Vomiting, retching, headache and restlessness after halothane-, isoflurane- and enflurane-based anaesthesia. An analysis of pooled data following ear, nose, throat and eye surgery.
BACKGROUND
Isoflurane has exceeded halothane and enflurane in usage. A literature search, however, revealed no data comparing the effects on emesis, headache and restlessness of these three agents.


METHODS
With hospital ethics committee approval and patient consent, a prospective, randomised, double-blind study of 556 patients undergoing ENT and eye surgery was undertaken to evaluate the effects of halothane, isoflurane and enflurane on vomiting, retching, headache and restlessness until 24 h after anaesthesia. Balanced general anaesthesia was administered comprising benzodiazepine premedication, induction with thiopentone-atracurium-morphine (ENT patients) or fentanyl (eye patients), controlled ventilation and maintenance with either halothane 0.4-0.6 vol% (n = 186), isoflurane 0.6-0.8 vol% (n = 184) or enflurane 0.8-1 vol% (n = 186) in nitrous oxide 67% and oxygen.


RESULTS
The three study groups were comparable, and comprised comparable subgroups having ear, nose, throat, intraocular and non-intraocular surgery. During early recovery from anaesthesia, the respective requirements for halothane, isoflurane and enflurane for analgesia (7%, 9% and 10%), frequency of emesis (6%, 8% and 8%), antiemetic requirements (1%, 1% and 2%), restlessness-pain scores and time spent in the recovery ward (27 SD 10, 31 SD 12 and 26 SD 9 min) were similar. During the ensuing 24-h postoperative period, patients who had isoflurane experienced emesis less often than those who had halothane (36% vs 46%, P < 0.025) but did so with similar frequency to those who had enflurane (46% vs 41%). Antiemetic requirements were least in those given isoflurane (isoflurane 12%, halothane and enflurane 23% each, P < 0.005), but headache and analgesic requirements were similar.


CONCLUSIONS
Isoflurane induces less postoperative emesis than halothane, but headache is similarly frequent after anaesthesia with any of these agents.
van den Berg
A A
AA
Department of Anaesthesia, Riyadh Armed Forces Hospital, Kingdom of Saudi Arabia.
Honjol
N M
NM
Mphanza
T
T
Rozario
C J
CJ
Joseph
D
D
D000328:Adult; D017109:Akathisia, Drug-Induced / Q000209:etiology; D000768:Anesthesia, General; D018685:Anesthetics, Inhalation / Q000009:adverse effects*; D000932:Antiemetics / Q000627:therapeutic use; D004311:Double-Blind Method; D004737:Enflurane / Q000009:adverse effects*; D005260:Female; D006221:Halothane / Q000009:adverse effects*; D006261:Headache / Q000139:chemically induced*; D006801:Humans; D007530:Isoflurane / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D013508:Ophthalmologic Surgical Procedures; D013517:Otorhinolaryngologic Surgical Procedures; D011446:Prospective Studies; D014839:Vomiting / Q000175:diagnosis* / Q000188:drug therapy
D018685:Anesthetics, Inhalation; D000932:Antiemetics; D004737:Enflurane; D007530:Isoflurane; D006221:Halothane