British journal of anaesthesia
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This review has indicated that barbiturates are useful in controlling ICP during anaesthesia in patients with intracranial hypertension. While laboratory data indicate that intraoperative administration of barbiturates during episodes of transient cerebral ischaemia, associated with surgical revascularization procedures, should be efficacious, current intraoperative results claiming benefit are anecdotal. Continuous high-dose barbiturate therapy (induced barbiturate coma) for occlusive stroke and persistently increased intracranial pressure is currently undergoing clinical trials. ⋯ Despite evidence that high-dose barbiturate therapy can reduce the area of infarction in occlusive stroke in the laboratory, organized clinical trials have not yet commenced. Until more definitive knowledge is available concerning the influence of high-dose barbiturate therapy in treating different forms of cerebral ischaemia, its application should be viewed sceptically and limited to centres willing to create an organized data base for inter-institutional evaluation of this form of treatment. If barbiturate therapy proves successful and the mechanisms involved are better understood, drugs with fewer side-effects and risks may become available to combat cerebral ischaemia.
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Randomized Controlled Trial Comparative Study Clinical Trial
Choice of local anaesthetic drug for extradural caesarean section. Comparison of 0.5% and 0.75% bupivacaine and 1.5% etidocaine.
One hundred women undergoing elective lower uterine segment Caesarean section under extradural anaesthesia received either 0.5% or 0.75% plain bupivacaine or 1.5% etidocaine with adrenaline 1:200 000 by random allocation. The time taken to establish satisfactory blockade for surgery was significantly shorter in the etidocaine group compared with either of the bupivacaine groups (P less than 0.001). There were no significant differences in the durations of either analgesia or motor blockade in the three groups. ⋯ Measurement of plasma bupivacaine concentrations in 34 of the patients revealed significantly increased umbilical venous concentrations at the time of birth in those who received 0.75% bupivacaine (P less than 0.05). There was no advantage in the use of bupivacaine in concentrations exceeding 0.5%. Etidocaine 1.5% may be of some value in situations where minimal delay in establishing adequate extradural blockade for surgery is desirable, but in view of its comparatively poor analgesic effects, routine use is not recommended.
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Thirty healthy women in active labour received an intrathecal injection of morphine 0.5 mg (n = 12) or 1 mg (n = 18) in 7.5% dextrose. Both doses provided excellent analgesia for labour, 93% of patients obtaining at least 50% pain relief. Analgesia began 15-60 min after injection and did not decrease until 6-8 h after injection. ⋯ These side effects were decreased by naloxone, which did not affect the degree of analgesia. There was no significant depression of ventilation in any patient. These results suggest that morphine 0.5 mg or 1 mg, administered intrathecally, effectively decreases the pain of labour, and that i.v. administration of naloxone can alleviate the common side effects.
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Extradural pressure was measured in the lateral and the supine positions in three groups of patients using the extradural catheter as a manometer. The groups consisted of 20 pregnant patients at or near term, 10 patients in the period after childbirth and 10 male surgical patients. In every patient, the extradural pressure in the supine position was greater than that in the lateral position. ⋯ It is suggested that the difference between the extradural pressures in the lateral and the supine positions is physiological and occurs irrespective of vena caval compression. Extradural pressure changes are probably the result of postural changes in the cerebrospinal fluid (CSF) pressure. The influence of CSF pressure on extradural pressure was confirmed further by measuring the extradural pressure in the prone position in five pregnant patients.