Caudal Additives in Pediatrics: A Comparison Among Midazolam, Ketamine, and Neostigmine Coadministered with Bupivacaine

Analgesic Efficacy of Adjuvant Medications in the Pediatric Caudal Block for Infraumbilical Surgery: A Network Meta-Analysis of Randomized Controlled Trials

Various adjuvants are added to local anesthetics in caudal block to improve analgesia. The comparative analgesic effectiveness and relative rankings of these adjuvants are unknown. This network meta-analysis (NMA) sought to evaluate the comparative analgesic efficacy and relative ranking of caudal adjuvants added to local anesthetics (versus local anesthetics alone) in pediatric infra-umbilical surgery. We searched the United States National Library of Medicine database (MEDLINE), PubMed, and Excerpta Medica database (Embase) for randomized controlled trials (RCTs) comparing caudal adjuvants (clonidine, dexmedetomidine, ketamine, magnesium, morphine, fentanyl, tramadol, dexamethasone, and neostigmine) among themselves, or to no adjuvant (control). We performed a frequentist NMA and employed Cochrane's 'Risk of Bias' tool to evaluate study quality. We chose the duration of analgesia (defined as 'the time from caudal injection to the time of rescue analgesia') as our primary outcome. We also assessed the number of analgesic dose administrations and total dose of acetaminophen within 24 h. The duration of analgesia [87 randomized control trials (RCTs), 5285 patients] was most prolonged by neostigmine [mean difference: 513 min, (95% confidence interval, CI: 402, 625)]. Dexmedetomidine reduced the frequency of analgesic dose administrations within 24 h [29 RCTs, 1765 patients; -1.2 dose (95% CI: -1.6, -0.9)] and the total dose of acetaminophen within 24 h [18 RCTs, 1156 patients; -350 mg (95% CI: -467, -232)] the most.  Among caudal adjuvants, neostigmine (moderate certainty), tramadol (low certainty), and dexmedetomidine (low certainty) prolonged the duration of analgesia the most. Dexmedetomidine also reduced the analgesic frequency and consumption more than other caudal adjuvants (moderate certainty).

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.

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.

A Comparative Study of Tramadol and Clonidine as an Additive to Levobupivacaine in Caudal Block in Pediatric Patients Undergoing Perineal Surgeries

Background:

Caudal block is a simple, safe procedure with fewer side effects to provide intraoperative and postoperative analgesia in pediatric patients. Many drugs were used as an additive to local anesthetics in caudal block. All these drugs had their own side effects.

Aims:

In this study, we compare the effects of tramadol and clonidine as an additive to levobupivacaine in caudal block in children undergoing perineal surgeries regarding hemodynamic changes, analgesic effects, and side effects.

Settings and Design:

This is a prospective, double-blind randomized, controlled study, conducted in Department of Paediatric Surgery, at King George's Medical University, Lucknow, Uttar Pradesh during 2017–2018.

Materials and Methods:

After informed consent and ethical clearance from institutional ethics committee, King Georges Medical University, Lucknow. Total 66 patients aged 1–10 year, planned for perineal surgery were randomly allocated according to computer-generated random number, into three groups. Group I - 0.25% levobupivacaine (1 mL.kg^-1) alone, Group II - 0.25% levobupivacaine (1 mL.kg^-1) with tramadol 1 mL.kg^-1, and Group III - 0.25% levobupivacaine (1 mL.kg^-1) with clonidine 1 μg.kg^-1. Perioperative pain was the primary outcome. Hemodynamic parameters: heart rate, mean arterial pressure, and peripheral oxygen saturation were recorded. Postoperative pain assessed by Children and Infants Postoperative Pain Scale (CHIPPS), sedation by Ramsay sedation score and requirement of rescue analgesia were recorded at predetermined time intervals.

Statistical Analysis:

The values were represented in number (%) and mean ± standard deviation. Comparison of quantitative variables between the study groups was done using ANOVA test and Mann–Whitney U-test. Categorical data were analyzed using Chi-square test.

Results:

Postoperative analgesic effect was significantly longer in levobupivacaine with clonidine group as compared to tramadol with levobupivacaine group and levobupivacaine alone group.

Conclusion:

Clonidine in a dose of 1 μg.kg^-1 when added to levobupivacaine in caudal block significantly prolongs the duration of analgesia as compared to tramadol with levobupivacaine and levobupivacaine alone without any clinically significant side effects. Thus, it is better to add additive like clonidine to enhance the effect of analgesia.

A randomized-controlled, double-blind study to evaluate the efficacy of caudal midazolam, ketamine and neostigmine as adjuvants to bupivacaine on postoperative analgesic in children undergoing lower abdominal surgery

Background: Caudal epidural is the most commonly used technique for the management of postoperative pain in children. The aim of the present study was to assess and compare the efficacy of caudal bupivacaine as a postoperative analgesic alone or combined with midazolam, ketamine, and neostigmine in pediatric patients undergoing lower abdominal surgery. Methods: Eighty pediatric patients categorized under the American Society of Anesthesiologists Physical Status I and II Classification System, who have been scheduled to undergo lower abdominal surgery were randomly designated into four groups to receive caudal block with either 1 ml/kg of 0.25% caudal bupivacaine for group B, 1 ml/kg of 0.25% caudal bupivacaine mixed with 2 μg/kg neostigmine for group BN, 1 ml/kg of 0.25% caudal bupivacaine mixed with 0.5 mg/kg ketamine for group BK or 1 ml/kg of 0.25% caudal bupivacaine mixed with 50 mcg/kg midazolam for group BM. Postoperative analgesia was examined by a blinded anesthetist utilizing a Revised Faces Pain Scale. Consumption of the total amount of rescue analgesic each 24 h, postoperative time to requirement of the first dose and any adverse effects were noted. Results: The four groups were comparable as regards age, sex, weight, duration of surgery, heart rate, blood pressure and the time from induction of anesthesia to response to voice. The Revised Faces Pain Scale was 2.6±1.5 in group BN, 3.1±1.8 in group BM, 4.4±2.4 in group BK, and 5.6±1.3 in group B (p=0.005). Postoperative duration of analgesia was 433±68 min, 769±118 min, 1097±126 min and 1254±176 min in groups B, BK, BM and BN respectively (P=0.001). The dose of rescue analgesic within 24 h in group B was significantly higher than those of the other three groups (P<0.05). Conclusion: Addition of either neostigmine, midazolam, or ketamine to caudal bupivacaine extended analgesia time and decreased rescue analgesic compared to bupivacaine alone in children who underwent lower abdominal surgery. (www.actabiomedica.it)

The impact of caudally administrated tramadol on immune response and analgesic efficacy for pediatric patients: a comparative randomized clinical trial

Background

Immune responses appear to be affected by anesthetics and analgesics. We investigated the effects of caudal tramadol on the postoperative immune response and pain management in pediatric patients.

Methods

Sixty ASA-I pediatric patients aged 3–10 years undergoing lower abdominal surgery. Patients were randomly assigned either to a caudal bupivacaine (0.25%) group (group B), or a group that received caudal tramadol (1 mg/kg) added to the bupivacaine (0.25%) (group T). Both were diluted in a 0.9% NaCl solution to a total volume of 1ml/kg. The systemic immune response was measured by collecting blood samples preoperatively, at the end of anesthesia, and at 24 and 72 hours postoperatively, and studied for interleukin IL-6, C-reactive proteins (CRP) cortisol levels, and leucocytes with its differential count. Postoperative pain was assessed along with sedation scales.

Results

Postoperative production of IL-6 was significantly higher in group B at the end of anesthesia, than at the 24^th hour, and at the 72^nd hour in group B and group T, respectively. The immune response showed leukocytosis with increased percentages of neutrophil and monocytes, and a decreased lymphocyte response rate within both groups with no significant differences between the groups. Cortisol and CRP were significantly higher in group B.

Conclusions

Adding tramadol to a caudal bupivacaine block can attenuate the pro-inflammatory cytokine response, Cortisol, and CRP in children undergoing lower abdominal surgery.

Efficacy and Safety of Clonidine as an Adjuvant to Bupivacaine for Caudal Analgesia in Paediatric Infra-Umbilical Surgeries

INTRODUCTION

Caudal analgesia, has gained popularity in paediatric intraoperative and postoperative pain management, more so with the use of adjuvants to prolong its duration, each of them having various results. Clonidine, an alpha2-adrenergic agonist is being used for its analgesic effects in various doses with 0.25% Bupivacaine.

AIM

The study was conducted to compare the analgesic efficacy, haemodynamic safety and side effects of 1 μg/kg Clonidine added to 1 ml/kg of 0.125% Bupivacaine solution for caudal analgesia.

MATERIALS AND METHODS

A prospective, randomised, double-blind, controlled study was carried out in 60 children of ASA Physical Status I, aged 1-10 years, scheduled for infraumbilical operations in a tertiary care centre. They were randomly assigned for caudal analgesia, to either group B: 1ml/kg of 0.125% Bupivacaine solution or group BC: 1ml/kg of 0.125% Bupivacaine and preservative free Clonidine 1μ/kg. All were premedicated with midazolam 0.75 mg/kg orally 30 minutes prior to induction of anaesthesia. Heart rate (HR), Mean Arterial blood Pressure (MAP) and oxygen saturation (SpO2) were monitored. General anaesthesia was induced with thiopentone (1.25%) 5mg/kg and inhalation of oxygen, nitrous oxide and sevoflurane. Postoperative pain, sedation and motor block was assessed by the various scores and patients were monitored for adverse effects.

RESULTS

The mean duration of postoperative analgesia was 3 times longer in group BC. Group B received significantly more doses of rescue analgesic than group BC (p-value of 0.004). There was no significant bradycardia, hypotension, sedation or urinary retention in either of the groups. There was no residual motor blockade at 6 hours. Incidence of vomiting was similar in both the groups.

CONCLUSION

Caudal Clonidine in the dose of 1 μg/kg in children is a satisfactory and efficacious adjuvant to caudal Bupivacaine for producing prolonged postoperative analgesia with minimum side effects.

Treatment of Postoperative Pain in Pediatric Operations: Comparing the Efficiency of Bupivacaine, Bupivacaine-Dexmedetomidine and Bupivacaine-Fentanyl for Caudal Block

BACKGROUND

Caudal analgesia is a common method for postoperative pain management in pediatric patients. Additive agents such as opioids and α₂ agonists have been used to enhance the analgesic effects of local anesthetics for caudal block.

OBJECTIVES

The aim of this study was to compare the additive effects of dexmedetomidine and fentanyl on bupivacaine-induced caudal analgesia in pediatric patients who had undergone elective inguinal hernia repair.

METHODS

This randomized, double-blind clinical trial included children aged 1 - 5 years who were divided into three groups: the bupivacaine group (Group B) received 0.25% bupivacaine (1 ml/kg), the bupivacaine-dexmedetomidine group (Group BD) received 0.25% bupivacaine (1 mL/kg) plus 2 µg/kg dexmedetomidine, and the bupivacaine-fentanyl group (Group BF) received 0.25% bupivacaine (1 mL/kg) plus 2 µg/kg fentanyl. The hemodynamic variables (heart rate, systolic blood pressure, respiratory rate, and peripheral arterial oxygen saturation) were measured perioperatively. Pain, sedation and motor block scores and adverse events (nausea and vomiting, pruritis, hypotension, bradycardia, urinary retention and respiratory depression) were documented at 30 and 60 minutes, and the 1st, 2nd, 4th, 6th, 12th and 24th hours after the operation. The other recordings include the duration of surgery and analgesic requirement.

RESULTS

A total of 61 patients were analyzed. The lowest pain scores were found in the BD group at all time points (P < 0.001). The sedation scores were higher in the BD group than in the other two groups at all time points (P < 0.001). No motor block was observed after the operation. Only three patients required analgesic administration 2 to 6 hours after the operation in group B. No side effects were observed in any of the groups, and there was no significant difference in the duration of surgery among the three groups.

CONCLUSIONS

The results show that the analgesic and sedative effects were better when dexmedetomidine was added to bupivacaine than when fentanyl was added or bupivacaine alone was administered in the pediatric population studied here that underwent elective inguinal hernia repair.

Efficacy of two doses of tramadol versus bupivacaine in perioperative caudal analgesia in adult hemorrhoidectomy

Background:

The study was conducted to evaluate the perioperative analgesic efficacy of the two doses of caudally administered tramadol versus bupivacaine in adult hemorrhoidectomy.

Patients and Methods:

A total of 90 patients, aged 20-50 years, undergoing hemorrhoidectomy were randomly scheduled to receive bupivacaine 0.25% in 20 ml (Group B; n = 30), tramadol 1 mg/kg in 20 ml (Group T₁; n = 30), tramadol 2 mg/kg in 20 ml (Group T₂; n = 30) through caudal route after induction of general anesthesia. Postoperative pain was assessed every hour until the visual analog scale was 6, which is 1^st time for rescue analgesia. Postoperative sedation, hemodynamic changes, serum cortisol, and epinephrine levels and incidence of side effects were also evaluated.

Results:

Duration of analgesia was longer in Group T₂ (20 [1.14] h] compared with the Group B (7 [1.2] h) or Group T₁ (12 [0.75] h); all P < 0.001. There were no significant hemodynamic changes. There were not incidences of side effects.

Conclusion:

Caudal tramadol 2 mg/kg provided a longer duration of postoperative analgesia with rapid onset and no incidence of complications or adverse effects in adult hemorrhoidectomy.

A comparison of ropivacaine, ropivacaine with tramadol and ropivacaine with midazolam for post-operative caudal epidural analgesia

BACKGROUND AND AIMS

Caudal epidural analgesia is the most commonly used method of post-operative analgesia in children undergoing subumbilical surgeries. Many additive drugs have been used to prolong the post-operative analgesia. The aim of this study was to compare the efficacy of tramadol or midazolam addition to caudal ropivacaine for post-operative analgesia in children undergoing subumbilical surgeries.

METHODS

In this prospective, randomised, double-blinded comparative study, sixty children of either gender, in the age group of 1-5 years and scheduled for elective subumbilical surgeries were randomly divided into three groups of twenty each. Children in Group R received an epidural injection of 1 mL/kg of 0.2% plain ropivacaine whereas children in Group RT received an epidural injection of 2 mg/kg of tramadol plus 1 mL/kg of 0.2% ropivacaine and Group RM received an epidural injection of 50 μg/kg midazolam plus 1 mL/kg of 0.2% ropivacaine. The primary outcome variable was the duration of time to rescue analgesia. The secondary outcome variables were motor block, sedation score and urinary retention. Statistical comparison among the three groups was performed using one-way ANOVA with post hoc analysis using Bonferroni. For qualitative variables, Chi-square test was used. Statistical significance was defined as P < 0.05.

RESULTS

The mean duration of time to rescue analgesia was significantly longer (P < 0.001) in Group RT (913 ± 315.5 min) and Group RM (769.2 ± 331.9 min) compared to Group R (437.75 ± 75.68 min). However, there was no significant difference in the duration of time to rescue analgesia between RT and RM groups. Motor block and sedation scores were comparable between groups.

CONCLUSIONS

The addition of tramadol or midazolam to caudal epidural ropivacaine prolongs the duration of analgesia without causing significant side effects.

Ketamine versus magnesium sulfate with caudal bupivacaine block in pediatric inguinoscrotal surgery: A prospective randomized observer-blinded study

INTRODUCTION

Possible approaches for postoperative analgesia after pediatric inguinoscrotal surgery are caudal block by bupivacaine/ketamine (BK) and bupivacaine/magnesium sulfate (BM).

AIM

The purpose of the following study is to compare the analgesic efficacy and safety of ketamine and magnesium sulfate in combination with bupivacaine for caudal blockade in pediatric patients after inguinoscrotal operations.

MATERIALS AND METHODS

Patients randomly received one of the two solutions for caudal epidural injection after induction of general anesthesia. Group-BK: Were given a mixture of 0.25% bupivacaine and 0.5 mg/kg of ketamine. Group-BM: Were given a mixture of 0.25% bupivacaine and 50 mg magnesium sulfate. Postoperatively, a blinded post-anesthesia care unit nurse assessed the quality of analgesia with a visual pain analog scale (VPAS). Significant pain is defined as one that has a VAPS of ≥3.

RESULTS

Forty American Society of Anesthesiologists I-II children (20 in each group) completed the study. The two groups were comparable regards age, sex, body mass index, anesthesia and surgery durations, recovery time and sevoflurane concentration. The mean duration of caudal analgesia ± standard deviation was 462 ± 17.2 min versus 398.05 ± 12.9 min for BK and BM groups, receptively (P < 0.001). Supplemental rectal paracetamol within 12 h postoperatively were 15% for BK group versus 25% for BM (P = 0.05). Four patients in BK group only experienced postoperative nausea and vomiting (P = 0.053).

CONCLUSION

Caudal administration of BK is efficient and safe for pediatric inguinoscrotal operations with longer postoperative analgesia than BM sulfate.

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.

Epidural administration of neostigmine-loaded nanofibers provides extended analgesia in rats

Background

In this study, neostigmine-loaded electrospun nanofibers were prepared and then their efficacy and duration of analgesic action were studied after epidural administration in rats by repeated tail flick and formalin tests.

Methods

The neostigmine poly vinyl alcohol (PVA) nanofibers were fabricated by electrospinning methods. The nanofibers (1 mg) were injected into the lumbar epidural space (L5-L6) of rats (n = 6). Cerebrospinal fluid samples of rats were collected 1, 5 and 24 hours after injection and then were sampled once weekly for 4 weeks. Free-neostigmine concentration was measured in the samples spectrophotometrically. Rat nociceptive responses were evaluated by repeated tail-flick and formalin tests for 5 weeks after the nanofibers (1 mg) injection. Locomotor activity of rats was measured in the open-field at the same period.

Results

The cerebrospinal fluid concentration of free neostigmine reached 5 μg/ml five hours after injection and remained constant until the end of the experiments. The tail-flick latency of treated rats was significantly (p < 0.01) increased and remained constant up to 4 weeks. Pain scores of the rats in both phases of formalin test were significantly (p < 0.01) reduced during the same periods, Epidural injection of the nanofibers had no effect on locomotor activity of rats in an open-field.

Conclusions

Our results indicate that the neostigmine nanofibers can provide sustained release of neostigmine for induction of prolonged analgesia after epidural administration. High tissue distribution and penetration of the nanofibers in dorsal horn can increase thermal and chemical analgesia duration without altering locomotor activity in rats for 4 weeks.

Adjuvants in pediatric regional anesthesia

SUMMARY Local anesthetics have a limited duration of action. Adjuvants are used to prolong the duration of action and to augment analgesia allowing lower concentrations of local anesthetic to be used. Adjuvants have been used more extensively with neuraxial blocks, particularly caudal epidural blocks, but more recently to supplement peripheral nerve blocks. Intrathecal adjuvants are not covered in this review since spinal anesthesia is not widely used in children except in ex-premature infants. Morphine is the historical gold-standard with which other adjuvants are compared. Clonidine is most useful and is becoming increasingly popular, while the side-effect profile of other agents reduces their utility. Concerns with regard to the neurotoxicity of ketamine in animal models has led to its withdrawal in some countries.

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.

Ketamine: use in anesthesia

The role of ketamine anesthesia in the prehospital, emergency department and operating theater settings is not well defined. A nonsystematic review of ketamine was performed by authors from Australia, Europe, and North America. Results were discussed among authors and the final manuscript accepted. Ketamine is a useful agent for induction of anesthesia, procedural sedation, and analgesia. Its properties are appealing in many awkward clinical scenarios. Practitioners need to be cognizant of its side effects and limitations.

Bayesian enhanced meta-analysis of post-operative analgesic efficacy of additives for caudal analgesia in children

BACKGROUND

The authors calculated the effect size for post-operative analgesia of three additives, clonidine, neostigmine, and tramadol to bupivacaine, ropivacaine, or levobupivacaine used for single-dose caudal extradural blockade in children.

METHODS

A meta-analysis was performed for three end points of efficacy: the increase of time until administration of analgesic drugs, the proportion of patients requiring analgesic drugs during the initial 24 post-operative hours, and the amounts of post-operative analgesic drugs. A Bayesian inference supporting direct statements about the probability of the magnitude of an effect was used to compare the effects size.

RESULTS

Neostigmine increased the duration of analgesia by 9.96 h (95% confidence interval: 7.75 to 12.16), as compared with 3.68 h (2.65 to 4.7) with clonidine and 4.45 (2.84 to 6.07) with tramadol. There is a 95% probability that neostigmine increases the duration of post-operative analgesia by more than 8 h, clonidine by more than 2.8 h, and tramadol by more than 3.25 h, as compared with local anesthetics alone. The odds ratios for the proportion of patients requiring analgesic drugs were 0.22 [0.13 to 0.37] for clonidine and 0.28 [0.10 to 0.75] for neostigmine. With tramadol, there was no statistically significant difference. All three additives reduced the amounts of post-operative analgesic drugs. Neostigmine and tramadol increase the probability for post-operative nausea or vomiting (PONV).

CONCLUSIONS

Neostigmine provides the longest post-operative analgesia. With clonidine, the duration of analgesia is shorter and sedation is increased, but the probability for PONV could be decreased.

Neuraxial analgesia in neonates and infants: a review of clinical and preclinical strategies for the development of safety and efficacy data

Neuraxial drugs provide robust pain control, have the potential to improve outcomes, and are an important component of the perioperative care of children. Opioids or clonidine improves analgesia when added to perioperative epidural infusions; analgesia is significantly prolonged by the addition of clonidine, ketamine, neostigmine, or tramadol to single-shot caudal injections of local anesthetic; and neonatal intrathecal anesthesia/analgesia is increasing in some centers. However, it is difficult to determine the relative risk-benefit of different techniques and drugs without detailed and sensitive data related to analgesia requirements, side effects, and follow-up. Current data related to benefits and complications in neonates and infants are summarized, but variability in current neuraxial drug use reflects the relative lack of high-quality evidence. Recent preclinical reports of adverse effects of general anesthetics on the developing brain have increased awareness of the potential benefit of neuraxial anesthesia/analgesia to avoid or reduce general anesthetic dose requirements. However, the developing spinal cord is also vulnerable to drug-related toxicity, and although there are well-established preclinical models and criteria for assessing spinal cord toxicity in adult animals, until recently there had been no systematic evaluation during early life. Therefore, in the second half of this review, we present preclinical data evaluating age-dependent changes in the pharmacodynamic response to different spinal analgesics, and recent studies evaluating spinal toxicity in specific developmental models. Finally, we advocate use of neuraxial drugs with the widest demonstrable safety margin and suggest minimum standards for preclinical evaluation before adoption of new analgesics or preparations into routine clinical practice.

Efficacy and adverse effects of ketamine as an additive for paediatric caudal anaesthesia: a quantitative systematic review of randomized controlled trials

BACKGROUND

The aim of this quantitative systematic review was to assess the efficacy and adverse effects of ketamine added to caudal local anaesthetics in comparison with local anaesthetics alone in children undergoing urological, lower abdominal, or lower limb surgery.

METHODS

The systematic search, data extraction, critical appraisal, and pooled data analysis were performed according to the PRISMA statement. All randomized controlled trials (RCTs) were included in this meta-analysis and relative risk (RR), mean difference (MD), and the corresponding 95% confidence intervals (CIs) were calculated using the Revman(®) statistical software for dichotomous and continuous outcomes.

RESULTS

Thirteen RCTs (published between 1991 and 2008) including 584 patients met the inclusion criteria. There was a significant longer time to first analgesic requirements in patients receiving ketamine in addition to a local anaesthetic compared with a local anaesthetic alone (MD: 5.60 h; 95% CI: 5.45-5.76; P<0.00001). There was a lower RR for the need of rescue analgesia in children receiving a caudal regional anaesthesia with ketamine in addition to local anaesthetics (RR: 0.71; 95% CI: 0.44-1.15; P=0.16).

CONCLUSIONS

Caudally administered ketamine, in addition to a local anaesthetic, provides prolonged postoperative analgesia with few adverse effects compared with local anaesthetics alone. There is a clear benefit of caudal ketamine, but the uncertainties about neurotoxicity relating to the dose of ketamine, single vs repeated doses and the child's age, still need to be clarified for use in clinical practice.

Efficacy of clonidine as an adjuvant to bupivacaine for caudal analgesia in children undergoing sub-umbilical surgery

Caudal epidural analgesia with bupivacaine is very popular in paediatric anaesthesia for providing intra- and postoperative analgesia. Several adjuvants have been used to prolong the action of bupivacaine. We evaluated the efficacy of clonidine added to bupivacaine in prolonging the analgesia produced by caudal bupivacaine in children undergoing sub-umbilical surgery. One hundred children, age one to three years, undergoing sub-umbilical surgery, were prospectively randomized to one of two groups: caudal analgesia with 1 ml/kg of 0.25% bupivacaine in normal saline (Group A) or caudal analgesia with 1 ml/kg of 0.25% bupivacaine with 1 µg/kg of clonidine in normal saline (Group B). Post-operative pain was assessed for 24 hours using the FLACC scale. The mean duration of analgesia was significantly longer in Group B (593.4 ± 423.3 min) than in Group A (288.7 ± 259.1 min); P < 0.05. The pain score assessed using FLACC scale was compared between the two groups, and children in Group B had lower pain scores, which was statistically significant. The requirement of rescue medicine was lesser in Group B. Clonidine in a dose of 1 µg/kg added to 0.25% bupivacaine for caudal analgesia, during sub-umbilical surgeries, prolongs the duration of analgesia of bupivacaine, without any side effects.

Ketamine for perioperative pain management in children: a meta-analysis of published studies

INTRODUCTION

Balanced analgesia, using both opioid and nonopioids agents, has become the standard care for postoperative pain management. Ketamine, a compound with analgesic and antihyperalgesic properties, has been shown to decrease postoperative pain and opioid requirements in adults. The goal of the present meta-analysis was to investigate postoperative analgesic properties of ketamine in pediatric patients.

MATERIAL AND METHODS

A comprehensive literature search was conducted to identify clinical trials that used ketamine as a perioperative analgesic compound in children and infants. Outcomes measured were postoperative analgesic consumption, pain intensity and duration of sensory block (when ketamine was used by caudal route) during the postoperative care unit (PACU) stay and the early postoperative period (6-24 h after leaving the operative room). The data from each trial were combined to calculate the pooled odds ratios or standard mean differences and their 95% confidence intervals.

RESULTS

Thirty-five randomized, blinded controlled studies were retrieved from the literature. Systemic ketamine was effective in decreasing PACU pain intensity and analgesic requirement but failed to influence early (6-24 h) pain intensity and analgesic requirement. Ketamine administered locally during tonsillectomy, decreased PACU and early (6-24 h) pain intensity and PACU analgesic requirements. Used as an adjuvant for caudal analgesia, ketamine increased the duration of sensory block and PACU analgesic requirement without impacting PACU pain intensity. Ketamine failed to exhibit a postoperative opioid-sparing effect.

CONCLUSIONS

This meta-analysis found that administration of ketamine was associated with decreased PACU postoperative pain intensity and nonopioid analgesic requirement. However, ketamine failed to exhibit a postoperative opioid-sparing effect.

Antiemetic effects of midazolam added to fentanyl-ropivacaine patient-controlled epidural analgesia after subtotal gastrectomy: A prospective, randomized, double-blind, controlled trial

BACKGROUND

Nausea and vomiting are frequent adverse effects of patient-controlled epidural analgesia (PCEA) with opioids.

OBJECTIVE

This study was designed to assess the antiemetic effect of midazolam added to fentanyl-ropivacaine PCEA.

METHODS

In a prospective, randomized, double-blind, controlled trial, smoking patients with gastric cancer undergoing elective subtotal gastrectomy were evenly allocated to 1 of 2 treatment groups to manage postoperative pain: 0.2% ropivacaine mixed with fentanyl 4 μg/mL and midazolam 0.2 mg/mL (test group) or 0.2% ropivacaine mixed with fentanyl 4 μg/mL (control group). The PCEA infusion was set to deliver 4 μL/h of the study solution, with a bolus of 2 mL per demand and a 15-minute lockout time. The incidence of postoperative nausea and vomiting (PONV), pain intensity, sedation score, usage of rescue analgesia and rescue antiemetic, respiratory depression, urinary retention, and pruritus were recorded at 2, 6, 12, 24, 48, and 72 hours after surgery. Total infused volume of PCEA at 72 hours after surgery was measured.

RESULTS

A total of 60 patients were approached and randomized to treatment. No patients were excluded by exclusion criteria and all enrolled patients completed this study. Incidence of nausea (7% vs 33%; P = 0.02) in the test group was significantly lower than in the control group. The overall frequency of PONV in the test group was significantly less than that of the control group (7% vs 40%; P = 0.006). In addition, the mean (SD) infused volume of PCEA in the test group was significantly lower than that in the control group (392.3 [68.9] vs 351.2 [49.8] mL; P = 0.01). However, there were no significant differences in pain intensity, usage of rescue antiemetics and rescue analgesics, and mild pruritus between groups. No patient reported moderate or severe sedation, respiratory depression, or hypoxemia. In addition, there were no severe adverse events.

CONCLUSIONS

Midazolam added to fentanyl-ropivacaine PCEA was associated with a significant reduction in the incidence of PONV compared with fentanyl-ropivacaine alone, and a significant decrease in the amount of PCEA administered without a significant increase in adverse events in these patients who underwent subtotal gastrectomy.

Quality of lidocaine analgesia with and without midazolam for intravenous regional anesthesia

PURPOSE

Midazolam has analgesic effects mediated by gamma aminobutyric acid-A receptors. This study was designed to evaluate the effect of midazolam on anesthesia and analgesia quality when added to lidocaine for intravenous regional anesthesia (IVRA).

METHODS

Forty patients undergoing hand surgery were randomly assigned to two groups to receive IVRA. The control group received 3 mg/kg lidocaine 2% w/v diluted with saline to a total volume of 40 ml, and the midazolam group received an additional 50 μg/kg midazolam. Sensory and motor block onset and recovery times, tourniquet pain, intraoperative analgesic requirements, sedation, and anesthesia quality were recorded. Postoperative pain and sedation scores, time to first analgesic requirements, analgesic use in the first 24 h, and side effects were noted.

RESULTS

Sensory and motor block onset and recovery times did not differ significantly between groups. Tourniquet pain scores were lower at 10, 15, 20, and 30 min (P < 0.0001) in the midazolam group. Three (15%) patients in the midazolam group required fentanyl for tourniquet pain compared with thirteen (65%) patients in the control group (P = 0.02). Patients in both groups received fentanyl once. Midazolam group showed that significantly less patients required diclofenac for postoperative analgesia (P < 0.01) and analgesic-free period during first postoperative 24 h was significantly longer (726.8 ± 662.8 min vs. 91.0 ± 35.9 min, P < 0.0001). Postoperative pain scores were lower (P < 0.0001) and sedation scores higher (P < 0.05) for the first 2 h in the midazolam group.

CONCLUSION

Addition of midazolam to lidocaine for IVRA improves anesthesia quality and enhances intraoperative and postoperative analgesia without causing side effects.

Efficacy of bupivacaine-neostigmine and bupivacaine-tramadol in caudal block in pediatric inguinal herniorrhaphy

BACKGROUND

Limited duration of analgesia is among the limitations of single caudal injection with local anesthetics. Therefore, the purpose of this study was to evaluate the effectiveness and safety of bupivacaine in combination with either neostigmine or tramadol for caudal block in children undergoing inguinal herniorrhaphy.

METHODS

In a double-blinded randomized trial, sixty children undergoing inguinal herniorrhaphy were enrolled to receive a caudal block with either 0.25% bupivacaine (1 ml x kg(-1)) with neostigmine (2 microg x kg(-1)) (group BN) or tramadol (1 mg x kg(-1)) (group BT). Hemodynamic variables, pain and sedation scores, additional analgesic requirements, and side effects were compared between two groups.

RESULTS

Duration of analgesia was longer in group BT (17.30 +/- 8.24 h) compared with group BN (13.98 +/- 10.03 h) (P = 0.03). Total consumption of rescue analgesic was significantly lower in group BT compared with group BN (P = 0.04). There were no significant differences in heart rate, mean arterial pressure, and oxygen saturation between groups. Adverse effects excluding the vomiting were not observed in any patients.

CONCLUSION

In conclusion, tramadol (1 mg x kg(-1)) compared with neostigmine (2 microg x kg(-1)) might provide both prolonged duration of analgesia and extended time to first analgesic in caudal block.

Two different doses of caudal neostigmine co-administered with levobupivacaine produces analgesia in children

SUMMARY BACKGROUND

This study was aimed to evaluate the analgesic efficacy duration of analgesia, and side effects of two different doses of caudal neostigmine used with levobupivacaine in children.

METHODS

Sixty boys, between 5 months and 5 years, undergoing genitourinary surgery were allocated randomly to one of three groups (n =20 each). Group I patients received caudal 0.25% levobupivacaine (1 ml.kg(-1)) alone. Groups II and III patients received neostigmine (2 and 4 microg.kg(-1) respectively) together with levobupivacaine used in the same does as Group I. Pain scores were assessed using Children's and Infant's Postoperative Pain Scale (CHIPPS) at 15th (t(1)) min after arrival to postanesthetic care unit, and 1st (t(2)), 2nd (t(3)), 3rd (t(4)), 4th (t(5)), 8th (t(6)), 16th (t(7)), and 24th (t(8)) hour postoperatively. Duration of analgesia, amount of additional analgesic (paracetamol), score of motor blockade and complications were recorded for 24 h postoperatively, and compared between groups.

RESULTS

CHIPPS scores were higher during t(2), t(3), t(6), t(7), and t(8) periods, duration of analgesia was shorter, and total analgesic consumption was higher in Group I compare to neostigmine groups (P < 0.05). Duration of postoperative analgesia and total analgesic consumption were similar in Groups II and III (P > 0.05). Adverse effects were not different between three groups.

CONCLUSIONS

Caudal neostigmine in doses of 2 and 4 microg.kg(-1) with levobupivacaine extends the duration of analgesia without increasing the incidence of adverse effects, and 2 microg.kg(-1) seems to be the optimal dose, as higher dose has no further advantages.

Improved postoperative analgesia with coadministration of preoperative epidural ketamine and midazolam

STUDY OBJECTIVE

To assess postoperative pain regulation and pharmacokinetic effects of preoperative administration of ketamine and midazolam.

DESIGN

Double-blind, randomized clinical study.

SETTING

University hospital.

PATIENTS

46 ASA physical status I and II patients (age, 26-58 yrs), scheduled for gastrectomy.

INTERVENTIONS

Patients were randomly assigned to three treatment groups: a preoperative epidural injection of 10 mL (1) ketamine (0.5 mg/kg) solution (Ket group); (2) ketamine (0.5 mg/kg) plus midazolam (0.05 mg/kg) solution (KM group); or (3) normal saline solution (Ctr group).

MEASUREMENTS

Analgesic effects were evaluated by Visual Analog Scale (VAS) pain scores at rest, time to first request for analgesic (TFA), and morphine consumption during the initial postoperative time of 48 hours. Plasma concentration of ketamine in the Ket group and the KM group was measured by high-performance liquid chromatography, and the elimination half-life of ketamine was calculated.

MAIN RESULTS

Compared with the Ctr group, the Ket and KM groups had lower VAS pain scores, longer TFA, and lower morphine consumption. The KM group had the longest TFA and the lowest morphine consumption of the three groups. The KM group also had higher plasma concentrations of ketamine 90 to 240 minutes after injection, and a longer elimination half-life of ketamine, than did the Ket group.

CONCLUSIONS

Preoperative epidural coadministration of a low dose of ketamine with midazolam is more effective in relieving postoperative pain than using ketamine alone. In addition, epidural midazolam prolongs the elimination of ketamine.

Use of neostigmine in the management of acute postoperative pain and labour pain: a review

Neostigmine is a parasympathomimetic agent that has been recently investigated for use as an adjunct analgesic agent in the perioperative and peripartum period. A number of studies have investigated the intrathecal, epidural, caudal and intra-articular routes of administration of this agent, as well as the addition of neostigmine to local anaesthetics used for brachial plexus block and intravenous regional anaesthesia. While the intrathecal administration of neostigmine produced useful analgesic effects in the postoperative period in some studies, the high incidence of adverse events, mainly nausea and vomiting, limit the clinical usefulness of this route of administration. Several studies investigated the postoperative analgesic effects of epidural neostigmine using a number of different regimens. Overall, this route of administration appeared to improve postoperative analgesia in most studies without increasing the incidence of adverse events, and merits further research. Neuraxial administration of neostigmine appears to be safe in the obstetric population, with no reported adverse effects in the mother or fetus. While intrathecal administration is limited by a high incidence of nausea and vomiting in this patient population, the epidural route appears more promising and requires further investigation. The addition of neostigmine to caudal local anaesthetics was associated with improved postoperative analgesia in a number of studies. A dose of 2 microg/kg proved to be effective in several studies but was associated with an increased incidence of vomiting in some studies. Intra-articular administration of neostigmine 500microg produced a useful analgesic effect in the postoperative period in several studies and was not associated with an increase in the incidence of adverse effects. Studies investigating the efficacy of adding neostigmine to the local anaesthetics used for brachial plexus block and intravenous regional anaesthesia reported conflicting results. Further studies are required to determine the place of the administration of neostigmine by these routes.

Some current controversies in paediatric regional anaesthesia

PURPOSE OF REVIEW

Controversial topics in paediatric regional anaesthesia are discussed.

RECENT FINDINGS

The performance of blocks under general anaesthesia, new local anaesthetics, adjuvants, location techniques, and risks of masking compartment syndromes are contemplated.

SUMMARY

The performance of regional blocks in anaesthetized patients is generally contra-indicated in adults but accepted in children. Levobupivacaine displays the same pharmacokinetic profile as racemic bupivacaine with possibly less cardiac toxicity. Ropivacaine undergoes slower absorption and, in some studies, concomitant increase in peak plasma concentration in infants. Conversely, continuous infusion of ropivacaine offers the safest therapeutic index. Many adjuvants have been used but only epinephrine, clonidine, and preservative-free ketamine offer clear advantages. Midazolam and neostigmine are effective but have potential drawbacks and raise safety questions. Needle and catheter positioning is critical. Electrocardiogram guidance and electrical stimulation occasionally help identify the migration of epidural catheters. Stimulating catheters might be useful for continuous peripheral blockade. Ultrasonography will probably become the reference technique for peripheral catheter placement. Patients at risk of compartment syndrome must be monitored (measurement of compartmental pressures); adequate pain management does not 'hide' this complication but, on the contrary, can facilitate early diagnosis since the increase in requirement for pain medication precedes other clinical symptoms by an average of 7.3 h.