Influence of volume preloading on uteroplacental and fetal circulation during spinal anaesthesia for caesarean section in uncomplicated singleton pregnancies.
Effects of volume preloading during spinal anaesthesia for elective caesarean section on maternal blood pressure, feto-maternal circulation and fetal outcome.
                In a pilot study a randomised trial was performed in 22 healthy women with uncomplicated, singleton pregnancies at 36-40 weeks of gestation undergoing elective caesarean section under spinal anaesthesia. In the low volume group (group A) patients received 150 ml of crystalloid solution for preloading, in the high volume group (group B) they were given 15 ml/kg of crystalloid solution for preloading before the initiation of spinal anaesthesia. Maternal blood pressure was monitored intermittently. Hypotension was defined as a decrease in systolic pressure to less than 80% of the baseline value. The Doppler flow evaluation consisted of measurements from the uterine artery at the placental site, fetal umbilical artery and fetal middle cerebral artery. Pulsatility indices were derived before and after fluid preloading, and when spinal anaesthesia was established. The neonatal outcome was assessed by Apgar scores, arterial acid base status and neurologic and adaptive capacity scores (NACS).
                The incidence of maternal hypotension in both groups was 45.5% (n = 10); 3 cases occurred in group A compared to 7 cases in group B (n.s.). There was no evidence that the high dose volume is useful in preventing maternal hypotension. The pulsatility indices of uterine arteries, umbilical arteries and middle cerebral arteries were not altered. Statistical analysis showed no changes in neonatal outcome concerning umbilical arterial pH, Apgar score and NACS (n.s.) between groups A and B.
                Our preliminary results suggest that high dose crystalloid volume preloading has no preventive function in the avoidance of maternal hypotension in healthy parturients undergoing elective caesarean section under spinal anaesthesia, and shows no harmful effects on neonatal outcome as long as maternal hypotension is corrected immediately. However, the statistical significance may reflect the small sample size, and larger series are needed before changing the current management.
                Copyright 2002 S. Karger AG, Basel
The findings indicate that music during planned caesarean section under regional anaesthesia may improve pulse rate and birth satisfaction score. However, the magnitude of these benefits is small and the methodological quality of the one included trial is questionable. Therefore, the clinical significance of music is unclear. More research is needed to investigate the effects of music during caesarean section under regional anaesthesia on both maternal and infant outcomes, in various ethnic pregnant women, and with adequate sample sizes.