An Evaluation of Pain Outcomes of Ketorolac Administration in Children Undergoing Circumcision

Overview

Circumcision is the most common surgical procedure performed by Pediatric Urologists. Ketorolac has been shown to have an efficacy similar to morphine in multi-modal analgesic regimens without the commonly associated adverse effects. This study aims to see if giving ketorolac during the operation will result in better pain control. We hypothesize that ketorolac will result in pain control similar to morphine with a lower incidence of side effects such as nausea and vomiting.

We performed a pilot study in 2017 evaluating the perioperative use of ketorolac in circumcision. Overall, there were no adverse reactions and ketorolac patients did not experience significantly less pain that the control group patients. However, parental perception of pain was lower in the ketorolac group when compared to the control and this required more investigation. Based on our findings of the pilot study, we determined that we needed at least 36 patients in each study group to come to a statistical conclusion. With a larger study group perhaps a statistical difference in pain as measured with a FLACC score may become apparent. Prospective, randomized, single-blinded study will be conducted from January 2021 - January 2022. A total of two groups will present with 50 children in each group. A computer-generated randomized block design program will be used to allocate patients to either the treatment (ketorolac) or control (no ketorolac) group. All children will receive a 15 mg/kg oral dose of acetaminophen prior to surgery unless contraindicated. General anesthesia will be induced with sevoflurane via facemask. After establishing venous access, a laryngeal mask will be inserted, and anesthesia maintained with 1 minimum alveolar anesthetic concentration (MAC) of sevoflurane in oxygen/air 50/50 mixture. The DPNB nerve block will be performed by a pediatric urologist using a 23 GA needle inserted below the Buck fascia. Once the needle tip is positioned appropriately, and after a negative aspiration test, 0.2mL/kg (maximum 10mL) of 0.25% bupivacaine is injected in small aliquots, with intermittent aspiration throughout. In all patients, skin incision is performed at least 5 min after placement of the nerve block. At the beginning of the circumcision procedure once the patient is asleep, patients in the treatment group will receive a 0.5 mg/kg intravenous dose of ketorolac. Patients will be advised to take ibuprofen and acetaminophen post-operatively as needed, but not ibuprofen within 6 hours of the procedure. A 6-hour window between ibuprofen and ketorolac is in line with our standard of practice at the Alberta Children's Hospital when using additional NSAIDs after ketorolac. Patients' demographic information, time needed to perform the block, time of block onset and duration of surgery will be recorded. The mean arterial pressure, heart rate and oxygen saturation, expired sevoflurane end tidal concentration and MAC will be systematically collected pre-operatively, intra-operatively and post-operatively in the recovery room. The primary outcome of post-operative pain will be evaluated through the use of the Face, Legs, Activity, Cry, Consolability (FLACC) pain score or Numerical Rating Scale (NRS) pain score ascertained by a nurse or research assistant blinded to the anesthetic technique. The usage of these two scales will be performed as deemed appropriate by the research assistant. The FLACC scale will be used in children who have difficulty verbalizing pain and in sleeping children (regardless of age) while the NRS pain score will be used in patients capable of self-assessment (\> 7 years of age). The FLACC score is a well-established postoperative pain measure using 5 items scored between 0-2, which has been validated in patients from 6 months up to 7 years of age. These faces are rated on a scale of 10. A FLACC or NRS pain score will be recorded every 15 minutes for the first hour and every 30 minutes for up to 2 hours following discharge from the PACU into the day stay surgical unit. If the score is found to be \>3 (moderate pain 4-6, severe pain 7-10), the patient will receive an intravenous morphine dose of 0.05mg/kg. An additional dose may be given 15 minutes following the initial dose of morphine if analgesia is inadequate (score \>4). Postoperatively, the child will be monitored every 15 minutes during the first hour and every 30 minutes for the next 2 hours until discharge home. Discharge will be based on normal institutional criteria including level of awareness, hemodynamic stability and absence of pain, bleeding, nausea and vomiting. Prior to discharge, parents will be provided with any additional analgesics required at home and will be contacted 24 hours following their surgery to complete the parents' postoperative pain measure (PPPM). The PPPM is a well-established post-operative pain assessment tool with high inter-rater reliability and construct validity, which has been designed specifically for use by parents in the post-operative care of their children. The measure includes 15 items scored between 0 and 1. The questionnaire will be completed over the telephone at a time corresponding to 24 hours post-surgical closure. Amount of pain and analgesia consumption data will then be collected by contacting the parents 24 hours post procedure.