DURATION OF SPINAL-ANESTHESIA IN INFANTS LESS-THAN ONE-YEAR OF AGE - COMPARISON OF 3 HYPERBARIC TECHNIQUES

Background and Objectives. Although numerous reports of the use of spi nal anesthesia have appeared in recent literature, little information is available on the duration of anesthesia provided by standard doses of the commonly used drugs: lidocaine with epinephrine, tetracaine, or tetracaine with epinephrine. The authors evaluated the duration of sp inal anesthesia using standard doses of local anesthetics and an objec tive endpoint of motor recovery in infants less than 1 year of age. Me thods. After reviewing historic literature to select doses, the durati on of hyperbaric spinal anesthesia in 100 infants from 1-month to 12-m onths of age undergoing surgery below the diaphragm was evaluated. Spi nal anesthesia was induced, cutaneous level of anesthesia determined b y the infant's response to tetanic stimulation with a peripheral nerve stimulator, and time from injection to flexion of hip in response to stimulus was recorded. Results. Lidocaine 3 mg/kg with epinephrine las ted 56 +/- 2.5 minutes, while tetracaine 0.4 mg/kg lasted 86 +/- 4 min utes and tetracaine 0.4 mg/kg with epinephrine lasted 128 +/- 3 minute s. Conclusions. The three subarachnoid techniques produced varying lev els of duration of motor block. The authors recommend lidocaine 3 mg/k g with epinephrine for very brief procedures, tetracaine 0.4 mg/kg for procedures with a potential duration of 1 hour or less, and tetracain e 0.4 mg/kg with epinephrine for procedures estimated to last 90 minut es in infants less than 1 year of age.