CHARACTER OF SHED BLOOD IN CARDIAC AND THORACIC-SURGERY PATIENTS - IMPLICATIONS FOR REINFUSION

Objective. To determine whether the independently observed increase in the levels of cardiac enzymes in peripheral blood can be accounted fo r by elevations from postoperative shed-blood reinfusion in patients w ho have undergone cardiac or thoracic operations. Design: Prospective case-controlled study. Setting: A cardiothoracic surgery unit at a uni versity referral centre. Patients. Thirty-four consecutive patients wh o underwent cardiac or thoracic surgery within a 3-week period. Interv entions: Coronary artery revascularization (23 patients), cardiac valv e replacement or repair (4) and lung resection (7). Main Outcome Measu res. Determination of levels of cardiac enzymes and isoenzymes in samp les of peripheral and shed blood. Statistical comparison was by paired t-tests within groups and by unpaired t-tests between groups. Results : Serum levels of creatine kinase, lactic dehydrogenase and aspartate aminotransferase were significantly (p < 0.001) elevated in samples of shed blood compared with peripheral blood in all groups. The elevatio ns were found to be related to skeletal muscle injury and were not of cardiac origin. In the absence of myocardial infarction, cardiac isoen zyme levels were significantly (p < 0.001) elevated in the peripheral blood of cardiac surgery patients compared with that of thoracic surge ry patients. Conclusion: Reinfusion of shed blood will result in eleva ted levels of cardiac enzymes in peripheral blood but will not increas e the percentage of isoenzymes.