The Journal of thoracic and cardiovascular surgery
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J. Thorac. Cardiovasc. Surg. · Feb 1983
Comparative StudyThe role of the activated clotting time in heparin administration and neutralization for cardiopulmonary bypass.
Precise guidelines for heparin administration and neutralization during cardiopulmonary bypass (CPB) are not established. To a large extent, the uncertainty originates from a disparity between the heparin dosage, the plasma heparin concentration, and the clinical heparin effect. We investigated these relationships in 44 consecutive patients at New York University Medical Center. ⋯ Mild heparin rebound was found in two patients (4.5%) but was not associated with excessive bleeding. Following bypass a comparison of heparin levels and ACTs demonstrated the ACT to be a poor indicator of residual circulating heparin. These data show: (1) that neither the heparin dosage nor the plasma heparin concentration can accurately predict the magnitude of the clinical heparin effect in patients undergoing CPB and emphasize the importance of the ACT as the best available measurement of safe anticoagulation, (2) heparin "rebound" was not clinically significant, and (3) heparin was neutralized with 2 to 3 mg/kg protamine in virtually all patients, regardless of the total heparin dose.
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J. Thorac. Cardiovasc. Surg. · Feb 1983
Early valve replacement in active infective endocarditis. Results and late survival.
In the past 14 years, 42 patients with active infective endocarditis underwent early valve replacement for severe congestive heart failure, major prosthetic dehiscence, intramyocardial abscesses, sepsis, or major embolization. Blood cultures were positive in 40 patients and the valve tissues were positive in two others. All patients received antimicrobials for from 1 to 4 weeks. ⋯ Survival for native valve involvement was 0.58 and for prosthetic endocarditis, 0.55. This study shows that after at least 1 week of antibiotics, early operation in patients with active endocarditis has an acceptable operative mortality. Clinical improvement is excellent in 95% and more than half survived 5 years or longer.
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J. Thorac. Cardiovasc. Surg. · Feb 1983
Regional blood flow during cross-clamping of the thoracic aorta and infusion of sodium nitroprusside.
Labeled microspheres, 15 microns in diameter, were used to determine cardiac output and regional blood flow response to cross-clamping of the midthoracic aorta and subsequent sodium nitroprusside (SNP) infusion in 11 dogs. During aortic cross-clamping, mean arterial pressure above the occlusion (MAPa) increased 30% to 35%, mean arterial pressure below the occlusion (MAPb) decreased 87%, cardiac index decreased 12% to 14%, left atrial pressure (LAP) doubled, and renal and spinal cord (lower part) blood flows decreased substantially (85% to 94%). SNP infusion returned MAPa to baseline values, decreased MAPb by half, and substantially and further decreased renal blood flow (to 3% to 5% of baseline values). ⋯ There was a strong association between cortical renal blood flow and MAPb (r2 = 0.92; p less than 0.0001), which suggests that blood flow through organs and tissues below the occlusion is pressure dependent. The data show that SNP infusion during thoracic aortic cross-clamping improves systemic and regional circulation above the occlusion but decreases MAPb and therefore blood flow below the occlusion. SNP infusion should be used with caution during aortic cross-clamping, since arterial hypotension of any degree may be deleterious to organs below the cross-clamp.