Alteration of maternal posture and its immediate effect on epidural pressure.

A study was undertaken to investigate the changes in pressure inside the epidural space in parturients in the first stage of labour. The purpose was to see whether acute local pressure changes in the epidural space were consistent with the hypothesis that there is physical movement of cerebrospinal fluid with certain changes in maternal posture. Pressure changes were measured via the epidural catheter through which continuous infusion epidural analgesia was administered, using a pressure transducer kept at the level of the lumbar spine. The mothers moved through a series of postures that reflected those expected during the course of labour and delivery. The pressure within the catheter was recorded during these manoeuvres. The pressure changes which were found, taken in conjunction with the associated investigations of others, are consistent with the hypothesis.