Alain J. Marengo-Rowe

The Treatment of Postperfusion Bleeding Using ε-Aminocaproic Acid, Cryoprecipitate, Fresh-Frozen Plasma, and Protamine Sulfate

Abstract The evaluation of excessive hemorrhage was carried out in 774 patients after cardiopulmonary bypass. Excessive hemorrhage was defined in any adult patient as chest tube drainage of more than 600 ml within the first eight hours after operation. Using the prothrombin time, partial thromboplastin time, fibrinogen level, and tri-F titer tests, it was possible to differentiate medical from surgical bleeding. Hyperfibrinolytic bleeding was the most frequently identifiable coagulation disorder and occurred in 159 patients (20%). All these patients were successfully treated with Amicar (e-aminocaproic acid) alone, or with Amicar supplemented with cryoprecipitate or fresh-frozen plasma. Three patients (0.4%) were noted to have residual heparin and required additional protamine sulfate. Five patients (0.6%) had normal coagulation studies and required immediate reexploration. The overall blood consumption per patient was 2.1 units of packed cells. Whole blood and platelets were not used.

Preliminary studies of photoinactivation of human immunodeficiency virus in blood

The transmission of human immunodeficiency virus (HIV) by blood or blood components is a major concern in blood banking. A photodynamic flow cell system was designed to inactivate cell‐free HIV mixed with blood from a healthy donor. Blood containing 4 × 103 infectious units of HIV was treated with 10 and 20 μg per mL of commercially available dihematoporphyrin ether (DHE) per mL. Aliquots of this mixture were then held in the dark or irradiated in a flow cell illuminated at a light energy density of 5 J per cm2 provided by a xenon light source equipped with a 630 ± 5 nm band‐pass interference filter; the aliquots were subsequently placed in A.301 cells. All infected cultures were assessed for reverse transcriptase (RT) activity for 17 days. RT activity for either concentration of dye was significantly reduced in irradiated samples as compared to that in samples held in the dark. Blood samples from volunteers also were assessed for the effects of the inactivation process on red cells at concentrations of DHE up to 200 micrograms per mL. No effects were observed on red cell 2,3 DPG or ATP, whole blood potassium concentrations, red cell osmotic fragility, or blood cell antigens.

The Evaluation of Hemorrhage in Cardiac Patients Who have Undergone Extracorporeal Circulation

The present study defines excessive bleeding in patients who undergo cardiopulmonary bypass, and evaluates the use of coagulation testing to predict those patients that bleed excessively. Evaluation of 774 consecutive patients undergoing aortocoronary bypass surgery was carried out. Cardiopulmonary bypass consisted of a bloodless prime and a Harvey bubble oxygenator. In the postoperative period, excessive hemorrhage was denned as that exceeding 600 ml chest tube drainage in the first eight hours. One hundred and sixty‐three patients (21%) were noted to be in this category. Excessive bleeding postoperatively was best predicted by a PTT greater than 45 seconds, a PT greater than 19 seconds, a fibrinogen level less than 225 mg/dl and a TFT equal to or less than 1:32. These laboratory findings occur singly or in combination. The assessment of platelet, numbers or function and fibrin(ogen) split products were of no prognostic value. Using these criteria, the re‐exploration rate for excessive hemorrhage and/or tamponade was 0.6 per cent (5 out of 774 patients). No preoperative laboratory test of hemostatic function was useful in predicting coagulopathies resulting from cardiopulmonary bypass.

Hematologic and coagulation studies on cotton rats, Sigmodon hispidus

1. Blood coagulation factor levels and the normal ranges of commonly used coagulation tests were established for Sigmodon hispidus. 2. The white cell, red cell and platelet counts have been determined together with the red cell parameters as measured by the Coulter model S-plus. 3. The relationship between the results reported here and those published for related species are discussed.

The Tri-F Titer: A Rapid Test for Estimation of Plasma Fibrinogen and Detection of Fibrinolysis, Fibrin(ogen) Split Products, and Heparin

Abstract The use of extracorporeal circulation has been associated with operative and postoperative hemorrhage. In patients on the pump there are a number of different pathogenetic mechanisms that lead to hemorrhagic disorders. In essence the hemorrhagic diathesis is caused by the increased utilization or destruction of hemostatic factors, the presence of circulating anticoagulants, a reduction in hemostatic factors due to underproduction or dilution by transfused banked blood, or all three. The tri-F titer (TFT) is a new rapid and reproducible test that gives an estimate of the fibrinogen concentration and detects the presence of fibrinolysis, fibrin(ogen) split products, and circulating heparin. The use of the TFT in the diagnosis of various coagulopathies is discussed. The TFT, which depends on the formation and observation of clots in vitro, is considered to have distinct advantages over other tests which rely on immunological, solubility, and other physicochemical phenomena.

Blood Chemical Changes in Cotton Rats, Sigmodon hispidus, Infected with Parastrongylus costaricensis (Nematoda: Angiostrongyloidea)

Abstract. Serum analytes of adult laboratory-raised cotton rats, Sigmodon hispidus, infected with Parastrongylus costaricensis were compared with those of ageand sexmatched control animals. Parasitism produced significant longand short-term changes in some analytes. Long-term changes included reductions in levels of sodium, chloride, creatinine, triglycerides, and calcium as well as elevation of lactate dehydrogenase (LDH) levels that occurred during the first 32 days of the infection. Short-term changes were correlated to specific developmental stages of the life cycle of the parasite. Thus, immediately after infection (when the third-stage larvae occur in mesenteric lymph nodes and vessels), an increase occurred in the levels of bilirubin, globulins, and proteins. As young juvenile worms matured in the mesenteric vasculature, globulin levels had a tendency to rise, and the elevation became significant at day 16. Egg laying was accompanied by decreases in levels of alkaline phosphatase (AP) and alanine aminotransferase (ALT). Hatching of eggs and passage of first-stage larvae through gut tissues had the most profound effect. At day 24, a dynamic decrease occurred in LDH, ALT, and aspartate aminotransferase (AST) while a downward drift in AP occurred. An electrolyte disturbance occurred in which potassium (K+ ) levels decreased (day 24) and then rebounded (day 28) while sodium (Na+) levels normalized and then declined. Changes were not observed in levels of creatinine phosphokinase (CPK), uric acid, carbon dioxide (CO2), glucose, protein, and cholesterol.

Hemostatic parameters of the blood of cotton rats, Sigmodon hispidus, infected with Parastrongylus costaricensis (Metastrongyloidea: Angiostrongylidae)

The hemostatic parameters of adult male cotton rats infected with 20-25 third-stage larvae of Parastrongylus costaricensis were compared with those of ageand sex-matched control animals. The normal range for whole blood clotting times was 85-140 seconds. The parasitic infection caused a decrease in these clotting times. The coagulation assays, performed on the plasma of animals infected for 30-40 days, showed decreases in factors VII, X, XI, and XII and an increase in fibrinogen. The activated partial thromboplastin time was elevated; however, the decrease in prothrombin time was not significant. These findings imply that the blood of cotton rats becomes hypercoagulable following infection, and this may be a defence mechanism facilitating repair of the vascular bed of the intestine when damaged by hatching and movement of the larvae. Adult Parastrongylus costaricensis (Morera & Cespedes, 1971) Ubelaker, 1986, a metastrongylid nematode, occur in the subserosal arteries of the cecum or in the ileocecocolic branch of the cranialmesenteric artery of the major host, a cotton rat, (Sigmodon hispidus). Occasionally, they are found in other mammals including humans (Morera & Cespedes, 1971; Tesh et al., 1973; Ubelaker, 1986). The life cycle is indirect, and cotton rats, as well as humans, become infected by ingesting molluscan intermediate hosts or vegetation containing mucus from snails contaminated with infectious third-stage larvae. The larvae then invade mesenteric lymph nodes where they undergo third and fourth molts. Eleven days following infection, the juvenile worms migrate to the adjacent mesenteric arteries and develop to sexual maturity. In the cotton rat, eggs are deposited by the female worms beginning 18 days after infection and the eggs become trapped in the capillary bed of the cecum. In normal hosts, such as cotton rats, the prepatent period is completed by the twenty-fourth day when larvae hatch from the eggs, traverse the intestinal mucosa, and exit the host in the feces. In unnatural hosts, such as humans, the larvae do not hatch and are destroyed by an intense inflammatory reaction (Morera, 1973; Tesh et al., 1973). Blood coagulation abnormalities have been found in animals infected with other parasites that occur in the blood stream. Tsang & Damian (1977) reported 1 The authors express their appreciation to Ms. J. Winford, and Ms. J. Roberts for excellent technical assistance and to Professor Richard Gunst for his interest and assistance in the statistical analysis. 2 Department of Special Hematology, Baylor University Medical Center, Dallas, Texas 75246,

Evaluation of the Bleeding Patient

The evaluation of the bleeding patient starts with the integration of data from the history and physical examination. From this results either one probable explanation that can easily be substatniated by laboratory studies or, as more commonly occurs in practice, several possibilities that are reasonable and must be investigated by more extensive laboratory tests. In either event, the initial laboratory evaluation usually includes examination of the peripheral blood and measurement of the platelet count, bleeding time, prothrombin time, partial thromboplastin time, and thrombin time. More specific laboratory tests are then performed if indicated.

Retinal Hemorrhage Associated with Thrombasthenia

A healthy 20-year-old man presented with a spontaneous unilateral retinal hemorrhage. Because of a history of easy bruisability, we obtained hematologic studies and diagnosed thrombasthenia, a hereditary hemorrhagic disorder. The association of retinal hemorrhage and thrombasthenia is rare. Thrombasthenia and other platelet functional disorders are becoming better defined as tests for these abnormalities become more reliable and available. Patients with apparent spontaneous retinal hemorrhages of unknown origin should be questioned about hemorrhagic tendencies, and the various tests for hemorrhagic disorders should be obtained. The hematologic survey should include the more sophisticated tests of platelet function. Patients with thrombasthenia should avoid aspirin intake.

Hepatitis C–A Virus for All Seasons

iver disease caused by the recently discovered hepatitis C virus (HCV) is an emerging infectious disease of growing concern. HCV is 1 of 6 identified viruses (A, B, C, D, E, and G) that together account for most cases of viral hepatitis (1, 2). First reported in the Wall Street Journal in 1988, HCV infection is a leading cause of cirrhosis and liver cancer and is now the major reason for liver transplantation in the USA.