A COMPARISON OF CLONIDINE WITH CONVENTIONAL PREANESTHETIC MEDICATION IN PATIENTS UNDERGOING CORONARY-ARTERY BYPASS-GRAFTING

In this controlled study, we compared clonidine with conventional prem edication in 35 patients undergoing coronary artery bypass grafting (C ABG). After premedication with clonidine 5 mu g/kg PO (Group C, n = 11 ), lorazepam 60 mu g/kg PO (Group L, n = 13), or morphine 0.1 mg/kg pl us scopolamine 6 mu g/kg IM (Group M, n = 11), sedation, anxiety, and quality of premedication were graded. After the administration of sufe ntanil 2.0 mu g/kg over 12.5 min, a computer-assisted infusion device targeted a sufentanil effect-site concentration of 0.75 ng/mL. Hemodyn amic variables, end-tidal isoflurane concentration (ET-ISO), the elect roencephalographic spectral edge, and the serum sufentanil concentrati on (SUF) were measured. There were no intergroup differences in anxiet y, sedation, quality of premedication, the dose of sufentanil causing unconsciousness, or the electroencephalographic (EEG) response to indu ction. Intraoperative SUF was stable, with no intergroup difference. T he average prebypass ET-ISO was lower in Group C than in Group M. The ET-ISO and peak ET-ISO after intense surgical stimulation were lower i n Group C versus Groups L and M. Mean arterial blood pressure was lowe r in Group C versus Groups L and M. There were no intergroup differenc es in pharmacologic intervention, time to extubation, or intensive car e unit stay. Clonidine produces sedation, anxiolysis, and quality of p remedication comparable to conventional premedication. Compared with o ther drugs, clonidine does not alter the dose of sufentanil inducing u nconsciousness or EEG slowing, but it uniquely reduces isoflurane requ irements. Implications: In patients undergoing coronary artery bypass grafting, clonidine produces sedation and relieves anxiety as effectiv ely as conventional premedication. Clonidine does not uniquely alter t he dose of sufentanil inducing unconsciousness or electroencephalograp hic slowing, but it significantly reduces isoflurane requirements.