The laryngeal mask in infants and children: what is the cuff pressure?

Unintended hyperinflation of the cuff of a laryngeal mask airway (LMA) has been associated with increased airway morbidity and postoperative pain. While the manufacturers recommend a cuff pressure of less than 60 cmH(2)O, in usual clinical practice, there is no method used to determine intracuff pressure of an LMA. The purpose of this prospective quality assurance study is to evaluate the incidence of LMA hyperinflation and excessive intracuff pressure in a busy tertiary care pediatric hospital.

There was no change dictated in clinical practice for these patients. Per our usual practice, the LMA was removed from the package and inserted with the cuff partially inflated. The cuff was further inflated as needed to ensure a seal during positive pressure ventilation to a peak inflating pressure of 20-25 cmH(2)O. During the first 30 min of the case, the pressure in the cuff of the LMA was measured using a hand held manometer. Additional data collected included the patient's demographic data (age, weight, and gender), the size of the ETT, and whether nitrous oxide was in use.

Of the 200 subjects in the current study, 106 had an LMA cuff pressure ≥ 60 cmH(2)O (53%). Patients who were greater than 8 years of age had significantly higher average cuff pressures and significantly more LMAs with an intracuff pressure ≥ 60 cmH(2)O when compared to patients younger than 4 years of age and patients 4-8 years of age. Similarly, larger LMAs were found to have significantly higher intracuff pressures.

Using current clinical practice to inflate the cuff of the LMA, a significant percentage of pediatric patients have an intracuff pressure greater than the generally recommended upper limit of 60 cmH(2)O. Risk factors identified in our study included age of the patient and the size of the LMA.