Effect of the adjuvant dexmedetomidine on the hemodynamic at combined spinal-epidural anesthesia induction of elderly patients with lower limb surgery

Abstract

Objective To investigate the influence of continuous infusion of low-dose dexmedetomidine (DEX) on the hemodynamic in elderly surgical patients during induction of combined spinal-epidural anesthesia (CSEA).Methods Fifty elderly lower limb surgical patients were randomly divded into DEX group and control group(25 cases each).After the cannulation of left radial artery,the non-invasive hemodynamic monitor was connected,and the hemodynamic index was continuously monitored,including systolic blood pressure (SBP),diastolic blood pressure(DBP),heart rate(HR);and respiratory index was monitored,including respiration rate(RR),pulse oxygen saturation( SpO2 ).Before CSEA,the patients in DEX group were administered DEX of loading dose(0.5 μg · kg-1),then continuously infused with DEX at 0.2 ～ 0.4μg · kg-1 · h-1 to keep Ramsay sedation score from 4point to 5point,and SpO2 ≥95％.Normal saline was administered with an equal volume in control group.The SBP,DBP,HR,RR,SpO2 were recorded immediately at the T0,T1,T2,T3,T4 and T5.Results All hemodyanmic and respiratory parameters in both groups were normal during induction.Compared with T2 in DEX group,differences of SBP and DBP between two groups were statistically significant,and the value significantly lower at T3 (P ＜ 0.05 ) ;compared T2 with T1 in control group,differences of SBP,DBP and HR among three groups were statistically significant,and the value was significantly higher at T2 ( P ＜ 0.05 ).Compared with T2,SBP,DBP,HR were significantly lower than T3,( P ＜0.05).And RR of T1,T2,T3,T4,T5 in DEX group was significanfly lower than T0,with statistical significance( P ＜0.05) ;the difference of RR among different time was not statistically significant in control group(P ＞ 0.05 ).Conclusion The continuous infusion of small-dosage DEX during CSEA in elderly lower limb surgical patients may have little impact on cardiac function index when achieved effective sedation and analgesia. Key words: Aged ; Anesthesia; Hemodynamic