During surgery, if the pressure exceeded 15 cm H2O, the cuff was deflated to < 15 cm H2O and if it was < 10 cm H2O, the cuff was inflated to 10–15 cm H2O. The time interval between corrections and the number of corrections were recorded.

Results
The cuff pressures in 18 neonates (60%) required correction during surgery. The cuff pressure exceeded 15 cm H2O in nine neonates (30%) and was corrected. The cuff pressures in 13 neonates were less than 10 cm H2O and required correction. The gender, weight, height, and duration of anaesthesia did not differ significantly between neonates who required correction of the cuff pressure and those who did not. Mean cuff pressures were similar at 15, 45, and 75 minutes of anaesthesia.

Conclusions
In 60% of neonates undergoing surgery in the prone position under general anaesthesia without nitrous oxide, the cuff pressure exceeded 15 cm H2O. In such cases, cuff pressure should be monitored continuously throughout the surgery.