The Feasibility Of Controlled Hypotension With Remifentanil Combined With Propofol During Endoscopic Nasal Sinus Surgery

Purpose To determine whether remifentanil combined with propofol could induce and sustain controlled hypotension, reduce blood loss, provide a "dry" operative field during endoscopic nasal Zsinus surgery, at the same time , to evalute the safety and controllability.Methods Thirty normotensive ASA physical status I -II patients (male 21, female 9) aged (18-50)yr weighting (45-85)Kg without heart and pulmonary disease undergoing endoscopic nasal sinus surgery were randomly divided into two groups : nitroglycerin group (N group n=15) and remifentanil group (R group n=15). All patients were fasted at least 12 hr before surgery. Proportion of sex, age ,weight and baseline hemodynamics data were not different between two groups . A 20-gauge catheter was inserted into a radial artery for direct determination of arterial blood pressure , HR and serial blood gas analysis . Controlled hypotension was induced before the main procedure of surgery. All patients assigned to N group were infused by a constant infusion of 4-10ug.Kg^-1.min^-1 nitroglycerin until the target pressure was reached, then infusion rate was adapted in order to sustain hypotension. In R group, remifentanil were delivered with a constant infusion rate of 0.25-0.7 ug.Kg^-1.min^-1 in order to induce controlled hypotension that was considered effective, then the rate was adapted according to hypotension. MAP was sustainted at 50-70mmHg till the main procedure of surgery was finished. HR, MAP ,ECG ,P_ETCO₂ and unjured hemodynamics were monitored throughout surgery. Meanwhile, arterial blood PH and blood gas were determined. The quality of surgical field in terms of blood loss and dryness was rated by the same attending surgeon who was unware of thepharmacological treatments.Results The two groups were comparable with regard to duration of surgery and the surgical field rating. Controlled hypotension was achieved at the target pressure of 50-70mmHg within 6.6 + 2.2 min, 6.5±2.3min for N group and R group respectively. In N group there was reflexible tachycardia during hypotension . While , remifentanil induced and sustained hypotension without reflexible tachycardia and rebounding hypertension. Variations of PH ,TCO2 and HCCVin two groups were not great(P>0.05). In N group, PCO2 increased significantly(P>0.01), PO2 decreased greatly(P<0.05); while in R group, PCO2 and PO2 decreased slightly(P>0.05). In N group, SV, TPR decreased significantly(P<0.01), CO and CW decreased greatly(P<0.05) ,EF did not change(P>0.05) after hypotension. In R group , SV, EF and TPR were comparable before and during hypotension(P>0.05), CO and CW decreased significantly(P<0.01). After surgery, cases in N group had longer postanesthetic recovery compared with those in R group(PO.Ol). There were no postoperative complications in both groups.Conclusion Remifentanil combined with propofol could induce and sustain controlled hypotension, reduce blood loss, provide a "dry" operation field during endoscopic nasal sinus surgery without reflexible tachycardia and any postoperative complications.