USE OF 20 MINUTE WHOLE BLOOD CLOTTING TIME IN PATIENTS OF SNAKEBITE; AN EXPERIENCE FROM KOHAT, KHYBER PAKHTUNKHAH

Objective: To study the diagnostic accuracy of 20-minute whole blood clotting time in hemotoxic snakebite. Study Design: Cross sectional validation study. Place and Duration of Study: Combined Military Hospital Kohat Pakistan, from Jul 2015 to Jun 2017. Methodology: Study included 52 patients who presented with the complaint of a snakebite. The data was recorded on predesigned proforma including clinical, laboratory features. All the patients were kept indoor for observation for a minimum of 72 hours from the time of presentation. Results: The study showed that males were more affected with age group between 20-50 years. Most common presenting features were local swelling 33 (71%) and pain and most common snakebite type was hemotoxic 33 (71%). The 20-minute whole blood clotting time was found to have low sensitivity (61%) and specificity (58%). A significant association was found between the dose of anti-snake venom and severity of coagulopathy (p<0.001), respiratory failure (p<0.001) and development of side effects due to anti snake venom (p<0.001). The mortality rate was 6.5% and was significantly related to age of the victims (p=0.003). The diagnostic accuracy of 20-minute whole blood clotting time was 60.25%. Conclusion: The use of 20-minute whole blood clotting time can not only be misleading but also a source of delay in administering anti snake venom given the low sensitivity and specificity and high false negative rate.

The Effect of Wheatgrass Lyophilizate on Blood Clotting Time in Rats

Wheatgrass is widely used in the alternative medicine, however, there is a lack of clinical evidence to support its efficacy. Although based on its chemical composition, data from animal experiments and clinical trials, the use of juice and extracts of Triticum shoots seems to be safe, clinical reports point out its potential interaction with oral anticoagulants. The aim of our study was to assess the interaction of wheatgrass with warfarin in rats and to assess its flavonoid content. Three groups of animals were treated orally with wheatgrass, warfarin, or the combination of wheatgrass and warfarin for five days. Clotting assays were performed using platelet-poor plasma. Prothrombin time was determined by optical and mechanical coagulometers. Flavonoid content of wheatgrass was measured by HPLC. The effect of wheatgrass on prothrombin time was not confirmed. Co-administration of wheatgrass and warfarin did not result in diminished anticoagulant activity. Low amount of flavonoids was detected in wheatgrass juice, the total flavonoid content was 0.467 mg/100 g lyophilized juice powder. The previously reported rutin, quercetin and apigenin was not detected by us. Our results do not confirm the probability of interaction of wheatgrass with oral anticoagulants. However, the low flavonoid content of wheatgrass does not support its use as an antioxidant.

On the question of functional diagnostics of the liver by Ѵidalа

In 1920, Vidal (1) proposed a functional liver test, substantiated by the following experimental data: if a dog takes blood from v. portae in the midst of digestion and inject it into the systemic circulation, the dog reacts to the introduction of blood by a drop in the number of leukocytes and blood pressure, a change in blood clotting time, a decrease in the refractometric index and a change in the leukocyte formula.

Snake extract–laden hemostatic bioadhesive gel cross-linked by visible light

Bioadhesives reduce operation time and surgical complications. However, in the presence of blood, adhesion strength is often compromised. Inspired by the blood clotting activity of snake venom, we report a visible light–induced blood-resistant hemostatic adhesive (HAD) containing gelatin methacryloyl and reptilase, which is a hemocoagulase (HC) extracted from Bothrops atrox. HAD leads to the activation and aggregation of platelets and efficiently transforms fibrinogen into fibrin to achieve rapid hemostasis and seal the tissue. Blood clotting time with HAD was about 45 s compared with 5 to 6 min without HAD. HAD instantaneously achieved hemostasis on liver incision (~45 s) and cut rat tail (~34 s) and reduced blood loss by 79 and 78%, respectively. HAD is also efficient in sealing severely injured liver and abdominal aorta. HAD has great potential to bridge injured tissues by combing hemostasis with adhesives.

Evolving Paradigm of Prothrombin Time Diagnostics with Its Growing Clinical Relevance towards Cardio-Compromised and COVID-19 Affected Population

Prothrombin time (PT) is a significant coagulation (hemostasis) biomarker used to diagnose several thromboembolic and hemorrhagic complications based on its direct correlation with the physiological blood clotting time. Among the entire set of PT dependents, candidates with cardiovascular ailments are the major set of the population requiring lifelong anticoagulation therapy and supervised PT administration. Additionally, the increasing incidence of COVID affected by complications in coagulation dynamics has been strikingly evident. Prolonged PT along with sepsis-induced coagulopathy (SIC score > 3) has been found to be very common in critical COVID or CAC-affected cases. Considering the growing significance of an efficient point-of-care PT assaying platform to counter the increasing fatalities associated with cardio-compromised and coagulation aberrations propping up from CAC cases, the following review discusses the evolution of lab-based PT to point of care (PoC) PT assays. Recent advances in the field of PoC PT devices utilizing optics, acoustics, and mechanical and electrochemical methods in microsensors to detect blood coagulation are further elaborated. Thus, the following review holistically aims to motivate the future PT assay designers/researchers by detailing the relevance of PT and associated protocols for cardio compromised and COVID affected along with the intricacies of previously engineered PoC PT diagnostics.

Design of a Randomized, Controlled Study to Evaluate Reversal of Anticoagulation of Ciraparantag in Healthy Adults: Whole Blood Clotting Time Assessed By Automated and Manual Methods

There is a need for safe and effective reversal agents for patients on chronic anticoagulant therapy in cases such as serious or life-threatening bleeding, urgent or emergency surgery, after major trauma, or in cases of anticoagulant overdose. Ciraparantag, an anticoagulant reversal agent in clinical development, which is believed to bind directly to anticoagulant molecules through non-covalent bonds, with no binding to blood coagulation factors or proteins in the blood. Phase 2 clinical studies have shown that ciraparantag reverses anticoagulation in healthy volunteers treated with edoxaban, enoxaparin, apixaban, or rivaroxaban as assessed by manual whole blood clotting time (WBCT). WBCT is the key pharmacodynamic marker because ciraparantag is cationic and binds to the anionic substances in standard blood collection tubes, and to anionic, colloidal activators used in the traditional coagulation assays such as PT or aPTT. Therefore, such assays are not appropriate markers for measuring ciraparantag's effect. WBCT is a direct measure of the time required for blood clot formation ex vivo and uses blood drawn into reagent-free collection equipment, using only glass as the activating agent. A Phase 2b clinical study is planned to evaluate the efficacy and safety of ciraparantag for reversal of anticoagulation as measured by WBCT using an automated point-of-care (PoC) coagulometer (developed by Perosphere Technologies, Inc.) compared with a manual testing method. This is a randomized, double-blind, placebo-controlled study in healthy adults 18 to 75 years of age who are anticoagulated with apixaban (10 mg PO twice daily) or rivaroxaban (20 mg PO once daily). Subjects who reach steady-state anticoagulation will be stratified into 2 age groups and randomized 2:1 to receive a single IV dose of ciraparantag or placebo, followed by serial WBCT testing and standard safety assessments over 24 hours. The primary efficacy endpoint is based on the extent and timing of reversal of anticoagulation following ciraparantag administration as compared with placebo, based on WBCT measured using the PoC coagulometer. Manual WBCT testing also will be performed at selected timepoints in order to describe the correlation between results obtained with the two methods. The coagulometer is expected to provide greater sensitivity and precision compared to the manual method. Further details of the design of this study will be provided. The results of this study will inform dose selection for the future Phase 3 clinical trial and will provide data on the use of the PoC coagulometer for assessment of ciraparantag for reversal of anticoagulation. Disclosures Villano: Amag Pharmaceuticals, Inc.: Consultancy. Bakhru:Pherosphere Technologies, Inc.: Current Employment. Luo:Amag Pharmaceuticals, Inc.: Current Employment. Freedman:Amag Pharmaceuticals, Inc.: Current Employment. OffLabel Disclosure: Ciraparantag is an investigational drug being evaluated for the reversal of anticoagulation induced by direct oral anticoagulant (DOAC) therapies.

Bedside Coagulation Tests in Diagnosing Venom-Induced Consumption Coagulopathy in Snakebite

Venom-induced consumption coagulopathy is the most important systemic effect of snake envenoming. Coagulation tests are helpful to accurately and promptly diagnose venom-induced consumption coagulopathy and administer antivenom, which is the only specific treatment available. However, bedside clotting tests play a major role in diagnosing coagulopathy in low-income settings, where the majority of snakebites occur. We conducted a literature search in MEDLINE® from 1946 to 30 November 2019, looking for research articles describing clinical studies on bedside coagulation tests in snakebite patients. Out of 442 articles identified, 147 articles describing bedside clotting assays were included in the review. Three main bedside clotting tests were identified, namely the Lee–White clotting test, 20-min whole blood clotting time and venous clotting time. Although the original Lee–White clotting test has never been validated for snake envenoming, a recently validated version has been used in some South American countries. The 20-min whole blood clotting time test is the most commonly used test in a wide range of settings and for taxonomically diverse snake species. Venous clotting time is almost exclusively used in Thailand. Many validation studies have methodological limitations, including small sample size, lack of case-authentication, the inclusion of a heterogeneous mix of snakebites and inappropriate uses of gold standard tests. The observation times for bedside clotting tests were arbitrary, without proper scientific justification. Future research needs to focus on improving the existing 20-min whole blood clotting test, and also on looking for alternative bedside coagulation tests which are cheap, reliable and quicker.

Influence of anemia on the perioperative blood loss during total hip arthroplasty in patients with end-stage renal disease

The OBJECTIVE was to determine the effect of anemia on the volume of blood loss during total hip arthroplasty in patients with end-stage renal disease. MATERIAL AND METHODS. The study was based on the data of 41 patients with pathology of hip joint who underwent primary hip replacement. In the group 1 – the group of comparison (n=20), there was no correction of anemia. In the group 2 – the main group (n=21), erythropoietin was applied 2 months before the operation, until the blood hemoglobin level exceeded 100 g/l, hematocrit – more than 30 %. RESULTS. In the first group of patients, there was the severe anemia: hemoglobin – (88.6±4.6) g/l, the number of red blood cells – (2.7±0.3·1012)/l, hematocrit – (27±2) %. In the second group, 2 months after using erythropoietin, hemoglobin level was (114.9±7.1) g/l, red blood cell count was (3.6±0.4·1012)/l, hematocrit was (33±2) %. Blood coagulation time before operation was (15.1±2.4) min in the first group, (8.7±1.8) min in the second group. Statistically significant difference was noted in blood loss: 59.2 %. In the first group, red blood cell mass transfusion was required in the volume of (554±205) ml for 18 patients (26 doses), plasma – in the volume of (641±67) ml for 20 patients (40 doses). In the second group, blood transfusion was performed for 3 patients in the volume of (321±116) ml. An inverse correlation between blood hematocrit, blood clotting time and blood loss was noted. The correlation coefficient was 0.9. CONCLUSION. The inverse correlation was indicated between the level of hematocrit, blood clotting time and blood loss. The use of erythropoietin in advance of reaching a blood hematocrit of >30 % could significantly reduce the risk of bleeding, reduce the amount of operating blood loss and reduce complications in the postoperative period.