Effects of epidural block with lignocaine and lignocaine-adrenaline on umbilical artery velocity wave ratios.

Umbilical artery blood velocity A/B ratios were recorded in term fetuses once before and twice after the maternal epidural injection of either 8 ml of lignocaine plain (15 women) or lignocaine with adrenaline 1:200,000 (40 micrograms) (16 women). The administration of lignocaine plain led to decreases in the ratio of varying degrees in all fetuses regardless of the height of the initial A/B ratio. The injection of lignocaine with adrenaline produced identical results in fetuses with initially normal A/B ratios. In contrast, all six fetuses with initially high A/B ratios (above 2.90) who received the adrenaline-containing anaesthetic reacted with a rise in the ratio, and two of these developed transient heart rate decelerations. Thus, if the initial resistance in umbilical blood flow is high, even the small epidural dose of 40 micrograms of adrenaline produces a further increase which may be associated with clinical implications.

Cardiac output measurements during and after triplet gestation.

In a gravida with a triplet gestation complicated by fainting attacks and transient episodes of apparently positional hypotension, cardiac output was measured noninvasively to determine the optimal posture during cesarean section. Before delivery, cardiac output and mean arterial pressure were highest in the left semilateral position and lowest in the right semilateral posture. Shortly after delivery of the infants, cardiac output was still highest in the left semilateral position but lowest in the supine posture. Twenty-four and 48 hours later, the values were almost identical in all three positions. Noninvasive cardiac output monitoring provided a simple method of detecting the occurrence and severity of caval compression and of determining the optimal position of the gravida during cesarean section.