Predicting recovery from deep neuromuscular block by rocuronium in children and adults

To compare the response to motor nerve stimulation at a rate of 1 Hz after 50 Hz tetanus [posttetanic count (PTC)] and 2 Hz for 2 seconds [train-of-four (TOF)] in children and adults during spontaneous recovery from blockade caused by rocuronium.

Prospective, clinical, observational, multicenter study.

Operating rooms of two university hospitals.

22 children (ASA physical status I and II) aged 2 to 5 years, scheduled to undergo dental treatment and 20 adults aged 18 to 60 years, scheduled to undergo elective general or orthopedic surgery during general anesthesia with tracheal intubation.

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

The first response to posttetanic and TOF nerve stimulation appeared earlier in children than in adults. The time from injection of rocuronium to appearance of the fourth response to TOF ranged from 27 to 62 minutes in children and from 37 to 94 minutes in adults. The average interval between the appearance of a posttetanic response and the first detectable response to TOF stimulation (T1) was also shorter in children, 7 minutes, than in adults, 16 minutes. The relationship between PTC and the time interval between a given PTC and the first detectable TOF response in both children and adults was exponential (R = -0.64 and R = -0.81, respectively).

Children recover faster than adults from neuromuscular blockade after administration of 1 mg x kg(-1) rocuronium. The relationship between PTC and time to first response to TOF is exponential both in children and adults during recovery from neuromuscular blockade caused by rocuronium.