Use of rapacuronium in a child with spinal muscular atrophy

We report the case of an 18-month-old girl with spinal muscular atrophy (SMA) that received 1 mg x kg(-1) rapacuronium for laryngospasm during induction of anaesthesia. Within 15 min, we observed some diaphragmatic recovery and, after emergence from anaesthesia, the child demonstrated adequate respiratory efforts. However, the child showed diminished strength of the upper extremity muscles. Since the preoperative workup had revealed bulbar symptoms and laryngeal function could not be easily assessed, the patient was kept intubated until upper extremity strength had returned to preoperative levels. Small doses of midazolam had been given to reduce the patient's anxiety but the patient was extubated within 5 h without any complications. Train of four (TOF) monitoring of the right adductor pollicis muscle, performed during anaesthetic recovery, was equivocal. In SMA, muscle groups are differentially affected so that TOF responses may be inconclusive and not reflect the state of the upper airway muscles. To our knowledge, this is the first report of use of a nondepolarizing neuromuscular blocking agent in a child with SMA.