house officers have put many general practitioners off. "GP trainees are reared on a diet of abnormality and fear. It's surprising they are not put off maternity care for life," he said. "GPs do not have the experience of helping midwives at home. The government may decide that a medical component in the community is unnecessary-all that is needed is a fast ambulance and an open road. It will probably just ask GPs to do their best."

NMDA receptor antagonists have a vital role in extinction, learning, and reconsolidation processes. During the reconsolidation window, memories are activated into a labile state and can be stored in an altered form. This concept might have significant clinical implications in treating PTSD. Using amygdala activity as a major biomarker of fear response, we tested the potential of a single subanesthetic intravenous infusion of ketamine (NMDA receptor antagonist) to enhance post-retrieval extinction of PTSD trauma memories. Post-extinction, ketamine recipients (vs midazolam) showed a lower amygdala and hippocampus reactivation to trauma memories. Post-retrieval ketamine administration was also associated with decreased connectivity between the amygdala and hippocampus, with no change in amygdala-vmPFC connectivity, which suggests that ketamine may enhance post-retrieval extinction of PTSD trauma memory in humans. These findings demonstrate the capacity to rewrite human traumatic memories and to modulate the fear response for at least 30 days post-extinction.

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Despite the increasing popularity of epidural analgesia in obstetrics, most Caesarean sections in the United Kingdom are still performed under general anaesthesia.' Where epidural analgesia has been established to provide pain relief in labour, extension of the block for Caesarean section is usually possible and can avoid the necessity for general anaesthesia. This paper reports the outcome of applying this policy in 722 consecutive cases. MethodThe implications of epidural analgesia for Caesarean section were explained to the patients and the block extended by a dose of 16 ml bupivacaine (Marcain) 0.5 %, without adrenaline, 8 ml with the patient in the left lateral position, and, after an interval of 5 min, the remainder in the right lateral position. When necessary, additional bupivacaine was given to ensure that analgesia extended to all nerve roots below the sixth thoracic dermatome. All patients received a fluid load (approximately I litre) of either dextrose 5 % in water or Hartmann's solution during extension of the block. The arterial blood pressure was recorded at intervals of I-min using an 'Arteriosonde' automatic blood pressure recorder. Hypotension, defined as a fall in systolic blood pressure below 90 mmHg or a reduction of more than 30% of the initial systolic value, was corrected by increasing the rate of intravenous infusion and, when considered necessary, by the intravenous administration of 10-15 mg ephedrine hydrochloride. A Crawford wedge was placed under the patient's right side and oxygen administered byaHudsonmaskwithaflowrateof 4litreslmin. AII patients remained unsedated until after delivery apart from any analgesic which may have been administered during labour before establishment of the epidural. Syntocinon 2 units was injected intravenously, followed by an infusion of 10 units syntocinon in 500 ml 5 : ; dextrose in water. When delivery was complete and the mother had seen her baby, most patients received intravenous papaveretum and hyoscine to a maximum dose of 20 and 0.4 mg respectively. The mothers were interviewed 2 to 3 days after operation and were encouraged to give a frank opinion of their experience. ResultsIn 168 patients (23.2%) no attempt was made to use the epidural for surgery and a general anaesthetic was administered for reasons summarised in Table 1. In the remaining 554 patients (76.8 %) it appcared that successful extension of the block had been achieved. In 533 of these patients (96.27;) the operation was completed under epidural analgesia alone; the

A randomized, double-blind study of the efficacy, duration of action and side effects of three analgesic regimens following Caesarean section is described. Patients received i.m. diamorphine 5 mg, extradural phenoperidine 2 mg or extradural diamorphine 5 mg. Analgesia was of rapid onset in all groups, as judged by reductions in linear analogue pain scores and rank pain scores. Time to next analgesia was significantly greater after extradural phenoperidine (5.96 h) and extradural diamorphine (8.39 h) than after i.m. diamorphine (3.40 h) (P less than 0.001). Itching was reported on direct questioning by 50% of patients in the extradural groups. No serious side effects were reported. Factors affecting the disposition of extradurally administered diamorphine are discussed.