Background
Intrauterine resuscitation (IUR) is to improve O2 delivery to the placenta and umbilical blood flow, for reversal of foetal hypoxia and acidosis. We evaluated whether maintaining a lateral position after an intrathecal injection of a relatively low dose of hyperbaric bupivacaine and high dose of fentanyl improving the efficacy of spinal anaesthesia, IUR and preventing hypotension during cesarean delivery.
Methods
One hundred and seventy two healthy women undergoing elective cesarean delivery were enrolled in a double blind prospective randomized study. Spinal anesthesia was conducted in the right lateral position which maintained for 6 min for all the patients participated in the study, and then the subjects were turned supine. Patients were randomly allocated to two groups: low-dose spinal bupivacaine (LD) group ( = 86) patients received 6 mg of hyperbaric bupivacaine 0.5% and 15 μg of fentanyl, high-dose spinal bupivacaine (HD) group ( = 86) patients received 10 mg of hyperbaric bupivacaine and 15 μg of fentanyl. The incidence of hypotension and nausea, ephedrine requirement, maximal block height, and Apgar score at 1 and 5 min.
Results
The authors found significant decrease in MAP in the group that was given the high dose of bupivacaine the incidence of hypotension was 80% but the LD spinal bupivacaine group was hemodynamically stable. The lowest blood pressure, boluses of inj. ephedrine used, or nausea were more significant in the HD group than in LD group. Onset of hypotension was more rapid (8 ± 3 vs. 16 ± 6 min,  < 0.001), and the sensory block level was more cephalad in HD group than in LD group (T2 [C8–T5] vs. T4 [T1–T6],  = 0.001). Apgar scores did not differ between the groups.
Conclusion
Maintaining the lateral position for 6 min after an intrathecal injection of a relatively low dose of hyperbaric bupivacaine and high dose of fentanyl resulted in improving the efficacy of spinal anaesthesia, IUR by more gradual and higher cephalad sensory block, without an increase in the incidence of maternal hypotension.