[Neuromuscular blockade with cisatracurium in infants andchildren. Its course under sevoflurane anesthesia]

To compare the onset, duration and maximum effect of 0.1 mg/kg cisatracurium during balanced anesthesia with sevoflurane and remifentanil between infants and children.

We measured the time course of the neuromuscular blockade in 15 infants and 15 children by electromyography. Anesthesia was induced with propofol/remifentanil and maintained with sevoflurane (constant 2% endtidal) and remifentanil according to the patients individual requirements. After injection of 0.1 mg/kg cisatracurium we measured the following parameters: onset time: time between the beginning of injection of cisatracurium and maximum T1 depression, clinical duration: time between injection of the drug and recovery of T1 to 25%, recovery index: time between recovery of T1 from 25% to 75%. TOFR 0.9: time between injection of cisatracurium and recovery of the train-of-four ratio to 90%. In addition, we determined the maximum neuromuscular blockade Tmax after 0.1 mg/kg cistracurium.

Both groups differed significantly with regard to onset time and clinical duration. In the infants, the onset time was shorter (74 s vs. 198 s) and the clinical duration longer (55 min vs. 41 min) compared to the older children. The TOFR 0.9 was 73 min (range 56-86 min) in the group of the infants and 59 min (range 43-72 min) in the group of the older children (p < 0.001). Tmax was 100% (range 97-100%) in the infants and 98% (range 92-100%) in the children (p < 0.01). However, the recovery index was comparable in both groups (21 vs. 16 min).

Infants are substantially more sensitive to cisatracurium than children, which can be demonstrated in a significantly shorter onset time, a prolonged clinical duration and a delayed neuromuscular recovery. As there exist large interindividual differences, we recommend the use of neuromuscular monitoring in the routine practice of pediatric anesthesia.