Methods of prolonging the effect of caudal block in children

Caudal epidural blockade is one of the most frequently administered regional anesthesia techniques in children. It is a supplement during general anesthesia and for providing postoperative analgesia in pediatrics for sub-umbilical surgeries, especially for genitourinary surgeries. However, the duration of the analgesic effect is occasionally unsatisfactory. In this review, we discuss the main advantages and disadvantages of different techniques to prolong postoperative analgesia for single-injection caudal blockade in children. A literature search of the keywords "caudal", "analgesia", "pediatric", and "children" was performed using PubMed and Web of Science databases. We highlight that analgesic quality correlates substantially with the local anesthetic's type, dose, the timing relationship between caudal block and surgery, caudal catheterization, and administration of epidural opioids or other adjuvant drugs.

Comparison of adjuvant pharmaceuticals for caudal block in pediatric lower abdominal and urological surgeries: A network meta-analysis

STUDY OBJECTIVE

Caudal block helps relieve pain after sub-umbilical surgery in pediatric patients; however, the duration for which it exerts its analgesic effect is limited. The addition of certain adjuvant agents to local anesthetics (LAs) that are used to administer caudal block can prolong postoperative analgesia. Therefore, we aimed to compare the efficiencies and side effects of caudal adjuvants in the settings of pediatric lower abdominal and urological surgeries.

DESIGN

A network meta-analysis (NMA).

PATIENTS

One hundred and twelve randomized controlled trials (RCTs) involving 6800 pediatric patients were included in the final analysis.

INTERVENTIONS

Different adjuvant agents, namely clonidine, dexamethasone, dexmedetomidine, fentanyl, ketamine, magnesium, midazolam, morphine, neostigmine, and tramadol.

MEASUREMENTS

The primary outcome was the duration of analgesia. The secondary outcomes included the requirement for additional analgesia, analgesic consumption, and postoperative complications. The effects and rankings were evaluated using NMA and the surface under the cumulative ranking curve scores, respectively.

RESULTS

Neostigmine, dexmedetomidine, and dexamethasone were found to be the three most effective adjuvants that prolong the duration of analgesia for caudal block, and these adjuvants extended this duration by 8.9 h (95% confidence interval [CI], 7.1-10.7), 7.3 h (95% CI, 6.0-8.6), and 5.9 h (95% CI, 4.0-7.7), respectively. Caudal neostigmine was associated with an increase in the incidence of postoperative nausea and vomiting, whereas dexmedetomidine and dexamethasone showed no postoperative complications.

CONCLUSIONS

This NMA provided evidence and suggested that dexmedetomidine and dexamethasone may be the most beneficial adjuvant pharmaceutics adding to LAs for caudal block in children. However, given the off-label status of caudal dexmedetomidine and dexamethasone, further high-quality RCTs are still warranted, especially to determine whether delayed neurological complications will occur.

Efficacy and safety of caudal dexmedetomidine in pediatric infra-umbilical surgery: a meta-analysis and trial-sequential analysis of randomized controlled trials

BACKGROUND

Dexmedetomidine is used as a local-anesthetics adjuvant in caudal block to prolong analgesia in pediatric infra-umbilical surgery.

OBJECTIVE

We evaluated the analgesic efficacy and safety of the addition of caudal dexmedetomidine to local anesthetics (vs local anesthetics alone) in pediatric infra-umbilical surgery.

EVIDENCE REVIEW

We searched 10 databases for randomized controlled trials (RCTs) of pediatric patients undergoing infra-umbilical surgery, comparing caudal block with and without dexmedetomidine as local anesthetic adjuvant. We performed a frequentist random-effects meta-analysis (R statistical package). We analyzed continuous outcomes as a ratio of means (ROM) and dichotomous data as relative risk (RR), along with 95% CI. We included 19 RCTs (n=1190 pediatric patients) in the meta-analysis. The primary outcome was duration of analgesia (defined as 'the time from caudal injection to the time at which the study-specific pain score was greater than a cut-off threshold').

FINDINGS

Data from 19 included RCTs (n=1190) suggested that compared with control (mean duration 346 min), the addition of caudal dexmedetomidine significantly prolonged the duration of analgesia (ratio of means 2.14, 95% CI 1.83 to 2.49, p<0.001; 'moderate' evidence). Trial-sequential analysis showed adequate 'information size' for the primary outcome. Caudal dexmedetomidine also reduced the number of analgesic administrations ('low' evidence), total acetaminophen dose ('moderate' evidence) and the risk of emergence delirium ('moderate' evidence). There were no significant differences in adverse effects such as hypotension, bradycardia, post-operative nausea and vomiting, urinary retention and respiratory depression.

CONCLUSIONS

Our results suggest that the addition of dexmedetomidine to local anesthetic in caudal block significantly improves the duration of analgesia and reduces the analgesic requirements, while maintaining a similar risk-profile compared with local anesthetic alone. Further data on neurological safety are needed.

Caudal dexmedetomidine in pediatric caudal anesthesia: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVES

To evaluate the efficacy and safety of caudal dexmedetomidine in pediatric caudal anesthesia (CA).

METHODS

We searched PubMed, Embased, and Cochrane Library (from inception to June 2019) for eligible studies. The primary outcomes were the time to first analgesia, time of postoperative eye opening, intraoperative endtidal sevoflurane concentration, and postoperative sedation score. We calculated pooled risk ratios (RR) and 95% CIs using random- or fixed-effects models.

RESULTS

Thirteen trials involving 793 patients were found. Meta-analysis showed that the time to first rescue pain medication and the time from the end of anesthesia to eye opening in the CA+dexmedetomidine group were significantly longer than in the CA group (P < .00001). The intraoperative end-tidal sevoflurane concentration in the CA+dexmedetomidine group was significantly decreased (P < .00001). Dexmedetomidine appeared to increase the rate of bradycardia in the CA+dexmedetomidine group (P = .04). Additionally, the sedation score in the CA+ dexmedetomidine group was significantly higher at 2 hours after the operation compared with the CA group (P < .00001 at 2 hours).

CONCLUSIONS

Caudally administered dexmedetomidine is a good alternative for prolonging postoperative analgesia with less pain, decreased intraoperative end-tidal sevoflurane concentration, and full postoperative sedation.

Addition of dexmedetomidine, tramadol and neostigmine to lidocaine 1.5% increasing the duration of postoperative analgesia in the lower abdominal pain surgery among children: A double-blinded randomized clinical study

Pain is a common complication after surgery. Insufficient control of postoperative pain has adverse effects on the physiological, metabolic and psychological state of the child. The use of local analgesics and anesthetics alone cannot produce complete anesthesia and intraoperative comfort. The addition of adjuvant drugs is commonly used to improve the quality of the block. Therefore, adding new supplements may increase the duration of analgesia. The aim of this study was to compare the addition of dexmedetomidine, tramadol and neostigmine to lidocaine 1.5% in increasing the duration of postoperative analgesia in the lower abdominal pain surgery in children aged 2–8 years. This double-blind randomized clinical trial was conducted on children candidate for lower abdominal surgery. The 96 patients were randomly divided into 3 groups including dexmedetomidine, neostigmine, and tramadol. For all children, 3 mg of midazolam was administered orally before entering the operating room. The patients underwent general anesthesia with 2 μg/kg fentanyl, 0.03 mg/kg midazolam, 0.5 mg/kg atracurium and 5–6 mg/kg thiopental. After determining the hiatus membrane, 2 mL syringes containing air and distilled water (each of which 1 mL) slowly entered the space. After eliminating caudal resistance, 1.5% lidocaine was injected at dose of 0.5 mL/kg. A total of 96 patients were enrolled in this study. The results revealed that pain scores in the dexmedetomidine group in recovery, 2, 6 and 12 hours after surgery were less than the other two groups. Furthermore, the tramadol group showed a lower score in comparison with the neostigmine group and the duration of analgesia in the dexmedetomidine group was more than the other two groups. In addition, the mean of analgesic at 24 hours after operation in the dexmedetomidine group was lower as compared to the other two groups, indicating the effect of dexmedetomidine as an adjuvant in increasing the duration of analgesia and reducing postoperative pain in patients along with lidocaine 1.5%. All three drugs (neostigmine, tramadol and dexmedetomidine drugs), along with other local anesthetic, increased the duration of analgesia and decreased postoperative pain in children. The effect of dexmedetomidine was greater than the other two drugs. The study was approved by the Ethics Committee of Arak University of Medical Sciences, Iran (approved No. IR.ARAKMU.REC.1396.112) on October 28, 2017, and registered at Iranian Registry of Clinical Trials (registration No. IRCT20141209020258N83) on August 29, 2018.

HYR-PB21-LA, a potential extended-release bupivacaine formulation, produces long-lasting local anesthesia in rats and guinea pigs

BACKGROUND

Effective postoperative pain management plays a key role in enhancing recovery of patients after surgery. Bupivacaine hydrochloride is one of the most commonly local anesthetics used for the postoperative pain control. However, the relatively short anesthesia duration of bupivacaine preparations limited their clinical application.

METHODS

Both guinea pig pin-prick study and rat tail-flick test were performed to evaluate the local anesthesia efficacy of HYR-PB21-LA, a new microparticle suspension injection of bupivacaine pamoate.

RESULTS

In the pin-prick test, the complete cutaneous trunci muscle reflex inhibitions were observed at 30 min in all treatment groups containing bupivacaine. In comparison with 6.7 mg/mL HYR-PB21-LA, both 10 and 20 mg/mL HYR-PB21-LA groups had significantly higher area under effect time curve (AUEC) values (p<0.001 and p<0.0001) and slower offset time (p<0.0001). Significantly higher AUEC (p<0.0001) and slower offset time (p<0.0001) were also found in 10 mg/mL HYR-PB21-LA treatment group compared with bupivacaine liposome injectable suspension (liposomal bupivacaine). In the rat tail-flick test, significantly increased local anesthesia effect was lasted for 5 hours after 2.5 mg/mL HYR-PB21-LA administration, which was fivefold longer than bupivacaine hydrochloride. The longer lasted efficacy of significantly increased local anesthesia was also observed in 5 mg/mLHYR-PB21-LA than those in liposomal bupivacaine (8 hour vs 1 hour).

CONCLUSIONS

The results demonstrated that the HYR-PB21-LA produced longer local anesthesia effect than current clinical preparations of bupivacaine in two animal models. These findings raise the potential clinical value of HYR-PB21-LA as a long-lasting local anesthesia for controlling postsurgical pain in humans.

Effects of adding dexmedetomidine to local infiltration of bupivacaine on postoperative pain in pediatric herniorrhaphy: a randomized clinical trial

Background

Postoperative pain is a major problem, especially in children, as their tolerance level is lower and several drugs are contraindicated in childhood. This study aimed to compare the effect of dexmedetomidine added to local infiltration of bupivacaine for postoperative pain relief in children undergoing inguinal herniorrhaphy.

Methods

This double-blind, randomized clinical trial included 60 children aged 6–72 months undergoing unilateral herniorrhaphy at selected hospitals in Shiraz, Iran, randomly allocated into two groups, 30 in each group. One group received 1 µg/kg dexmedetomidine plus local infiltration of 0.2 ml/kg bupivacaine 0.5% at the incision site before surgery (BD), and the other group received bupivacaine and normal saline (BO). Analgesic requirements, emergence time, and nausea/vomiting, postoperative pain and sedation scores were assessed for 4 h after the operation. Heart rate (HR), systolic blood pressure (SBP), and oxygen saturation (SaO₂) were recorded at baseline, and at 10 and 20 min after injection.

Results

Eighty percent were boy in each group; mean age was 22.75 ± 18.63 months. SaO₂ and SBP were not different between the groups, while HR was significantly lower in the Group BD at 10 and 20 min after injection (P < 0.05). Group BD had a lower pain score at 1 and 2 h after the operation, a higher sedation score at the first three time intervals, and longer emergence time than Group BO (all P < 0.001). Group BD had a lower pain score at 1 and 2 h after the operation (P < 0.001, P < 0.047 respectively).

Conclusions

Addition of dexmedetomidine to local infiltration of bupivacaine in children undergoing herniorrhaphy significantly reduced postoperative pain and increased sedation.

Comparison of Dexmedetomidine and Morphine as Adjuvants to Bupivacaine for Epidural Anesthesia in Leg Fracture Surgery: A Randomized Clinical Trial

Background

Epidural block approach and drugs are common options for improving the sensory and motor block duration and postoperative pain management.

Objectives

The study aimed to compare the analgesic effects of dexmedetomidine and morphine as adjuvants to bupivacaine for epidural anesthesia in leg fracture surgery.

Methods

This prospective clinical trial was conducted on patients (n = 80, age range: 18 - 60 years) categorized as ASA class I or II. After a clinical examination, the patients were allocated to receive either lumbar epidural bupivacaine + morphine (BM) (12 mL bupivacaine 0.5% + morphine 2 mg) or bupivacaine + dexmedetomidine (BD) (12 mL bupivacaine 0.5% + dexmedetomidine 1 µg/kg). After drug administration, the sensory block level was assessed at 2-min intervals using the Cold Swab method until it reached the T12 level. At the T12 level of sensory block, the surgery began when motor block reached grade 3 of the modified Bromage scale.

Results

The BD group had a significantly shorter time to reach the sensory and motor block than the BM group (P < 0.001). The duration of sensory and motor block was significantly longer in the group BD than in the BM group (P < 0.001). Moreover, the BD group showed lower VAS scores (P < 0.0001) and longer time to first analgesia demand than the BM group.

Conclusions

Combined bupivacaine + dexmedetomidine prolongs the sensory and motor block duration and controls postoperative pain more effectively, indicating that it is an appropriate combination for epidural anesthesia.

Retrobulbar dexmedetomidine in pediatric vitreoretinal surgery eliminates the need for intraoperative fentanyl and postoperative analgesia: A randomized controlled study

Purpose

This study evaluated the efficacy of retrobulbar ropivacaine plus dexmedetomidine compared with systemic fentanyl in pediatric vitreoretinal (VR) surgery.

Methods

This prospective double-blind, randomized controlled study was performed in 60 children undergoing VR surgery, age from 2 to 7 years. After general anesthesia, the following procedure was administrated: (1) retrobulbar block with 0.5% ropivacaine plus dexmedetomidine 1 μg/kg (group RD, n = 20), (2) retrobulbar block with 0.5% ropivacaine (group RB, n = 20), and (3) control group with general anesthesia only (group F, n = 20). Hemodynamics, postoperative pain scores, anesthetics consumption (remifentanil, propofol, fentanyl), and emergence agitation were recorded.

Results

Respiratory depression was observed in 7 of the 20 patients in group F after the laryngeal mask airway was removed in the operating room, compared with none in groups RD and RB. All patients in group F required intraoperative rescue fentanyl (average intraoperative fentanyl consumption, 26.6 ± 12.6 μg per patient). Some rescue fentanyl was required in group RB (three patients required one dose of rescue fentanyl). Patients in group RD required none. Groups RD and RB reported lower pain scores than group F at 4 h postoperatively (RD group: P < 0.001; RB group: P =0.002); pain scores in group RD were lower than that in group F at 6 h postoperatively (P < 0.001).

Conclusion

Retrobulbar dexmedetomidine as an adjuvant to ropivacaine is a safe and effective alternative to systemic fentanyl. This regimen provides better pain management, hemodynamic stability, and stress response suppression in pediatric VR surgery.

Effects of Caudal Epidural Dexmedetomidine on Pain, Erythrocyte Sedimentation Rate and Quality of Life in Patients with Failed Back Surgery Syndrome; A Randomized Clinical Trial

Objective

To evaluate the effects of dexmedetomidine in caudal epidural on controlling pain, erythrocyte sedimentation rate (ESR) and quality of life in patients with failed back surgery syndrome (FBSS).

Methods

The study was a single-blind clinical trial. From the total of 70 patients suffering from low back pain caused by a failed back surgery syndrome were referred to Akhtar and Imam Hossein Hospitals between the ages of 25 to 75 years with a history of back pain more than 12 weeks and a visual analogue scale (VAS) score of higher than 3, and 50 people were randomly selected and divided into two groups of dexmedetomidine and control. The control group received an epidural dose of 10 cc containing triamcinolone and bupivacaine, and the dexmedetomidine group received an epidural dose of 10 cc, containing dexmedetomidine, triamcinolones and bupivacaine with diluted normal saline. Epidural caudal injections were performed in the abdomen in a laid down position. Before starting the study and at the end of the fourth week, the two test groups were measured for visual analogue scale (VAS) and ESR and were asked to complete the quality of life questionnaire.

Results

Overall, 50 patients with FBSS were enrolled. The mean age was 53.88 ± 8.9 years (range 25-75); 54% (27/50) were men. The results showed that the injection of dexmedetomidine in epidural caudal was associated with decreased pain (p=0.001) and improved quality of life (p=0.022), while showed no significant effect on ESR (p=0.110).

Conclusion

Administration of dexmedetomidine in the epidural caudal is effective in controlling pain and quality of life in patients with failed back surgery syndrome.

The Efficacy and Safety of Dexmedetomidine Combined with Bupivacaine on Caudal Epidural Block in Children: A Meta-Analysis

BACKGROUND This meta-analysis was conducted to evaluate the analgesics effect and safety of dexmedetomidine (DEX) combined with bupivacaine (BU) on caudal epidural block. MATERIAL AND METHODS Published studies were identified using the PubMed, EMBASE, Web of Science, and the Cochrane Library from inception until October 2017. Relative risk (RR), the standardized mean difference (SMD), and the corresponding 95% confidence interval (CI) were calculated using the STATA 12.0. RESULTS Ten randomized controlled trials (RCTs) were selected for this meta-analysis, involving a total of 691 patients. There was a longer duration of postoperative analgesia in children receiving DEX (SMD=3.19, 95% CI: 2.16-4.22, P<0.001). Furthermore, there was a lower number of patients requiring rescue analgesics in the (BU) + (DEX) group (6 hours: RR=0.09, 95% CI: 0.05-0.17, P<0.001; 12 hours: RR=0.50, 95% CI: 0.32-0.79, P=0.003; 24 hours: RR=0.66, 95% CI: 0.51-0.85, P=0.002). Finally, the occurrence of adverse events, between BU and DEX + BU group, was not statistically significant (RR=0.96, 95% CI: 0.58-1.58, P>0.05). CONCLUSIONS DEX seems to be a promising adjuvant to BU increase duration of caudal analgesia without an increase in side effects in children. However, the result may be influenced by clinical heterogeneity. More large-scale, multicenter, approaching, double-blinded RCTs are required to confirm our results.

Caudal and intravenous dexmedetomidine similarly prolong the duration of caudal analgesia in children: A randomized controlled trial

BACKGROUND

Dexmedetomidine can prolong the duration of action of a local anesthetic agent, but the route of administration that is the most beneficial remains unclear. The purpose of this study was to compare the clinical effectiveness of caudal or intravenous dexmedetomidine administration on postoperative analgesia in children undergoing inguinal hernia repair given caudal levobupivacaine.

METHODS

This was a prospective, randomized, double-blinded, placebo-controlled trial. Ninety ASA I subjects, aged 2-5 year, undergoing unilateral inguinal hernia repair were enrolled. The children were randomized in a double-blind fashion to three groups. The L-Dcau group received 1 mL/kg of caudal 0.25% levobupivacaine plus 1 μg/kg dexmedetomidine and IV 20 mL saline. The L-Div group received 1 mL/kg of caudal 0.25% levobupivacaine and IV 1 μg/kg dexmedetomidine in 20 mL saline. The L group received 1 mL/kg of caudal 0.25% levobupivacaine and IV 20 mL saline. The primary outcome was the duration of analgesia, which was defined as the time from the caudal block to a Postoperative Pain Scale (CHIPPS) score ≥4. Secondary outcomes were the number of patients requiring rescue analgesia, pain intensity, the incidence of emergence agitation, intraoperative hemodynamic variations, residual motor block, and adverse effects.

RESULTS

The median duration of analgesia in the L-Dcau group was 14.2 hour compared to 6 hour in the L group with a median difference of 8.5 hour [95% CI (6.5, 10.5), P < 0.001]. The median duration of analgesia in the L-Div group was 12.4 hour compared to 6 hour in the L group with a median difference of 6.4 hour [95% CI (4, 8.5), P < 0.001]. Fewer patients in the L-Dcau and L-Div groups required rescue analgesia in the first 24 hour postoperatively compared to the L group, although there was no significant difference between the L-Dcau and L-Div groups for these outcomes. Both dexmedetomidine routes reduced the pain and the incidence of emergence agitation. No bradycardia, hypotension, or motor block was observed in any of the three groups.

CONCLUSION

Caudal and IV dexmedetomidine similarly prolong the duration of analgesia produced by caudal levobupivacaine.

Caudal Analgesia for Hypospadias in Pediatrics: Comparative Evaluation of Adjuvants Dexamethasone and Dexmedetomidine Combination versus Dexamethasone or Dexmedetomidine to Bupivacaine: A Prospective, Double-Blinded, Randomized Comparative Study

Background:

Caudal block is the most commonly used regional anesthetic technique in pediatric surgeries; different additives have been used for better and safer outcome.

Aim:

The aim of this study is to compare the combination of dexamethasone and dexmedetomidine as adjuvants to bupivacaine versus using each agent solely with bupivacaine in pediatric caudal block as regards their efficiency in pain relief (the duration of postoperative analgesia, first time to request analgesia, and modified objective pain score [MOPS]).

Study Design:

This was a prospective, double-blinded, randomized study.

Patients and Methods:

Patients and Methods: Sixty-three children scheduled for hypospadias surgery wererandomized into three groupsaccording to the adjuvant drug added to caudal bupivacaine : Group I (n = 21): dexamethasone 0.1 mg/kg + 0.5 mg/kg bupivacaine 0.25%, Group II (n = 21): dexmedetomidine0.01 μg/kg + 0.5 mg/kg bupivacaine 0.25% and Group III (n = 21): dexamethasone 0.1 mg/kg + dexmedetomidine 0.01 μg/kg + 0.5 mg/kgbupivacaine 0.25%. Intraoperative and postoperative hemodynamics were recorded. In postoperative anesthesia care unit and then the ward, MOPS and sedation score were recorded at 30 min and 1, 2, 3, 6 and 12 h. Further, the time of first analgesic request and side effects were recorded.

Statistical Analysis:

Categorical data were presented as frequencies (%) and analyzed using Chi-square test. Continuous data were presented as mean (standard deviation) and median (quartiles). Continuous data were analyzed using one-way analysis of variance for single measures and two-way mixed model for repeated measures. Kaplan–Meier analysis was performed for the duration of analgesia.

Results:

In Group III, MOPS was lower than Groups I and II at the study times. Further, Group III had prolonged time for first request of analgesic. Sedation scores were prolonged in Group III and Group II than in Group I. There was a reduction in heart rates in Group III more than Group I and Group II but with no significant difference. However, there was a significant reduction in mean arterial blood pressure 30 min intraoperatively and postoperatively in Group III as compared to Groups I and II.

Conclusion:

The addition of combined dexmedetomidine at a dose of 1 μg/kg and dexamethasone 0.1 mg/kg to caudal bupivacaine seemed to be an attractive alternative to each drug if used alone with more prolonged analgesia and almost no adverse effects.

Perineural versus intravenous dexamethasone as an adjuvant in regional anesthesia: a systematic review and meta-analysis

Background

Dexamethasone is a common adjuvant for local anesthetics in regional anesthesia, but the optimal route of administration is controversial. Therefore, we did a systematic review and meta-analysis of randomized controlled trials to assess the effect of perineural versus intravenous dexamethasone on local anesthetic regional nerve-blockade outcomes.

Materials and methods

Medline (through PubMed), Embase, Cochrane, Web of Science, and Biosis Previews databases were systematically searched (published from inception of each database to January 1, 2017) to identify randomized controlled trials. The data of the selected trials were statistically analyzed to find any significant differences between the two modalities. The primary outcome was the duration of analgesia. Secondary outcomes included duration of motor block, postoperative nausea and vomiting, and postoperative analgesic dose at 24 hours. We conducted a planned subgroup analysis to compare the effects between adding epinephrine or not.

Results

Ten randomized controlled trials met the inclusion criteria of our analysis, with a total of 749 patients. Without the addition of epinephrine, the effects of perineural and intravenous dexamethasone were equivalent concerning the duration of analgesia (mean difference 0.03 hours, 95% CI –0.17 to 0.24). However, with the addition of epinephrine, the analgesic duration of perineural dexamethasone versus intravenous dexamethasone was prolonged (mean difference 3.96 hours, 95% CI 2.66–5.27). Likewise, the impact of epinephrine was the same on the duration of motor block. The two routes of administration did not show any significant differences in the incidence of postoperative nausea and vomiting, nor on postoperative analgesic consumption at 24 hours.

Conclusion

Our results show that perineural dexamethasone can prolong the effects of analgesic duration when compared to the intravenous route, only when epinephrine is coadministered. Without epinephrine, the two modalities show equivalent effect as adjuvants on regional anesthesia.

Nonopioid (Dexmedetomidine, Dexamethasone, Magnesium) Adjuvant to Ropivacaine Caudal Anesthesia in Pediatric Patients Undergoing Infraumbilical Surgeries: A Comparative Study

Background:

Desirable adjuvants to caudal ropivacaine are the one which prolongs analgesia and free of side effects. We compared nonopioid drugs dexmedetomidine, dexamethasone, and magnesium as adjuvants to ropivacaine caudal analgesia in pediatric patients undergoing infraumbilical surgeries.

Materials and Methods:

This study was done on 128 pediatric patients (3–12-year olds) undergoing infraumbilical surgeries; they were randomly allocated to four groups to receive normal saline, dexmedetomidine 1 μg/kg, dexamethasone 0.1 mg/kg, and magnesium sulfate 50 mg with injection ropivacaine 0.2% in the dose 0.5 ml/kg caudally. Modified Objective Pain Score and Ramsay Sedation Score, duration of analgesia, hemodynamic changes, and side effects were assessed. ANOVA test was used for numerical values as data were expressed in mean and standard deviation. Kruskal–Wallis test was used for postoperative pain and sedation score as data were expressed as median and range.

Results:

The demographic data and hemodynamics were comparable. There was a significant prolongation of duration of analgesia in all study groups, dexmedetomidine (406.2 ± 45.5 min), dexamethasone (450.0 ± 72.6 min), and magnesium (325.0 ± 45.8 min) as compared to ropivacaine (285.9 ± 52.7 min) group. None of the adjuvants resulted in either excess or prolonged sedation. No side effects were encountered.

Conclusion:

The adjuvants dexmedetomidine, dexamethasone, and magnesium added to ropivacaine prolong caudal analgesic duration without any sedation or side effect.

The Effect of Dexmedetomidine on Lumbar Epidural Injection for Failed Back Surgery Syndrome

Purpose. Failed back surgery syndrome is a chronic pain condition requiring rapid, effective, and efficient management. This study evaluates the effect of adding dexmedetomidine to lumbar epidural steroids in patients with failed back surgery syndrome. Methods. Fifty patients suffering from failed back surgery syndrome were randomly assigned to one of two groups, receiving an epidural injection of 20 mL of either a mixture of betamethasone (14 mg) and bupivacaine 0.5 mg (group C) or a mixture of betamethasone (14 mg), bupivacaine 0.5 mg, and dexmedetomidine (0.5 μg/kg) (group D) adjusted to the volume with normal saline. The effect was evaluated using visual analogue scale (VAS), analgesic requirement, and Oswestry disability index 2 weeks, 4 weeks, 8 weeks, and 12 weeks after injection. Results. VAS and ibuprofen consumption showed a significant reduction in group D. The Oswestry disability index was significantly improved in group D. There were no records of hypotension, bradycardia, sedation, or hypoxemia in both groups. Conclusion. The present study demonstrated potential safe and effective usage of adding dexmedetomidine to epidural steroid to control pain in patients with failed back surgery syndrome.

Perineural Dexmedetomidine as an Adjuvant Reduces the Median Effective Concentration of Lidocaine for Obturator Nerve Blocking: A Double-Blinded Randomized Controlled Trial

Research suggests that the addition of dexmedetomidine to local anesthetics can prolong peripheral nerve blocks; however, it is not known whether dexmedetomidine can reduce the quantity of local anesthetic needed. We hypothesized that adding dexmedetomidine as an adjuvant to an obturator nerve block could reduce the median effective concentration of lidocaine. In this double-blinded randomized trial, 60 patients scheduled for elective transurethral resection of bladder tumors on the lateral wall were randomly divided into two groups: the control group (C group, n = 30) and the dexmedetomidine group (D group, n = 30). Two main branches of the obturator nerve (i.e., anterior and posterior) were identified using neural stimulation at the inguinal level, with only lidocaine used for the C group and 1 μg/kg dexmedetomidine combined with lidocaine used for the D group. The median effective concentration was determined by an up-and-down sequential trial. The ratio of two consecutive concentrations was 1.2. The median effective concentration (95% confidence interval) of lidocaine was 0.57% (0.54%-0.62%) in the C group and 0.29% (0.28%-0.38%) in the D group. The median effective concentration of lidocaine was significantly lower in the D group than in the C group (p < 0.05). These results indicate that dexmedetomidine (1 μg/kg) in combination with lidocaine for obturator nerve block decreases the median effective concentration of lidocaine.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02066727.

Effect of Continuous Paravertebral Dexmedetomidine Administration on Intraoperative Anesthetic Drug Requirement and Post-Thoracotomy Pain Syndrome After Thoracotomy: A Randomized Controlled Trial

OBJECTIVES

To assess the effect of paravertebral administration of dexmedetomidine as an adjuvant to local anesthetic on the intraoperative anesthetic drug requirement and incidence of post-thoracotomy pain syndrome.

DESIGN

Prospective, randomized, controlled, double-blind trial.

SETTING

Single university hospital.

PARTICIPANTS

The study comprised 30 patients who underwent elective thoracotomy and were assigned randomly to either the Ropin or Dexem group (n = 15 each).

INTERVENTIONS

All patients received the study medications through paravertebral catheter. Patients in the Ropin group received a bolus of 15 mL of 0.75% ropivacaine over 3-to-5 minutes followed by an infusion of 0.2% ropivacaine at 0.1 mL/kg/hour. Patients in the Dexem group received 15 mL of 0.75% ropivacaine plus dexmedetomidine, 1 µg/kg bolus over 3-to-5 minutes followed by an infusion of 0.2% ropivacaine plus 0.2 µg/kg/hour of dexmedetomidine at 0.1 mL/kg/hour.

MEASUREMENTS AND MAIN RESULTS

The primary outcome of the study was intraoperative anesthetic drug requirement. The secondary outcome was the incidence of post-thoracotomy pain syndrome 2 months after surgery. The amount of propofol required for induction of anesthesia was significantly less in the Dexem group (Dexem 49.33±20.51 v 74.33±18.40 in the Ropin group, p = 0.002). End-tidal isoflurane needed to maintain target entropy was significantly less in the Dexem group at all time points. Intraoperative fentanyl requirement was lower in the Dexem group (Dexem 115.33±33.77 v 178.67±32.48 in the Ropin group, p = 0.002). Postoperative pain scores and morphine consumption were significantly less in the Dexem group (p<0.001). The incidence of post-thoracotomy pain syndrome was comparable between the 2 groups (69.23% v 50%, p = 0.496).

CONCLUSIONS

Paravertebral dexmedetomidine administration resulted in decreased intraoperative anesthetic drug requirement, less pain, and lower requirements of supplemental opioid in the postoperative period. However, it had no effect on the incidence of post-thoracotomy pain syndrome.

Dexmedetomidine as an adjuvant to bupivacaine in caudal analgesia in children

Context:

Postoperative pain management is becoming an integral part of anesthesia care. Various techniques of pediatric pain relief have been designed among which the most commonly practiced is caudal epidural block. Several adjuvants have been used to prolong the duration of caudal analgesia such as clonidine, neostigmine, ketamine, opioids, and ephedrine. We have designed the study using dexmedetomidine as an adjuvant to assess analgesic efficacy, duration of postoperative analgesia, hemodynamic stability, postoperative sedation, and any adverse effects in children.

Aims:

The aim is to study the effects of dexmedetomidine as an adjuvant to bupivacaine in caudal analgesia in pediatric patients posted for infraumbilical surgeries.

Settings and Design:

This is a randomized, double-blind study in which effect of dexmedetomidine is studied when added to bupivacaine in the caudal epidural block. The observations are made intraoperatively for hemodynamic stability and postoperatively for the duration of analgesia.

Subjects and Methods:

This study was conducted in 100 children of American Society of Anesthesiologists physical status I and II, aged 2–10 years, undergoing elective infraumbilical surgeries. They were divided into two groups as follows: Group A: (0.25%) bupivacaine 1 ml/kg + normal saline (NS) 1 ml. Group B: (0.25%) bupivacaine 1 ml/kg + 1 μg/kg dexmedetomidine in 1 ml NS. As this study was double-blind, patients were randomly assigned to receive either (bupivacaine + saline) or (bupivacaine + dexmedetomidine) in each group. The patients were observed for hemodynamic stability, respiratory depression, and postoperative pain using face, legs, activity, cry, consolability (FLACC) pain scale for 24 h postoperatively.

Statistical Analysis Used:

Unpaired Student's t-test.

Results:

The mean duration of effective analgesia in Group A patients was 4.33 ± 0.98 h versus 9.88 ± 0.90 h in Group B patients. Likewise, the difference in mean FLACC score of both the groups was also statistically significant, 7.21 ± 0.76 and 6.49 ± 1.72 in Group A and Group B, respectively.

Conclusion:

Dexmedetomidine as adjuvant to Bupivacaine increases duration of caudal analgesia and improves hemodynamic stability without an increase in adverse effects in children undergoing infraumbilical surgeries.

Comparison of caudal bupivacaine alone with bupivacaine plus two doses of dexmedetomidine for postoperative analgesia in pediatric patients undergoing infra-umbilical surgery: a randomized controlled double-blinded study

BACKGROUND

Data are still insufficient about the effects of different concentrations of caudal dexmedetomidine when used to prolong postoperative analgesia in children. The aim of this study was to assess the analgesic efficacy and side effects of two doses of caudal dexmedetomidine (1 and 2 μg·kg(-1)) co-administered with bupivacaine in terms of postoperative pain scores and requirement of postoperative analgesia over 24 h in children undergoing infra-umbilical surgery.

METHODS

Ninety-one children, aged 1-6 years, undergoing infra-umbilical surgery were included and randomly allocated into three groups of caudal block. Group B received 0.25% bupivacaine 2 mg·kg(-1) (0.8 ml·kg(-1)). Groups BD1 and BD2 received dexmedetomidine 1 and 2 μg·kg(-1), respectively along with bupivacaine 2 mg·kg(-1) in a total volume of 0.8 ml·kg(-1). Anesthesia was induced and maintained with sevoflurane in 100% oxygen. Hemodynamic and other routine intraoperative monitoring was carried out in addition to endtidal sevoflurane concentration. Time to spontaneous eye opening and postoperative pain and sedation scores were recorded in addition to time to first analgesia, paracetamol analgesic requirements, and any side effects during the first 24 postoperative hours.

RESULTS

Time to first analgesia requirement was significantly longer in BD1 and BD2 groups compared to B group with mean values (95% CI) of 809 min (652-965), 880 (733-1026), and 396 (343-448), respectively, P < 0.001. Postoperative paracetamol analgesic requirements over 24 h were higher in group B compared to BD1 and BD2 groups (Mean (95% CI): 3.2 (2.9-3.5) doses, 1.9 (1.5-2.3), and 1.6 (1.3-1.9), respectively), P < 0.001. The dexmedetomidine groups had significantly higher postoperative sedation scores compared to plain bupivacaine group that were dose dependent and for longer time in BD2 group. Two patients in BD2 group developed bradycardia and hypotension, and one developed urine retention compared to none in other groups.

CONCLUSION

A 1 μg·kg(-1) dose of caudal dexmedetomidine achieved comparable prolongation of postoperative analgesia to 2 μg·kg(-1) dose, with shorter duration of postoperative sedation and lower incidence of other side effects.

Retrobulbar dexmedetomidine decreases the MLAC of ropivacaine in vitreoretinal surgery in children

PURPOSE

Dexmedetomidine can prolong the duration of local anesthetics, but the effect of retrobulbar dexmedetomidine on the potency of ropivacaine for retrobulbar block has not been investigated. Our study was designed to determine the effect of retrobulbar dexmedetomidine on ropivacaine for retrobulbar block in children.

METHODS

A group of 90 children aged 10-16 years scheduled for vitreoretinal surgery who received retrobulbar block were randomly assigned to 1 of 3 groups: group L (retrobulbar ropivacaine), group LD1 (ropivacaine plus 0.5 µg.kg-1 dexmedetomidine), or group LD2 (ropivacaine plus 1 µg.kg-1 dexmedetomidine). The minimum local anesthetic concentration (MLAC) was determined according to a Dixon-Massey protocol. The primary endpoint of the study was MLAC. Secondary outcomes were duration of postoperative analgesia, postoperative pain scores, dexmedetomidine side effects, and time to hospital discharge.

RESULTS

The MLAC values of retrobulbar ropivacaine were 0.314%, 0.259%, and 0.246% in groups L, LD1, and LD2, respectively. The median (interquartile range) durations of analgesia in the postoperative period were 66 (54-117), 89 (40-157), and 168 (120-194) minutes in groups L, LD1, and LD2, respectively (L vs LD1 or LD2, p&lt;0.05). Wake-up time was significantly increased in groups LD1 and LD2.

CONCLUSIONS

Retrobulbar dexmedetomidine reduces the MLAC values of ropivacaine and improves postoperative analgesia in children without any neurologic side effects.

Analgesic effect and adverse events of dexmedetomidine as additive for pediatric caudal anesthesia: a meta-analysis

BACKGROUND

Dexmedetomidine has become a popular additive for regional anesthesia. Aim of this meta-analysis was to assess the effect of this additive on the duration of postoperative analgesia and possible adverse events in pediatrics undergoing orchidopexy or lower abdominal surgery.

METHODS

The literature databases of PubMed, Google Scholar, and Cochrane Library were searched for randomized, controlled trials (RCTs). Odds ratio (OR), weighted mean difference (WMD), and the corresponding 95% confidence intervals (CIs) were calculated using the RevMan software, version 5.2, for data synthesis and statistical analysis, which in accordance with the PRISMA statement.

RESULTS

Six RCTs were selected for this meta-analysis, involving a total of 328 pediatric patients. There was a significant longer duration of caudal analgesia (time to first analgesic requirements) in patients receiving dexmedetomidine with CA compared with CA alone (WMD: -8.21 h; 95% CI: -11.40 to -5.02; P < 0.00001). Side effects in these two groups were comparable (OR: 1.02; 95% CI: 0.51-2.04; P = 0.95). Subgroup analysis indicated there was no significant difference in hemodynamic changes during operation (WMD: 1.78; 95% CI: -3.20 to 6.77; P = 0.48) and the emergence time (time from the end of surgery to opening the eyes on calling) after surgery (WMD: 0.47 min; 95% CI: -5.27 to 6.22; P = 0.87).

CONCLUSIONS

Dexmedetomidine as an additive to local anesthetic provides a significantly longer postoperative analgesia with comparable adverse effects and hemodynamic changes, when compared to local anesthetics alone. There were insufficient data of the effects of different concentrations of dexmedetomidine; further studies are required to explore this issue.

A comparative study of the effect of caudal dexmedetomidine versus morphine added to bupivacaine in pediatric infra-umbilical surgery

BACKGROUND

One of the most commonly used regional anesthetic techniques in pediatric surgeries is the caudal epidural block. Its main disadvantage remains the short duration of action. Hence, different additives have been used. Dexmedetomidine is a potent as well as highly selective α2 adrenergic receptor agonist. The aim of this randomized, double-blinded, study was to compare the duration of postoperative analgesia of caudal dexmedetomidine versus morphine in combination with bupivacaine in pediatric patients undergoing lower abdominal or perineal surgery.

PATIENTS AND METHODS

A total of 50 pediatric patients 1-5 years old The American Society of Anesthesiologists status I, II scheduled for lower abdominal and perineal surgeries were included in the study. The patients were enrolled into 2 equal groups: Group A patients (n = 25) received dexmedetomidine with bupivacaine while Group B patients (n = 25) received morphine with bupivacaine. Patients were placed in a supine position then inhalational general anesthesia was induced, and laryngeal mask airway (LMA) was placed. Patients were then given caudal epidural analgesia. By the end of surgery reversal of muscle relaxation was done and the LMA was removed. Post-operatively, the sedation as well as pain score were observed and recorded.

RESULTS

The current study showed that minor complications were recorded in the post-anesthesia care unit; in addition, significantly longer periods of analgesia and sedation were detected in Group A. However, no significant differences in demographic data, as well as in the duration of surgery, and the time of emergence from anesthesia and patient condition during recovery were detected.

CONCLUSION

The present study suggested that use of dexmedetomidine, during single dose injection, as an additive to the local anesthetic bupivacaine in caudal epidural analgesia prolongs the duration of post-operative analgesia following lower abdominal as well as perineal surgery compared with caudal morphine with no side-effects on the vital signs. Postoperative side effects were seen with caudal morphine injection rather than with dexmedetomidine.

Does dexmedetomidine as a neuraxial adjuvant facilitate better anesthesia and analgesia? A systematic review and meta-analysis

Background

Neuraxial application of dexmedetomidine (DEX) as adjuvant analgesic has been invetigated in some randomized controlled trials (RCTs) but not been approved because of the inconsistency of efficacy and safety in these RCTs. We performed this meta-analysis to access the efficacy and safety of neuraxial DEX as local anaesthetic (LA) adjuvant.

Methods

We searched PubMed, PsycINFO, Scopus, EMBASE, and CENTRAL databases from inception to June 2013 for RCTs that investigated the analgesia efficacy and safety for neuraxial application DEX as LA adjuvant. Effects were summarized using standardized mean differences (SMDs), weighed mean differences (WMDs) or odds ratio (OR) with suitable effect model. The primary outcomes were postoperative pain intensity and analgesic duration, bradycardia and hypotension.

Results

Sixteen RCTs involving 1092 participants were included. Neuraxial DEX significantly decreased postoperative pain intensity (SMD, −1.29; 95% confidence interval (CI), −1.70 to −0.89; P<0.00001), prolonged analgesic duration (WMD, 6.93 hours; 95% CI, 5.23 to 8.62; P<0.00001) and increased the risk of bradycardia (OR, 2.68; 95% CI, 1.18 to 6.10; P = 0.02). No evidence showed that neuraxial DEX increased the risk of other adverse events, such as hypotension (OR, 1.54; 95% CI, 0.83 to 2.85; P = 0.17). Additionally, neuraxial DEX was associated with beneficial alterations in postoperative sedation scores and number of analgesic requirements, sensory and motor block characteristics, and intro-operative hemodynamics.

Conclusion

Neuraxial DEX is a favorable LA adjuvant with better and longer analgesia. The greatest concern is bradycardia. Further large sample trials with strict design and focusing on long-term outcomes are needed.

New therapeutic uses for an alpha2 adrenergic receptor agonist--dexmedetomidine in pain management

Dexmedetomidine was initially approved for clinical use as a sedative. Its development in pain management has been limited. Dexmedetomidine has analgesic effects and analgesic-sparing properties, especially for patients with obstructed airways. Mixing dexmedetomidine with local anesthetics is a promising new avenue to enhance local anesthetics' effectiveness. Peripheral, spinal and supraspinal α(2A)-ARs are responsible for the analgesic function of dexmedetomidine. Animal studies have shown that antinociceptive synergism results from co-application of dexmedetomidine and opioids or local anesthetics. Dexmedetomidine has potential adverse effects such as hypotension and bradycardia. Therefore, dexmedetomidine is contraindicated for patients suffering from bradycardia or using β-adrenergic antagonists. Clinical trials of dexmedetomidine in chronic pain or hyperalgesia are lack.

Caudal dexmedetomidine decreases the required concentration of levobupivacaine for caudal block in pediatric patients: a randomized trial

BACKGROUND AND OBJECTIVES

Dexmedetomidine (D) can prolong the duration of local anesthetics, but the effect of caudal dexmedetomidine on the potency of levobupivacaine (L) for caudal block has not been investigated. This study was designed to determine the effect of caudal dexmedetomidine on levobupivacaine for caudal block in pediatric patients.

METHODS

Eighty-nine children scheduled for elective inguinal hernia repair or hydrocele were randomly assigned to one of the three groups: Group L (caudal levobupivacaine), Group LD1 (levobupivacaine plus 1 μg·kg(-1) dexmedetomidine), or Group LD2 (levobupivacaine plus 2 μg·kg(-1) dexmedetomidine). The primary endpoint was the minimum local anesthetic concentration (MLAC), which was determined using the Dixon up-and-down method. The secondary endpoints were the duration of analgesia and sedation.

RESULTS

The MLAC values (sd) of caudal levobupivacaine were 0.103 (0.01)%, 0.068 (0.02)%, and 0.055 (0.03)% in Groups L, LD1, and LD2, respectively. The values of EC50 and EC95 (95% CI) of caudal levobupivacaine from logistic regression analysis were 0.094 (0.083-0.105)% and 0.129 (0.1-0.159)%, 0.058 (0.044-0.072)% and 0.106 (0.067-0.144)%, and 0.046 (0.033-0.059)% and 0.091 (0.055-0.127)% in Groups L, LD1, and LD2, respectively. The mean durations of analgesia in the postoperative period were 141, 378, and 412 min in Groups L, LD1, and LD2, respectively (L vs LD1 or LD2, P < 0.001). The mean durations of sedation in both Groups LD1 and LD2 also were significantly prolonged, compared with Group L (P < 0.01).

CONCLUSIONS

Caudal dexmedetomidine reduces the MLAC values of levobupivacaine and improves postoperative analgesia in children without any neurological side effects.

Intracerebroventricular Application of Dexmedetomidine Produces Antinociception and Does not Cause Neurotoxicity in Rats

BACKGROUND

Alpha2 agonists contribute to pain control at the level of the medulla spinalis. Alpha2 agonists are generally added to local anaesthetics to prolong spinal or epidural anaesthesia time.

AIMS

In the present study, we aimed to evaluate the antinociceptive and neurotoxic effects of dexmedetomidine given intracerebroventricularly for 5 days.

STUDY DESIGN

Animal experimentation.

METHODS

After intraventricular cannulation, rats (n=32) were divided into two groups (n=16 each). Rats in the dexmedetomidine group (Group D, n=16) received 3 µg (0.03 mL) dexmedetomidine and the control group (Group C, n=16) received 0.03 mL physiological serum through an intracerebroventricular catheter once a day, for 5 days. Antinociceptive, sedative, and motor effects were evaluated before the injection and for 90 min after injection. The tail-flick and hot plate tests were used to assess thermal nociceptive threshold. For histopathological evaluation, half of the rats in both groups were sacrificed on the 6(th) day and the remaining rats were sacrificed on the 21(st) day. Then the perfusion fixation method was applied. The first tissue section was obtained from the cervical spinal cord 1 cm distal to the proximal end of the spinal cord. The second sample was retrieved from the region 1 cm distal from the thoracic 13-lumbar 1 vertebra. On morphological evaluation, nonspecific changes like edema and gliosis, signs of neuronal degeneration demonstrating a severe reaction, and density of inflammatory cells were examined.

RESULTS

In dexmedetomidine-administered rats, on the first day reaction times at 5, 10, and 20 min and on the other days, reaction times at 5, 10, 20, and 30 min in hot plate tests were significantly longer compared with baseline values (p<0.05). In dexmedetomidine-administered rats, on the 1(st), 4(th), and 5(th) days reaction times at 5, 10, 20, 30, and 40 min and on the 2(nd) and 3(rd) days reaction times at 5, 10, 20, and 30 min in tail-flick tests were significantly longer compared with baseline values (p<0.05). First-degree sedation lasting for 60 min and first-degree motor block lasting for 30-40 min were observed in the dexmedetomidine group. Similar rates of nonspecific changes such as edema and gliosis were seen in both groups. Signs of severe reactions such as neuronal degeneration and diffuse inflammatory cell infiltration were not encountered in any group. There was no significant difference between groups according to morphological findings of the spinal cord on the 6(th) and 21(st) days (p>0.05).

CONCLUSION

We observed that intracerebroventricular administration of 3 μg dexmedetomidine produced antinociception and did not cause neurotoxicity.