Increased maternal sympathetic nervous system activity may decrease placental perfusion and cause adverse neonatal effects. We have studied the catecholamine response and neonatal outcome in Chinese patients with uncomplicated, singleton pregnancies undergoing Caesarean section. Anaesthesia was induced with thiopentone 4 mg kg-1 (n = 32) or propofol 2 mg kg-1 (n = 30) followed by suxamethonium. Laryngoscopy was performed after 1 min and tracheal intubation completed by 2 min. Anaesthesia was continued with atracurium, nitrous oxide and isoflurane. Maternal venous blood samples were taken at 0, 1, 2, 3, 4 min and at delivery for assay of catecholamines. The increase from baseline values in mean arterial pressure after tracheal intubation was greater in the thiopentone group (29 (SD 15) mm Hg) compared with the propofol group (18 (14) mm Hg) (P < 0.01). The concentrations of noradrenaline and adrenaline increased in both groups after tracheal intubation. Maximum noradrenaline concentrations were greater in the thiopentone group (413 (177) pg ml-1) compared with the propofol group (333 (108) pg ml-1) (P < 0.05), but there were no differences between groups in adrenaline concentrations. Neonatal Apgar scores, neurobehavioural testing and umbilical catecholamine, blood-gas tension and oxygen content analysis were similar between groups. Propofol attenuated the hypertensive and catecholamine response associated with laryngoscopy and tracheal intubation but there was no improvement in neonatal outcome.

. After pooling the data, median (range) gastric volume in groups C and M C (55(0-360) mi) was greater than in groups ml, p c 0.05). Median (range)pH was lower in groups C and M C (4.97t0.766.99)) than in groups OC, RC,, p c 0.001). The proportion of patients with pH < 3.5 and volume >25ml in the C and MC groups (431 185) was greater than that in the OC, RC, OMC and RMC groups (1 8/ 199, p < 0.001

SummaryOne hundred and sixty-two Chinese women undergoing emergency Caesarean section were allocated at random on admission to the labour ward to receive one of three regimens for orally administered chemoprophylaxis against acid aspiration: ranitidine 150 mg 6 hourly with sodium citrate at induction of anaesthesia, omeprazole 40 mg I2 hourly with sodium citrate. or omeprazole 40 mg 12 hourly alone. Intragastric pH and volume were measured immediately after induction of anaesthesia. Ten patients ( I 7%) in the omeprazole-only group, three ( 6 % ) in the omeprazole and citrate group and one ( 2 % ) in the ranitidine group had an intragastric pH < 2.5 and volume 7 25 ml ( p < 0.05). The use of sodium citrate resulted in higher intragastric pH but larger intragastric volumes ( p < 0.05). The sodium citrate and ranitidine regimen was the most cost-effective among the three.