The Journal of thoracic and cardiovascular surgery
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J. Thorac. Cardiovasc. Surg. · Nov 1994
Comparative StudyRecombinant platelet factor 4 reversal of heparin in human cardiopulmonary bypass blood.
The ability of recombinant platelet factor 4, a protein of human origin with high heparin affinity, and the present clinical heparin reversal agent, protamine, to neutralize heparin in human whole blood was studied by means of three standard whole blood coagulation tests: whole blood clotting time, heparin assay, and activated clotting time. Ten subjects were chosen at random among patients undergoing cardiopulmonary bypass operations. Heparinized blood, free of protamine, was obtained from the bypass reservoir for testing. ⋯ The quantity of each agent required to reverse the ten samples, using 95% upper confidence bounds (t distribution) was determined for each method. Recombinant platelet factor 4 reversed heparin at 40 micrograms/ml and protamine at 20 micrograms/ml, suggesting a reversal ratio for recombinant platelet factor 4/protamine of 2:1 on a milligram basis. Further, currently available methods for testing coagulation should be reliable, without modification, to monitor the restoration of normal coagulation parameters with recombinant platelet factor 4 after cardiopulmonary bypass.
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J. Thorac. Cardiovasc. Surg. · Oct 1994
Monitoring of hepatic venous oxygen saturation for predicting acute liver dysfunction after Fontan operations.
Acute liver dysfunction after Fontan operations may result from inadequate hepatic perfusion along with low cardiac output and high central venous pressure. We monitored hepatic venous oxygen saturation in 15 patients after Fontan operations to determine whether oxygen saturation predicts the occurrence and severity of acute liver dysfunction. We measured oxygen saturation from hepatic venous blood samples every 4 to 5 hours for at least 24 hours after the operation and used the mean hepatic venous oxygen saturation value for the first 24 hours after the operation to analyze the relationship between oxygen saturation and hepatic function. ⋯ The interpretation of these relationships is that hepatic indices are constant above the critical mean hepatic venous oxygen saturation values but are correlated with mean hepatic venous oxygen saturation below critical points in the range of 21% to 26%. Thus a hepatic venous oxygen saturation value below about 25% during the first 24 hours after a Fontan operation predicts the occurrence and the severity of acute liver dysfunction. We suggest that monitoring hepatic venous oxygen saturation is useful for management of critically ill patients after Fontan operations.
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J. Thorac. Cardiovasc. Surg. · Oct 1994
Dissection of the descending thoracic aorta extending into the ascending aorta. A therapeutic challenge.
Proper management of dissections of the descending thoracic aorta with intimal disruption close to the left subclavian artery and retrograde extension of the dissection into the aortic arch or the ascending aorta is controversial, because the standard approach for ascending aortic aneurysms is surgical repair, which is difficult to achieve through a median sternotomy if the predominant aortic lesion is located in its descending part. Sixteen patients with descending thoracic aortic dissection, intimal disruption close to the subclavian artery, and extension of the dissection into the aortic arch or the ascending aorta are described here: Eleven patients underwent surgical repair including 9 emergency (82%) and 2 elective (18%) procedures. Retrograde aortic dissection included the aortic arch in 11 of 11 patients (100%) and the ascending aorta in 7 of 11 (63%). ⋯ Considering the technical difficulties of simultaneous repair of dissections of the ascending and the descending thoracic aorta, we recommend that descending thoracic aortic dissection extending into the arch or the ascending aorta be managed in accordance with the site of the predominant lesion. Replacement of the arch with a varying portion of ascending aorta via a median sternotomy is recommended in patients with enlarged aortic diameter, pericardial effusion, and/or aortic insufficiency. Predominantly distal dissections with dilated descending thoracic aorta and/or distal complications are best approached via a lateral thoracotomy.
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J. Thorac. Cardiovasc. Surg. · Oct 1994
Circulating cytokines in patients undergoing normothermic cardiopulmonary bypass.
To determine the cytokine release during normothermic cardiopulmonary bypass, we have measured plasmatic levels of tumor necrosis factor-alpha and interleukins-1 beta, 6, and 8 in 10 patients during the first 24 hours after the start of bypass. Arterial blood samples were collected at intervals before, during, and after bypass. Interleukin-1 beta was not detectable in the plasma, and traces of tumor necrosis factor-alpha were detected in only three patients at times independent of the cardiopulmonary bypass procedure. ⋯ A local production of these cytokines cannot be excluded, because interleukin-6 and interleukin-8 are produced by stimulated macrophages and monocytes in response to tumor necrosis factor-alpha and interleukin-1 beta. Our results, at normothermia, show a similar pattern of interleukin-6 and interleukin-8 release when compared with release during hypothermic cardiopulmonary bypass. Interleukin-8, an important chemotactic neutrophil factor, might play a role in reperfusion injuries observed in lungs and heart after cardiopulmonary bypass.
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J. Thorac. Cardiovasc. Surg. · Sep 1994
Experimental study of cerebral autoregulation during cardiopulmonary bypass with or without pulsatile perfusion.
Twenty-four adult mongrel dogs were divided into four equal groups according to the following method of cardiopulmonary bypass: normothermic continuous (so-called nonpulsatile) perfusion, normothermic pulsatile perfusion, hypothermic continuous perfusion, and hypothermic pulsatile perfusion. Cerebral blood flow was determined by measuring the volume of sagittal sinus venous blood outflow with a transit-time ultrasonic flowmeter. Cardiopulmonary bypass was initiated at a flow rate of 80 ml/kg per minute. ⋯ The correlation between cerebral blood flow and perfusion pressure was described as two separate lines determined by linear regression. The slope of the regression line relating cerebral blood flow to perfusion pressure was 0.16 +/- 0.08 for a cerebral perfusion pressure above 50 mm Hg and 0.68 +/- 0.11 below 50 mm Hg in the normothermic continuous perfusion group; 0.14 +/- 0.09 and 0.32 +/- 0.09 with normothermic pulsatile perfusion; 0.10 +/- 0.04 and 0.62 +/- 0.18 with hypothermic continuous perfusion; 0.09 +/- 0.08 and 0.39 +/- 0.04 in the hypothermic pulsatile perfusion group. The slope above 50 mm Hg was significantly smaller and closer to zero in all groups than it was at a perfusion pressure below 50 mm Hg (p < 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)