Study Objectives: To determine the pharmacodynamics and intubating conditions of cisatracurium 0.2 mg/kg in children aged 2 to 12 years.

Design: Open-label, randomized study.

Setting: Operating room of a university-affiliated hospital.

Patients: 42 ASA physical status I and II patients, 24 to 155 months of age.

Interventions: Patients were assigned to one of two groups: halothane anesthesia (G1) and opioid anesthesia (G2). Subsequently, each group was divided into two age subgroups: 24–59 months and 60–155 months. All patients were premedicated with midazolam intranasal 0.1 to 0.2 mg/kg. In G1, anesthesia was induced with halothane up to 3% and N₂O/O₂ (60–70/30–40%). Halothane was reduced to ≤2%, 2 minutes before cisatracurium was administered. In G2, anesthesia was induced with fentanyl 2 μg/kg and thiopental 5 mg/kg. Anesthesia was maintained with halothane 0.8–1.5% in N₂O/O₂ in G1, and it was maintained with fentanyl, thiopental, and N₂O/O₂ in G2. Electromyography (EMG) assessed the neuromuscular function of the adductor pollicis every 10 seconds with single-twitch supramaximal stimulus at induction and train-of-four at recovery. After obtaining EMG baseline, cisatracurium was administered. Onset time, time to 90% block, percentage of maximal block, clinical duration, and intubating conditions were recorded. For statistical analysis, Chi-square test, analysis of variance, and Tukey’s test were used, with p-value less than 0.05.

Measurements and Main Results: Only first twitch (T₁) recovery to 25% was significantly longer in patients aged 24 to 59 months who received halothane-based anesthesia, compared with those who received opioid-based anesthesia (p < 0.05). Onset time, maximum block, and intubating conditions did not differ between groups (p > 0.05).

Conclusions: Cisatracurium 0.2 mg/kg offered acceptable intubating conditions at 90 seconds in 98% of pediatric patients, regardless of the anesthesia-based technique. Longer clinical duration in the halothane group in younger children may be due to age-related potentiation or to the small number of patients enrolled in the younger subgroup.