The Effect of 1 µg/kg Dexmedetomidine Combined with High-Volume/Low-Concentration Caudal Ropivacaine in Children Undergoing Ambulatory Orchiopexy

Abstract

When local anesthetics are used, the administration of dexmedetomidine (DEX) can prolong analgesic duration. However, the effect of caudal DEX on high volume/low concentration (HVLC) local anesthetics has not been studied. We investigated the analgesic effect of DEX added to a HVLC of ropivacaine for caudal block in children. Eighty children (the American Society of Anesthesiologists (ASA) status I; age, 1-6 years) undergoing ambulatory orchiopexy were enrolled in the study. Children were randomly assigned to undergo a caudal block with 1.5 mL/kg of 0.15% ropivacaine and either 1 µg/kg of DEX (DEX group, n 40) or the same amount of saline (Control group, n 40) under general anesthesia. The results showed that the time to first analgesic request was significantly longer in the DEX group than in the control group. The sevoflurane requirement for anesthesia and frequency of emergence agitation (EA) were also significantly lower in the DEX group. There was no difference in adverse events between the two groups. In conclusion, a dose of 1 µg/ kg of caudal DEX prolonged the first analgesic request time, although the immediate postoperative pain scores were comparable in both groups. Furthermore, caudal DEX significantly reduced the sevoflurane requirement and the frequency of EA.Key words dexmedetomidine; caudal block; child; orchiopexy Caudal block is common method for postoperative analgesia in children undergoing infra-umbilical surgery. One major limitation of caudal block is a relatively short analgesic duration owing to the single-injection. Thus, adjuvants such as ketamine, clonidine, or opioids are frequently added to the local anesthetics in order to improve analgesic efficacy and duration.1,2) The effectiveness of local anesthetics using in caudal block is dependent upon the dose, volume, and concentration of the local anesthetic solution, but high-concentration local anesthetics can increase the incidence of motor weakness, delayed micturition, or urinary retention. In children undergoing ambulatory surgery, such adverse effects can prolong the discharge time and may result in inadvertent admission. Recently, high-volume/low-concentration (HVLC) regimens for caudal blocks in children (1.5 mL/kg of 0.1-0.2% local anesthetics) have gained popularity following a report by Silvani et al. that demonstrated that a HVLC regimen provides a longer analgesic duration with less adverse effects than conventional dose/concentration. [3][4][5][6][7][8] However, the analgesic duration is still limited in caudal block with single-injection.Dexmedetomidine (DEX) is a highly selective α 2 adrenoceptor agonist with an α2/α1 selectivity ratio of 1600 : 1, and is eight times more potent than clonidine. 9) DEX is successfully used as an adjuvant in caudal blocks for children in order to reduce pain without inducing any significant respiratory and hemodynamic effects. Several studies have reported that in children, caudal DEX (1-2 µg/kg) with 0.25% bupivacaine (1 mL/kg) prolongs postoperative analgesic duration by 2.5-3 fold comp...

The Effect of Dexmedetomidine on Emergence Agitation or Delirium in Children After Anesthesia—A Systematic Review and Meta-Analysis of Clinical Studies

“…Five trials in the included studies were CCTs ( 36 , 46 , 65 , 66 , 76 ). The patients in 17 trials ( 20 , 22 , 28 – 30 , 32 , 39 , 43 , 49 , 50 , 52 , 54 , 61 , 64 , 72 , 74 , 78 ) underwent otolaryngology surgeries, those in 5 trials ( 36 , 44 , 66 , 67 , 70 ) underwent dental or cleft palate surgeries, those in 9 trials ( 19 , 26 , 38 , 40 , 53 , 55 – 57 , 63 ) underwent ophthalmic surgeries, those in 11 trials ( 21 , 27 , 33 , 34 , 37 , 41 , 42 , 47 , 68 , 69 , 71 ) underwent general or urological surgeries, those in 4 trials ( 23 , 31 , 62 , 73 ) underwent orthopedic surgeries, those in 1 trial ( 65 ) underwent cardiac surgery, those in 8 trials ( 24 , 45 , 46 , 58 – 60 , 75 , 79 ) underwent invasive examination or treatment, those in 5 trials ( 25 , 35 , 76 , 77 , 81 ) underwent non-invasive examination or treatment, and those in 3 trials ( 48 ,…”

“…Random sequence generation was assessed as a low risk of bias in 57 studies (98%), allocation concealment was assessed in 36 studies (62%), blinding of participants was assessed in 38 studies (66%), blinding of outcome assessment was assessed in 34 studies (59%), incomplete outcome data were assessed in 58 studies (100%), and selective outcome reporting was assessed in 56 studies (97%). Nineteen RCTs ( 24 , 26 , 27 , 32 , 33 , 37 , 41 , 45 , 53 , 54 , 56 , 58 – 61 , 64 , 67 , 73 , 81 ) were assessed to be of high quality ( Supplementary Figures 1 , 2 ). Bias risk of 5 CCTs ( 36 , 46 , 65 , 66 , 76 ) was assessed by NOS, and the number of stars was 7 from the study of Keles et al ( 36 ), 8 from the study of Riveros et al ( 46 ), 5 from the study of Jiang et al ( 65 ), 5 from the study of Long et al ( 66 ), and 8 from the study of Mason et al ( 76 ), respectively.…”

Caudal dexmedetomidine in pediatric caudal anesthesia

“…Of these, 5 were excluded for the following reasons: unpublished studies, [ 13 ] no available data on the outcome of interest in references, [ 14 , 15 ] non-English language, [ 16 ] and caudal anesthesia with lidocaine. [ 17 ] Finally, the remaining 12 studies [ 2 , 3 , 18 – 27 ] with existing data met our selection criteria and were included in the systematic review. Data of 5 studies, [ 18 , 20 , 21 , 24 , 25 ] which mainly involved in sedation score, was estimated from the median, range, and the size of the sample.…”

“…The aggregated results were studied in 11 trials [ 2 , 3 , 18 – 24 , 26 , 27 ] and shown in Figure 3 . The results suggest that the time to first rescue pain medication in CA+dexmedetomidine group was significantly longer than in the CA group (WMD = 7.32, 95% CI: 5.74–8.91, P < .00001).…”

“…[ 1 , 2 ] The effectiveness of local anesthetics used in caudal blocks depends on the dose, volume, and concentration of the local anesthetic solution, but high-concentration local anesthetics can increase the incidence of motor weakness, delayed micturition, or urinary retention. [ 3 ] In children undergoing ambulatory surgery, such adverse effects can prolong the discharge time and might result in inadvertent admission.…”