[Spinal anesthesia in infancy using bupivacaine 0.5%. The effect of an adrenaline addition on duration and...

The duration of spinal anaesthesia in infants is short compared to adult patients. When tetracaine is used, the addition of epinephrine significantly prolongs the duration. For bupivacaine, however, the influence of epinephrine on the duration is not clear. We investigated the effects of epinephrine 1:200,000 added to bupivacaine 0.5% on duration and haemodynamics. PATIENTS AND METHODS. Ten former pre-term infants with postnatal respiratory problems, scheduled for bilateral inguinal hernia repair, were enrolled in the study after informed parental consent had been obtained. The infants were fasted at least 4 h prior to surgery. If they did not receive i.v. infusions before surgery, a bolus of 10 ml/kg Ringer's acetate was injected after inserting the i.v. cannula, followed by a continuous infusion of 8 ml/kg 2/3 N NaCl with 5% dextrose. Spinal anaesthesia was performed in a sitting position with 0.6 ml bupivacaine 0.5%. Five patients received plain bupivacaine (group I) and five bupivacaine with epinephrine 1:200,000 (group II). Heart rate registered by ECG and non-invasive blood pressure were recorded prior to positioning the baby for lumbar puncture and 2, 5, 10, and 20 min after injection of bupivacaine. The duration of spinal anaesthesia was defined as the time from injection to the time when the first movements of the legs were observed after stimulation. For testing statistical differences the U test was used between the groups and the Wilcoxon and Wilcox test within the groups. RESULTS. (expressed as median and range). Additional epinephrine significantly prolonged the duration of spinal anaesthesia (group II: 95 min [60-120] vs group I: 50 min [37-85]). Haemodynamic parameters did not differ at any time between or within the groups. In group I, one infant had high spinal anaesthesia with impaired respiration but without cardiovascular effects; after 10 min of assisted ventilation by mask, sufficient respiration as judged by pulse oximetry and clinical observation had returned. The duration of spinal anaesthesia in this child was 60 min. CONCLUSIONS. Epinephrine 1:200,000 significantly prolongs the duration of spinal anaesthesia in former preterm infants. Haemodynamic parameters in this age group remain unchanged during spinal anaesthesia and are not influenced by the addition of epinephrine.