Hematological and hemostaseological alterations after warm and cold limb ischemia-reperfusion in a canine model / Alterações hematológicas e hemostaseológicas após isquemia-reperfusão morna e fria de membro inferior em modelo canino

PURPOSE: Acute ischemia-reperfusion (I/R) of extremities means serious challenge in the clinical practice. Furthermore, the issue of preventive cooling is still controversial. In this canine model we investigated whether limb I/R -with or without cooling- has an influence on hematological and hemostaseological factors. METHODS: Femoral vessels were exposed and clamped for 3 hours. After release the clamps, 4-hour reperfusion was secured. The same procedures with cooling using ice bags, as well as warm and cold sham-operations were performed. Before operations, from the excluded limb by the end of ischemia, during the reperfusion, and for 5 postoperative days afterwards blood samples were collected for testing hematological and blood coagulation parameters. RESULTS: After I/R activated partial thromboplastin time was elongated on 2nd-4th postoperative days. The highest values were on the 2nd day in cold I/R group, accompanied by increased prothrombin time values. The hematological parameters and fibrinogen level showed non-specific changes. In excluded ischemic limb the blood composition showed controversial data. Cold ischemia induced larger alterations, however platelet count, hematocrit changed more expressly in warm ischemia. CONCLUSION: These results indicate the risk of coagulopathy following limb I/R on early post-eventually days, which risk is higher in the case of cold I/R.

OBJETIVO: Isquemia-Reperfusão aguda (I/R) de extremidades representa um desafio sério na prática clínica. Além disso, o tema de prevenção pelo resfriamento é ainda controverso. Nesse modelo canino, investigou-se se I/R de membros -com ou sem resfriamento- tem influência nos fatores hematológicos e hemostaseológicos. MÉTODOS: Os vasos femorais foram expostos e clampeados por 3 horas. Após liberação dos clampes, foi realizada a reperfusão por 4-horas. Os mesmos procedimentos com e sem resfriamento usando bolsas de gelo, assim como operações simuladas com e sem resfriamento foram realizados. Antes das operações, do membro excluído ao final da isquemia, durante a reperfusão e por 5 dias de pós-operatório, amostras sanguíneas foram colhidas para exames hematológicos e parâmetros de coagulação. RESULTADOS: Após I/R, o tempo de tromboplastina parcial ativada foi alargado no 2º.-4º. dias de pós-operatório. Os valores mais altos foram no 2º.dia no grupo deI/R fria, acompanhada pelo aumento dos valores do tempo de protrombina. Os parâmetros hematológicos e o nível de fibrinogênio mostraram mudanças não específicas. No membro isquêmico excluído a composição sanguínea mostrou dados controversos. A isquemia fria induziu maiores alterações, entretanto, a contagem de plaquetas e o hematócrito mudaram mais expressivamente na isquemia morna. CONCLUSÃO: Estes resultados indicam risco de coagulopatia após I/R de membros nos dias mais precoces após o evento, sendo mais elevado no caso da I/R fria.

Viper bite with continuous defibrination despite adequate treatment with antivenom.

A case of envenomation due to viperine snakebite poisoning is presented. Patient showed continuous defibrination, without any other signs of poisoning, which could not be reversed with more than double the usual dose of polyvalent antivenom. This phenomenon could be due to envenomation caused by a snake, probably from Viperidae family, which is not covered by the polyvalent antivenom available in India.

Pattern of coagulopathy in viperidae snake bite

The study was carried out in the Department of Physiology, Isra University, Hyderabad. Seventy three cases of viperidae snake bite were studied to observe the pattern of coagulopathy. All had prolonged clotting time at the time of admission. Prothrombin time was increased in 56 cases, activated partial thromboplastin time was increased in 63 cases, bleeding time was normal in all cases. Platelet count was decreased in 28 cases and fibrinogen levels were decreased in 36 cases. Disseminated intravascular coagulation was found to be the predominant pattern of coagulopathy in viperidae snake bite cases

Acute renal failure in viperidae snake bite victims

This study included 10 cases of viperidae snake bite that developed acute renal failure out of 73 cases admitted to various wards of Liaquat Medical College hospital during the last two years. All these patients reported to the hospital 3-5 days after the bite. All had signs of severe envenomation with incoagulable blood and prolonged PT and APTT. All has bleeding manifestations. Blood urea and serum creatinine were increased in all patients and four were anuric. Leucocytosis and thrombocytopenia were found in 7 cases, serum bilirubin was increased in 4 cases, 4 patients required dialysis and 4 out of 10 cases expired. Bad prognostic features included severe envenomation, leucocytosis, thrombocytopenia, and necessity for dialysis. We conclude that acute renal failure is a serious complication of viperidae snake bite with high mortality rate and it necessitates early and effective treatment

Effects of prolonged poisoning by cobra venom on blood coagulation, platelets and fibrinolysis

The effects of Cobra Venom [CV] on blood coagulation, platelets and fibrinolytic system were studied in rabbits after injecting repeated doses of 0.05 MLD of the Venom. Thrombocytopenia was the earliest change to appear. It was followed by rise in serum fibrinogen degradation products and prolongation of prothrombin time, [PT] activated partial thromboplastin time [APTT] and thrombin time [TT] indicating a progressive consumption coagulapathy and activation of fibrinolysis. Red blood cell morphology was unchanged during first three weeks; whereas fragmentation appeared after fourth week and it increased in severity with further envenomations i.e., when chronic disseminated intravascular clotting was established

Thrombophilic risk factors in breast cancer patients

Activation of the coagulation system in cancer patients is a long known but still poorly understood phenomenon. To clarify the role of some thrombophilic risk factors in cancer patients, activated protein C sensitivity ratio [APC-SR], protein C activity and antithrombin III [AT III] activity, protein S activity as well as antiphospholipid activity [IgG, IgM] were assessed in 24 women with lymph node positive breast carcinoma, 12 of them had proven distant metastases and another 12 of them had no evidence of distant metastases, in addition to 20 matched healthy control subjects. From this study, there is significant decrease in APC-SR, protein C activity, protein S activity in breast cancer patients compared to control group. Also, there is a significant decrease in the same parameters in patients with metastases compared to those without metastases. The odds ratio for risk of thrombosis associated with breast cancer patients in presence of APC resistance phenotype is 3 and 95% confidence interval [C.l.] is 0.633- 16.89. From this study, we can conclude that APC-resistant phenotype is the most frequent thrombophilic risk factor in cancer breast patients. So, screening assay of APC-SR should be encouraged in cancer breast patients especially those having distant metastases, aiming to reduce the risk of thrombosis

Avaliação do dímero D (D-Di) na doença hipertensiva específica da gravidez (DHEG) / D-dimer plasma levels assessment in preeclampsia

A doença hipertensiva específica da gravidez (DHEG), na sua forma pura, caracteriza-se pelo aparecimento, em grávida normotensa, após a vigésima semana de gestaçäo, da tríade sintomática: hipertensäo, proteinúria e edema. A DHEG está associada a vasoconstriçäo generalizada, anormalidades da coagulaçäo e deposiçäo de fibrina na microcirculaçäo da placenta. A fibrina compromete a perfusäo adequada da placenta, contribuindo para a prematuridade, o baixo peso fetal e a mortalidade neonatal. Os dímeros D (D-Di) constituem os menores fragmentos dos produtos de degradaçäo da fibrina (pdf) e säo produzidos após a lise, pela plasmina, da ligaçäo cruzada da fibrina. Níveis plasmáticos aumentados de D-Di indicam tanto uma exacerbaçäo da formaçäo de fibrina como um aumento da açäo da plasmina. O presente trabalho teve por objetivo avaliar e comparar os níveis plasmáticos de D-Di, obtido por Elisa (Stago) em gestantes-controle (n = 26), gestantes com DHEG nas formas leve e moderada (n = 23) e gestantes com DHEG na forma grave (n = 20), visando a investigar a possível utilizaçäo desse marcador laboratorial para diagnóstico e/ou prognóstico da doença. As médias e os desvios padröes obtidos para os três grupos avaliados foram 1.146,6 ± 311,2; 1.060,3 ± 259,2 e 1.497,8 ± 435,3ng/ml, respectivamente. A análise estatística das médias dos resultados obtidos revelou um aumento significativo de D-Di plasmático no grupo com DHEG grave, comparando-se aos grupos com DHEG leve/moderada (p < 0,001) e grupo-controle (p < 0,01). Considerando-se os resultados obtidos, pode-se sugerir que há uma exacerbaçäo da coagulaçäo na forma grave da DHEG e que o sistema fibrinolítico está atuante buscando remover a excessiva quantidade de fibrina formada. O D-Di constitui uma potencial ferramenta para se avaliar a gravidade da doença

Hemostatic alterations in beta-thalassemia/hemoglobin E patients.

To search for evidence of coagulation activation ex vivo, the levels of human prothrombin fragment 1+2 (F1+2) were examined in 69 beta-thalassemia/Hb E patients. Levels of protein C inhibitor (PCI) and activated protein C - PCI (APC:PCI) complex were also determined in 9 of the above patients in conjunction with protein C (PC) antigen and activity, in an attempt to detect increased consumption of PC. In mean level of F1+2, there was a statistically significant difference between normal control and post-splenectomized patients (p < 0.05) but not between normal control and non-splenectomized patients (p > 0.05). The mean levels of PC activity and PC antigen in the patients were much lower than in normal controls. However, the mean levels of PCI and the mean level of APC:PCI complex in the patients were not significantly different from those in normal controls (p > 0.05). The high level of F1+2 in post-splenectomized patients found in this study agreed well with clinical and other laboratory findings. The normal level of PC inhibitor and APC:PCI complex found in this study provided no evidence of increased consumption of protein C in thalassemia patients.

Incidence and possible reasons for discordant results between positive FDP and negative D-dimer latex assays in clinical specimens

In general, FDP and D-dimer values have a correlation in clinical conditions associated with disseminated intravascular coagulation(DIC) or coagulation activation. However, there are some patients with discordant results who demonstrate elevated FDP and negative D-dimer results by latex agglutination assays. The incidence and possible reasons for the discordance between FDP and D-dimer results were investigated through simultaneous measurements (n = 763) from clinical patients with suspected DIC or coagulation activation. 24.8% (189/763) of samples with elevated FDP were negative for D-dimer assays by the latex agglutination method. Further detailed analysis on randomly-selected discordant samples (n = 41) revealed that the most common reason for the discordance was the lower sensitivity of the semiquantitative latex agglutination method for D-dimer, compared with quantitative enzyme or other latex immunoassay. The other contributing factors to the discordance were accelerated fibrinogenolysis without secondary fibrinolysis, elevated soluble fibrin monomer and rheumatoid factor.

Haemostatic abnormalities in patients with liver disease associated with viral hepatitis.

Clinical and laboratory findings were studied in 56 patients with liver disease (10 acute hepatitis, 10 fulminant hepatitis and 36 cirrhosis). Spontaneous bleeding occurred in 19 patients (8 fulminant hepatitis, 11 cirrhosis) and another 8 cirrhotic patients had variceal bleeding. There were 22 deaths (36%), 12 of these patients had spontaneous bleeding. Depletion of antithrombin III (AT III) occurred in fulminant hepatitis (mean +/- S.D. = 27 +/- 16%) and cirrhosis (49 +/- 23%) but thrombin-antithrombin III complexes (TAT) were significantly higher in the former (45 +/- 22 vs 8.6 +/- 7.0 ng/ml; p = 0.006). Within subgroups of cirrhosis (with or without spontaneous bleeding or with variceal bleeding), there were no significant differences in levels of AT III or TAT. Of all patients, those with spontaneous bleeding had persistently lower AT III levels but had variable changes of other coagulation parameters (PT, PTT, TT, FDP, fibrinogen and platelet counts). This study showed that coagulopathic consumption is an important cause of AT III deficiency in fulminant hepatitis but not in cirrhosis. Serial changes in AT III levels correlated with bleeding risk in patients with liver disease.

Pregnancy induced hypertension: changes in coagulation profile of newborns.

Coagulation parameters and platelet count were studied in 30 neonates of mothers with pregnancy induced hypertension (PIH). 30 neonates born to normotensive mothers were taken as controls. The test group was further subdivided as neonates born to mothers with gestational hypertension, pre-eclamptic toxemia and eclampsia. The values of Prothrombin Time, Partial Thromboplastin Time with Kaolin, Thrombin Time, Fibrinogen Degradation Products were significantly raised and Fibrinogen and Platelet count were reduced significantly in both term and preterm test groups as compared to controls. The derangement in coagulation parameters was more marked with increasing severity of PIH.

Acquired bleeding disorders: bleeding in obstetrics and surgery.

Hemorrhage continues to be the leading cause of maternal mortality and morbidity throughout the world. In England and Wales from 1970-87 hemorrhage, including ectopic pregnancy, was a major factor in over 40 maternal deaths. In the majority of deaths the care was substandard. In 70% of obstetric deaths from hemorrhage defective hemostasis contributes to the bleeding. Inappropriate correction of hypovolemia, failure to recognise and treat coagulation failure, and failure to control traumatic bleeding are the main causes of preventable death. In developing countries, cross matched blood and blood products may not be readily available. Surgical intervention should be preceded or accompanied by correction of the hemostatic defect with fresh frozen plasma and if necessary platelet concentrates. Teamwork with experienced staff is the essence of successful management of severe hemorrhage in obstetrics and surgery. A protocol should be agreed between medical nursing and laboratory staff for dealing with massive blood loss.