Dose–response relationship and effective time to satisfactory intubation conditions after rocuronium in children

Abstract

SummaryWe assessed the neuromuscular blocking effects of, and intubation conditions following, rocuronium in 81 children aged 2-12 years. The study was conducted in three parts. Parts 1 and 2 were undertaken during anaesthesia with thiopentone, alfentanil and nitrous oxide. Neuromuscular blockade was evaluated by recording the force of contraction of the adductor pollicis in response to train-of-four stimulation at 2 Hz repeated every 10 s. In Part 1 the potency of rocuronium was determined in 15 children using a single dose-response technique; in Part 2 onset and recovery times were determined in six children following rocuronium 0.6 mg.kg ¹1 . In Part 3 of the study, intubation conditions were assessed in five groups of 12 children whose tracheas were intubated 30, 40, 50, 60 and 70 s after rocuronium 0.6 mg.kg ¹1 during anaesthesia with thiopentone. The times to satisfactory intubation conditions in 50% and 90% of children were determined by probit analysis. The effective doses of rocuronium to produce 50% and 95% twitch depression were 151 mg. ...................................................................................... Correspondence to: Dr G. Meakin Accepted: 10 November 1996 Rocuronium is a recently introduced steroid nondepolarising neuromuscular blocking drug with a rapid onset, an intermediate duration of action and relatively low potency [1][2][3]. In view of its rapid onset of action, rocuronium may be an alternative to suxamethonium when rapid intubation of the trachea is required [4,5]. While several authors have quantified the neuromuscular blocking effects of rocuronium in children in terms of twitch depression [3,6,7], there is little information concerning the minimum time to achieve satisfactory intubation conditions. Therefore, in the present study we were interested to determine the effective dose for 95% depression of thumb twitch (ED 95 ), the onset time and duration after a dose of approximately twice the ED 95 and the effective times for satisfactory intubation conditions in 50% and 90% of children. Methods

Avaliação das condições de intubação traqueal com rocurônio aos 60 segundos em crianças, adultos e idosos

“…A outra explicação para as condições ruins pode ter sido o tempo insuficiente de instalação do bloqueador neuromuscular. Hopkins e col. 25 indicaram que, para a dose de 0,6 mg.kg -1 de rocurônio, o tempo ideal para a obtenção de melhores condições está em torno de 70 segundos. Diferenças no comportamento do relaxamento entre crianças e adultos têm sido identificadas 26 .…”

“…A different explanation for poor conditions could have been insufficient time for relaxation. Hopkins et al 25 have indicated that for 0.6 mg.kg -1 rocuronium, optimal time to obtain best conditions is approximately 70 seconds. Differences in relaxation behavior in children and adults have already been identified 26 , among them potency.…”

Evaluation of Intubating Conditions in Paediatric Patients- A Comparative Study of Succinylcholine and Two Different Doses of Rocuronium

“…All children enrolled had either Mallampati class I or II and no contraindication for rapid sequence induction of anaesthesia. [5][6][7][8] Pre-Anaesthetic Check-up (PAC) and necessary investigations done on the day before surgery to ascertain the medical and physical fitness. Selected patients were divided into Three Groups.…”

Role of muscle relaxants in pediatric anesthesia

“…In children anesthetized with thiopental-nitrous oxide, satisfactory intubating conditions were observed in 98 and 100% of cases 90 and 70 s after the administration of 2 Â ED 95 doses of mivacurium or rocuronium, respectively [26,27]. Similarly, in a study of 60 children aged 2-7 years, good/excellent intubating conditions were achieved in all patients at 1 MAC anesthesia with sevoflurane 2 min after injection of rocuronium 0.3 mg/kg (around 1 Â ED 95 ) [28].…”