Haemodynamic effects of induction of epidural analgesia in labour

Abstract

p < 0.05). and in SBP , DBP , Impairment of uterine blood flow (UBF) during labour is an hnportaul cause of fetal asphyxia and neonatal mortality and morbidity. Direct measurement of UBF in humans, requiring either vascular canuulation or radio-isotope techniques, is limited by ethical considerations. Since UBF is a component of maternal cardiac output (CO), investigation of the relationships between maternal CO and blood pressure (BP) is central to understanding the factors which influence uterine blood flow and placental perfusion during pregnancy and parturition.Haemodynamie investigation of the normal parturient has been restricted by the practical and ethical limitations

The arterial system in pre‐eclampsia and chronic hypertension with superimposed pre‐eclampsia

“…We designated this preterm labour group as the primary control group that controlled for the largest number of confounders because all pre‐eclamptic patients were receiving magnesium sulphate. Another potential confounder was the effect of epidural analgesia 19,20 . Here we compared unanesthetised normal labouring patients (secondary control group A) to those receiving continuous epidural analgesia (secondary control group B), and no haemodynamic differences were noted, thus eliminating epidural anaesthesia as a confounding factor.…”

Evaluation of cerebral perfusion pressure changes in laboring women: effects of epidural anesthesia

“…When epidural anesthesia was assessed in patients in the lateral decubitus position, previous authors reported a decrease in cardiac output and mean arterial pressure starting approximately 30 min after anesthesia, followed by a return to baseline 45 min after anesthesia 5 .…”

“…Although this increase is mainly due to a rise in stroke volume, the heart rate changes will also affect the cardiac output response to labor. The increase in cardiac output during labor is generally thought to result from anxiety and pain and this is supported by the observation that cardiac output increases less in the presence of any form of analgesia 4,5 . Labor and delivery obviously represent a period of considerable additional hemodynamic demands.…”

“…The lack of change in the cerebral blood flow during pushing and during the Valsalva maneuver in the epidural patients in comparison to the non-epidural group is not fully explained. Epidural anesthesia results in a decrease in pain and anxiety 4,5,18,19 ; this may prevent an increase in cerebral perfusion pressure in this group during contractions or the Valsalva maneuver. Pain during contractions with the increase in hyperventilation may decrease the pCO2 with a significant impact on cerebral blood flow velocity.…”

“…Epidural anesthesia is used in labor for pain relief. Epidural anesthesia, by relieving pain and decreasing anxiety, causes a reduction in blood pressure 5 . The mechanisms by which these changes in maternal hemodynamics relate to epidural anesthesia and affect the cerebral circulation are unknown.…”