A comprehensive task analysis of the anesthetist's activities during coronary-artery bypass procedures was carried out using time-lapse cinematography. This film was analyzed frame by frame to detect types of activities and the proportion of time spent on each. Link analysis was used to reveal recurring sequences of activities. Of the 9 activity categories, the anesthetist spends the greatest portion of time observing the patient and scanning the entire operative and monitoring field. Ten to 15% of the time is spent logging data on the anesthetic record. The challenge for the anesthetist is to optimize his performance, and those under his direction, in the face of the changing workload resulting from variations in patients' conditions. Use of an automated monitoring system that charts patient vital signs would allow the anesthetist to apportion this time among other tasks.

The IBC in-vivo oxygen electrode may be used during anesthesia. The possibility that three common inhalation anesthetics--halothane, enflurane, and methoxyflurane--might be reduced at the electrode, thereby changing the PO2 value, was tested. Enflurane and methoxyflurane do not affect the current produced at the electrode; halothane significantly increases PO2 readings at oxygen tensions below 105 torr. It is suggested that PaO2 readings below 105 torr be confirmed by the standard bench method.

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Suxamethonium chloride (Sch) was administered i.v. to 36 adult males at six rates: 0.25 mg s-1 to 20 mg s-1. The infusion was discontinued either when there was no muscular response to tetanic stimulation of the ulnar nerve or when Sch 120 mg was exceeded. Six additional patients received a 30-mg i.v. bolus dose. Fasciculations in six areas of the body were scored from 0 to 3 and summated as a total fasciculation score. The times to first fasciculation, twitch suppression and tetanus suppression were inversely related to the infusion rates. Fasciculations in the six areas and the total fasciculation score were related directly to the rate of infusion. Total fasciculation scores in the 30-mg bolus group and the 5-mg s-1 and 20-mg s-1 infusion groups were not significantly different.