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Cerebral arteriovenous difference of oxygen during gradual and sudden increase of the concentration of isoflurane for induction of deliberate hypotension
Author(s) -
Haraldsted V. Y.,
Asmussen J.,
Herlevsen P.,
Cold G. E.
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.tb03441.x
Subject(s) - isoflurane , medicine , anesthesia , blood pressure , cerebral blood flow , oxygen , chemistry , organic chemistry
In 20 patients undergoing surgery for cerebral aneurysms, hypotension was induced with either gradual (over 5 min) or sudden increase of inspiratory concentration of isoflurane from 0.5% to 3%. Both modes elicited the same speed of induction of deliberate hypotension and similar decreases of cerebral arteriovenous difference of oxygen (AVDo 2 ). The overall median values of mean arterial blood pressure decreased from 75.5 (range 64–90) mmHg (10 (8.5–12.0) kPa) to 55 (40–66) mmHg (7.3 (5.3–8.8) kPa) and the overall AVDo 2 decreased from 6.75 ml/100 ml (3.8–9.4 ml/100 ml) to 5.85 ml/100 ml (2.6–8.1 ml/100 ml) within 10 min. It is concluded that irrespective of gradual or sudden increase of isoflurane concentration, cerebral blood flow is in surplus of metabolism and a favourable oxygen demand/supply ratio is maintained during induction of deliberate hypotension by isoflurane below 2.5 MAC.