International journal of obstetric anesthesia
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Int J Obstet Anesth · Oct 1998
Incidence of epidural catheter replacement in parturients: a retrospective chart review.
We noted in our practice of obstetric anesthesia at a large teaching hospital that the epidural catheter failure rate was higher than previously reported. We undertook this study to determine the incidence of epidural catheter failure in parturients and to determine the primary causes of failure. After institutional approval, we evaluated the charts of parturients who received epidural analgesia for labor or anesthesia for cesarean section for 6 randomly selected months spanning one year. ⋯ The major causes of catheter failure were no analgesia and unilateral block. The experience of the anesthesiologist, the mode of delivery, patient age, patient weight, type of epidural catheter, occurrence of paresthesia and the use of CSE were all associated with significantly different epidural catheter replacement rates. Despite the initially high failure rate, the overall patient satisfaction rate was greater than 98%.
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Int J Obstet Anesth · Oct 1998
Acute airway obstruction during spinal anaesthesia for caesarean section.
A 30-year-old primiparous Caucasian woman with known placenta praevia required an emergency caesarean section for a mild antepartum haemorrhage at the onset of spontaneous term labour. Following intravenous prehydration with 500 ml gelatin colloid (Haemaccel trade mark ), spinal anaesthesia was induced in the sitting position with 2.6 ml of 0.5% hyperbaric bupivacaine (13 mg). The patient was then placed in the recumbent position with left lateral tilt, whereupon she suddenly became dyspnoeic. ⋯ Since parturients have a higher incidence of difficult airway management than the general population, anaphylactoid reactions presenting as angioneurotic oedema pose a particular challenge for the anaesthetist. The lower incidence of allergy associated with hydroxyethyl starch (Hetastarch) may make it a more appropriate choice of colloid in this setting. However, the balance of evidence now suggests that vasopressors, particularly ephedrine, are superior to fluids for maintenance of blood pressure during regional anaesthesia for caesarean section.
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Int J Obstet Anesth · Oct 1998
Cardiovascular consequences of the concomitant administration of nifedipine and magnesium sulfate in pigs.
There is concern regarding the interaction of magnesium sulfate and nifedipine used concomitantly in obstetrical patients, because both are calcium channel antagonists and may induce myocardial depression as well as peripheral vasodilatation. The objective of this study was to determine the hemodynamic consequences of concomitant administration of nifedipine and magnesium sulfate in anesthetized pigs. Twelve pigs were anesthetized with sodium pentobarbital, intubated mechanically ventilated. ⋯ Treatment with calcium chloride or ephedrine was only partially successful in improving myocardial contractility. Phenylephrine increased peripheral vascular resistance and MAP, but did not improve myocardial function. In conclusion, the depressive effects of nifedipine and magnesium sulfate on the cardiovascular system are potentiated when administered concomitantly.