Clinics in chest medicine
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The pharmacologic treatment of any pregnant patient with a respiratory illness should occur only after careful consideration of the effects of altered maternal physiology and the potential effects on the developing fetus. Pregnancy changes gastrointestinal absorption of drugs, creates an increased volume of distribution, decreases protein binding, and increases renal excretion and hepatic metabolism of most drugs. These changes may necessitate variation in dose or dosing interval of drugs administered during pregnancy. ⋯ Important exceptions do exist and certain agents should be avoided. When the patient expresses concern over a pharmacologic or radiologic exposure during pregnancy, a detailed history of the type, timing, and duration of exposure and genetic consultation should be obtained. Finally, drug treatment of serious illness in the pregnant patient should not be withheld unless the risk of the agent in question clearly outweighs the fetal and maternal risk of untreated disease.
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Restrictive ventilatory defects characterized by a reduction in lung volumes and an increase in the ratio of forced expiratory volume in 1 second to forced vital capacity occur when lung expansion is limited because of alterations in the lung parenchyma or because of abnormalities in the pleura, chest wall, or neuromuscular apparatus. Few studies have examined pregnant women with carefully defined restrictive lung disorders. The majority of pulmonary diseases have their onset after the childbearing years. ⋯ Respiratory complications during pregnancy in patients with kyphoscoliosis have been reported but in general are not serious if appropriately managed. As a rule, patients with severe restrictive lung disease (i.e., vital capacity < 1 L) should be advised to avoid pregnancy or consider therapeutic abortion. If such a patient decides to continue the pregnancy she should be provided with optimal medical management of her underlying disease and should consider delivery by cesarean section.
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Amniotic fluid embolism is the most unpredictable and catastrophic complication of pregnancy, accounting for 10% to 20% of maternal deaths. The pulmonary edema commonly seen in this syndrome is probably due primarily to alveolar capillary leakage and may be potentiated by high maternal extracellular volume, low colloid osmotic pressure, and, in some patients, by depressed myocardial function. In patients in whom resuscitation is successful, diuresis leads to rapid resolution of pulmonary edema. Amniotic fluid does not ordinarily enter the maternal circulation, and the identification of large numbers of fetal squames in the postpartum pulmonary microvasculature is probably of clinical significance.
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Clinics in chest medicine · Dec 1992
ReviewDyspnea during pregnancy. Distinguishing cardiac from pulmonary causes.
Dyspnea is common during normal pregnancy; however, a variety of significant cardiac and pulmonary disorders present with this as a cardinal symptom. This article describes the cardiopulmonary and clinical findings of pregnancy as well as specific disease indicators in the more common causes of cardiac and pulmonary dyspnea during pregnancy.
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Acute respiratory failure in pregnancy is an important cause of maternal and fetal morbidity and mortality. Causes include: ARDS, venous air embolism, beta-adrenergic tocolytic therapy, asthma, thromboembolic disease, pneumothorax, and pneumomediastinum. The most common predisposing diseases for ARDS complicating pregnancy are sepsis, pneumonia, aspiration of gastric contents, and amniotic fluid embolism. ⋯ Respiratory failure from status asthmaticus is treated with vigorous bronchodilator therapy, high-dose glucocorticosteroids, magnesium sulfate, and careful ventilator management. Occasionally, more experimental therapies (e.g., isoproterenol infusion, halothane anesthesia) are indicated. Certain strategies can help prevent respiratory failure from aspiration of gastric contents, beta-adrenergic tocolytic therapy, and thromboembolic disease.