The Journal of thoracic and cardiovascular surgery
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J. Thorac. Cardiovasc. Surg. · May 1984
Relationship of brain blood flow and oxygen consumption to perfusion flow rate during profoundly hypothermic cardiopulmonary bypass. An experimental study.
A study was made of the relation of brain blood flow and oxygen consumption to changes in perfusion flow rate during cardiopulmonary bypass at 20 degrees C in nine cynomolgus monkeys. Four perfusion flow rates varying from 0.25 to 1.75 L X min-1 X m-2 were randomly instituted, each for a 10 minute period. At the end of each period, brain arteriovenous oxygen content difference was measured and 15 mu radioactive microspheres were injected into the arterial perfusion line. ⋯ There was a greater reduction of blood flow in the cortical white matter (p = 0.01) than in other regions of the brain. Brain oxygen consumption was the same (p = 0.5) at all perfusion flow rates, related to an increasing percent oxygen extraction with decreasing perfusion flow rate (p less than 0.0001). The data indicate that all areas of the brain remain perfused, even at low perfusion flow rates, during profoundly hypothermic cardiopulmonary bypass, and that brain oxygen consumption is maintained in part by increased oxygen extraction and in part by redistribution of the perfusate from the remaining body to the brain.
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J. Thorac. Cardiovasc. Surg. · Apr 1984
Comparative StudyUse of the pulmonary artery for left ventricular venting during cardiac operations.
Data relating to the hemodynamic efficaciousness and mechanism of action of a pulmonary artery catheter or vent used for left ventricular venting during cardiac operations are presented. The pulmonary artery vent is a plastic sump catheter that is introduced into the main pulmonary artery through a purse-string suture and connected via a roller pump to the venous reservoir of the heart-lung perfusion machine. Placement and removal require only a few minutes. ⋯ The effectiveness of left ventricular decompression was evaluated in 20 patients also undergoing bypass grafting. Use of the pulmonary artery vent consistently and significantly decreased left heart pressures, compared to the control situation with the vent off, with the aortic cross-clamp applied, and in both the fibrillating and beating heart in the early postischemic reperfusion period. We reached the following conclusions: (1) The pulmonary artery vent withdraws left heart blood via the pulmonary vasculature, in addition to returning right heart spillover and retrieving bronchial flow. (2) Left heart pressures are reduced to levels which reduce oxygen demands and preserve endocardial perfusion, therefore protecting myocardium, during fibrillation and during coronary reperfusion of the beating heart. (3) Because of its effectiveness and safety, especially the impossibility of introducing air into the left ventricle, the pulmonary artery vent is recommended for routine left ventricular venting.
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Information on the role of the intensivist in postoperative cardiovascular patient care was obtained from a national survey of cardiac surgeons. The cardiac surgeon today retains overall responsibility for patient care. ⋯ Intensivists are less likely to practice in nonteaching hospitals and less likely to be present in those cardiac surgical units that are not combined with other services. Because of the preponderance of intensivists in training programs, the surgical resident's role in patient care may be reduced in the future.
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J. Thorac. Cardiovasc. Surg. · Apr 1984
Favorable ten-year experience with valve procedures for active infective endocarditis.
We have reviewed our 1972 to 1982 experience with valve procedures for infective endocarditis in 52 consecutive patients to evaluate the results of an interdisciplinary policy of early operation for uncontrolled complications. There were 47 patients with native valve endocarditis and five with prosthetic valve endocarditis. Twenty-seven were drug addicts and 25 were not. ⋯ The late actuarial survival rate was 64% at 5 years and 54% at 10 years. Seven of nine deaths in the addict group were related to continued drug use, with five deaths occurring in the first 18 months. These results support a policy of early operation for uncontrolled complications with attention to the particular problems of active endocarditis.