No abstract

Five hundred and seventeen women in labour receiving extradural analgesia, using bupivacaine plain solution, were randomly allocated to one of three groups. Group A received 6-8ml of 0.5% solution, group B 10-14ml of 0.25% solution, and group C 6-8 ml of 0.25% solution. Spontaneous delivery occurred in 31.7% of patients in group A, 38.7% in group B and 53% in group C (P less than 0.001). The percentage of rotational forceps, ventouse and Caesarean section deliveries was similar in the three groups. Analgesia was most effective in group A, and at least in group C, both during labour and at delivery, although assessment by linear analogue score suggested that the differences between the three groups were slight. Motor block was most frequent and rapidly progressive in groups A, but was progressive in all groups, and after five or more top-up injections, was similar in the three groups. Difficulties with micturition following delivery were significantly more common in group A.

Regurgitation of stomach contents, as distinct from vomiting, is the result of a sufficiently high intragastric pressure overcoming the competence of the cardia.In the last fifteen years there have been several studies designed to demonstrate the nature of the cardiac sphincter and to evaluate the pressure required to cause retrograde flow through it13zp 3,4. By contrast, there has been much less consideration given to values for intragastric pressure.Our interest in this matter stemmed from anxiety for the pregnant woman with a breech presentation, already in the lithotomy position, requiring general anaesthesia for delivery of the after-coming head. It seemed that the combination of an intra-abdominal mass together with positioning which would raise the mass higher in the abdominal cavity might be expected to raise intragastric pressure above the non-pregnant value. We have set out to determine the magnitude and significance of the increase. METHODSFour groups of patients have been investigated: 23 men, 36 children, 43 non-pregnant women, all for elective surgery under general anasthesia; and 31 pregnant women, at term, for delivery under general anasthesia. No selection was made with regard to height, weight and age although these were recorded. The children ranged in age from 7 months to 12 years.The patients were pre-medicated with an opiate, where appropriate, and all were given atropine or scopolamine. All adults were pre-oxygenated and anaesthesia induced with a sleep dose of thiopentone which was immediately followed by lOOmg suxamethonium. Without attempting to ventilate the lungs, a cuffed endotracheal tube 249