Background: In clinical research, neuromuscular monitoring must present a stable response for a period of 2 to 5 min before administration of a neuromuscular blocking agent. The time required to reach this stable response may be shortened by applying a 5-s tetanic stimulus.
Objectives: The aim of this study was to test whether tetanic stimulation interferes with onset and recovery times after a single dose of rocuronium 0.6 mg kg followed by spontaneous recovery.
Design: A randomised, open-label, controlled trial.
Setting: A single-centre trial, study period from January 2014 to July 2015.
Patients: Fifty children aged 2 to 11 years scheduled for elective paediatric surgery.
Intervention: Patients were randomly allocated to receive either tetanic stimulation (group T) or not (group C) before calibration of the neuromuscular monitor.
Main outcome measures: Onset and recovery times. Initial and final T1 height, time to obtain initial T1 height stability and monitor settings were also analysed.
Results: There was no significant difference in mean onset time [(C: 57.5 (± 16.9) vs. T: 58.3 (± 31.2) s; P = 0.917]. Mean times to normalised train-of-four (TOF) ratios of 0.7, 0.8 and 0.9 were significantly shorter in the tetanic stimulation group [C: 40.1 (±7.9) vs. T: 34.8 (±10) min; P = 0.047, C: 43.8 (±9.4) vs. T: 37.4 (±11) min; P = 0.045 and C: 49.9 (±12.2) vs. T: 41.7 (±13.1) min; P = 0.026, respectively]. The mean time required for T1 height stabilisation was similar in the two groups [C: 195.0 (± 203.0) vs. T: 116.0 (± 81.6) s; P = 0.093], but the initial and final T1 height values were significantly lower in the tetanic stimulation group (C: 98.0 vs. T: 82.7%; P < 0.001 and C: 95.3 vs. T: 69.3%; P < 0.001, respectively).
Conclusion: Tetanic stimulation shortened the mean times to normalised TOF ratios of 0.7, 0.8 and 0.9, but there was no difference in the mean onset time or the mean time required for T1 height stabilisation after a single dose of rocuronium 0.6 mg kg followed by spontaneous recovery in children aged 2 to 11 years.
Trial registration: Clinicaltrials.gov. identifier: NCT02498678.