SPINAL-ANESTHESIA IN FORMER PRETERM INFAN TS WITH BUPIVACAINE 0.5 PERCENT - EFFECT OF ADDED EPINEPHRINE ON DURATION AND HEMODYNAMICS

The duration of spinal anaesthesia in infants is short compared to adu lt patients. When tetracaine is used, the addition of epinephrine sign ificantly prolongs the duration. For bupivacaine, however, the influen ce of epinephrine on the duration is not clear. We investigated the ef fects of epinephrine 1:200000 added to bupivacaine 0.5% on duration an d haemodynamics. Patients and Methods. Ten former pre-term infants wit h postnatal respiratory problems, scheduled for bilateral inguinal her nia repair, were enrolled in the study after informed parental consent had been obtained. The infants were fasted at least 4 h prior to surg ery. 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. cannu la, followed by a continuous infusion of 8 ml/kg 2/3 N NaCl with 5% de xtrose. 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 1:200000 (group II). Heart r ate registered by ECG and non-invasive blood pressure were recorded pr ior to positioning the baby for lumbar puncture and 2, 5, 10, and 20 m in after injection of bupivacaine. The duration of spinal anaesthesia was defined as the time from injection to the time when the first move ments of the legs were observed after stimulation. For testing statist ical differences the U test was used between the groups and the Wilcox on and Wilcox test within the groups. Results (expressed as median and range). Additional epinephrine significantly prolonged the duration o f 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 w ithin the groups. In group I, one infant had high spinal anaesthesia w ith 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. Epinephri ne 1:200000 significantly prolongs the duration of spinal anaesthesia in former preterm infants. Haemodynamic parameters in this age group r emain unchanged during spinal anaesthesia and are not influenced by th e addition of epinephrine.