Dose of remifentanil for minimizing the cardiovascular changes to tracheal intubation in pediatric patients

BACKGROUND: The purpose of this study was to investigate a dosage of remifentanil for attenuating cardiovascular changes during anesthetic induction in pediatric anesthesia. METHODS: We examined the effect of remifentanil on the cardiovascular responses to intubation in 90 children ASA 1 patients, aged 4-15 years, randomly allocated to receive 1.0 ug/kg remifentanil as a bolus (R 1), or 1.5 ug/kg remifentanil (R 1.5), or 2.0 ug/kg remifentanil (R 2). Before induction, IV midazolam 0.05 mg/kg was given for sedation. After glycoppylorate 5 ug/kg, thiopental 4.0 mg/kg was injected within 10 seconds and followed by remifentanil. Following check the unconsciousness, patients were received rocuronium 0.6 mg/kg and tracheal intubation were performed 90s later, and anesthesia was maintained with 2% sevoflurane in air/oxygen. Systolic arterial pressure (SAP), mean arterial pressure (MAP) and heart rate (HR) were measured at before induction of anesthesia (B), before, just after and at 1, and 3 minutes after tracheal intubation. RESULTS: SAP and HR were increased than B values in the three groups just after intubation (P < 0.05). The percentage increases of SAP and HR were 30% and 30% of B values, respectively, in R 1; 19% and 24% in R 1.5; 10% and 22% in R 2. There were significant differences between R 2 group and other two groups in SAP and HR (P < 0.05). CONCLUSIONS: In pediatric anesthesia, a bolus injection of 2 ug/kg remifentanil (R 2) was a dosage to attenuate the cardiovascular responses after intubation in pediatric patients.