The Annals of thoracic surgery
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Protamine sulfate, which is used for heparin neutralization, has been reported to induce catastrophic pulmonary vasoconstriction after infusion. However, in the systemic circulation, protamine infusion induces hypotension due to peripheral vasodilation. ⋯ Protamine-mediated pulmonary vasodilatation could be an important mechanism to protect against the constrictive effects of autocoids generated during heparin neutralization. Such a mechanism might be dysfunctional in certain persons and put them at risk for pulmonary vasoconstriction after protamine infusion.
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Guidelines for transfusion practice have had limited impact in altering physician transfusion behavior in patients undergoing cardiac operations. This may be due to a lack of consensus on the relative risks and benefits of blood in these patients who are anemic, limited access to timely data that are necessary on which to base transfusion decisions, the recognition that empiric hemoglobin/hematocrit thresholds are limited clinical indicators of the need for blood, or a combination of these. We present an overview of current transfusion and blood conservation practices in this setting, along with possible approaches to guide the decision-making process by coupling the use of transfusion algorithms with point of care testing to use more physiologic indicators of the need for blood transfusion.
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Extracorporeal membrane oxygenation (ECMO) has emerged as an effective technique for the mechanical support of many pediatric postcardiotomy patients with medically refractory cardiac failure. ⋯ Extracorporeal membrane oxygenation is most effective in salvaging pediatric cardiac surgical patients who demonstrate medically refractory hemodynamic deterioration at some interval after being successfully weaned from cardiopulmonary bypass. The right atrial pressure after extracorporeal membrane oxygenation decannulation is an independent predictor of hospital death.
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Comparative Study
Aortic valve replacement with allograft/autograft: subcoronary versus intraluminal cylinder or root.
From April 1990 to May 1994, 89 patients (median age, 42 years; range, 10 days to 66 years) underwent aortic valve or root replacement with allografts or autografts. Thirteen patients were less than 18 years old at the time of operation. Indication for aortic valve replacement was aortic stenosis (50 patients, 56%), small stenotic prosthesis (2 patients, 2%), aortic valve endocarditis (19 patients, 21%), isolated aortic regurgitation (17 patients, 19%), and type II truncus arteriosus (1 patient, 1%). ⋯ Echocardiographic studies were obtained serially in every patient. Four patients, 2 in group A and 2 in group B underwent reoperation because of mild-to-moderate aortic regurgitation (rate of reoperation, 5%). Two valves were repaired and two were replaced by an allograft.(ABSTRACT TRUNCATED AT 250 WORDS)
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The surgical options available and the associated operative risks for repeat aortic valve replacement after free-standing homograft root replacement with reimplantation of the coronary arteries are as yet undefined. We therefore reviewed our experience with repeat aortic valve replacement between January 1976 and July 1994 and identified 22 such procedures performed on 21 patients after homograft or autograft root replacement. Reoperation was indicated for structural deterioration in 16 and for bacterial endocarditis in 6 patients. ⋯ Univariate analysis failed to identify any variables predictive of outcome. We conclude that repeat aortic valve replacement after homograft root replacement, even in the presence of significant calcification, can be undertaken with an acceptable operative risk and should not be delayed until irreversible ventricular dysfunction has occurred. The same options available at initial valve replacement may be employed at reoperation, although extensive calcification mandates repeat root replacement.