Abstract

Background
Patients with hypertension may be more prone to develop hypotension as a consequence of opioid administration under general anesthesia. The hemodynamic and bispectral index responses to a remifentanil bolus in neurosurgical hypertensive patients under target-controlled infusion with propofol and remifentanil are addressed.
Material and Method
Ten healthy patients and 10 patients with diagnosed hypertension under pharmacological treatment were studied. A 2 microg/kg remifentanil bolus was administered to all patients before skin incision under target-controlled infusion with propofol and remifentanil. Mean arterial pressure, heart rate, and the area under the curve for the bispectral index of the electroencephalogram were analyzed within the groups and compared between them every 30 seconds for two minutes following the bolus.
Results
Two minutes after the remifentanil bolus, remifentanil predicted effect-site concentrations reached maximum values of 8.46+/-0.91 ng/ml and 9.74+/-1.29 ng/ml in the healthy and hypertensive patients, respectively. Both groups showed a significant decrease in mean arterial pressure, heart rate, and in the area under the curve for the bispectral index. Mean arterial pressure decreased by 17.3+/-10% and 24+/-9%, heart rate by 11.1+/-8% and 12+/-8%, and the bispectral index by 13+/-9.2% and 8.6+/-8.4% in the healthy and hypertensive patients, respectively, 120 seconds after the remifentanil bolus.
Conclusions
In a clinical situation in which high remifentanil doses may be required, hypertensive patients are expected to have hemodynamic and bispectral index responses similar to those observed in healthy patients.

Keywords: Physical Stimulation, Neurosurgical Procedures, Hypertension - surgery, Electroencephalography, Demography, Dose-Response Relationship, Drug, Consciousness Monitors, Area Under Curve, Analgesics, Opioid - pharmacology, Piperidines - pharmacology, Propofol - pharmacology