Effects of Intrathecal Dexmedetomidine on Low-Dose Bupivacaine Spinal Anesthesia in Elderly Patients Undergoing Transurethral Prostatectomy

Abstract

Low-dose bupivacaine can limit the spinal block level with minimal hemodynamic effects and yield a rapid recovery, but sometimes it may not provide adequate anesthesia for surgery. Dexmedetomidine, a selective α2-adrenoreceptor agonist, was shown to be a potent antinociceptive agent when given intrathecally in animals and humans. The purpose of this study was to evaluate the adjuvant effects of intrathecal dexmedetomidine in elderly patients undergoing transurethral prostate surgery with low-dose bupivacaine spinal anesthesia. Fifty-four patients undergoing transurethral prostate surgery were randomized into two groups receiving either dexmedetomidine 3 µg (n=27) or normal saline (n=27) intrathecally with 6 mg of 0.5% hyperbaric bupivacaine. The characteristics of the spinal block and postoperative analgesic effects were evaluated. The peak block level was similar for the two groups. However, the dexmedetomidine group demonstrated a faster onset time to the peak block and longer duration of spinal block than the saline group (p<0.01). The motor block scales at the time of peak sensory block and regression of 2-sensory dermatomes were higher in the dexmedetomidine group than in the saline group ( p<0.001). There was less analgesic request and the time to the first analgesic request was longer in the dexmedetomidine group than in the saline group (each 487, 345 min, p<0.05). Dexmedetomidine 3 µg when added to intrathecal bupivacaine 6 mg produced fast onset and a prolonged duration of sensory block and postoperative analgesia in elderly patients for transurethral surgery. However, recovery of motor block could be delayed in dexmedetomidine-added patients.Key words anaesthesia; spinal; dexmedetomidine; transurethral resection of prostate; bupivacaine; elderly patient Spinal block is a common anesthetic technique for patients undergoing transurethral resection of prostate (TURP). Most patients indicated for TURP are elderly and frequently associated with cardiopulmonary, endocrine, or other comorbidities.1) Thus, it is important to limit the block level to minimize hemodynamic changes during the spinal anesthesia in such patients.2,3) Low-dose local anesthetics can limit the block level and induce rapid recovery from anesthesia, but sometimes these low-dose local anesthetics may not provide an adequate anesthetic level for surgery. Intrathecal opioids or clonidine are frequently co-administered with local anesthetics to improve the anesthetic quality and postoperative analgesia [2][3][4][5][6][7][8] ; the synergistic action of clonidine with local anesthetics is well-established.6-8) Unlike opioids, intrathecal clonidine does not produce respiratory depression or pruritus, but usual dose of clonidine (15-150 µg) may be associated with bradycardia, hypotension, or sedation. 6-8)Dexmedetomidine is an S-enantiomer of medetomidine with a higher specificity for α2-adrenoreceptor (α2 : α1, 1620 : 1) compared to clonidine (α2 : α1, 220 : 1). It was first introduced into practical use as intravenous sedative after the appro...

Comparative Study of Bupivacaine alone versus Bupivacaine and Dexmedetomidine for Spinal Anesthesia in Hysterectomies

“…It has an added advantage because, if the sensory block is achieved earlier at T6 dermatome, surgery can also be started earlier in group II as compared with group I. Previously it was also observed that time taken for regression of sensory block to S1 dermatome was delayed with the addition of dexmedetomidine to bupivacaine [12,[16][17][18] , which is in accordance with the present study. Complete motor blockade was achieved earlier and the duration of motor block was more prolonged in group II as compared with group I.…”

“…Addition of dexmedetomidine to intrathecal bupivacaine produced prolonged postoperative analgesia, and requirement of rescue analgesia in the postoperative period was also decreased [13,[16][17][18][19] . In the present study, no sedative was given during premedication, and thus most of the patients had sedation score in the range of 0 and 1 at all measured intervals in both groups.…”

Comparison of effect of intrathecal dexmedetomidine and clonidine as an adjuvant to hyperbaric bupivacaine in patients undergoing surgery for fracture femur and tibia

“…24 In other studies, it was observed that addition of various doses of clonidine to bupivacaine intrathecally significantly prolongs duration of analgesia of bupivacaine, 16,27,28 while others reported that addition of dexmedetomidine to bupivacaine significantly prolongs the duration sensory and motor block and post-operative analgesia. 23,25,[29][30][31] …”

Effect of Different Doses of Dexmedetomidine as Adjuvant in Bupivacaine -Induced Subarachnoid Block for Traumatized Lower Limb Orthopaedic Surgery: A Prospective, Double-Blinded and Randomized Controlled Study

“…Previous few other studies have described the intrathecal use of dexmedetomidine in a wide range (2-10 μg) [17][18][19][20].…”