Effects of Varying Doses of Plain Bupivacaine with Fentanyl in Patients Undergoing Cesarean Section: Haemodinamics and Neonatal Outcome

Abstract

Aim. The purpose of this study was to evaluate a three different regimes of spinal anaesthesia for caesarean delivery as well the incidence and severity of maternal hypotension and its influence over neonatal outcome. Material and Methods. Sixty (60) term healthy (ASA I) parturients scheduled for elective or non-elective caesarean delivery without fetal distress under spinal anaesthesia were randomly divided in three groups: group SA F10 (n = 20) received plain bupivacaine 12 mg plus 10 μg fentanyl, group SA F20 (n = 20) received 11 mg plus 20 μg fentanyl and SA LD group (low dose, n = 20 ) received 8 mg bupivacaine plus 20 μg fentanil. Ephedrine 5-10 mg i.v. bolus was given when systolic blood pressure (SBP) was < 95 mmHg. Maternal blood pressures, efedrin dosage, sensory level of anaesthesia, Apgar scores and neonatal umbilical cord blood acid-base (Ua) status were evaluated. Results. Spinal block provided surgical anaesthesia in all patients. Peak sensory level was higher in the greatest bupivacaine group (4.9 ± 1.33, 5.0 ±1.21 vs. 5.4 ±1.55). Parturient who received 12 mg bupivacaine (SA F10 group) develop significantly decrease of SBP - 97.9 ± 8.9 mmHg (23.8%), after spinal blockade compared with low dose group SA LD - 125.0 ± 12.9, (6.0 %, p< 0.05) and 115.1 mmHg (17.5%) in the SA F20 group. The total amount of ephedrine to treat hypotension was significantly lower in the low dose group (SA LD) compared with two other group (1.75 ± 1.0 mg vs. 13.75 ± 6.5 mg (SA F10) and 11.75 ± 6.2 (SA F20, p<0.5). Neonatal Ua pH was significantly lower with SA F10 group than low dose spinal group-SA LD (7.22 ± 0.07 vs. 7.27 ± 0.04, p < 0.05; 7.23 ± 0.04 SA F20 group). Conclusion. spinal anaesthesia for caesarean delivery with a low dose bupivacaine of 8 mg in conjunction with 20 μg fentanyl leads to less hypotension and ephedrine requirements with better neonatal outcome when compared with 12 and 11 mg bupivacaine – fentanyl spinal anaesthesia.