Artificial organs
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Although the debate still continues over the effectiveness of pulsatile versus nonpulsatile perfusion, it has been clearly proven that there are several significant physiological benefits of pulsatile perfusion during cardiopulmonary bypass (CPB) compared to nonpulsatile perfusion. However, the components of the extracorporeal circuit have not been fully investigated regarding the quality of the pulsatility. In addition, most of these results have been gathered from adult patients, not from neonates and infants. ⋯ Although the same oxygenator was used for Group 2, the quality of the pulsatile flow decreased when using a different aortic cannula. Group 3 did not meet any of the criteria for physiologic pulsatility. In conclusion these data suggest that in addition to a pulsatile pump, the aortic cannula and the membrane oxygenator must be chosen carefully to achieve physiologic pulsatile flow during CPB.
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Multicenter Study Comparative Study
Substitution of acetic acid for hydrochloric acid in the bicarbonate buffered dialysate.
In a multicenter study including 5 dialysis units, blood acetate changes during 4 h dialysis sessions in 141 patients treated with a 4 mM acetate-containing bicarbonate dialysate (ABD) were evaluated and compared to the values of 114 patients using an acetate-free bicarbonate dialysate (AFD). Acetate-free bicarbonate dialysate was delivered by a dialysis machine from the mixing with water for dialysis of a 1/26.2 bicarbonate concentrate, and a 1/35 acid-concentrate in which acetic acid was substituted for hydrochloric acid (Soludia, Fourquevaux, France). This new type of dialysate was routinely in use for 3 years on average (range, from 2 to 5 years). ⋯ Hyperacetatemia was controlled with AFD in patients whose predialysis acetate plasma concentration of 316+/-82 decreased to 55 +/-23 microM (n = 6) at the end of the dialysis session whereas the acetate plasma concentration remained high when the predialysis concentration was 580+/-76 microM, with a postdialysis concentration of 233+/-39 microM (n = 28). It is concluded that in patients whose predialysis blood acetate levels were in the physiologic range, acetate-containing bicarbonate dialysate induces hyperacetatemia whereas postdialysis blood acetate remains in the normal range in such dialysis patients treated with acetate-free dialysate. Chronic hyperacetatemia, which could be found in dialysis patients, is well controlled by dialysis using an acetate-free dialysate.
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Our objective was to evaluate the safety of coronary anastomosis on the beating heart by measuring the release of cardiac troponin I during minimally invasive coronary artery bypass grafting (MICABG). Cardiac troponin I (cTnI) is a reliable marker of cardiac ischemia during heart operations under cardiopulmonary bypass (CPB). Ten patients (8 males and 2 females, aged 41-63) underwent MICABG with single vessel bypass grafting for left anterior descending coronary artery (LAD) stenosis (n = 7) or occlusion (n = 3). ⋯ Percutaneous angioplasty was performed on the right coronary artery, complicated with dissection and cardiac failure. This patient died 3 months after the MICABG despite support from a ventricular assist device. In conclusion, collateral circulation developed in the setting of chronic coronary occlusion may be efficient for myocardial preservation during short periods such as coronary anastomosis. cTnI immunoassay confirmed the safety of coronary anastomosis on the beating heart during minimally invasive coronary operations.
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The effectiveness of the blood substitute neo red cells (NRC) on hemorrhagic shock was evaluated in dogs. Shock was induced by bloodletting, and NRC was infused immediately until the dogs recovered from shock; the process was repeated 3 times (mild shock), or NRC was infused after shock was maintained for 30 min, and the process was repeated 3 times (severe shock). In mild shock, NRC with low viscosity reduced the peripheral vascular resistance and increased the cardiac index. ⋯ In severe shock, the total oxygen consumption increased, but red blood cells or plasma did not change the oxygen transport and did not meet the increased oxygen demand. However, the NRC increased the oxygen transport and supplied the increased oxygen demand. In mild shock on the other hand, no increase was observed in the total oxygen consumption or the oxygen transport.
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To evaluate the clinical results of circulatory support for severe heart failure after operation, we examined 62 patients (39 males and 23 females) who underwent circulatory support for postoperative heart failure from 1984 to 1996. Their ages ranged from 22 to 78 (mean 52) years. In 62 patients, 35 had valvular, 25 had ischemic, and 2 had congenital heart disease. ⋯ The remaining 5 patients received a pulsatile left ventricular assist device (LVAD). The weaning and discharge rates of the patients by type of support were 51.7% and 31.0% with VAB, 75.0% and 55.0% with BVB, 87.5% and 37.5% with LVB, and 60.0% and 40.0% with LVAD, respectively. The complete results of this series (64.5% weaning rate and 40.3% discharge rate) were acceptable.