The Annals of thoracic surgery
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The purpose of this study was to determine whether cerebral cortical microvascular responses to platelet-derived vasoactive substances are altered after normothermic cardiopulmonary bypass (CPB), and whether these alterations are modified by moderate hypothermia. ⋯ This study demonstrates that normothermic extracorporeal circulation reduces endothelium-dependent relaxation responses to products of platelet activation in the cerebral microcirculation. Moderate hypothermia attenuates the CPB-induced impairment of endothelium-dependent relaxation, but has no effect on baseline cerebral blood flow after rewarming.
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Significant right ventricular (RV) dysfunction as measured by increased end-diastolic volume and reduced ejection fraction has been documented in the postoperative period after pulmonary resection. We hypothesized that changes in RV contractile state or afterload may contribute to this RV pump dysfunction. ⋯ The present study suggests that RV dysfunction after pulmonary resection is not caused by primary alterations in contractility or immediate changes in afterload. Better control of heart rate with minimal effect on inotropy may enhance RV pump function.
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Comparative Study
Open drainage of massive tuberculous empyema with progressive reexpansion of the lung: an old concept revisited.
This study examined the results of open drainage of massive tuberculous empyema. ⋯ These totally collapsed "entrapped" lungs expanded to fill the entire pleural space despite the presence of bronchopleural fistulas and an "open" pleura. Reexpansion was progressive, gradual, and dependent on improved compliance, clearing of bronchial inflammation and obstruction, and pleural cleansing. Criteria are established that identify those patients in whom complete reexpansion may take place and the disease may be cured.
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Ice/saline slush used along with cold cardioplegia for heart arrest in cardiac operations can cause hypothermic damage to certain structures, an important one being the left phrenic nerve, damage of which results in raised left hemidiaphragm and delayed recovery of the patient. In coronary artery bypass grafting, opening of the pleura and collection of the ice/saline slush in the pleural cavity increases the incidence of injury. ⋯ The left recurrent nerve as it arches around aorta lies in the thorax very close to the parietal pleura and may be prone to hypothermic injury by ice/slush collecting in the pleural cavity during cardiac operations. Judicious use of ice/saline slush had helped in eliminating the problem to some extent.
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Despite the incidence of heart disease during pregnancy falling to 1.5% over the last 25 years, when a cardiac operation is required the risk is obviously greater as two lives are at risk. The risk to the mother is now similar to that for nonpregnant female patients (3% overall) but the fetal mortality remains high (19%). Cardiac operation is ill advised except in extreme emergencies during the first two trimesters as the incidence of teratogenesis is high. ⋯ Finally, uterine contractions occur in response to bypass, possibly due to a dilutional effect from the stabilizing influence of progesterone. Various techniques to modify this include the administration of progesterone, beta2-agonists, and intravenous alcohol, all with some effect. Uterine monitoring is essential to allow early control of these contractions as they are associated with significant fetal loss.