Severe anaphylactic reaction to thiopentone: case report.

In view of the estimated millions of thiopentone injections given annually, and the frequent reports of cutaneous manifestations of allergy to barbiturate drugs, it is surprising that anaphylaxis to barbiturates is so rarely reported. We believe that some cases may be unrecognized or misdiagnosed. A woman of 58 with carcinoma of the bladder had been treated seven years previously, in 1958, by transurethral resection. Thereafter at intervals of six months she had had 10 cystoscopic examinations , occasionally with diathermy of the bladder. General anaesthesia on each occasion had consisted of intravenous thiopentone, nitrous oxide, oxygen, and volatile supplement, and had been uneventful. In September 1964 the patient " collapsed " in a private hospital after a routine cystoscopy under general anaesthesia, which had included intravenous thiopentone, 0.5 g. The premedica-tion was papaveretum, 20 mg., and atropine, 0.6 mg. She had remained unconscious for six hours, during which time she was given atropine, 1.2 mg., methoxamine, 20 mg., and metaraminol, 5 mg. intravenously and 10 mg. intramuscularly. The present anaphylactic episode occurred in March 1965. Pre-operative examination had shown a robust woman who gave no history of reactions to drugs, but she stated that she had received an "overdose " during the previous anaesthesia. She was pre-medicated 90 minutes pre-operatively with pethidine, 50 mg., and hyoscine, 0.4 mg. Anaesthesia was induced cautiously with intravenous thiopentone. After 0.25 g. an unsuccessful attempt to lift the legs into the lithotomy position indicated that anaesthesia was too light, and a further 0.1 g. of thiopentone was given. It was then noticed that the patient had become cyanosed, the radial pulse was impalpable, and there was moderate bronchospasm. The lungs were gently inflated by assisted ventilation with halothane and oxygen, and the cystoscopy was completed after a further 10 minutes. Oxygen was given intranasally, and she was observed for 15 minutes. The peripheral pulses were impalpable, and the blood-pressure was unrecordable. The pupils remained small. During the next 10 minutes metaraminol was given intravenously, 1 mg. at a time to a total of 5 mg. ; then the pulse became palpable at a rate of 168 per minute, and the systolic blood-pressure record-able at 75 mm. of mercury. Hydrocortisone sodium succinate, 100 mg., was given intravenously, and again eight hours later. She regained consciousness three hours after induction, but metar-aminol, 5 mg. intramuscularly, was needed two-hourly for 12 hours to maintain the systolic blood-pressure …