Dexmedetomidine during total knee arthroplasty performed under spinal anesthesia decreases opioid use: a randomized-controlled trial

Abstract

Background It remains unclear whether the opioidsparing effects of dexmedetomidine seen in patients undergoing general anesthesia are reproducible in patients undergoing spinal anesthesia. We hypothesized that the administration of intravenous dexmedetomidine for sedation during total knee arthroplasty under spinal anesthesia would decrease postoperative morphine consumption in the first 24 hr following surgery. Methods We conducted this prospective double-blind randomized-controlled trial in 40 patients (American Society of Anesthesiologists physical status I-III) undergoing total knee arthroplasty with a standardized spinal anesthetic. Patients were randomized to receive either a dexmedetomidine loading dose of 0.5 lgÁkg -1 over ten minutes, followed by an infusion of 0.5 lgÁkgÁhr -1 for the duration of the surgery, or a normal saline loading dose and an infusion of an equivalent volume. The primary outcome was the consumption of morphine delivered via patientcontrolled analgesia in the first 24 hr following surgery. Results The mean (SD) cumulative morphine at 24 hr in the dexmedetomidine group was 29.2 (11.2) mg compared with 61.2 (17.2) mg in the placebo group (mean difference, 32.0 mg; 95% confidence interval, 22.7 to 41.2; P \ 0.001). In the dexmedetomidine group, there was a delay in the time to first analgesic request (P = 0.003) and a reduction in the mean morphine use at six and 12 hr following surgery (both P \ 0.001).Conclusions Dexmedetomidine was associated with a significant decrease in morphine use in the first 24 hr following total knee arthroplasty. Our study shows that an intraoperative infusion of dexmedetomidine for sedation in patients receiving spinal anesthesia can produce postoperative analgesic effects. This offers another potential adjunct in the multimodal pain management of these patients. This trial was registered at ClinicalTrials.gov (identifier NCT02026141).

Postoperative pain treatment after total knee arthroplasty: A systematic review

“…The remaining trials demonstrated statistically significant analgesic effects. Four trials demonstrated a statistically significant effect on opioid-related adverse events: Sciatic nerve block a reduction in PONV [97, 98], dexmedetomidine a reduction in PONV and pruritus [125], and epidural analgesia with ropivacaine and morphine an increase in pruritus [115] (Table 9). …”

Effects of Inhalation Anesthesia vs. Total Intravenous Anesthesia (TIVA) vs. Spinal-Epidural Anesthesia on Deep Vein Thrombosis After Total Knee Arthroplasty

“…The effects of anesthesia were evaluated as good if pain was sensed during the operation process that was tolerable and did not affect the surgery. The effects of anesthesia were evaluated as bad if obvious pain was recorded during the operation process and consequently resulted in the surgery being unable to be carried out smoothly [ 17 ].…”

Methods for saving opioids in the perioperative period via intravenous, via neuraxial and in nervous blocks

“…A Cochrane review [6], that included 422 patients included in 7 RCTs concluded that their use in continuous intraoperative infusion at a dose of 0.5-1 μg/kg in bolus ± intraoperative infusion produced a statistically signifi cant reduction in opioid consumption in the fi rst 24 hours postoperatively despite not decreasing pain intensity measured on the analog visual scale (VAS). Most recent studies included patients in abdominal surgery [7], although subsequent studies have demonstrated its effi cacy in gynecologic [8], orthopedic [9], and neurosurgery surgery [10].…”