The 2018 European Society of Regional Anaesthesia and Pain Therapy (ESRA) and the American Society of Regional Anesthesia and Pain Medicine (ASRA) developed a joint committee practice advisory on local anesthetics (LAs) and adjuvants dosage in pediatric regional anesthesia. While the panel did not provide a recommendation for a specific dose, it was stated that dexmedetomidine has been employed to extend postoperative analgesia when utilized alongside neuraxial blocks (i.e., caudal block). However, due to the scarcity of toxicity data in children, it is advisable to administer the minimum effective dose to attain the desired benefits while mitigating potential adverse effects (Evidence A2). Corticosteroids, such as dexamethasone, have been examined in limited studies as a neuraxial adjuvant in pediatric patients. According to the available clinical evidence at the time of the publication of this guideline, the advisory committee does not endorse the utilization of corticosteroids as a neuraxial adjuvant in children (Evidence B2). [1]
A 2022 network meta-analysis (NMA) compared the safety and efficacy of caudal adjuvants in pediatric lower abdominal and urological surgeries. The final analysis included 112 randomized controlled trials (RCTs) involving 6,800 pediatric patients. Ten adjuvants were evaluated: clonidine, dexamethasone, dexmedetomidine, fentanyl, ketamine, magnesium, midazolam, morphine, neostigmine, and tramadol. Neostigmine, dexmedetomidine, and dexamethasone were the three most effective adjuvants for prolonging the duration of analgesia for caudal block, extending the duration by 8.9 hours (95% confidence interval [CI] 7.1 to 10.7 hours), 7.3 hours (95% CI 6.0 to 8.6 hours), and 5.9 hours (95% CI 4.0 to 7.7 hours), respectively. Dexmedetomidine dosage ranged from 0.5 mcg/kg to 2 mcg/kg with 1 to 2 mcg/kg as the most reported dose. The dosing of 1 to 2 mcg/kg have been indicated as effective in multiple review articles. The hemodynamic effects, particularly bradycardia, were infrequent and primarily associated with the 2 mcg/kg. [2], [3]
All included studies reported a dexamethasone dosage of 0.1 mg/kg. Dexmedetomidine and dexamethasone showed no postoperative complications such as nausea and vomiting. These findings suggest that dexmedetomidine and dexamethasone may be the most beneficial adjuvants to add to LAs for caudal block in children. However, further high-quality RCTs are warranted, especially to determine whether delayed neurological complications will occur, given the off-label status of caudal dexmedetomidine and dexamethasone. [2]
Another 2022 NMA, aimed to assess the comparative analgesic effectiveness and ranking of caudal adjuvants when added to LAs in pediatric infraumbilical surgery. The analysis included a total of 5,285 participants across 87 RCTs. Nine caudal adjuvants, namely clonidine, dexmedetomidine, ketamine, magnesium, morphine, fentanyl, tramadol, dexamethasone, and neostigmine, were compared among themselves or to a control group with no adjuvant. According to the treatment rankings and the surface under the cumulative ranking curve (SUCRA), neostigmine emerged as the most effective adjuvant, followed by tramadol and dexmedetomidine. In comparison to the control group, dexmedetomidine demonstrated a significant reduction in the frequency of analgesic dose administration within 24 hours (29 RCTs, 1,765 patients; weighted mean difference [WMD] -1.2 dose, 95% CI -1.6 to -0.9) and the total dose of acetaminophen within the same time frame (18 RCTs, 1,156 patients; WMD -350 mg, 95% CI -467 to -232). Dexmedetomidine was administered at doses ranging from 1 mcg/kg to 2 mcg/kg, while dexamethasone dosing was set at 0.1 mg/kg. Among the caudal adjuvants, neostigmine (with moderate certainty), tramadol (with low certainty), and dexmedetomidine (with low certainty) exhibited the most prolonged duration of analgesia. Dexmedetomidine, with moderate certainty, also outperformed other caudal adjuvants in reducing analgesic frequency and consumption. Caution is warranted in interpreting these findings due to variations in demographics, differences in local anesthetics and adjuvant doses, potential biases in the source trials, and the limitations of small study sizes. [4]
In a meta-analysis conducted in 2018, the investigation focused on the use of dexamethasone as an adjuvant in caudal blockade for pediatric patients. The analysis included 14 RCTs with a total of 1,315 pediatric patients, primarily undergoing lower abdominal operations such as orchidopexy, inguinal hernia repair, and hypospadias repair. The caudal dose of dexamethasone ranged from 0.1 to 0.2 mg/kg, while intravenous (IV) administration varied from 0.5 to 1.5 mg/kg, typically up to 10 mg. Dexamethasone demonstrated a significant extension in the duration of analgesia for both caudal (5.43 hours, 95% CI 3.52 to 7.35; p <0.001; I2 = 99.3%) and intravenous routes (5.51 hours; 95% CI 3.56 to 7.46; p <0.001; I2 = 98.9%) compared to the control group. Moreover, it led to a reduction in the need for narcotic rescue analgesia in the postanesthetic care unit (relative risk [RR] 0.30; 95% CI 0.18 to 0.51; p <0.001; I2 = 0.0%), diminished subsequent postoperative rescue analgesia requirement (RR 0.46; 95% CI 0.23 to 0.92; p = 0.03; I2 = 96.0%), and lower incidence of postoperative nausea and vomiting (RR 0.47; 95% CI 0.30 to 0.73; p = 0.001; I2 = 0.0%). Rare adverse events were associated with dexamethasone. The findings suggest that both caudal and intravenous administration of dexamethasone are comparably effective in extending the duration of analgesia in caudal blockade, resulting in a doubled to tripled duration. Considering the off-label status of caudal dexamethasone, intravenous administration is recommended, although the studies have primarily investigated higher intravenous doses (0.5 mg/kg up to 10 mg). [5]