International journal of obstetric anesthesia
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Three cases of transient osteoporosis of the hip in pregnancy are reported, and the implications of this rare condition for anaesthetists are considered.
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Int J Obstet Anesth · Jan 1997
Determination of the minimum local analgesic concentration of epidural chloroprocaine hydrochloride in labor.
The aim was to determine the effective concentration in 50% of patients (EC(50)) of chloroprocaine in the first stage of labor. A constant dose modification of a model where EC(50) was previously defined as the minimum local analgesic concentration (MLAC) was used. Parturients (n = 36) requesting epidural analgesia in labor, at cervical dilatation not exceeding 7 cm, were enrolled into this prospective, double-blinded study. ⋯ MLAC (95%CI) was 0.42%w/v (0.34 to 0.5) using the formula of Dixon & Massey and as a sensitivity test was 0.4%w/v (0.35 to 0.46) using probit regression analysis. In conclusion, MLAC of chloroprocaine was 0.42%w/v in these parturients, equivalent to 14 millimolar solution. This study confirmed that concentration rather than dose could be used as a measure of efficacy in this constant dose model.
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Int J Obstet Anesth · Jan 1997
Total intravenous anaesthesia for caesarean section in a patient with Marfan's syndrome.
The case is described of a pregnant patient with Marfan's syndrome scheduled at 39 weeks' gestation for elective caesarean section carried out for the first time by total intravenous anaesthesia (TIVA) with continuous intravenous (i.v.) infusion of propofol. The diagnosis was based on a positive family history, classic phenotype, scoliosis, arachnodactyly, high narrow palate, hyperextensible joints, ectopia lentis and mitral valve prolapse, with a secondary low mitral insufficiency. Maternal and fetal surveillance did not detect complications during the course of pregnancy. ⋯ Apgar scores were 9 at 1 and 5 min. The post-delivery course was unremarkable and post partum echocardiography showed no changes from before caesarean section. The cardiovascular problems of Marfan's syndrome, the risk of haemodynamic changes associated with pregnancy and delivery, its anaesthetic implications and the possible advantages of TIVA with continuous i.v. infusion of propofol in the anaesthetic management of caesarean section in patients with this disease are discussed.
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Although hypothermia has been reported during epidural anesthesia performed for nonobstetrical surgery or cesarean section, epidural analgesia for labor may lead to hyperthermia. Its incidence, time-course and intensity are influenced by multiple factors including site of measurement, duration of labor preceding epidural analgesia and perhaps ambient temperature and occurrence of shivering. During the first 2-5 h of epidural analgesia, a significant increase in temperature is not usually observed. ⋯ However, fetal tachycardia may occur and the potential for a deleterious effect on the fetus remains controversial. Various measures for cooling the mother have been proposed but their efficacy has not been evaluated. The recognition that epidural analgesia may provoke hyperthermia may help to avoid inappropriate use of antibiotics or fetal extraction.
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Int J Obstet Anesth · Jan 1997
Hamman's syndrome: pneumomediastinum and subcutaneous emphysema occurring in labour.
The syndrome of pneumomediastinum and subcutaneous emphysema is a rare and interesting complication of labour. The first case was recorded in 1784 and since that time some 200 other cases have been published. However, very little has appeared in the anaesthetic journals. ⋯ Chest X-ray showed a pneumomediastinum. It is postulated that the use of nitrous oxide may have exacerbated and so highlighted a pre-existing pneumomediastinum since there were no other features of the anaesthetic to account for this pathology. The pathophysiology, diagnosis and management of this condition are discussed together with a historical literature review.