Propofol is a new venous anesthetics with following characters in-cluding rapid induction, stable effects, easy to control, no remarkable accumulation after long times continuous infusion, rapid and complete recovery without excitement or vomiting or nausea, and less complica-tions. But people are always paying attention to its inhibition on cardi-ovascular system. Heart rate variability analysis is a new research method about autonomic nerve system function. Many studies had proved that HRV monitoring could be applied in measuring the depth of anesthesia, researching on anesthetics pharmacological characteris-tics, outcome of patients, and so on. In our study, we clinically com-pared propofol and etomidate by power spectral analysis of HRV, to provided research proofs of propofol in clinical work.MethodsMethods: 40 patients with high risk factors for coronary heart dis-ease , ASA grade II ~III , were selected and divided into two groups randomly. Group P (propofol group, n =20) is test group, and groupE ( etomidate group, n = 20) is contrast group. The average age of patients was 64.7 ?1.2 years old, Body weight was 66.9 ?18. 3 kg. The risk of coronary heart disease had been identified properly, with normal functions of brain, lungs, liver and kidneys. The high risk fac-tors for coronary heart disease included; (1). age older than 65 years, (2). hypertension, (3). smoking (more than 15 packs/year) , (4). ser-ai cholesterol#6. 2 mmol/1, (5). diabetes mellitus. Group at high risk of coronary heart disease could be defined as person who suffered two of those factors above simultaneously. The patients suffered hyperten-sion in this study were in stage I. Patients who suffered arrhythmias, unstable angina pectoris , valvular heart disease and medication relat-ed to CNS were excluded to avoid interfering the analysis of HRV. All the cases received phenobarbital 0. Ig, 30min before anesthesia. In group P following intravenous injection of Vecuronium 0. Img/kg, Mi-dazolame 40ug/kg, Fentanyl 5ug/kg. Propofol was infused at 6ml/ min ( Graseby 3500) until the patients were asleep. The criteria of sleeping included; no response to instruction , no eyelash relextion. In group E: the same as those in group P except 0. 3mg/kg Etimidate in-fused instead of propofol. Endotracheal intubation was performed 2min after muscle relaxation and mechanical ventilation began. No medica-tion applied within 5min after intubation, and no surgery in 10 mi-nutes after anesthesia, to avoid any interference in HRV analysis. Bp, HR, Spo2, PETC02 were recorded before and after anesthesia. The parameters of HRV , included total power (TP) ;low frequency (LF) ; high frecmency (HF) , ratio of LF/HF and changes of BIS.ResultsDuring the combined anesthesia with small dose propofol; LF, HF showed no changes. There was no difference between the value of IgLF ,lgHF and its baseline ( p > 0. 05). Compared with group E, IgLF and IgHF at each timepoint showed no statistical difference ( p > 0.05 ). The ratio of LF/HF in group P increased at 1,3min after intu-bation , No statistical changes had been found inter - or intra groups ( p > 0.05 ). SBP in group P decreased at 2min after induction and 3 , 5min after intubation compared with baseline, (p < 0. 05) , SBP in group P decreased remarkably compared those in group E at 1, 3min after intubation (p <0. 05). DBP and HR in both groups were not changed much at each timepoint ( p > 0. 05 ). The product of systolic blood pressure and heart rate ( DRPP) in group P decreased at 2min after induction and 5min after intubation ( p < 0. 05 ) , No statistical changes had been found inter - or intra groups ( p > 0. 05 ). In both groups , BIS measured before anesthesia showed significant difference compares with those at other timepoint after anesthesia induction and intubation (p <0.05).DiscussionThe study showed that during the combined anesthesia using propofol with small dose,HR didnt change obviously and there was no difference compared HRV parameters with that on baseline. Only at...
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