Does a remifentanil bolus attenuate the haemodynamic response to rigid bronchoscopy?

Introduction

The pressor response to rigid bronchoscopy resulting in tachycardia and hypertension is well recognized. Patients undergoing this procedure are often elderly and many have coexisting cardiovascular impairment. Haemodynamic stability is therefore crucial. Propofol alone causes an initial drop in blood pressure, which then rises above control levels after intubation with a significant rise in the patients' heart rate. Several studies have shown that a remifentanil bolus attenuates the pressor response to intubation. The rapid recovery afforded by remifentanil is ideal for day-case bronchoscopies. The aim of this prospective, double-blind, randomized, controlled trial was to assess the efficacy of a remifentanil bolus given before propofol in attenuating the haemodynamic responses to rigid bronchoscopy.

Methods

Eighty patients were randomly assigned to receive a bolus of one of four drugs: remifentanil 1 μg/kg, remifentanil 2 μg/kg, alfentanil 10 μg/kg or saline (control). The anaesthetist was blinded to the solution used. Anaesthesia was then induced with a target controlled infusion (TCU) of propofol, and suxamethonium (1.5 mg/kg)was used as relaxant. Heart rate and noninvasive arterial pressures were recorded at minute intervals throughout the procedure. Repeated measures analysis of variance and area under curve analysis were used. Power analysis required 20 patients in each group to achieve a power of 0.9 and significance of P < 0.05.

Results

Patient characteristics were similar. The TCI propofol requirement was significantly higher in the saline group (P = 0.0018). Changes in heart rate and arterial pressure were significantly higher in the saline group (P = 0.0075 and P < 0.0001, respectively; Fig. 1). No clinically significant difference was seen between the opioids. No patients complained of nausea and there were no differences in time to return of spontaneous ventilation, wake up times or use of rescue vasopressors.

Figure 1

Mean (SE) changes in heart rate from baseline during rigid bronchoscopy.

Conclusion

An opioid bolus significantly attenuates the haemodynamic response to rigid bronchoscopy without delaying recovery. However, remifentanil, in a dose of either 1 μg/kg or 2 μg/kg,was not clinically superior to alfentanil 10 μg/kg.