Caudal Block Compared to Acetaminophen for Prospective Pain Relief in Pediatric Patients

Abstract

Postoperative pain assessment and management in the pediatric population has long been difficult and inadequate. Caudal blocks have long been shown to be effective and safe for providing analgesia and anesthesia. Acetaminophen is a commonly administered analgesic, however time, dose and route influence the therapeutic level for analgesia. The purpose of this single blinded study was to compare acetaminophen to a caudal block in providing effective and equivalent pain control for pediatric patients having inguinal surgical procedures. It was hypothesized that acetaminophen would be as effective as a caudal block in postoperative pain control. The study population included ASA I and II pediatric patients, 55 weeks gestation to 10 years of age, undergoing inguinal surgical procedures. Pediatric patients were randomly assigned into two groups. After establishing general anesthesia, Group I received acetaminophen suppositories of 30 mg/kg, Group II received caudal block using 0.6 ml/kg of 0.25% bupivacaine. Both Group I and II received 20 mg/kg/dose of oral acetaminophen for 24 hours postoperatively every six hours. A blinded investigator assessed pain using the Objective Pain Scale (1-10) completed at three intervals postoperatively: upon awakening, upon discharge from the post anesthesia care unit and upon discharge from the ambulatory surgical unit. A follow up phone survey assessed adequacy of pain control and parental satisfaction approximately 24 hours after discharge on a linear scale. Power analysis as determined by STATPAC Gold statistical program, required a sample size of 41 with a 95% confidence level and 5% acceptable difference. Student's T-test and Chi square were used to analyze comparative data. Forty one patients were enrolled, 23 received acetaminophen suppositories and 18 received a caudal block. Initial mean PACU pain score for the acetaminophen group was 4.1 ± 3.1,compared to 2.3 ± 3.0 in the caudal group. Fifty six percent of the acetaminophen patients required a first time dose of morphine compared to 22% of the caudal patients (p=0.02). Forty three percent of the acetaminophen patients received a second dose of morphine compared to none in the caudal group (p=0.001). Forty three percent of the acetaminophen group (10 out of 23 patients) experienced nausea compared to 11 % of the caudal group (2 out of 18) (p=0.023). Follow up 24 hour assessment of parental satisfaction and rating of pain control showed no significant difference between the two groups. In summary, our results suggest pediatric patients undergoing inguinal procedures received better pain control from caudal blocks and experienced less nausea than from high dose acetaminophen suppositories. Clinically, our results support the use of a caudal block for postoperative pain control for pediatric inguinal surgeries.