Caudal additives in children--solutions or problems?

Intrathecal clonidine in the neonatal rat: dose-dependent analgesia and evaluation of spinal apoptosis and toxicity

BACKGROUND

Neuraxial clonidine is used for perioperative analgesia in children of all ages. Preclinical studies in the postnatal rat allow comparison of the relative toxicity and safety of spinal analgesics throughout postnatal development.

METHODS

Rat pups aged 3, 7, or 21 postnatal (P) days were briefly anesthetized for intrathecal injections of saline or clonidine. At each age, the maximum tolerated, antinociceptive (increased hindlimb mechanical withdrawal threshold) and antihyperalgesic (hindpaw carrageenan inflammation) doses were determined. Lumbar spinal cord sections were assessed for apoptosis and cell death (histology, activated caspase-3 immunohistochemistry, Fluoro-Jade C staining), histopathology (hematoxylin and eosin staining), and increased glial reactivity (microglial and astrocytic markers). P3 intrathecal ketamine sections served as positive controls. In additional groups, thermal latency and mechanical withdrawal threshold were measured at P35.

RESULTS

Intrathecal clonidine produces age- and dose-dependent analgesia in rat pups. Maximal doses of clonidine did not alter the degree or distribution of apoptosis or increase glial reactivity in the neonatal spinal cord. No spinal histopathology was seen 1 or 7 days after injection at any age. Intrathecal clonidine did not produce persistent changes in reflex sensitivity to mechanical or thermal stimuli at P35.

CONCLUSIONS

Intrathecal clonidine in the postnatal rat did not produce signs of spinal cord toxicity, even at doses much larger than required for analgesia. The therapeutic ratio (maximum tolerated dose/antihyperalgesic dose) was >300 at P3, >30 at P7, and >10 at P21. These data provide additional information to inform the clinical choice of spinal analgesic drug in early life.

Arthrogryposis multiplex congenita: An anesthetic challenge

Children with arthrogryposis multiplex congenita often require multiple orthopedic corrective procedures. We present a case of a child with arthrogryposis multiplex congenita posted for contracture release of both lower limbs that were successfully managed with total intravenous anesthesia and caudal epidural analgesia with Bupernorphine as an additive.

Caudal blocks

Caudal anesthesia is the single most important pediatric regional anesthetic technique. The technique is relatively easy to learn (1), has a remarkable safety record (2), and can be used for a large variety of procedures. The technique has been reviewed in the English (3) and French (4) literature, as well as in German guidelines (5) and in pediatric anesthesia textbooks (6).

Caudal additives do not improve the analgesia afforded by levobupivacaine after hypospadias repair

Background:

Caudal analgesia is commonly employed to provide excellent intra- and postoperative analgesia for primary hypospadias repair in children. Several additives to local anesthetics are commonly employed to increase the block duration, although these have uncertain benefits.

Objectives:

This study investigated whether, in caudal analgesia with levobupivacaine 0.25%, the addition of S (+)-ketamine, clonidine, or both agents combined, would prolong postoperative analgesia in patients undergoing primary hypospadias repair.

Patients and Methods:

We conducted a retrospective chart analysis for all patients who underwent hypospadias repair with caudal analgesia over a consecutive 3-period at this institution. The study examined four patient groups, classified according to the analgesia used:

Primary outcome measures were as follows: time to the first postoperative request for analgesia, total first 24-hour postoperative analgesia, and time to hospital discharge.

Results:

The 87 patients included had a mean ± SD age of 21.4 ± 13.5 months and weight of 11.9 ± 2.4 kg. The median doses of levobupivacaine, S (+)-ketamine, and clonidine were 0.7 mg/kg (range, 0.4–1.3), 0.5 mg/kg (0.2–1.1), and 1.8 μg/kg (0.8–2.3), respectively. The addition of S(+)-ketamine, clonidine, or both did not increase the time to first oral analgesia request. Neither did it reduce the total first 24-hour postoperative analgesia requirements or alter hospital discharge time. However, the additive drugs in combination did increase postoperative sedation.

Conclusions:

The addition of S (+)-ketamine or clonidine to levobupivacaine 0.25% in caudal analgesia for hypospadias repair appears to be of no benefit. However, use of the additives in combination increased postoperative sedation.

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.

Caudal ropivacaine-clonidine: A better post-operative analgesic approach

The aim was to determine qualitative and quantitative aspects of caudal block, haemodynamic effects, and post-operative pain relief of ropivacaine 0.25% versus ropivacaine 0.25% with clonidine for lower abdominal surgeries in paediatric patients. A double-blind study was conducted among 44 paediatric patients in the Department of Anaesthesiology and Intensive Care of our institute. A total of 44 ASA-I paediatric patients between the ages of 1 and 9 years, scheduled for elective hernia surgery, were enrolled in this randomised double-blind study. The caudal block was administered with ropivacaine 0.25% (Group I) and ropivacaine 0.25% and clonidine 2 µg/kg (Group II) after induction with general anaesthesia. Haemodynamic parameters were observed before, during and after the surgical procedure. Post-operative analgesic duration, total dose of rescue analgesia, pain scores and any side effects were looked for and recorded. All the results were tabulated and analysed statistically. The variables in the two groups were compared using the non-parametric tests. For all statistical analyses, the level of significance was P < 0.05. Forty-four patients were enrolled in this study and their data were subjected to statistical analysis: 22 patients in both the groups were comparable with regard to demographic data, haemodynamic parameters and other vitals and were statistically non-significant (P>0.05). The duration of analgesia was significantly prolonged in Group II (P<0.05). The dose requirement for post-operative pain relief was also significantly lesser in Group II. The incidences of side effects were almost comparable and non-significant. A caudal block with 0.25% of isobaric ropivacaine combined with 2 µg/kg of clonidine provides efficient analgesia intra-operatively and prolonged duration of analgesia post-operatively.

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.

Use of transcutaneous electrical nerve stimulation as an adjunctive to epidural analgesia in the management of acute thoracotomy pain

The present randomized study was conducted in our institute of pulmonary medicine and tuberculosis over a period of 1 year. This study aimed to evaluate the effectiveness of transcutaneous electrical nerve stimulation (TENS) as an adjunctive to thoracic epidural analgesia for the treatment of postoperative pain in patients who underwent posterolateral thoracotomy for decortication of lung. Sixty patients in the age group 15–40 years scheduled to undergo elective posterolateral thoracotomy were divided into two groups of 30 each. Patients were alternatively assigned to one of the groups. In group I, only thoracic epidural analgesia with local anaesthetics was given at regular intervals; however, an identical apparatus which did not deliver an electric current was applied to the control (i.e. group I) patients. While in group II, TENS was started immediately in the recovery period in addition to the epidural analgesia. A 0–10 visual analog scale (VAS) was used to assess pain at regular intervals. The haemodynamics were also studied at regular intervals of 2 h for the first 10 h after the surgery. When the VAS score was more than three, intramuscular analgesia with diclofenac sodium was given. The VAS score and the systolic blood pressure were comparable in the immediate postoperative period (P = NS) but the VAS score was significantly less in group II at 2, 4, 6, 8 h (P < 0.01, P < 0.05, P < 0.05, P < 0.05, respectively), and at 10 h the P value was not significant. Similarly, the systolic blood pressure was significantly less in group II at 2, 4, 6 h after surgery, that is P < 0.02, P < 0.01, P < 0.01, respectively, but at 8 and 10 h the pressures were comparable in both the groups. Adding TENS to epidural analgesia led to a significant reduction in pain with no sequelae. The haemodynamics were significantly stable in group II compared to group I. TENS is a valuable strategy to alleviate postoperative pain following thoracic surgery with no side effects and with a good haemodynamic stability; however, the effects are short lasting.

Pharmacotherapy for acute pain in children: current practice and recent advances

INTRODUCTION

Acute pain in children may be undertreated. Improved understanding of developmental neurobiology and paediatric pharmacokinetics should facilitate better management of pharmacotherapy. The objective of this review is to discuss current paediatric practice and recent advances with these analgesic agents by using an evidence-based approach.

AREAS COVERED

Using PubMed an extensive literature review was conducted on the commonly used analgesic agents in children from 2000 to April 2010.

EXPERT OPINION

A multimodal analgesic regimen provides better pain control and functional outcome in children. The choice of pharmacological treatment is determined by the severity and type of pain. However, more research and evidence is required to determine the optimal drug combinations.

Validation of a preclinical spinal safety model: effects of intrathecal morphine in the neonatal rat

BACKGROUND

Preclinical studies demonstrate increased neuroapoptosis after general anesthesia in early life. Neuraxial techniques may minimize potential risks, but there has been no systematic evaluation of spinal analgesic safety in developmental models. We aimed to validate a preclinical model for evaluating dose-dependent efficacy, spinal cord toxicity, and long-term function after intrathecal morphine in the neonatal rat.

METHODS

Lumbar intrathecal injections were performed in anesthetized rats aged postnatal day (P) 3, 10, and 21. The relationship between injectate volume and segmental spread was assessed postmortem and by in vivo imaging. To determine the antinociceptive dose, mechanical withdrawal thresholds were measured at baseline and 30 min after intrathecal morphine. To evaluate toxicity, doses up to the maximum tolerated were administered, and spinal cord histopathology, apoptosis, and glial response were evaluated 1 and 7 days after P3 or P21 injection. Sensory thresholds and gait analysis were evaluated at P35.

RESULTS

Intrathecal injection can be reliably performed at all postnatal ages and injectate volume influences segmental spread. Intrathecal morphine produced spinally mediated analgesia at all ages with lower dose requirements in younger pups. High-dose intrathecal morphine did not produce signs of spinal cord toxicity or alter long-term function.

CONCLUSIONS

The therapeutic ratio for intrathecal morphine (toxic dose/antinociceptive dose) was at least 300 at P3 and at least 20 at P21 (latter doses limited by side effects). These data provide relative efficacy and safety for comparison with other analgesic preparations and contribute supporting evidence for the validity of this preclinical neonatal safety model.

Effects of intrathecal ketamine in the neonatal rat: evaluation of apoptosis and long-term functional outcome

BACKGROUND

Systemic ketamine can trigger apoptosis in the brain of rodents and primates during susceptible developmental periods. Clinically, spinally administered ketamine may improve the duration or quality of analgesia in children. Ketamine-induced spinal cord toxicity has been reported in adult animals but has not been systematically studied in early development.

METHODS

In anesthetized rat pups, intrathecal ketamine was administered by lumbar percutaneous injection. Changes in mechanical withdrawal threshold evaluated dose-dependent antinociceptive and carrageenan-induced antihyperalgesic effects in rat pups at postnatal day (P) 3 and 21. After intrathecal injection of ketamine at P3, 7, or 21, spinal cords were examined for apoptosis (Fluoro-Jade C and activated caspase-3), histopathologic change, and glial responses (ionized calcium-binding adapter molecule 1 and glial fibrillary acid protein). After maximal doses of ketamine or saline at P3 or P21, sensory thresholds and gait analysis were evaluated at P35.

RESULTS

Intrathecal injection of 3 mg/kg ketamine at P3 and 15 mg/kg at P21 reverses carrageenan-induced hyperalgesia. Baseline neuronal apoptosis in the spinal cord was greater at P3 than P7, predominantly in the dorsal horn. Intrathecal injection of 3-10 mg/kg ketamine in P3 pups (but not 15 mg/kg at P21) acutely increased apoptosis and microglial activation in the spinal cord and altered spinal function (reduced mechanical withdrawal threshold and altered static gait parameters) at P35.

CONCLUSIONS

Because acute pathology and long-term behavioral change occurred in the same dose range as antihyperalgesic effects, the therapeutic ratio of intrathecal ketamine is less than one in the neonatal rat. This measure facilitates comparison of the relative safety of spinally administered analgesic agents.

Acute pain management in children

The greatest advance in pediatric pain medicine is the recognition that untreated pain is a significant cause of morbidity and even mortality after surgical trauma. Accurate assessment of pain in different age groups and the effective treatment of postoperative pain is constantly being refined; with newer drugs being used alone or in combination with other drugs continues to be explored. Several advances in developmental neurobiology and pharmacology, knowledge of new analgesics and newer applications of old analgesics in the last two decades have helped the pediatric anesthesiologist in managing pain in children more efficiently. The latter include administering opioids via the skin and nasal mucosa and their addition into the neuraxial local anesthetics. Systemic opioids, nonsteroidal anti-inflammatory agents and regional analgesics alone or combined with additives are currently used to provide effective postoperative analgesia. These modalities are best utilized when combined as a multimodal approach to treat acute pain in the perioperative setting. The development of receptor specific drugs that can produce pain relief without the untoward side effects of respiratory depression will hasten the recovery and discharge of children after surgery. This review focuses on the overview of acute pain management in children, with an emphasis on pharmacological and regional anesthesia in achieving this goal.

A survey of pediatric caudal extradural anesthesia practice

BACKGROUND

Caudal extradural blockade is one of the most commonly performed procedures in pediatric anesthesia. However, there is little information available on variations in clinical practice.

OBJECTIVES

To perform a survey of members of the Association of Paediatric Anaesthetists of Great Britain and Ireland who undertake caudal anesthesia.

METHODS

An 'online' World Wide Web questionnaire collected information on various aspects of clinical practice. The survey ran from April to June 2008.

RESULTS

There were 366 questionnaires completed. The majority of respondents had >5 years of pediatric experience and performed up to ten caudal extradural procedures a month. The commonest device used was a cannula (69.7%) with 68.6% using a 22G device. There was a trend toward the use of a cannula in those anesthetists with <15 years experience, while those with >15 years experience tended to use a needle. Most anesthetists (91.5%) did not believe that there was a significant risk of implantation of dermoid tissue into the caudal extradural space. The majority used a combination of clinical methods to confirm correct placement. Only 27 respondents used ultrasound. The most popular local anesthetics were bupivacaine (43.4%) and levobupivacaine (41.7%). The most common additives were clonidine (42.3%) and ketamine (37.5%). The caudal catheter technique was used by 43.6%. Most anesthetists (74%) wear gloves for a single shot caudal injection.

CONCLUSIONS

This survey provides a snapshot of current practice and acts a useful reference for the development of enhanced techniques and new equipment in the future.

Effect of dexmedetomidine on the characteristics of bupivacaine in a caudal block in pediatrics

BACKGROUND

Dexmedetomidine (DEX) is a highly selective alpha(2)-adrenoceptor agonist that has been used increasingly in children. However, the effect of caudal DEX has not been evaluated before in children. This prospective randomized double-blinded study was designed to evaluate the analgesic efficacy of caudal DEX with bupivacaine in providing pain relief over a 24-h period.

METHODS

Sixty children (ASA status I) aged 1-6 years undergoing unilateral inguinal hernia repair/orchidopexy were allocated randomly to two groups (n = 30 each). Group B received a caudal injection of bupivacaine 2.5 mg/ml, 1 ml/kg; Group BD received the same dose of bupivacaine mixed with DEX 1 microg/kg during sevoflurane anesthesia. Processed electroencephalogram (bispectral index score), heart rate, blood pressure, pulse oximetry and end-tidal sevoflurane were recorded every 5 min. The characteristics of emergence, objective pain score, sedation score and quality of sleep were recorded post-operatively. Duration of analgesia and requirement for additional analgesics were noted.

RESULTS

The end-tidal sevoflurane concentration and the incidence of agitation were significantly lower in the BD group (P < 0.05). The duration of analgesia was significantly longer (P < 0.001) and the total consumption of rescue analgesic was significantly lower in Group BD compared with Group B (P < 0.01). There was no statistically significant difference in hemodynamics between both groups. However, group BD had better quality of sleep and a prolonged duration of sedation (P < 0.05).

CONCLUSION

Caudal DEX seems to be a promising adjunct to provide excellent analgesia without side effects over a 24-h period. It has the advantage of keeping the patients calm for a prolonged time. Implications statement: Caudally administered DEX (1 microg/kg), combined with bupivacaine, was associated with an extended duration of post-operative pain relief.

Comparison of caudal epidural bupivacaine with bupivacaine plus tramadol and bupivacaine plus ketamine for postoperative analgesia in children

This study compared the effect of single-dose caudal epidural bupivacaine, bupivacaine plus ketamine and bupivacaine plus tramadol for postoperative pain management in children having surgery for inguinal hernia. Following ethics committee approval and informed parental consent, 75 children ASA PS I and II, between three and nine years of age and scheduled for elective unilateral inguinal hernia repair with general anaesthesia were recruited. The patients were randomly divided into three groups to receive 0.5 ml/kg caudal bupivacaine 0.25% (group B), bupivacaine 0.25% plus tramadol 1 mg/kg (group BT) or bupivacaine 0.25% plus ketamine 0.5 mg/kg (group BK). The injections were performed under general anaesthesia. Mean arterial pressure, heart rate, pulse oximetry, respiratory rate and sedation and pain scores were recorded at defined intervals following recovery from anaesthesia. The groups were similar in age, weight and duration of operation (P >0.05). No patient experienced hypotension, bradycardia or respiratory depression. Duration of analgesia was (mean+/-SD) 6.5+/-4.1 h in group B, 9.2+/-3.9 h in group BK, and 8.5+/-3.1 h in group BT (P <0.05). More patients in group B required supplementary analgesics in the first 24 h (P <0.05). Sedation scores were comparable in all groups. Incidence of emesis and pruritus was similar in all the groups. Caudally administered 0.5 ml/kg bupivacaine 0.25% plus ketamine or bupivacaine 0.25% plus tramadol 1 mg/kg provided significantly longer duration of analgesia without an increase in the adverse effects when compared to bupivacaine alone.

A Comparison of Single-Dose Caudal Clonidine, Morphine, or Hydromorphone Combined with Ropivacaine in Pediatric Patients Undergoing Ureteral Reimplantation

BACKGROUND

Caudal blockade is a common technique for pediatric postoperative analgesia. While safe and effective, caudal opioids are associated with troublesome side effects. Caudal clonidine may offer significant analgesic benefits. We prospectively compared the analgesic, side effect, and rehabilitation profiles of caudal clonidine, hydromorphone, or morphine in a group of 60 pediatric patients undergoing ureteral reimplantation.

METHODS

Patients aged 6 mo to 6 yr were evenly and randomly enrolled in a double-blind manner. Patients received a single caudal dose of 2 mcg/kg of clonidine, 10 mcg/kg of hydromorphone, or 50 mcg/kg of morphine, combined with 1.0 mL/kg of 0.2% ropivacaine with epinephrine. After sevoflurane in oxygen/air anesthesia, all subjects received proxy nurse-controlled analgesia with morphine. Postoperative pain intensity, use of IV morphine, and side effects were assessed during the first 24 h. Oral intake and discharge home were recorded.

RESULTS

Caudal clonidine resulted in less postoperative nausea and vomiting (P = 0.01) and pruritus (P = 0.007) than did caudal hydromorphone or caudal morphine. Caudal morphine produced more sustained initial analgesia than did caudal clonidine (P = 0.02). No difference was observed in pain scores, total morphine use, time to first oral intake or discharge home. No postoperative respiratory depression, excessive sedation, hypotension, or bradycardia was identified.

CONCLUSIONS

Although caudal morphine may result in more sustained initial analgesia, caudal clonidine combined with nurse-controlled analgesia appears to provide comparable analgesia with fewer side effects. Based on these results, the use of caudal clonidine may be superior to caudal opioids after pediatric ureteral reimplantation.

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.

Clonidine in paediatric anaesthesia: review of the literature and comparison with benzodiazepines for premedication

BACKGROUND

Children undergoing anaesthesia and surgery can experience significant anxiety and distress during the peri-operative period, but whether routine premedication is necessary is currently debated. Benzodiazepines are the most frequently used drugs as premedication in paediatric anaesthesia. In the US, 50% of young children undergoing surgery receive premedication and midazolam is the most frequently used drug in this context (1). Nishina and coworkers (2) concluded in a review article in 1999 that clonidine, administered via an oral, rectal, or caudal route, is a promising adjunct to anaesthetics and analgesics to enhance quality of peri-operative management in infants and children. Later publications also support the use of clonidine for premedication (3-6). The aim of this communication is to review the use of clonidine in paediatric anaesthesia and to propose clonidine as a promising alternative to midazolam. Clonidine is associated with a number of beneficial effects in the context ofanaesthesia both in adults and children. Why clonidine is not routinely use in clinical practice despite the massive publication list is to a large extent due to the lack of marketing efforts from the pharmaceutical industry since multiplegeneric preparations are now readily available on most markets. Midazolam is also associated with a number of beneficial effects, but is far from an ideal premedicant in children, especially with regards to the amnesia, confusion and long term behavioural disturbances. Clonidine has contrary to midazolam no effect on respiration. We believe that clonidine is a good alternative to midazolam as premedication in infants and children.

Comparison of caudal ketamine with lidocaine or tramadol administration for postoperative analgesia of hypospadias surgery in children

BACKGROUND

This study was designed to investigate whether the addition of tramadol or lidocaine to ketamine would enhance the quality of intra- and postoperative analgesia for hypospadias surgery in children.

METHODS

Sixty-two ASA PS I or II children, between 1 and 10 years of age, scheduled for hypospadias surgery were recruited. Anesthesia was induced with 6-8% sevoflurane and maintained with 0.5-2.5% sevoflurane-50% N2O in oxygen. Children were allocated randomly to receive one of two study drugs. Children in group KL received caudal ketamine (0.25 mg.kg(-1)) plus lidocaine (2%, 2 mg.kg(-1)) and in group KT ketamine (0.25 mg.kg(-1)) plus tramadol (1 mg.kg(-1)). Systemic blood pressure, heart rate, peripheral O2 saturation, sedation, and pain scores (CHEOPS) were recorded at 1, 5, 10, 15, 30, 45 min and 1, 2, 3 h following recovery from anesthesia.

RESULTS

Duration of analgesia was similar in the two groups (P > 0.05). CHEOPS in group KL was lower than in group KT during the study period, except at first 15 min. Sedation scores were higher in group KL than group KT in the first 10 min (P < 0.05). Incidence of postoperative nausea and vomiting was similar in the two groups (P > 0.05) Sevoflurane concentration required was significantly lower in group KL than group KT peroperatively (P < 0.001).

CONCLUSIONS

Caudal ketamine (0.25 mg.kg(-1)), plus lidocaine (2% 2 mg.kg(-1)) significantly reduced sevoflurane concentration compared with ketamine (0.25 mg.kg(-1)) + tramadol (1 mg.kg(-1)). We suggested that both ketamine + lidocaine and ketamine + tramadol provided very effective and long duration of analgesia, similarly. However, analgesia quality is superior in the ketamine-lidocaine group postoperatively.

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

Single-shot "kiddie caudal" with bupivacaine alone is losing popularity because of its duration of 4-8 h. In a prospective randomized double-blind clinical study, we assessed and compared the efficacy of ketamine, midazolam, and neostigmine coadministered with bupivacaine in a caudal epidural to provide intraoperative and postoperative pain relief. Eighty children (ASA status I) aged 5-10 yr undergoing unilateral inguinal herniotomy were allocated randomly in equal numbers (n = 20) into 4 groups to receive a caudal injection of 0.25% bupivacaine (1 mL/kg) with or without ketamine (0.5 mg/kg), midazolam (50 microg/kg), and neostig-mine (2 microg/kg), after the induction of standardized general anesthesia without premedication. Monitoring for pain, sedation, postoperative nausea/vomiting, dizziness, and pruritus was performed by anesthesiologists blinded to the study allocation. The time to first analgesic administration (paracetamol syrup) was longer (P < 0.05) in the bupivacaine-neostigmine group and the bupivacaine-midazolam group than in the other groups. Undesirable effects, such as emesis, pruritus, and dizziness, were comparable in all groups. However, the incidence of hallucination was more frequent in the bupivacaine-ketamine group compared with the other groups. This study shows that single-shot caudal coadministration of bupivacaine-neostigmine and bupivacaine-midazolam was associated with an extended duration of postoperative pain relief.

Caudal analgesia and anesthesia techniques in children

PURPOSE OF REVIEW

Caudal epidural blockade remains the cornerstone of pediatric regional anesthesia. In this article we provide a comprehensive review of the recent developments in caudal anesthesia in infants and children.

RECENT FINDINGS

Research has focused on prolonging the duration of single-shot caudal blocks and accurately positioning continuous caudal catheters. New local anesthetics with similar potencies but less toxicity have been introduced. Opioids prolong the duration of analgesia of local anesthetic, but have also been associated with unacceptable side effects, particularly in pediatric outpatients. Various non-opioid adjuncts with more favorable side-effect profiles may increase the duration of analgesia. New ultrasound and nerve-stimulation techniques have been developed to accurately guide epidural catheters to a specific spinal level.

SUMMARY

The addition of ketamine or clonidine to a caudal local anesthetic prolong the duration of the block. However, a preservative-free preparation of ketamine that is suitable for neuraxial use is not widely available. Ultrasound imaging and electrical stimulation are promising options to accurately position a caudal needle. However, because ultrasound imaging is more difficult in older children, nerve stimulation is a more-suitable technique to accurately guide caudal catheters in this patient population. Although complications associated with caudal block are rare, the risks and benefits must be carefully considered on an individual basis.

The addition of clonidine 2 microg.kg-1 does not enhance the postoperative analgesia of a caudal block using 0.125% bupivacaine and epinephrine 1:200,000 in children: a prospective, double-blind, randomized study

BACKGROUND

In this prospective, randomized, double-blind study, we compared the efficacy of 0.125% bupivacaine and epinephrine 1:200,000 with and without clonidine 2 microg.kg-1 for 'single shot' pediatric caudal analgesia.

METHODS

Thirty ASA I and II children, ages 2-8 years, undergoing outpatient surgical procedures below the umbilicus received 1 ml.kg-1 0.125% bupivacaine with fresh epinephrine 1:200,000 and clonidine 2 microg.kg-1 (group-C) or 1 ml.kg-1 0.125 % bupivacaine with epinephrine 1:200 000 (group-NC). All patients received a standardized general anesthetic (induction with 67% N2O in O2 and sevoflurane followed by isoflurane maintenance). Primary outcome measures were time to first rescue analgesic and number of patients requiring rescue analgesic at 4, 6, 8, 12, and 24 h after caudal placement. Secondary outcome measures included: extubation times, Objective Pain Scale (OPS) scores, sedation scores, time in postanesthesia care unit (PACU), discharge time, number of analgesic doses given in 24 h following caudal blockade, and adverse effects (vomiting, hypotension, and bradycardia).

RESULTS

There were no differences in demographics, investigated parameters, or adverse effects between groups.

CONCLUSIONS

We found that the addition of clonidine 2 microg.kg-1 to 0.125% bupivacaine with fresh epinephrine 1:200,000 for caudal analgesia did not significantly delay the time to first rescue analgesic or decrease the overall need for rescue analgesics in children 2-8 years undergoing surgical procedures below the umbilicus.

Postoperative pain management in children

There is increased awareness of the need for effective postoperative analgesia in infants and young children. A multi-modal approach to preventing and treating pain usually is used. Mild analgesics, local and regional analgesia, and opioids when indicated, frequently are combined to minimize adverse effects of individual drugs or techniques.

What’s new and novel in obstetric anesthesia? Contributions from the 2003 scientific literature

THE PREGNANT PATIENT: Age; maternal disease; prophylactic antibiotics; gastroesophageal reflux; obesity; starvation; genotyping; coagulopathy; infection; substance abuse; altered drug responses in pregnancy; physiological changes of pregnancy. THE FETUS: Fetal monitoring; intrauterine surgery. THE NEWBORN: Breastfeeding; maternal infection, fever, and neonatal sepsis evaluation. OBSTETRIC COMPLICATIONS: Embolic phenomena; hemorrhage; preeclampsia; preterm delivery. OBSTETRIC MANAGEMENT: External cephalic version and cervical cerclage; elective cesarean delivery; fetal malpresentation; vaginal birth after cesarean delivery; termination of pregnancy. OBSTETRIC ANESTHESIA: Analgesia for labor and delivery; anesthesia for cesarean delivery; anesthesia for short obstetric operations; complications of anesthesia. MISCELLANEOUS: Consent; ethics; history; labor support; websites/books/leaflets/journal announcements.

Anesthetic considerations for pediatric outpatient surgery

At least 60% of all pediatric surgical procedures are performed as outpatients. Successful outpatient practice requires that both the patients and the procedures are appropriate for outpatient management. Appropriate scheduling ensures that the overall function of the outpatient unit is not compromised. While not all scheduled patients need be perfectly healthy, care must be taken to provide adequate resources to those patients who are not, without diverting resources away from other patients. Anesthesia must be managed with attention to the unique physiologic and psychological challenges of children. Anesthetic management of postoperative nausea and vomiting and provision of adequate postoperative analgesia, including regional techniques, are important elements of the care plan.

Recent developments in paediatric regional anaesthesia

PURPOSE OF REVIEW

This review will focus on recently published data concerning side effects and complications of paediatric regional anaesthesia, putting into perspective the currently used techniques.

RECENT FINDINGS

Penile block is clearly a technique with a very large benefit and minimal side effects. Ilioinguinal nerve block, on the other hand, quite commonly leads to complications. Single-shot caudal anaesthesia is considered a safe and effective technique; however, even with this widely used block, complications such as sacral osteomyelitis can occur. Recent review articles have focussed on the role of additives for prolonging the duration of paediatric caudal anaesthesia. The use of ketamine or s-ketamine as an additive appears to be most promising for the future.

SUMMARY

Paediatric regional anaesthesia is now widely used for postoperative pain relief in children. However, a careful risk-benefit analysis is always mandatory before such medical interventions are undertaken.

Caudal bupivacaine supplemented with caudal or intravenous clonidine in children undergoing hypospadias repair: a double-blind study

BACKGROUND

Clonidine is used increasingly in paediatric anaesthetic practice to prolong the duration of action of caudal block with a local anaesthetic agent. Which route of administration of clonidine is the most beneficial remains unknown. We compared the effects of caudal and i.v. clonidine on postoperative analgesia produced by caudal bupivacaine after hypospadias repair.

METHODS

Forty-six children (ASA I or II) aged 24-104 months received standardized premedication with midazolam, a general anaesthetic and a caudal block with bupivacaine 0.25%, 0.5 ml kg(-1). The children were randomized in a double-blind fashion to two groups: the i.v. group received clonidine 2 micro g kg(-1) i.v. and simultaneously the same volume of saline caudally. The caudal group received clonidine 2 micro g kg(-1) caudally and a similar volume of saline i.v. After surgery, all children received acetaminophen 20 mg kg(-1) rectally or orally 6-hourly and were given a patient-controlled or nurse-controlled analgesia (PCA/NCA) pump with i.v. morphine (bolus of 25 micro g kg(-1) and an 8-min lockout period with no background infusion). Monitoring of scores for pain, sedation, motor block, and postoperative nausea and vomiting was performed by nurses blinded to the study allocations. Time to first activation of the PCA/NCA pump and 0-24 h and 24-48 h morphine consumption were also recorded.

RESULTS

Forty-four children completed the study. Age, weight and duration of anaesthesia and surgery were similar in the two groups. The median (range) time to first activation of the PCA/NCA pump was similar in the two groups: 425 (150-1440) min in the i.v. group and 450 (130-1440) min in the caudal group. The number of children not requiring postoperative morphine was four and seven respectively. Morphine consumption during 0-24 h and 24-48 h was similar between groups.

CONCLUSIONS

The analgesic effect of clonidine 2 micro g kg(-1) as an adjunct to caudal block with bupivacaine 0.25%, 0.5 ml kg(-1) is similar whether administered i.v. or caudally.