Journal of perinatology : official journal of the California Perinatal Association
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Malignant hyperthermia (MH) is a rare genetic myopathy that was first described as a fatal complication of general anesthesia in 1960. It is estimated to affect approximately 1 in 15,000 pediatric patients and 1 in 40,000 adult middle-aged patients. The mode of transmission is genetic: the severest form is autosomal dominant, and the less severe, autosomal recessive. ⋯ The definitive diagnosis is suspected susceptible individuals is revealed by exposing an intact muscle fiber to caffeine and halothane in varying concentrations. An abnormal contracture response is hypothesized to be the result of an increase in the release of calcium ion from the sarcoplasmic reticulum in response to neuronal stimulation leading to a hypermetabolic state. The mainstay of treatment is dantrolene, given either prophylactically in susceptible patients or immediately whenever a malignant hyperthermic episode is suspected.
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Patients with multiple gestations or recalcitrant preterm labor are at very high risk for preterm birth in spite of adequate tocolysis. Subcutaneous infusion of tocolytic medications on an ambulatory basis has been used in several small series and has effectively prolonged gestation. This retrospective analysis presents data from 992 patients at very high risk for preterm delivery who were prescribed this therapy. ⋯ The therapy extended the gestation a mean of 38 +/- 23 days and average gestational age at delivery was 36.3 +/- 2.6 weeks with a mean birthweight of 2759 +/- 681 g. This study, utilizing a large number of patients, confirms earlier reports that for women at very high risk for preterm delivery subcutaneous tocolytic infusion therapy is beneficial. Prospective studies evaluating such treatment on a randomized basis are indicated.