Preeclampsia: the effect of intravenous fluid preload on vasoactive peptide secretion during caesarean section under spinal anaesthesia

We followed the haemodynamic parameters and determined the peripheral venous levels of ANF, ET-1 and NO before and after, intravenous volume preload of I litre Ringer's solution, followed by a further load of the same volume under spinal anaesthesia in 15 healthy and I5pre-eelamptic women. Blood pressure was decreased significantly in both groups after spinal anaesthesia and such decrease was less in the preeclamptic group. The baseline concentration of ANP was higher in preeclamptic women than in normal pregnancy women. It increased significantly in both groups after the JSI infusion, the.2 nd infusion and after delivery. The CVP increased more during the preload period in the preeclamptic group than in healthy women. The increase in the concentrations of ANP correlated significantly with the increase in CVP in total study group. The baseline concentration of ET-1 was higher in preeclamptic women than in healthy women, it decreased significantly in both groups after the first and second infusions. The plasma concentrations of ET-1 increased significantly in the cord sample both groups. NO increased more in the preeclamptic group during the preload period in healthy women while the same increase was noted after the second infusion in groups. After delivery NO concentration in the cord sample was higher in the preeclamptic group than in healthy women. There was no significant difference in the number of neonates with Apgar score < 7, NACS and the parameters of arterial blood gas between the two groups. We conclude from this study that the release of ANP increases in response to a rapid intravenous infusion of a crystalloid solution during elective Caesarean delivery which is exaggerated in women with preeclampsia. This may help in the vasculatory adaptation to the volume load by increasing its capacity. The increase ANP release was not sufficient to decrease maternal arterial blood pressure, but may counteract vasospasm locally in the maternal and uteroplacental circulation