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Labetalol attenuates the negative effects of deliberate hypotension induced by isoflurane
Author(s) -
Toivonen J.,
Virtanen H.,
Kaukinen S.
Publication year - 1992
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/j.1399-6576.1992.tb03428.x
Subject(s) - isoflurane , labetalol , medicine , anesthesia , blood pressure
The effect of labetalol on deliberate hypotension was studied in 24 adult patients undergoing middle‐ear surgery. Hypotension was induced in Group I (12 patients) with isoflurane 3.0 vol% in inspiratory gas, and in Group II (12 patients) with labetalol 0.5 mg±kg ‐1 i.v., in addition to isoflurane. The induction time of hypotension was 4.9±1.0 (s.e. mean) min in Group I, and 1.8±0.2 min in Group II ( P <0.01). The mean isoflurane concentration in inspiratory gas for the maintenance of hypotension was 1.4±0.2 vol% in Group I, and 0.7±0.1 vol% in Group II ( P <0.01). There were no differences in urine flow rates (UF) between the groups during any phase, though UF decreased in Group I from the prehypotensive value 0.58±0.12 ml±min ‐1 to 0.07±0.02 ml±min ‐1 during hypotension ( P <0.01) and increased to 1.28±0.17 ml±min ‐1 after anaesthesia ( P <0.05). UF in Group II were 0.56±0.17, 0.25±0.10 and 0.56±0.06 ml±min ‐1 , respectively. Creatinine clearances per 1.73 m 2 body surface area (C Creat ) in Group I were 78±14 ml±min ‐1 , and in Group II 78±11 ml±min ‐1 before hypotension. During hypotension, C Creat were lower in Group I (8±1 ml±min ‐1 ) than in Group II (33±8 ml±min ‐1 ) ( P <0.01). After anaesthesia, there was no difference in C Creat between the groups (Group I: 110±17 ml±min ‐1 and Group II: 120±17 ml±min ‐1 ). The results indicate that labetalol has a favourable effect on deliberate hypotension induced by isoflurane.