SummaryThrombelastography, although proven as a useful research tool has not been evaluated for its clinical utility against common coagulation laboratory tests. In this study we compare the thrombelastographic measurements with six common tests (the hematocrit, platelet count, fibrinogen, prothrombin time, activated thromboplastin time and fibrin split products). For such comparisons, two samples of subjects were selected, 141 normal volunteers and 121 patients with cancer. The data was subjected to various statistical techniques such as correlation, ANOVA, canonical and discriminant analysis to measure the extent of the correlations between the two sets of variables and their relative strength to detect blood clotting abnormalities. The results indicate that, although there is a strong relationship between the thrombelastographic variables and these common laboratory tests, the thrombelastographic variables contain additional information on the hemostatic process.

SummaryWe simultaneously evaluated platelet and fibrinolytic parameters to assess their individual and combined contributions to postoperative blood loss in cardiopulmonary (CP) bypass patients. Platelet count, platelet aggregability, hematocrit, plasminogen (PLG) concentration, alpha2-antiplasmin (AP) concentration, free protease activity (fPA), and antithrombin-III (AT-III) were measured in nine patients undergoing surgery using cardiopulmonary bypass. Chest tube drainage was used as the measure of postoperative blood loss. Hematocrit, platelet count, PT .G , AP and AT-TTT all decreased during CP bypass, with PLG and AT-III decreasing much more than dilution. During CP bypass, platelet aggregability to A DP did not change significantly from pre-bypass, but aggregability to arachidonic acid (AA) decreased significantly. Following protamine administration there was a large increase (83%) in fPA, the platelet count showed a further drop (from 61 % to 50% of pre-bypass levels) . and platelet aggregability decreased significantly (from 95% to 34% of prebypass levels for ADP, and from 55% to 11.9% for A A). Chest tube drainage during the first four postoperative hours correlated positively (p <0.05) with the combination of increase in free protease activity and decrease in platelet count. The total chest tube drainage correlated significantly with the combination of decrease in platelet count and the decrease in platelet aggregability. These combinations of changes correlated significantly with postoperative blood loss whereas the individual changes did not. These data indicate that during the early postoperative period the increased fibrinolytic activity and the decreased platelet count together contribute toward postoperative blood loss in CP bypass patients, and that during the entire first 24 hour period postoperatively the decreased platelet number and decreased platelet function are important contributors to blood loss.

Seventy-seven surgical patients, high risk for D.V.T., were randomized and stratified using 17 risk factors; 39 patients were assigned long leg elastic hose (TED) and 38 patients long leg sequential pneumatic compression devices (SCD). The TED or SCD were placed on the patient immediately following the anesthesia and continued for at least 72 hours postoperatively. Doppler, impedance, and 125I-fibrinogen scans were done daily and venography performed if these screening tests indicated thrombosis. Daily coagulation and fibrinolytic studies were done on all patients. Abdominal surgical patients were 65% of the group, 13% were orthopedic, 10% neurosurgical, and 10% genitourinary. Screening tests were positive in 7 (9.1%) patients, but only 3 (3.9%) of the seven had positive venograms. 5.3% of TED patients (2/39) developed nonfatal DVT. One TED patient developed nonfatal pulmonary embolus (2.5%). One SCD patient (2.6%) had both nonfatal DVT and pulmonary embolus. Statistically significant increase in fibrinolytic activity was only seen in the orthopedic-neurologic SCD group. An additional 88 patients not randomized for this protocol were studied. These patients had fibrinogen scans and contrast venography if the scans were positive. 60 (68%) had TED hose; 15 (17%) were controls, and 13 (14.7%) had SCD. In all, 60% were orthopedic patients; 25% were abdominal surgery, and 15% were miscellaneous. 8 TED patients (13.3%) developed calf vein thrombosis of which 2 had clots extending proximally and one death occurred 3 days postoperatively from myocardial infarction. One SCD patient developed nonfatal pulmonary emboli (7.6%) while 4/15 of control patients (26.6%) developed calf vein thrombosis. These studies suggest that SCD and TED are both effective thrombosis prophylaxis methods compared to the control group. Subgroup differences in fibrinolytic activity may reflect pathologic problems, length of immobilization, method of leg compression, etc.