The Effects Of Dexmedetomidine Combined With Nitroglycerin In Controlled Hypotension During Endoscopic Sinus Surgery

Objective To compare the effects of using dexmedetomidine combined withnitroglycerin and nitroglycerin alone in controlled hypotension during endoscopic sinussurgery.Methods Forty ASA Ⅰor Ⅱ patients, aged20-60yr, weighting50-76kg, undergoing endoscopic sinus surgery, were randomly divided into2groups（n=20each）:dexmedetomidine combined with nitroglycerin group（group ND） and nitroglyceringroup（group N）. Midazolam, refentanl, propofol and cis-atracurium were usedfor rapid intravenous induction. refentanl, propofol and cis-atracurium were administrated for anesthesia maintenance. Group ND received dexmedetomidine1μg/kgover15min before intubation followed by0.5μg kg-1h-1infusion during maintenance, while group D received the same amounts of saline. When the surgeonsbegan to sterilize the nasal cavity, nitroglycerin was administrated from1μg kg-1min-1and titrated according to target MAP.The target MAP during controlled hypotension was maintained between55and65mmHg. MAP and HR were recorded at the time points of beforep harmacological intervention （T0）,15min（T₁）,30min（T₂） and45min（T₃） after controlled hypotension and15min afterextubation（T4）. The Fromme scores of surgical field were assessed by the samesurgeon, blinded to the study drugs. Concentrations of circulating cortiso andblood glucose were measured at the time points of T0, T₁and T₃. The time of MAP returning to preoperative level, operation time, extubation time and the total dosage of nitroglycerin were recorded.Results Compared with T0, MAP in both group decreased and HR in group N increasedsignificantly at T₁～T₃during operation （p<0.05）. Compared with group N, HRremained stable, the time operation time was shorter and the total dosage ofnitroglycerin was less in group ND （p<0.05）. Meanwhile, group ND had lower Frommescores （p<0.05）. Time of MAP returning to baseline and extubation time were nosignificant in two groups. In both groups, plasma cortisol and blood glucose increasedsignificantly relative to baseline during operation. However, the values weresignificantly higher in the group N compared with the DEX group ND （P<0.05）Conclusion Dexmedetomidine combined with nitroglycerin can be used to achievecontrolled hypotension safely and effectively during endoscopic sinus surgery, with lessdosage of nitroglycerin and more clear surgery field.