Low Dose IV Dexamethasone in Prolonging Caudal Anesthesia in Children Undergoing Genitourinary Surgery

Overview

Caudal injection of local anesthetic is a neuraxial technique routinely performed on young children for postoperative analgesia after lower abdominal and lower extremity surgical procedures. One of the major limitations of the use of single shot neuraxial injections for this purpose is the limited duration of action of the injected local anesthetic. Adjuvant medications, such as clonidine and epinephrine, have been added to the local anesthetic to prolong the duration of the neuraxial block, with varying results. Dexamethasone is a synthetic glucocorticoid steroid commonly used in the perioperative setting for a multitude of indications, including the prolongation of local anesthetic based analgesia. It has been shown that the administration of dexamethasone either intravenously or via perineural injection can significantly increase the duration of analgesia derived from a local anesthesia based peripheral nerve block. Literature also suggests that the effect of dexamethasone is equivalent whether given intravenously or perineurally. Interest in dexamethasone enhanced caudal analgesia exists and a previous study noted that caudal anesthesia can be prolonged by intravenous dexamethasone. The study was criticized for using a higher dose of dexamethasone (0.5 mg/kg) than is routinely used in the pediatric population outside of airway procedures, which may expose patients to dose related side effects of dexamethasone. A large meta-analysis has suggested that 0.1 mg/kg is effective for analgesic prolongation, but no direct study of low dose intravenous dexamethasone in combination with caudal anesthesia has been performed.

As dexamethasone is an inexpensive and commonly used medication, it would be beneficial to know if a similar prolongation of analgesia occurs when a local anesthetic is given neuraxially in combination with low dose intravenous dexamethasone. This project will investigate the efficacy of low dose intravenous (IV) dexamethasone in prolonging the duration of post operative analgesia provided by an intraoperative caudal injection of local anesthetic. All patients will be enrolled in the study the day of surgery, in the preoperative waiting area. The study will be explained by an anesthesiologist with extensive knowledge of the protocol. Computer randomization will occur for each patient. Randomization will not increase the risk to either group as all medications and techniques utilized for this study are commonly accepted for routine care for these patients.