The neuromuscular sensitivity of 71 patients (A.S.A. class I or II) was tested by scoring on a scale from 1 to 6 the ability to lift the upper eyelid 2 minutes after pretreatment with 1 mg of pancuronium. Subsequently, each patient also received an additional “intubation dose” of pancuronium (in milligrams) equal to the eye-opening test score (group I), or either 1 mg (group II) or 2 mg (group III) in excess. The resultant depression of the neurally evoked muscle response of the little finger was quantified by another score (the response score) which allowed for assessment of neuromuscular block beyond the limit of 100% depression of the twitch. The criteria for the response score, in the order of increasing magnitude of block, were: (1) visible twitch responses to all 4 of the train-of-four stimulation remained; (2) part of the train-of-four twitches was eliminated; (3) all twitches were eliminated; (4) tetanus was eliminated; (5) post-tetanic twitch following a 5-second 50 Hz tetanus was also eliminated; and (6) not even the post-tetanic twitch became elicitable again in 30 minutes. It was found that 1 mg of pancuronium depressed the eye-opening score to 4.0 ± 0.2, from 5.1 ± 0.1 (mean ± SEM, p < 0.01). Following the additional “intubation dose” of pancuronium, patients in group I had an average response score of 2.2 ± 0.3, those in group II a score of 3.4 ± 0.2, and those in group III, a score of 4.8 ± 0.6. Each additional 1 mg of pancuronium (increasing from group I to III) linearly increased the average response score. In terms of frequency response, patients in group I had more than a 50% chance of being scored 1, while those in group II had a greater than 50% chance of being scored 3, 4, or 5, and those in group III had more than a 50% chance of being scored 6. It Is concluded that sensitivity to pancuronium can be quantified by the ptotic response to a 1-mg test dose of pancuronium, and that a sensitivity-adjusted additional “intubation dose” of pancuronium can be predetermined in individual patients.
Received from the Departments of Anesthesiology, UCLA Medical Center, Los Angeles, California, and Harbor/UCLA Medical Center, Torrance, California.
© 1980 International Anesthesia Research Society