Sedative, hemodynamic, and respiratory effects of dexmedetomidine, propofol, and ketamine for intraoperative sedation during spinal anesthesia

ABSTRACT

This prospective, randomized study was performed to investigate and compare the effect of ultra operative sedatives dexmedetomidine, propofol, and ketamine, in patients undergoing urological procedures under spinal anesthesia with respect to sedation, hemodynamics, respiration, and side effects. The study included 60 adult male patients undergoing urological procedures [e.g. stone ureter and uretroscopy] under spinal anesthesia. Patients were randomized into 3 groups [n=20 in each group], all patients received spinal anesthesia followed by i.v. sedation with dexmedetomidine [bolus dose of 1 micro g/kg over 10 mm followed by iv. infusion of 0.2-0.5 micro g/kgm.], propofol [bolus dose of 0.5mg/kg followed by an intravenous infusion of 1-3mg/kg/h], or ketamine, after iv. administration of 0.01mg/kg midazolam, a continuous infusion of ketamine [0.5mg/kg/h] was started till the end of surgery. Hemodynamic data, oxygen saturation, and respiratory rate were monitored continuously and recorded at the beginning of the procedure and every 10min till the end of surgery and at 1 and 2h post operative. The sedation levels of the patients were assessed by the Ramsay sedation score and measured at 10-minute intervals; a score of 4 was targeted. Serum cortisol level was assessed before surgery [baseline], at 30 mm after skin incision, and 2h post operative. After surgery, the patients were observed in the recovery room until the motor block resolved. Time to the first analgesic demand [VAS 4-5] was recorded. The onset of sedation, and recovery time were also recorded. Side effects such as respiratory depression, hypotension, bradycardia, increased secretions, nausea, vomiting, and visual disturbances were recorded. Demographic and clinical data were comparable in all groups as regards age, sex, ASA physical status, body weight, and operative time. Hemodynamic parameters [SBP, DBP and HR] were comparable in the three groups at baseline. Significant reduction in SBP and DBP was recorded in the three groups after spinal anesthesia which responded well to fluid resuscitation. After 10min of starting sedative infusion SBP and DBP significantly reduced in dexmedetomidine and propofol groups [compared to group III] till the end of the study. HR mean values also showed significant reduction in the three study groups after spinal anesthesia [as compared to baseline]. HR was significantly lower in dexmedetomidine group after starting sedative infusion till end of the study. Serum cortisol level was significantly increased in the three groups compared to baseline reading at 30min and 2h of the study. Serum cortisol at 30min after skin incision in the three groups respectively [19.64 +/- 1.4 micro g/dL] - [23.31 +/- 2.4 micro g/dL] - [23.20 +/- 2.6 micro g/dL]. Serum cortisol at 2h post operative [19.90 +/- 1.3 micro g/dL] - [25.92 +/- 2.7 micro g/dL] - [24.14 +/- 3.1 micro g/dl] in the three groups respectively. Significant lower cortisol level was recorded in dexmedetomidine group compared to group II and III at 30min and 2h post operative. Respiratory rate was decreased significantly from baseline in all groups during sedation [p<0.05] with insignificant difference between groups before or during sedation. Spo2 did not fall below 93% in any patient in dexmedetomidine and ketamine groups during the study, but Spo2<93% was observed in two patients in propofol group. As regards complications, 2 patients in propofol group had respiratory depression. 2 patients in dexmedetomidine group had bradycardia [HR<50 beat/min]. Hypotension was recorded in 1 patient in dexmedetomidine group. Increased secretion was observed in 2 patients in ketamine group. There was no nausea, vomiting, visual disturbances, or hallucinations in the three groups in the postoperative period. In adult patients undergoing urological procedures under spinal anesthesia dexmedetomidine can be used safely. It can provide easily controllable analgesia and sedation without respiratory depression and good attenuating effect on stress response