Labetalol attenuates the negative effects of deliberate hypotension induced by isoflurane.
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 less than 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 less than 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 less than 0.01) and increased to 1.28 +/- 0.17 ml.min-1 after anaesthesia (P less than 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 m2 body surface area (CCreat) in Group I were 78 +/- 14 ml.min-1, and in Group II 78 +/- 11 ml.min-1 before hypotension. During hypotension, CCreat were lower in Group I (8 +/- 1 ml.min-1) than in Group II (33 +/- 8 ml.min-1) (P less than 0.01). After anaesthesia, there was no difference in CCreat between the groups (Group I: 110 +/- 17 ml.min-1 and Group II: 120 +/- 17 ml.min-1).(ABSTRACT TRUNCATED AT 250 WORDS)
Toivonen
J
J
Department of Anaesthesia, South Saimaa Central Hospital, Lappeenranta, Finland.
Virtanen
H
H
Kaukinen
S
S
D000328:Adult; D000762:Anesthesia Recovery Period; D000768:Anesthesia, General; D001786:Blood Glucose / Q000032:analysis; D001794:Blood Pressure / Q000187:drug effects; D002245:Carbon Dioxide / Q000097:blood; D003243:Consciousness / Q000187:drug effects; D004562:Electrocardiography / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006488:Hemostasis, Surgical; D006801:Humans; D007023:Hypotension, Controlled; D007530:Isoflurane / Q000008:administration & dosage / Q000494:pharmacology*; D007741:Labetalol / Q000008:administration & dosage / Q000494:pharmacology*; D007773:Lactates / Q000097:blood; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D013997:Time Factors; D014554:Urination / Q000187:drug effects
D001786:Blood Glucose; D007773:Lactates; D002245:Carbon Dioxide; D007530:Isoflurane; D007741:Labetalol; D010100:Oxygen