Predicting recovery from deep neuromuscular block by rocuronium in the elderly.
OBJECTIVE
To determine the influence of aging on the relationship between posttetanic count (PTC) and train-of-four (TOF) response during intense neuromuscular blockade caused by rocuronium.


METHODS
Prospective, observational, clinical comparison study.


METHODS
Operating room of a university hospital.


METHODS
42 ASA physical status I and II patients, 20 of whom were elderly (ages 65 to 80 yrs) and 22 younger control patients (ages 18 to 40 yrs), who were scheduled for elective orthopedic surgery and ear, nose, and throat surgery with a planned duration of 2 hours.


METHODS
Neuromuscular blockade was evaluated with accelerometry of the thumb, using posttetanic twitch (PTT) and TOF stimulation of the ulnar nerve, in patients who received rocuronium 1 mg x kg(-1).


RESULTS
The first responses to posttetanic nerve stimulation were seen at mean times of 38.5 and 35.2 minutes after the injection of rocuronium in the elderly and in the young, respectively (NS). The average interval between the appearance of a posttetanic response and the first response to TOF stimulation (T1) was longer in the elderly than the young (22.3 +/- 8.1 (SD) vs.14.8 +/- 4.2 min, p < 0.05). There was a significant correlation between PTC and the time to first response to TOF nerve stimulation both in the elderly and in the young (r = -0.73, p < 0.0001 and r = -0.87, p < 0.0001, respectively).


CONCLUSIONS
Posttetanic twitch stimulation is a useful method of monitoring intense neuromuscular blockade caused by rocuronium in both age groups. The interval between the earliest appearance of a posttetanic response and the first response to TOF stimulation (T1) is greater in the elderly than in the young.
D000293:Adolescent; D000328:Adult; D000368:Aged / Q000502:physiology*; D000732:Androstanols; D000762:Anesthesia Recovery Period; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009407:Nerve Block; D003473:Neuromuscular Nondepolarizing Agents; D011237:Predictive Value of Tests; D011446:Prospective Studies; D000077123:Rocuronium; D014459:Ulnar Nerve
D000732:Androstanols; D003473:Neuromuscular Nondepolarizing Agents; D000077123:Rocuronium