Anaesthesia
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This study was conducted to investigate the effect of voluntary tetanus on the recovery from neuromuscular block produced by a nondepolarising drug, vecuronium, in the isolated forearm. We have studied the recovery indices and train of four fade at different levels of recovery following vecuronium in both isolated forearms simultaneously, in six sets of experiments. In one hand the volunteer performed a maximum contraction of his thumb repeatedly at fixed intervals. ⋯ The train-of-four fade also showed a sustained reduction in the isolated forearm which underwent voluntary tetanus. During the later phase of recovery the train-of-four fade showed significant difference statistically (p < 0.01). The findings of this study supports the hypothesis that more rapid recovery associated with voluntary tetanus is due to a reduction in the presynaptic block thus resulting in an increased rate of transmitter release.
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The forces required to break and to remove catheters from epidural spaces were investigated. Provided the patient's back is fully flexed and a slow steady pull is applied to the epidural catheter, the extraction forces required at both thoracic and lumbar levels are well below the minimum force required to break the same catheters.