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Abstracts of Posters; Presented at the International Anesthesia Research Society; 73rd Clinical and Scientific Congress; Los Angeles, CA; March 12-16, 1999: Pediatric Anesthesia

*THE MINIMAL EFFECTIVE DOSE OF FENTANYL TO PREVENT EMERGENCE AGITATION FOLLOWING DESFLURANE ANESTHESIA IN CHILDREN

Cohen, I.T. MD; Hannallah, R. MD; Hummer, K. RN

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doi: 10.1097/00000539-199902001-00289
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Abstract S292

INTRODUCTION: General anesthesia with desflurane allows for rapid emergence and recovery. However, emergence agitation following unmodified desflurane anesthesia is common. [1] Success in modifying this response by the use of analgesia and/or sedatives has been reported. The purpose of this study was to determine the dose of fentanyl that would decrease the incidence of agitation without prolonging emergence and recovery in pediatric ENT patients; a population in which rapid and complete recovery, and ability to regain full control of the airway is desirable.

METHODS: With IRB approval, 32 ASA I and II patients 2-9 years old undergoing adenoidectomies were randomized to receive general anesthesia with desflurane and fentanyl. All patients had anesthesia induced with a N2 O/O2/sevoflurane gas mixture. Mivacurium 0.25 mg/kg was used to facilitate tracheal intubation. Patients also received one of the following doses of fentanyl: 1.25 mcg/kg, 1.875 mcg/kg, 2.8 mcg/kg or 4.2 mcg/kg. The dose given was determined by the classic up-down method. All patients had N2 O/O2/desflurane (4-6%) gas mixture administered for maintenance of general anesthesia. Desflurane, which was not tapered, and N2 O were discontinued simultaneously at the end of surgery. Time to first cough, grimace, eye opening, purposeful movement and extubation were recorded. An observer blinded to the anesthetic technique assessed level of agitation and pain by appropriate scales in OR and the PACU. [1,2] Time to meet discharge criteria from the PACU and the SSRU were also noted. Data from the up-down dosing were interpreted as described by Dixon and Massey. [3] Demographic data and time intervals for the major treatment groups were analyzed using Student and Mann-Whitney tests.

RESULTS: At this time 23 patients have been studied with four receiving 1.25 mcg/kg, 11 receiving 1.875 mcg/kg, 7 receiving 2.8 mcg/kg and 1 receiving 4.2 mcg/kg. The minimal effective dose of fentanyl to prevent emergence agitation was determined to be 2.56 +/- 0.58 mcg/kg with a confidence interval of 0.59. Demographic data and emergence times are reported for the two major treatment groups only: (Table 1 and Table 2)

Table 1
Table 1:
Demographic Data:
Table 2
Table 2:
Time to Achieve Recovery Characteristics (min) +/- SD

DISCUSSION: Our results indicate that an approximate dose of 2.5 mcg/kg is sufficient to prevent emergence agitation associated with desflurane anesthetics in children undergoing adenoidectomies without prolonging emergence. Comparison between the two major treatment groups showed no significant differences. When desflurane is not tapered, a minimal delay in time to extubation is seen, but is not statistically significant. PACU and SSRU stays were comparable.

Supported by a grant from Baxter Pharmaceutical Products, Inc.

REFERENCES

1. Anesthesiology 1994;80:298-302.
2. Anesthesiology 1991;75:A934,
3. Introduction to Statistical Analysis 1983;428-439.
© 1999 International Anesthesia Research Society