Skin electrical resistance is determined by the degree of sweating of the skin which is, in turn, related to sympathetic nervous system activity in the area concerned. It is increased when the nerves supplying the area are damaged or blocked by local anaesthetic agents. We have assessed the temporal and spatial relationship between the onset of sympathetic and sensory loss in the hand following brachial plexus block in 44 patients. Skin electrical resistance, measured using a simple ohm meter, has been shown to increase within 2 min of brachial plexus blockade with 1% lignocaine and adrenaline 1:200,000. This increase is an early and reliable indicator of subsequent, and occasionally delayed, sensory loss.

The effects of pancuronium and atracurium on the lower esophageal sphincter pressure (LESP) were studied in 24 healthy patients anesthetized with 0.5% halothane in 66% nitrous oxide in oxygen. After pancuronium (0.1 mg X kg-1) given intravenously there was a significant increase in LESP from a control value of 36 +/- 4.0 cm H2O to 50 +/- 4.6 cm H2O at 1 min. This produced an increase in barrier pressure (BRP) from 26 +/- 3.7 cm H2O to 41 +/- 4.3 cm H2O. These changes were sustained for 5 min accompanied by a significant increase in arterial pressure and heart rate. Atracurium (0.6 mg X kg-1) had no cardiovascular effects and produced little changes in either LESP or BRP. The findings of this study suggest that pancuronium may be of benefit in a rapid sequence induction.

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