A COMPARISON OF SEVOFLURANE WITH HALOTHANE, ENFLURANE, AND ISOFLURANEON BRONCHOCONSTRICTION CAUSED BY HISTAMINE

This study was conducted to assess the effect of sevoflurane on lung r esistance and compliance, and its responsiveness to histamine. We stud ied eight dogs to compare the effect of sevoflurane, isoflurane, enflu rane, and halothane on bronchoconstriction caused by histamine. Baseli ne values of pulmonary resistance (R(L)) and dynamic pulmonary complia nce (C-dyn) were measured prior to administration of histamine. Histam ine 12, 4, and 8 mu g.kg(-1) were administered iv, and the values of R (L) and Cd, at the time of peak effect were recorded Under 1 or 2 MAC anaesthesia, sevoflurane as well as the other three anaesthetics had n o bronchoactive effects. The four anaesthetics, including sevoflurane, demonstrated inhibitory effect on increases in R(L) and decreases in C-dyn caused by histamine. At 1 MAC anaesthesia, % changes in R(L) cau sed by 2, 4, or 8 mu g. kg(-1) of histamine were 38 +/- 11, 85 +/- 21, or 132 +/- 24% (mean +/- SE) for halothane, and 65 +/- 11, 132 +/- 15 , or 172 +/- 19% for sevoflurane, respectively Sevoflurane was less ef ective than halothane in preventing increases in R(L). In preventing d ecreases in C-dyn sevoflurane was less effective than halothane only a t 8 mu g.kg(-1) of histamine under 1 and 2 MAC anaesthesia. There was no difference in attenuating effect on changes in R(L) and C-dyn betwe en sevoflurane and isoflurane or enflurane. We concluded that sevoflur ane was less potent than halothane in attenuating changes in R(L) and C-dyn in response to iv histamine.