Caudal 0.2% ropivacaine is less effective during surgery than 0.2% levobupivacaine and 0.2% bupivacaine: a double-blind, randomized, controlled trial

Update on Local Anesthetic Toxicity, Prevention and Treatment During Regional Anesthesia in Infants and Children

Local anesthetic agents play a key role in the treatment and prevention of pain in children. Although generally safe and effective, as with any pharmacologic agent, adverse effects may occur with the administration of these medications. Systemic absorption or inadvertent systemic injection during bolus dosing or continuous infusion can result in local anesthetic systemic toxicity with life-threatening neurological and cardiac complications. The following article reviews the pharmacology of local anesthetic agents, outlines previous reports of systemic toxicity during regional anesthesia, and discusses prevention and treatment algorithms.

Measuring the depth of the caudal epidural space to prevent dural sac puncture during caudal block in children

BACKGROUND

Caudal blocks are performed through the sacral hiatus in order to provide pain control in children undergoing lower abdominal surgery. During the block, it is important to avoid advancing the needle beyond the sacrococcygeal ligament too much to prevent unintended dural puncture. This study used demographic data to establish simple guidelines for predicting a safe needle depth in the caudal epidural space in children.

METHODS

A total of 141 children under 12 years old who had undergone lumbar-sacral magnetic resonance imaging were included. The T2 sagittal image that provided the best view of the sacrococcygeal membrane and the dural sac was chosen. We used Picture Achieving and Communication System (Centricity^® PACS, GE Healthcare Co.) to measure the distance between the sacrococcygeal ligament and the dural sac, the length of the sacrococcygeal ligament, and the maximum depth of the caudal space.

RESULTS

There were strong correlations between age, weight, height, and BSA, and the distance between the sacrococcygeal ligament and dural sac, as well as the length of the sacrococcygeal ligament. Based on these findings, a simple formula to calculate the distance between the sacrococcygeal ligament and dural sac was developed: 25 × BSA (mm).

CONCLUSION

This simple formula can accurately calculate the safe depth of the caudal epidural space to prevent unintended dural puncture during caudal block in children. However, further clinical studies based on this formula are needed to substantiate its utility.

A Ropivacaine-Lidocaine Combination for Caudal Blockade in Haemorrhoidectomy

A single dose of caudal lidocaine does not provide a sufficiently long anaesthetic duration and is not generally used for complicated anorectal surgery. This study evaluated the safety and efficacy of a ropivacaine–lidocaine combination for caudal anaesthesia in patients undergoing haemorrhoidectomy. A total of 287 haemorrhoid patients with successful initial caudal anaesthesia were randomized to receive either a mixture of 0.375% ropivacaine and 1.0% lidocaine (ropi–lido group; n = 146) or 1.0% lidocaine alone (placebo-lido group; n = 141). Significantly fewer patients in the ropi–lido group required intra-operative supplemental anaesthesia than in the placebo-lido group. Patients treated with the ropivacaine–lidocaine combination had significantly lower scores for pain at each post-operative time point, and a longer mean time to the first requirement for post-operative analgesic than patients in the placebo-lido group. These results suggest that caudal anaesthesia with a combination of ropivacaine and lidocaine is a safe and effective method of inducing anaesthesia during haemorrhoidectomy.

Caudal ropivacaine and bupivacaine for postoperative analgesia in infants undergoing lower abdominal surgery

Objective:

To compare the postoperative analgesic efficacy of ropivacaine 0.175% and bupivacaine 0.175% injected caudally into infants for lower abdominal surgery.

Methods:

Eighty infants, aged 3-12 months, ASA I-II scheduled to undergo lower abdominal surgery were randomly allocated to one of the two groups: Group R received 1ml.kg^-1 0.175% ropivacaine and Group B received 1ml.kg^-1 0.175% bupivacaine via caudal route. Postoperative analgesia, sedation and motor block were evaluated with modified objective pain scale, three-point scale and modified Bromage scale respectively. Postoperative measurements including mean arterial pressure (MAP), heart rate (HR), pain (OPS), sedation and motor block score were recorded for four hours in the postoperative recovery room. Parents were contacted by telephone after 24 hours to question duration of analgesia and side effects.

Results:

No significant differences were found among the groups in demographic data, MAP, HR, OPS and sedation scores during four hours postoperatively. The duration of analgesia was 527.5±150.62 minutes in Group R, 692.77±139.01 minutes in Group B (p=0.004). Twelve (30%) patients in Group R, 16 (40%) patients in groupB needed rescue analgesics (p=0.348). Rescue analgesics were administered (1 time/2 times) (9/3) (22.5/7.5%) in Group R and 16/0 (40/0%) in Group B, where no statistically significant difference was determined between the groups (p=0.071). Motor blockade was observed in 7 (17.5%) patients in Group R, and 8 (20%) patients in Group B (p=0.774).

Conclusion:

This study indicated, that a concentration of 0.175% ropivacaine and 0.175% bupivacaine administered to the infants via caudal route both provided effective and similar postoperative pain relief in infants, who underwent lower abdominal surgery.

[Central blockades in Pediatrics: A review of current literature]

Pediatric neuraxial anesthesia is an effective tool that can be used as a supplement or alternative to general anesthesia. However, there have always been doubts about its usefulness and risk-benefit ratio. The purpose of this review is to describe the current role of central blockades in pediatric patients, upgrade practical and safety aspects, and review the latest technological advances applied to this procedure.

Caudal blockade for children undergoing infra-abdominal surgery

The assessment and management of pain in children can be complicated by their inability to communicate effectively; therefore, it is important that every attempt be made to circumvent the undertreatment of pain. Caudal blockade is associated with excellent pain relief and minimal side effects, and it is an established technique used in conjunction with general anesthesia for children undergoing infra-abdominal surgery. Available local anesthetic agents have a relatively short analgesic duration period, so anesthesia professionals often combine their use with adjuvant medications (eg, epinephrine, clonidine, fentanyl, morphine, preservative-free ketamine, neostigmine). Additional consideration should be given to intraoperative care, postoperative observation (eg, measuring sedation, motor blockade, postoperative nausea and vomiting, pain), and discharge instructions for the patient's caregiver.

Comparison of bupivacaine, ropivacaine, and levobupivacaine in an equal dose and concentration for sympathetic block in dogs

BACKGROUND AND OBJECTIVES

The aim of this study was to compare the potency of bupivacaine, ropivacaine, and levobupivacaine in an equal dose and concentration for sympathetic block.

METHODS

We measured mean arterial pressure, heart rate (HR), and right and left brachial artery blood flow (BABF) before and after cervicothoracic sympathetic block in 24 dogs. The experimental protocol was designed as follows: (1) left cervicothoracic sympathetic block with 1.0 mL of 0.25% bupivacaine (n = 8), (2) left cervicothoracic sympathetic block with 1.0 mL of 0.25% ropivacaine (n = 8), and (3) left cervicothoracic sympathetic block with 1.0 mL of 0.25% levobupivacaine (n = 8).

RESULTS

Mean arterial pressure and heart rate did not change significantly throughout the study in either group. Left cervicothoracic sympathetic block with 0.25% bupivacaine increased left BABF significantly from 5 to 100 mins after the block (baseline, 100%; peak at 20 mins after the block, 218% +/- 48%; P < 0.01). Left cervicothoracic sympathetic block with 0.25% ropivacaine increased left BABF significantly from 5 to 100 mins after the block (baseline, 100%; peak at 10 mins after the block, 254 +/- 38%; P < 0.01). Left cervicothoracic sympathetic block with 0.25% levobupivacaine increased left BABF significantly from 5 to 80 mins after the block (baseline, 100%; peak at 20 mins after the block, 183% +/- 38%; P < 0.01).

CONCLUSIONS

Ropivacaine may induce a greater increase in vasodilation than bupivacaine and levobupivacaine at the same dose and concentration for sympathetic block in dogs.

Longer than expected-duration of caudal analgesia with two different doses of levobupivacaine in children undergoing hypospadias repair

OBJECTIVE

To assess our study design and to obtain preliminary data for a dose-effect study on levobupivacaine for caudal analgesia in patients undergoing hypospadias repair.

STUDY DESIGN

non randomised, non-blinded pilot study.

METHOD

For this non-randomized, non-blinded pilot study, 20 patients (median age 17 months, median weight 10.5 kg) were allocated to two groups receiving either 0.5 mL kg(-1) levobupivacaine 0.125% (Group 0) or 0.5 mL kg(-1) levobupivacaine 0.375% (Group 1) caudally after induction of anaesthesia for pain control. No further analgesia was given before, during or after the procedure. Pain scores (Children's and Infants' Postoperative Pain Scale) were recorded throughout the observation period, which lasted from the start of the procedure until hospital discharge on the following day.

RESULTS

Group 0: six out of 10 patients remained pain free throughout the observation period. Group 1: six out of seven patients remained pain free throughout the observation period.

CONCLUSION

Both concentrations of levobupivacaine provided excellent analgesia throughout surgery. The postoperative analgesia with both doses of levobupivacaine was found to be significantly longer lasting than previously reported. The study design, with a tight and extensive observation scheme, proved to be feasible, but given the surprisingly long-lasting analgesia, the observation period needs to be extended in future studies.

Levobupivacaine-tramadol combination for caudal block in children: a randomized, double-blinded, prospective study

BACKGROUND

The aim of this prospective study was to compare the postoperative analgesic efficacy and duration of analgesia after caudal levobupivacaine 0.125% or caudal tramadol 1.5 mg.kg(-1) and mixture of both in children undergoing day-case surgery.

METHODS

Sixty-three American Society of Anesthesiologists (ASA) I or II children between 1 and 7 years old scheduled for inguinal hernia repair under sevoflurane anesthesia were randomized to receive caudal levobupivacaine 0.125% (group L), caudal tramadol 1.5 mg.kg(-1) (group T) or mixture of both (group LT) (total volume of caudal solution was 1 ml.kg(-1)). Duration of analgesia and requirement for additional analgesics were noted. Postoperative pain was evaluated using the Children's and Infants' Postoperative Pain Scale (CHIPPS) every 15 min for the first hour, and after 2, 3, 4, 6, 12, and 24 h. Analgesia was supplemented whenever pain score was > or =4.

RESULTS

No patient experienced significant intraoperative hemodynamic response to surgical incision. Duration of analgesia was significantly longer in group LT than in group L and group T (545 +/- 160 min vs 322 +/- 183 min and 248 +/- 188 min, respectively) (P < 0.01). There were no significant differences between the group L and group T for duration of analgesia (P > 0.05). There were no significant differences among the groups in the number of patients requiring analgesia after operation (P = 0.7). No signs of motor block were observed after the first postoperative hour in any of the patients.

CONCLUSION

Addition of tramadol increased the duration of analgesia produced by caudal levobupivacaine in children.

Relative analgesic potencies of levobupivacaine and ropivacaine for caudal anesthesia in children

BACKGROUND

Comparing relative potency of new local anesthetics, such as levobupivacaine and ropivacaine, by the minimum local analgesic concentration model has not been described for caudal anesthesia. Therefore, we performed a prospective, randomized, double-blind study to determine the minimum local analgesic concentrations of a caudal single shot of ropivacaine and levobupivacaine in children and to describe the upper dose-response curve.

METHODS

We performed a two-stage prospective, randomized, double-blind study comparing the dose-response curves of caudal ropivacaine and levobupivacaine in children. In phase 1, 80 boys were randomized to receive either ropivacaine or levobupivacaine. In the second phase a further 32 patients were randomly allocated to receive caudal anesthesia with doses designed to delineate the upper dose-response range (the 50% effective dose [ED(50)]-ED(95) range).

RESULTS

There were no significant differences in ED(50) values for caudal ropivacaine and levobupivacaine. The ED(50) for levobupivacaine estimated from the Dixon Massey method was 0.069% (95% CI 0.056%-0.082%) and for ropivacaine was 0.075% (95% CI 0.058%-0.092%). Estimated by isotonic regression the ED(50) and ED(95) respectively of levobupivacaine were 0.068 (0.04-0.09) and 0.20% (95% CI 0.16%-0.24%). For ropivacaine ED 50 and ED95 were 0.066 (0.033-0.098) and 0.225% (95% CI 0.21%-0.24%).

CONCLUSIONS

In children receiving one minimum alveolar anesthetic concentration of sevoflurane, there were no significant differences in the ED(50) for caudal levobupivacaine and ropivacaine. The potency ratio at ED(50) was 0.92 and 0.89 at ED(95), indicating that caudal levobupivacaine and ropivacaine have a similar potency.

The optimum initial pediatric epidural bolus: a comparison of four local anesthetic solutions

BACKGROUND

There is no consensus on the concentration or type of local anesthetic used for initiation of epidural anesthesia. The aim of this randomized, double-blind, controlled trial was to compare the clinical effectiveness of epidural administration of both levobupivacaine and bupivacaine in 0.2% and 0.25% concentrations in pediatric patients undergoing abdominal and urological surgery.

METHODS

One hundred and forty-one children scheduled for lower abdominal and urological surgery were randomized to receive 0.4-0.6 ml.kg(-1) epidural, 0.25% bupivacaine, 0.2% bupivacaine, 0.25% levobupivacaine or 0.2% levobupivacaine. Initial epidural volumes, onset times; hemodynamic consequences, postoperative pain scores and degree of residual postoperative motor block were all recorded.

RESULTS

There were no significant differences in the proportion of children with effective analgesia after incision [0.20% bupivacaine 97%, 0.25% bupivacaine 94%, 0.20% levobupivacaine 91%, 0.25% levobupivacaine 92% (P=0.73)] when a median volume of 0.55 ml.kg(-1) was used. There was no association between the volume used for thoracic, lumbar, or sacral epidural anesthesia and the effectiveness of the agents used. There was a significantly greater incidence of pain on awakening with the 0.2% solutions compared with the 0.25% solutions, but no differences in the incidence of residual motor block between groups.

CONCLUSIONS

While there is no difference in the proportion of effective surgical anesthesia, the lower incidence of pain and distress with the 0.25% solutions suggests that this concentration has clinical advantages over the 0.2% solutions for pediatric epidural anesthesia.

Bupivacaine caudal epidural anesthesia: assessing the effect of general anesthetic technique on block onset

BACKGROUND

The primary objective of this prospective, randomized trial was to compare the effect of propofol and sevoflurane on effectiveness of regional anesthesia. As a secondary objective, we aimed at evaluating the influence of age on neuraxial block profile.

METHODS

One hundred and thirteen healthy children aged <10 years, scheduled for general or urological surgical procedures were randomly allocated to receive either propofol or sevoflurane induction and maintenance. Children received caudal or lumbar epidural block depending on their weight and expected surgery. Time to onset of surgical anesthesia, intraoperative analgesic effectiveness, residual motor blockade, postoperative pain, and adverse effects were evaluated. To assess the influence of age on these measures children were further divided into three age groups: 0-24, 25-60 and >60 months.

RESULTS

The mean time to onset of surgical anesthesia was significantly shorter in the sevoflurane group than the propofol group (3.1 vs 4.7 min, P < 0.01), independent of the type of regional technique employed. Distress on arousal in recovery was increased in children receiving sevoflurane (P = 0.03). There was no significant difference in residual motor blockade between the groups but children between 0 and 24 months receiving sevoflurane had a higher incidence of residual motor blockade 3 h after local anesthetic injection (P = 0.01).

CONCLUSIONS

This study has demonstrated that general anesthesia with sevoflurane decreases the time to onset of surgical anesthesia relative to propofol anesthesia. This effect was most marked when sevoflurane anesthesia preceded caudal epidural blockade. The basis for this effect is most likely to be related to differential binding of the two anesthetic agents to receptors in the spinal cord that mediate immobility in response to surgical stimuli.