The neuromuscular blocking effects of the new monoquaternary analogue of pancuronium, Org NC 45, have been investigated in anaesthetized patients. In different doses administered as a single i.v. bolus or as an initial bolus followed by several small maintenance doses or by a continuous infusion. Org NC 45 appears to be approximately as potent as pancuronium, but has a more rapid onset of action, considerably shorter duration of action and faster recovery rate than pancuronium. It showed no cumulative effects even after 10 maintenance doses were injected in succession. Doses of 0.08 mg kg-1 provided ideal intubating conditions in 90--95 s. Infusions of Org NC 45 provided much smoother control of neuromuscular blockade than did pancuronium. No cardiovascular side-effects were noted even at the greatest dose (0.12 mg kg-1) used. Org NC 45 has clear advantages over pancuronium and represents a potentially valuable addition to the armamentarium of clinically useful muscle relaxants.

The hypnotic and analgesic components of anaesthesia can be assessed using middle latency auditory evoked potentials (MLAEPs) and somatosensory evoked potentials (SEPs). To monitor these potentials reliably during clinical anaesthesia, we have developed an evoked potential (EP) system based around a portable personal computer, a DSP board and an isolated pre-amplifier unit. Unlike many currently available systems, this amplifier is largely immune to diathermy interference due to excellent isolation via a digital fibre optical link, small size and RF screening and filtering. The pre-amplifier unit has integral auditory and somatosensory stimulators, and automatic calibration and impedance checking. Stimulus intensity and profile are under software control and SEP stimulus level is constantly monitored. The unit is powered by two AA cells and battery status continuously monitored by the PC software. Up to eight channels of EEG may be recorded and displayed in a smoothly scrolling window and as moving average MLAEPs and SEPs.

Summary Spontaneous movement following injection of propofol at induction was