Background
Objective neuromuscular monitoring is essential to prevent residual neuromuscular block in patients receiving neuromuscular blocking agents. However, the small size of pediatric hands and the lack of appropriately sized neuromuscular equipment have made quantitative neuromuscular monitoring at the ulnar nerve (UN) difficult. In such cases, the tibial nerve (TN) can serve as an alternative site. This study aimed to compare train-of-four (TOF) monitoring using acceleromyography (AMG) and electromyography (EMG) at the TN and UN in children aged 3–24 months. We hypothesized that the time to reach a train-of-four ratio (TOFR) ≥ 0.9 would be shorter with AMG compared to EMG.
Methods
In this observational study, a total of 107 pediatric patients scheduled to elective surgery under general anesthesia with rocuronium 0.6 mg/kg were included. Patients were allocated to either bilateral tibial nerve (TN) or bilateral ulnar nerve (UN) monitoring using AMG and EMG. The primary outcome was time to TOFR ≥ 0.9. Other outcomes were time to TOFC = 0 (onset); reappearance of post tetanic count (PTC) = 1, TOFC = 1, TOFC = 2, and symptoms of residual neuromuscular block.
Results
Fifty patients were bilaterally monitored at TN and 50 patients were bilaterally monitored at UN. At TN time to TOFR ≥ 0.9 was 81 min (SD 29) with AMG and 112 min (SD 34) with EMG with a mean difference of 34 min (95% CI: 29–39; p < 0.0001). At UN time to TOFR ≥ 0.9 was 71 min (SD 29) with AMG and 82 min (SD 28) with EMG, with a mean difference of 11 min (95% CI: 6–15; p < 0.0001). Seventeen patients exhibited symptoms of residual neuromuscular block.
Conclusion
Time to TOFR ≥ 0.9 after rocuronium 0.6 mg/kg in children aged 3–24 months was significantly shorter with AMG compared to EMG at both the UN and TN. AMG may underestimate the duration of action.