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Cerebral blood flow, cerebral metabolic rate of oxygen and relative CO 2 ‐reactivity during craniotomy for supratentorial cerebral tumours in halothane anaesthesia. A dose‐response study
Author(s) -
Madsen J. B.,
Cold G. E.,
Hansen E. S.,
Bardrum B.
Publication year - 1987
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.1399-6576.1987.tb02602.x
Subject(s) - halothane , medicine , cerebral blood flow , anesthesia , craniotomy , nitrous oxide , fentanyl , oxygen , oxygen metabolism , ventilation (architecture) , chemistry , mechanical engineering , organic chemistry , engineering
Fourteen patients were studied during craniotomy for small supratentorial cerebral tumours. Cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRo 2 ) were measured twice by a modification of the Kety‐Schmidt technique using 133 Xe intravenously. Anaesthesia was induced with thiopental 4–6 mg kg ‐1 , fentanyl and pancuronium, and maintained with an inspiratory halothane concentration of 0.45% in nitrous oxide 67% at a moderate hypocapnic level. In one group of patients (n = 7) the inspiratory halothane concentration was maintained at 0.45% throughout anaesthesia. About 1 h after induction of anaesthesia CBF and CMRo 2 averaged 35 ± 2 ml 100 g ‐1 min ‐1 and 2.7 ± 0.3 ml O 2 100 g ‐1 min ‐1 (mean ± s.e mean), respectively. During repeat studies 1 h later CBF and CMRo 2 did not change. In another group of patients (n = 7) an increase in halothane concentration from 0.45% to 0.90% was associated with a significant decrease in CMRo 2 from 2.3 ± 0.1 to 2.0 ± 0.1 ml o 2 100 g ‐1 min ‐1 . The CO 2 reactivity measured after the second flow measurement was preserved. It is concluded that halothane in this study induces a dose‐dependent decrease in cerebral metabolism, an increase in CO 2 while CO 2 ‐reactivity is maintained.