The Journal of thoracic and cardiovascular surgery
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J. Thorac. Cardiovasc. Surg. · Aug 1990
Brain tissue pH, oxygen tension, and carbon dioxide tension in profoundly hypothermic cardiopulmonary bypass. Pulsatile assistance for circulatory arrest, low-flow perfusion, and moderate-flow perfusion.
The brain tissue pH, oxygen tension, and carbon dioxide tension were experimentally examined during profoundly hypothermic cardiopulmonary bypass with core cooling and core rewarming. Sixty-minute circulatory arrests (n = 28, group I), 120-minute low-flow perfusions (25 ml/kg/min; n = 16, group II), and 120-minute moderate-flow perfusions (50 ml/kg/min; n = 16, group III) were accomplished with and without pulsatile flow. In group I, progressive brain tissue acidosis and hypercapnia were recovered with pulsatile assistance. ⋯ In group III mild acidosis was eliminated with pulsatile assistance where the pH was significantly higher than in groups I and II, and brain tissue carbon dioxide pressure was significantly lower than in groups I and II with and without pulsatile assistance. Brain tissue hypoxia was severe in group I, slight in group II, but not found in group III. We concluded that a perfusion flow rate will decide the safe period, and a pulsatile assistance will promote brain protection at any flow rate in profoundly hypothermic cardiopulmonary bypass.
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J. Thorac. Cardiovasc. Surg. · Aug 1990
Comparative StudyReoperative coronary surgery. Comparative analysis of 6591 patients undergoing primary bypass and 508 patients undergoing reoperative coronary artery bypass.
During an 18-year period a consecutive series of 6591 patients underwent primary coronary bypass grafting and 508 patients underwent reoperative bypass. The mean patient age for the reoperative group was identical to that of the primary group, 59.8 years, but the mean age at initial operation for the reoperative group was 55.2 years. Mammary grafts were done at initial operation in 59% of patients who have had one operation versus only 46% of patients who subsequently required reoperation (p less than 0.001). ⋯ Ten years after reoperation, 30% of operative survivors were free of heart-related morbidity and mortality compared with 50% of patients having a primary operation. Univariate analysis of factors increasing the probability of reoperation include the absence of a mammary graft and younger age at operation. Patients undergoing a second bypass operation represent a substantially higher risk subgroup than patients undergoing initial operation in terms of perioperative morbidity, mortality, decreased long-term survival, and decreased relief of recurrent cardiac morbidity.
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J. Thorac. Cardiovasc. Surg. · Jul 1990
Changes in hemodynamic variables during hypothermic cardiopulmonary bypass. Effects of flow rate, flow character, and arterial pH.
During hypothermic cardiopulmonary bypass, the effects on hemodynamic variables of alternating pump flow rate between 1.5 and 2.0 L.min-1.m-2, flow character between nonpulsatile and pulsatile perfusion, and acid-base management between pH- and alpha-stat control were studied in a crossover factorial experiment. Twenty-four patients who were undergoing elective coronary artery bypass grafting were studied during stable hypothermic (27 degrees to 29 degrees C) cardiopulmonary bypass. A minimum of two (when time allowed, three) consecutive 10-minute periods (period 1, 2, or 3) were investigated. ⋯ Alteration in flow rate, but not flow character or arterial pH, had a significant effect on peripheral vascular resistance. It is hypothesized that the increase in peripheral vascular resistance during the course of cardiopulmonary bypass results from an active capillary mechanism, whereas the increase that is associated with reduction in flow rate reflects a passive mechanism. The increase in peripheral vascular resistance with decrease in flow rate indicates impaired tissue perfusion, unlike that occurring with stage.
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J. Thorac. Cardiovasc. Surg. · Jul 1990
Randomized Controlled Trial Clinical TrialIs transfusion of fresh plasma after cardiac operations indicated?
Patients undergoing cardiac operations constitute the majority of recipients of fresh frozen plasma. In most centers the reason for transfusing fresh frozen plasma is to replace clotting factors. However, the decrease of clotting factors during cardiopulmonary bypass is not sufficient in most patients to cause abnormal bleeding. ⋯ Each group later received the remainder of the blood unit, with similar results. The results suggest that improvement of platelet function in patients receiving fresh whole blood after cardiac operations is not related to plasmatic factors. Therefore the massive use of fresh frozen plasma in patients after cardiopulmonary bypass should be reconsidered.
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The bidirectional cavopulmonary shunt improves systemic arterial oxygen saturation without increasing ventricular work or pulmonary vascular resistance. Since 1983, 17 patients have undergone a cavopulmonary shunt procedure (five primary operations, 12 secondary operations). Diagnoses were single ventricle complex (n = 4), hypoplastic right heart syndrome (n = 10), and hypoplastic left ventricle (n = 3). ⋯ The cavopulmonary shunt is an excellent palliative procedure when right atrium-pulmonary artery connection (modified Fontan) must be deferred because of age, weight, or anatomic considerations. Five patients have undergone right atrium-pulmonary artery connection later. In addition, at the time of the modified Fontan operation, the cavopulmonary shunt approach may optimize the anatomic connection (eight additional patients).