Can Lower Alveolar Concentration Reduce the Adverse Effects of Sevoflurane Anesthesia?

Bae, Hong Beom; Jeong, Seong Wook; Jeong, Chang Young

Abstract

BACKGROUND
The bispectral index, a parameter of electroencephalography (EEG) and a tool for the measurement of sedative state has been used in general anesthesia and for the assessment of sedative degree in intensive care units. The adverse effects of inhalation agents are various although hepatic toxicity, renal toxicity, postoperative nausea, and vomiting have been reported. This study was designed to evaluate the adverse effect of inhalation agents.
METHODS
Forty-four adult patients scheduled for thyroidectomy under general anesthesia were randomly assigned to one group with a BIS below 40 (BIS40 group, n = 23) or to a group with a BIS from 50 to 60 (BIS60 group, n = 21). Hgb, WBC count, PLT count, renal function, and liver function were measured pre-and post-operatively (after 24 hrs). The degree of postoperative nausea and vomiting were estimated using the Rhodes Index of Nausea, Vomiting and Retching (RINVR) in postoperative 6 hrs, 12 hrs and 24 hrs.
RESULTS
The amount of fentanyl used during the operation were greates in the BIS60 group than in the BIS40 group for adequate analgesia, and the preoperative and postoperative values of Hgb, WBC count, PLT count, AST, ALT, ALP, s-BUN, and s-creatine were not significantly different between the BIS40 and BIS60 groups. 6 hrs, 12 hrs and 24 hrs post-operatively no differences were observed between groups by RINVR in terms of nausea and vomiting.
CONCLUSIONS
The adverse effect of an inhalation agent appears not to be related to its concentration when sevoflurane with BIS monitoring are used to reduced the amount of agent inhaled.