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Acceleromyography is characterised by an increase of the twitch response T1 (first twitch of the train-of-four [TOF]) during first 30 min of monitoring known as the staircase phenomenon. In adults the staircase phenomenon can be avoided by tetanic prestimulation. This study examined, if tetanic prestimulation eliminates the staircase phenomenon in children. After written informed consent, the neuromuscular function of 80 children, 10 in each age group ( 6 months, 6-12 months, 12-24 months, 2-3 years, 3-6 years, 6-12 years, 12-18 years, and ≥ 18 years) was measured on both arms simultaneously over 30 min under general anaesthesia. The ulnaris nerve was stimulated using the TOF technique every 15 s. The twitch response (T1, TOF ratio [TOFR]) was measured by acceleromyography. Before calibration, tetanic prestimmulation (50 Hz for 5 s) was administered to one randomly selected arm. The effect of tetanic prestimulation and age was analysed using general linear models based on the normalized T1 and TOFRs of both arms. Tetanic prestimulation significantly affected T1 values avoiding the staircase phenomenon (p 0.0001). After 5.8 min [1.0-17.2 min] the normalized T1 values increased to 117% [102-147%] without prestimulation (p 0.0001) independent of the age group (p = 0.539). The normalized TOFR was stable throughout the observation period of 30 min 100% [95-107%]. Infants ( 12 weeks), children, and young adults ( 18 years) develop similar characteristics of the staircase phenomenon than adults. Tetanic prestimulation prevents the staircase phenomenon in these age groups. The stability of the TOFR reading confirms its value to monitor neuromuscular function over time.Registration: The study was registered as NCT02552875 on Clinical Trials.gov on July 29, 2014.

Myasthenia gravis, affecting neuromuscular transmission, leads to a large variability in sensitivity to depolarising and non-depolarising neuromuscular blocking drugs. We report the successful use of the modified mu-cyclodextrin sugammadex in a myasthenic patient to reverse a rocuronium-induced deep level of neuromuscular block. After spontaneous neuromuscular recovery of T2 (second twitch of the train-of-four series), we administered 2 mg.kg(-1) of sugammadex intravenously, reversing neuromuscular blockade to a train-of-four ratio (T4/T1) > 90% within 210 s. Sugammadex, in combination with objective neuromuscular monitoring, can be used to reverse rocuronium-induced neuromuscular blockade in patients with myasthenia gravis, thereby avoiding the need for reversal with acetylcholinesterase inhibitors.