The Journal of thoracic and cardiovascular surgery
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J. Thorac. Cardiovasc. Surg. · Apr 1989
The effect of age on cerebral blood flow during hypothermic cardiopulmonary bypass.
Cerebral blood flow was measured in 20 patients by xenon 133 clearance methodology during nonpulsatile hypothermic cardiopulmonary bypass to determine the effect of age on regional cerebral blood flow during these conditions. Measurements of cerebral blood flow at varying perfusion pressures were made in patients arbitrarily divided into two age groups at nearly identical nasopharyngeal temperature, hematocrit value, and carbon dioxide tension and with equal cardiopulmonary bypass flows of 1.6 L/min/m2. The range of mean arterial pressure was 30 to 110 mm Hg for group I (less than or equal to 50 years of age) and 20 to 90 mm Hg for group II (greater than or equal to 65 years of age). ⋯ In 12 patients, a second cerebral blood flow measurements was taken to determine the effect of mean arterial pressure on cerebral blood flow in the individual patient. Changes in mean arterial pressure did not correlate with changes in cerebral blood flow (p less than 0.90). We conclude that age does not alter cerebral blood flow and that cerebral blood flow autoregulation is preserved in elderly patients during nonpulsatile hypothermic cardiopulmonary bypass.
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J. Thorac. Cardiovasc. Surg. · Apr 1989
Studies of retrograde cardioplegia. II. Advantages of antegrade/retrograde cardioplegia to optimize distribution in jeopardized myocardium.
This study tests the hypothesis that retrograde/antegrade cardioplegic delivery can overcome the limitations of poor cardioplegic distribution resulting from either technique alone and, potentially, may expand the safety of using internal mammary artery grafts in cardiac muscle in jeopardy of inadequate cardioplegic protection. Jeopardized myocardium was produced in 20 dogs by ligating the left anterior descending coronary artery for 15 minutes before starting cardiopulmonary bypass and by 1 hour of aortic clamping with multidose 6 degrees C cold blood cardioplegia. Five dogs received antegrade cardioplegia via the aortic root. ⋯ Retrograde cardioplegia produced homogeneous cooling (17 degrees C) and allowed near normal recovery of global and regional left ventricular function (99% and 86%), but right ventricular cooling was variable (19 degrees to 30 degrees C) and right ventricular function recovered inconstantly (range 64% to 100%, average 82%). The best myocardial protection occurred after retrograde/antegrade cardioplegia; myocardial cooling was homogeneous, left ventricular and right ventricular global function recovered completely (95% and 90%), and regional contractility in muscle supplied by the left anterior descending coronary artery returned to 84% of control. We conclude that retrograde/antegrade cardioplegia provides better myocardial protection than either technique alone, ensures good cardioplegic distribution to the left and right ventricles, and allows regional delivery of cardioplegic flow to segments supplied by occluded arteries.(ABSTRACT TRUNCATED AT 400 WORDS)
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A cuff technique is introduced to anastomose pulmonary vein and pulmonary artery in rat lung transplantation. In 11 consecutive cases, the average graft ischemic time was 13.5 +/- 2.0 minutes and operating time 100.7 +/- 4.8 minutes: The time for ischemia was less than one third of previous reports and the time for operation one half of previous reports. Excluding two operative deaths, the survival rate was 88.8% (8/9) on postoperative day 11, when contralateral pneumonectomy revealed excellent graft function supporting the oxygenation of the animals.