Circulation
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Comparative Study
Myocardial acidosis associated with CO2 production during cardiac arrest and resuscitation.
Previous studies from our institution demonstrated significant hypercarbic acidosis in the mixed venous (pulmonary artery) blood in animals and human patients during cardiac arrest and cardiopulmonary resuscitation (CPR). In the present study, the acid-base state of the myocardium during cardiac arrest was investigated. Cardiac arrest was electrically induced in 11 pentobarbital-anesthetized and mechanically ventilated domestic pigs. ⋯ The PCO2 in cardiac vein blood was significantly greater than that of mixed venous blood, demonstrating disproportionate myocardial production of CO2 during CPR. Accordingly, it is CO2 production during ischemia that is implicated as the predominant mechanism accounting for myocardial [H+] increases during cardiac arrest. Important clinical implications for buffer therapy during CPR and, in particular, treatment with bicarbonate emerge from these observations.
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Comparative Study
Effects of cardiopulmonary bypass on cerebral blood flow in neonates, infants, and children.
Cardiopulmonary bypass (CPB) management in neonates, infants, and children requires extensive alterations in temperature, pump flow rate, and perfusion pressure, with occasional periods of circulatory arrest. The effect of these alterations on cerebral blood flow (CBF) are unknown. This study was designed to determine the relation of temperature and mean arterial pressure to CBF during hypothermic CPB (18 degrees-32 degrees C), with and without periods of total circulatory arrest. ⋯ In group C, no significant increase in CBF was observed during rewarming after total circulatory arrest (32 +/- 12 minutes) or after weaning from CPB. During moderate-hypothermic CPB (25 degrees-32 degrees C), there was no association between CBF and mean arterial pressure. However, during deep-hypothermic CPB (18 degrees-22 degrees C), there was an association between CBF and mean arterial pressure.(ABSTRACT TRUNCATED AT 250 WORDS)
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Deep-hypothermic cardiopulmonary bypass with selective cerebral perfusion (SCP) was used in 34 consecutive patients with aneurysms involving the aortic arch or the adjacent part of the aorta. The ages ranged from 25 to 79 years (mean, 56 years). Atherosclerotic aneurysms were present in 14 patients, dissecting aortic aneurysms in 16, and other lesion types in four. ⋯ Neurological sequelae occurred in one patient (cerebral infarction), but significant respiratory and hemorrhagic problems were not encountered. For the SCP protocols, we advise that perfusion pressures at bilateral superficial temporal arteries be kept at approximately 50 mm Hg and that venous oxygen saturation of the superior vena caval line or internal jugular vein be kept at above 90%. With appropriate monitoring, this method can be performed in aortic arch or related surgeries with low morbidity results.
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Review
Surgery for mitral regurgitation associated with ischemic heart disease. Results and strategies.
Analysis of published reports indicates that ischemic mitral insufficiency is associated with higher operative mortality (10-30%) than is nonischemic mitral valve procedures. Probable incremental risk factors include emergency operation, acute myocardial infarction, hemodynamic instability, poor left ventricular function, pulmonary hypertension, advanced age, and renal failure. ⋯ Although the technique of repair of nonacute ischemic mitral insufficiency is not standardized, repair with revascularization is preferred. Preliminary data suggest that long-term results are primarily related to the severity of left ventricular dysfunction.
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Comparative Study
Asymptomatic left main coronary artery disease in the Coronary Artery Surgery Study (CASS) registry.
Left main coronary artery disease (i.e., greater than or equal to 50% stenosis) was found in 1,477 of 20,137 patients in the Coronary Artery Surgery Study (CAS) registry. Of these patients, 53 (3.6%) were asymptomatic. Asymptomatic and symptomatic patients were similar in regard to 1) severity of left main coronary artery stenosis (67% vs. 70%), 2) extent of proximal coronary artery disease (no differences in number of or severity of proximal stenoses), 3) left ventricular end-diastolic pressure (13 mm Hg vs. 14 mm Hg), 4) left ventricular wall motion score 9.1 vs. 8.7), and 5) number of coronary artery segments with greater than 70% stenosis (4.4 vs. 4.8). ⋯ Medical management of left main coronary artery disease produced a 5-year survival rate of 57% for asymptomatic patients and 58% for symptomatic patients. Within the asymptomatic subgroup, 88% of those surgically treated survived 5 years, whereas only 57% of those medically treated survived 5 years (p = 0.02). Thus, for CASS patients with left main coronary artery disease, the percentage of those that were asymptomatic is low (3.6%); asymptomatic and symptomatic patients with left main coronary artery disease had no significant difference in severity of left main coronary artery stenosis, extent of overall coronary artery disease, or left ventricular function.(ABSTRACT TRUNCATED AT 250 WORDS)