Cuff Volume of Laryngeal Mask Airway ProSealTM in Korean Adults / 대한마취과학회지

BACKGROUND: The purpose of this study was to determine the cuff volume of the laryngeal mask airway ProSeal(TM)(PLMA (TM)) in Korean adults, which was measured at an intracuff pressure of 60 cmH2O. METHODS: A size 3 PLMATM was used for females (n = 57) and a size 4 PLMATM for males (n = 45). Anesthesia was induced with thiopental and rocuronium and maintained with sevoflurane, nitrous oxide and oxygen. After 5 minutes of conventional mask ventilation, the PLMATM was inserted using an the index finger in one motion. Increments of air up to a final intracuff pressure of 60 cmH2O were introduced and the patency of the airway was confirmed. Following successful placement during ventilation, the intracuff pressure was maintained at 60 cmH2O during anesthesia. The volume of air required to inflate the cuff to this pressure was measured, first after successful insertion of the mask (CV ins), and then 10 minutes before the end of anesthesia (CV end). Each patient was asked whether they had a sore throat, just before leaving the postanesthesia care unit (PACU) and again 24h after surgery. Data is presented as means standard error of mean (SEM). Statistical analysis was performed by bivariate correlation analysis, and by the paired t-test. Significance was accepted when P < 0.05. RESULTS: CV ins was 15-26 ml (22.8+/-0.3 ml)(female), 23-45 ml (33.6+/-0.6 ml)(male) and CV end was 17-27 ml (23.2+/-0.3 ml)(female), 22 45 ml (33.8+/-0.7 ml)(male). There were no significant correlation between BMI (body mass index), thyromental distance, sternomental distance and cuff volume (CV ins). In males, there was no significant difference between CV ins and CV end, but, in females, there was a significant difference between CV ins and CV end (CV ins < CV end)(P < 0.05). Incidences of postoperative sore throat just before leaving the PACU were 22.8% in females, 15.6% in males, and 24 hrs after surgery, these were 7% in females, 4.4% in males. CONCLUSIONS: We conclude that CV ins in both male and female was widely variable and that there is no correlation between anatomical variation and inflated cuff volume. Moreover, we could not prevent postopertative sore throat by changing cuff volume at an intracuff pressure of 60 cmH2O. Especially in Korean females, the cuff volume required to inflate the cuff to 60 cmH2O increased with anesthesia.

The Effect of Laryngeal Mask Airway ProSeal(TM) Cuff Inflation Prior to Insertion by the Inexperienced on the Success Rate of Inserting the PLMA(TM) and on Postoperative Sore Throat / 대한마취과학회지

Backgroud: The purpose of this study was to assess the effect of inflating a laryngeal mask airway ProSeal(TM) (PLMA(TM)) cuff, prior to insertion, on the degree of difficulty of inserting a PLMA(TM) by the inexperienced, and the incidence of postoperative sore throat. METHODS: Before induction, we measured the thyromental and sternomental distance. PLMA(TM) insertions were conducted by those with experience of less than 15 previous insertions. One hundred and five consecutive patients undergoing general anesthesia were randomized into 3 groups: In group 1, the PLMA(TM) was inserted with the cuff fully deflated, in group 2, the cuff was partially inflated (i.e., filled with half the recommended air), in group 3, the cuff was fully inflated. Successful insertion was judged primarily by the clinical function of the airway. The number of insertion attempts to achieve a satisfactory airway were recorded. Each patient was asked whether he had a sore throat, dysphonia, or dysphagia just before leaving the postanesthesia care unit (PACU) and again 24 hr after surgery. RESULTS: The number of insertion attempts required to achieve a satisfactory airway and the failure rate of insertion were not significantly different in the 3 groups. However, the 3 groups were significantly different in terms of the incidence of postoperative sore throat in the PACU. This was highest in group 3 (P<0.05). The incidences of other variables of laryngopharygeal morbidity in the PACU and 24 hrs after surgery were not significantly different in the 3 groups. CONCLUSIONS: Inflation of the cuff prior to insertion did not affect the success rate of inserting a PLMA(TM) by the inexperienced, and PLMA(TM) insertion after partial inflation was associated with higher incidence of postoperative sore throat in the PACU. Thus, in general anesthesia, it is desirable that the inexperienced insert the PLMA(TM) with the cuff fully deflated.