Overpressure isoflurane at caesarean section: a study of arterial isoflurane concentrations.
In this study we have measured arterial concentrations of isoflurane obtained during Caesarean section in two groups of patients. Patients in group 1 received 1% isoflurane throughout operation, whilst those in group 2 received 2% isoflurane for the first 5 min, 1.5% for the next 5 min and 0.8% thereafter. We found that arterial isoflurane concentrations were significantly greater in group 2 than in group 1 (ANOVA, P < 0.05). Isoflurane concentrations greater than 30 micrograms ml-1 were achieved rapidly in most patients in both groups, but there was a large scatter of results. The isoflurane concentration at which awareness or recall may occur is not known, but an "overpressure" technique as described for patients in group 2 may result in fewer patients being at risk of awareness.
McCrirrick
A
A
Sir Humphry Davy Department of Anaesthesia, Bristol Royal Infirmary.
Evans
G H
GH
Thomas
T A
TA
D000293:Adolescent; D000328:Adult; D000768:Anesthesia, General; D000773:Anesthesia, Obstetrical; D001364:Awareness; D002585:Cesarean Section; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D007530:Isoflurane / Q000008:administration & dosage / Q000097:blood*; D011247:Pregnancy; D011434:Proprioception / Q000187:drug effects; D012018:Reflex / Q000187:drug effects; D013997:Time Factors
D007530:Isoflurane