Age-based Local Anesthetic Dosing in Pediatric Spinal Anesthesia: Evaluation of a New Formula – A Pilot Study in Indian Patients

BACKGROUND: Spinal anesthesia is a safe alternative to general anesthesia and often the anesthetic technique of choice in many lower abdominal and lower limb surgeries in children. As the vertebral column and spinal cord grows variedly with age and not weight, we planned to administer an age-based dosing schedule of hyperbaric bupivacaine in the intra-thecal space in select infra umbilical surgeries in children. The aim was to find out the efficacy and complications associated with this dosage. METHODOLOGY: Twenty-five pediatric patients between 2 and 12 years, posted for elective infra umbilical surgeries were given a sedation as a combination of effective doses of pentazocine, midazolam, and atropine. In all those patients, spinal anesthesia was administered at a dose of age/5 of hyperbaric bupivacaine. The number of attempts, the onset of blockade, the mean sensory level, and the duration of anesthesia were noted. Any other complications were also noted. RESULTS: The mean and standard deviation of age is 7.68 ± 2.49 years. Intra-thecal anesthesia was administered successfully in the first attempt in 88% of cases whereas the remaining needed the second attempt. Three patients needed intravenous ketamine of 0.25 mg/kg additionally for preoperative sedation. The sensory level was between T6 and T10 with a mean of T8.5. There were no intra-operative complications. In all patients, surgery was finished within the duration of anesthesia of approximately 60 min. There was no conversion to general anesthesia in any case, but a three patients required dose of 0.25 mg/kg of intravenous ketamine as a calming dose. CONCLUSION: Administration of age-based local anesthetic dosing of hyperbaric bupivacaine in the intra-thecal space by utilizing a new formula of age/5 (Partha formula) is successful in a pilot study in Indian children for infra-umbilical surgeries. There were no observed complications.