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Optimum concentration of bupivacaine for combined caudal--general anesthesia in children
J B Gunter1, C M Dunn, J B Bennie
1Department of Anesthesiology, Washington University School of Medicine, St. Louis Children's Hospital, Missouri 63178.
Insights
For pediatric outpatient surgery, 0.175% bupivacaine offers optimal caudal anesthesia, balancing reduced halothane requirements and faster postanesthesia care unit discharge. Higher concentrations increased leg weakness, while lower ones led to greater pain scores.
Area of Science:
- Anesthesiology
- Pediatric Surgery
- Pharmacology
Background:
- Caudal epidural anesthesia is a standard for pediatric pain management and intraoperative anesthesia supplementation.
- Determining optimal bupivacaine concentrations is crucial for balancing efficacy and side effects in children.
Purpose of the Study:
- To identify the most effective bupivacaine concentration for combined general-caudal anesthesia in pediatric patients undergoing outpatient inguinal herniorrhaphy.
- To evaluate the impact of different bupivacaine concentrations on anesthetic requirements, recovery, and postoperative complications.
Main Methods:
- A double-blind, randomized trial involving 122 children (1-8 years) receiving caudal anesthesia with bupivacaine at concentrations ranging from 0.125% to 0.25%.
- Anesthetic depth was monitored via end-tidal halothane, and patient recovery was assessed by postanesthesia care unit (PACU) discharge time.
- Postoperative outcomes included pain scores, leg weakness, and paresthesia incidence.
Main Results:
- A 0.175% bupivacaine concentration correlated with lower end-tidal halothane requirements and significantly faster PACU discharge compared to 0.15%.
- Higher bupivacaine concentrations (≥0.2%) showed a trend towards increased leg weakness, though not statistically significant (P=0.057).
- Leg weakness and paresthesia incidence positively correlated with bupivacaine concentration (r=0.706, P=0.05), and 0.125% bupivacaine resulted in higher PACU pain scores than 0.2%.
Conclusions:
- 0.175% bupivacaine appears to be an optimal concentration for caudal anesthesia in pediatric outpatient herniorrhaphy, offering a favorable balance of anesthetic efficacy and recovery.
- Concentrations of 0.2% or higher may increase the risk of motor blockade (leg weakness), while concentrations below 0.15% may be associated with inadequate pain control.
- Further research could explore even lower concentrations or alternative adjuncts to minimize motor block while ensuring adequate analgesia.
Abstract:
Caudal epidural anesthesia has become widely accepted as a means of providing postoperative pain relief and intraoperative supplementation to general anesthesia for children. To determine the best concentration of bupivacaine for combined general-caudal anesthesia in children, 122 children aged 1-8 yr scheduled for outpatient inguinal herniorrhaphy were randomized to receive, in a double-blind fashion, caudal anesthesia with bupivacaine in one of six concentrations (0.125, 0.15, 0.175, 0.2, 0.225, or 0.25%). After incision, a programmed reduction in inspired halothane resulted, if tolerated by the subject, in an inspired halothane concentration of 0.5% 10 min after incision. End-tidal halothane concentration at hernia sac ligation for subjects receiving 0.175% bupivacaine (0.55 +/- 0.03%) was less than that for subjects receiving 0.15% bupivacaine (0.75 +/- 0.05%; P less than 0.05). Subjects receiving 0.175% bupivacaine also were discharged earlier from the postanesthesia care unit (PACU) (27 +/- 1 min) than were subjects receiving 0.15% bupivacaine (38 +/- 5 min; P = 0.05). Children receiving greater than or equal to 0.2% bupivacaine tended to complain more of leg weakness after surgery; however, the difference did not reach statistical significance (39 of 67 vs. 16 of 47; P = 0.057). The incidence of complaints of leg weakness and paresthesia was positively correlated with bupivacaine concentration (r = 0.706; P = 0.05). Subjects receiving 0.125% bupivacaine had higher pain scores on arrival to the PACU than did those receiving 0.2% bupivacaine (P = 0.05); there were no other differences in pain scores.(ABSTRACT TRUNCATED AT 250 WORDS)