Assessment of neuromuscular blockade in children at the time of block reversal and the removal of the endotracheal tube.

BACKGROUND AND OBJECTIVES

Studies show the importance of monitoring neuromuscular function in preventing the residual block. However, most anesthesiologists in their daily practice base their evaluation of the recovery of neuromuscular function on clinical data. The aim of this study was to assess the degree of neuromuscular blockade in children undergoing general anesthesia at the time of block reversal and the removal of the endotracheal tube.

METHOD

We evaluated children between 3 months and 12 years of age undergoing general anesthesia with the use of atracurium or rocuronium. Monitoring was initiated at the time of reversal of neuromuscular blockade and/or removal of the endotracheal tube. The anesthesiologist was not informed about the T₄/T₁ value; he/she was only alerted when the time was inadequate for the removal of the endotracheal tube. Since the start of the monitoring process, the degree of neuromuscular blockade was registered, as well as the interval of recovery of the T(4)/T₁ ≥ 0.9 ratio, the doses of neostigmine and blocker used, the expired fraction of the inhalational agent, the duration of the anesthesia, and core and peripheral temperatures.

RESULTS

Neuromuscular blockade was reversed in 80% of the children of the Rocuronium Group and in 64.5% of the Atracurium Group. The reversal was incorrect in 45.8% of the Rocuronium Group and in 25% of the Atracurium Group. The incidence of T₄/T₁ < 0.9 at the time of the removal of the endotracheal tube was 10% in both groups.

CONCLUSIONS

When deciding to remove the endotracheal tube based on clinical criteria, 10% of children had T₄/T₁ < 0.9 regardless the blocker received. A considerable number of patients had the neuromuscular blockade incorrectly reversed when the blockade was still too deep or even already recovered.