The Journal of thoracic and cardiovascular surgery
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J. Thorac. Cardiovasc. Surg. · Jan 1993
Effect of cardiopulmonary bypass on systemic release of neutrophil elastase and tumor necrosis factor.
Leukocyte counts, plasma neutrophil elastase, tumor necrosis factor-alpha and C-reactive protein were determined serially in 19 patients undergoing elective coronary artery surgery with cardiopulmonary bypass. Neutrophil counts (mean +/- standard deviation 3.85 +/- 1.20 x 10(9)/L preoperatively) peaked 4 hours postoperatively at 10.35 +/- 4.24 x 10(9)/L (p < 0.001) and remained significantly elevated 48 hours postoperatively at 7.80 +/- 2.70 x 10(9)/L, p < 0.05. Plasma neutrophil elastase level (187 +/- 74 ng/ml preoperatively) peaked at 698 +/- 323 ng/ml at the end of surgery (p < 0.001) and remained significantly elevated at 424 +/- 146 ng/ml 48 hours postoperatively (p < 0.01). ⋯ Oxygenation, determined by the respiratory index, was impaired at the end of operation (2.07 +/- 0.82) and remained impaired 24 hours postoperatively (2.48 +/- 0.83). Impairment of oxygenation was temporally related to elevated elastase levels, but neither peak elastase levels nor the change in elastase levels with lung reperfusion correlated significantly with the area under the respiratory index curve up to 6 hours postoperatively. This study demonstrates neutrophil elastase release during cardiopulmonary bypass but fails to show a definite role for neutrophil activation or tumor necrosis factor-alpha in the etiology of pulmonary dysfunction after cardiopulmonary bypass.
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J. Thorac. Cardiovasc. Surg. · Dec 1992
The acoustic filter: an ultrasonic blood filter for the heart-lung machine.
Cardiopulmonary bypass-associated encephalopathy is thought to be due in part to continuous microembolization of the brain with gas microbubbles more than 40 microns in diameter during bypass. Current barrier filter technology cannot effectively remove such small microbubbles in fragile fluids such as blood. The design concepts for a new nonbarrier ultrasound-based fluid filtration system (an "acoustic filter") capable of filtering small microbubbles from blood are presented. ⋯ Inactivated, the acoustic filter neither removed nor added microbubbles to the fluid. Activated, the acoustic filter provided total or near-total clearing of microbubbles. We conclude that the acoustic filter can remove microbubbles from a cardiopulmonary bypass-like apparatus.
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J. Thorac. Cardiovasc. Surg. · Dec 1992
Polyethylene glycol-conjugated superoxide dismutase attenuates reperfusion injury when administered twenty-four hours before ischemia.
Covalent linkage of polyethylene glycol to superoxide dismutase prolongs the serum half-life of the enzyme and may facilitate intracellular access. We tested the myocardial protective effect of polyethylene glycol superoxide dismutase administered once, 24 hours before ischemia. Because hearts were studied ex vivo in a crystalloid perfused system, cardioprotection could be ascribed to intramyocardial or membrane-bound polyethylene glycol superoxide dismutase accumulation. ⋯ Although an improved return of function was shown in the lower dose PEG-SOD 10,000 group, the margin of difference when compared with any of the control groups was determined to be insignificant at all times of reperfusion and at 60 minutes (75.9% +/- 3.2%). These data demonstrate that high, but not low, doses of polyethylene glycol superoxide dismutase significantly reduce reperfusion injury when administered 24 hours before initiation of global ischemia. Moreover, since the perfusate was superoxide dismutase free, this effect was most likely intramyocardial or membrane bound and therefore might be added to protection afforded by circulating superoxide dismutase.
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J. Thorac. Cardiovasc. Surg. · Dec 1992
Endothelial dysfunction caused by University of Wisconsin preservation solution in the rat heart. The importance of temperature.
The superiority of the University of Wisconsin solution over routinely used crystalloid cardioplegic solutions for myocardial preservation has been demonstrated in animal studies. We have investigated the effect of the University of Wisconsin solution at different temperatures on endothelial function by examining its influence on 5-hydroxytryptamine- and nitroglycerin-induced increase in coronary flow in the isolated rat heart. Thirty-eight rat hearts were perfused on a modified Langendorff preparation. ⋯ The increase after University of Wisconsin solution infusion at 4 degrees C and at 10 degrees C was similarly not significant. Coronary vascular resistance increased significantly following infusion of University of Wisconsin solution at 15 degrees C (p < 0.001) or at 20 degrees C (p < 0.01). We conclude that University of Wisconsin solution produces temperature-dependent endothelial dysfunction in the isolated rat heart.
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J. Thorac. Cardiovasc. Surg. · Dec 1992
Dynamic cardiomyoplasty acutely impairs left ventricular diastolic function.
In patients with congestive heart failure, medical treatment has a high rate of mortality and morbidity, and transplantation is limited by the availability of donor hearts. Dynamic cardiomyoplasty is being investigated as surgical therapy to improve left ventricular function in these patients. To evaluate the early postoperative effects of this procedure on left ventricular diastolic function, we studied seven dogs through the use of sonomicrometry and micromanometry in a canine model of dynamic cardiomyoplasty. ⋯ The latissimus dorsi muscle wrap prolonged relaxation and increased left ventricular passive stiffness. Synchronous latissimus dorsi muscle stimulation with left ventricular contraction did not improve diastolic function in this model. The results suggest that in the early postoperative period, dynamic cardiomyoplasty impairs diastolic function.