Comparing modified Lee and White method against 20-minute whole blood clotting test as bedside coagulation screening test in snake envenomation victims

Abstract Background: Twenty-minute whole blood clotting test (20WBCT) and Modified Lee and White (MLW) method are the most routinely employed bedside tests for detecting coagulopathic snake envenomation. Our study compared the diagnostic utility of MLW and 20WBCT for snakebite victims at a tertiary care hospital in Central Kerala, South India. Methods: This single-center study recruited 267 patients admitted with snake bites. 20WBCT and MLW were performed simultaneously at admission along with the measurement of Prothrombin Time (PT). The diagnostic utility of 20WBCT and MLW was determined by comparing the sensitivity (Sn), specificity (Sp), positive and negative predictive values, likelihood ratios, and accuracy at admission with an INR value > 1.4. Results: Out of 267 patients, 20 (7.5%) patients had VICC. Amongst those who had venom-induced consumption coagulopathy (VICC), MLW was prolonged for 17 patients, (Sn 85% 95% confidence interval [CI]: 61.1-96.0) whereas 20WBCT was abnormal for 11 patients (Sn 55%, 95% CI: 32.04-76.17). MLW and 20WBCT were falsely positive for the same patient (Sp 99.6%, 95% CI: 97.4-99.9%). Conclusion: MLW is more sensitive than 20WBCT to detect coagulopathy at the bedside amongst snakebite victims. However, further studies are necessary for standardizing bedside coagulation tests in snakebite cases.

Delayed double reading of whole blood clotting test (WBCT) results at 20 and 30 minutes enhances diagnosis and treatment of viper evenomation

The whole blood clotting test (WBCT) is a simple test of coagulation that is often used in the assessment, diagnosis, and therapeutic monitoring of snakebite patients in sub-Saharan Africa. WBCT requires only a clean glass tube and several milliliters of venous blood and is ideal for use in poorly equipped health centers throughout the rural areas where 95% of snakebites occur. However, questions surrounding the accuracy and reliability of the test remain unanswered due to variations in testing conditions and a lack of comparative research with which to validate them. This is the first study to evaluate WBCT results at both 20-min (WBCT20) and 30-min (WBCT30) reading times in the same group of snakebite patients. Methods In order to define the best reading time, the authors compared the results of serial WBCT evaluation at both 20 and 30 min after collection in 23 patients treated for snake envenomation in Bembèrèkè, northern Benin. Results WBCT results were identical at both reading times in patients without coagulopathy or when coagulation was restored permanently following a single dose of antivenom. Out of 17 patients with coagulopathy, 14 showed discrepancies between WBCT20 and WBCT30 results in at least one pair of serial evaluations. These could be completely contradictory results (e.g. normal clot at WBCT20 and no clot at WBCT30) or a marked difference in the quality of the clot (e.g. no clotting activity at WBCT20 and an unstable partial clot at WBCT30). WBCT discrepancies were encountered most frequently in three situations: initial normalization of hemostasis following antivenom therapy, detection of a secondary resumption of coagulopathy, or final restoration of hemostasis after a secondary resumption had occurred. Conclusions This study suggests that the WBCT is robust and that a sequential reading should improve the diagnosis and monitoring of venom-induced coagulopathies. It also indicates the possibility of discrepancies in the sensitivity of WBCT20 and WBCT30 for detecting the resolution or reoccurrence of coagulopathy and identifies how these findings, if confirmed, may be used to increase the efficacy and efficiency of antivenom treatment in the field.(AU)

Delayed double reading of whole blood clotting test (WBCT) results at 20 and 30 minutes enhances diagnosis and treatment of viper evenomation

The whole blood clotting test (WBCT) is a simple test of coagulation that is often used in the assessment, diagnosis, and therapeutic monitoring of snakebite patients in sub-Saharan Africa. WBCT requires only a clean glass tube and several milliliters of venous blood and is ideal for use in poorly equipped health centers throughout the rural areas where 95% of snakebites occur. However, questions surrounding the accuracy and reliability of the test remain unanswered due to variations in testing conditions and a lack of comparative research with which to validate them. This is the first study to evaluate WBCT results at both 20-min (WBCT20) and 30-min (WBCT30) reading times in the same group of snakebite patients. Methods In order to define the best reading time, the authors compared the results of serial WBCT evaluation at both 20 and 30 min after collection in 23 patients treated for snake envenomation in Bembèrèkè, northern Benin. Results WBCT results were identical at both reading times in patients without coagulopathy or when coagulation was restored permanently following a single dose of antivenom. Out of 17 patients with coagulopathy, 14 showed discrepancies between WBCT20 and WBCT30 results in at least one pair of serial evaluations. These could be completely contradictory results (e.g. normal clot at WBCT20 and no clot at WBCT30) or a marked difference in the quality of the clot (e.g. no clotting activity at WBCT20 and an unstable partial clot at WBCT30)...

Accidente ofídico en pacientes del Hospital Básico de Jipijapa (Manabí-Ecuador) / Snake accident in patients of the Basic Hospital of Jipijapa (Manabí-Ecuador)

Introducción: el accidente ofídico es el cuadro clínico producido por la mordedura de una serpiente venenosa. En el Ecuador se describen 41 especies de serpientes venenosas. Objetivo: caracterizar clínica y epidemiológicamente el accidente ofídico en pacientes del Hospital Básico de Jipijapa (Manabí-Ecuador). Método: se realizó un estudio observacional retrospectivo durante enero 2008 - abril 2012, a partir de las historias clínicas de los pacientes hospitalizados con diagnóstico de accidente ofídico o mordedura de serpiente en el Servicio de Medicina Interna del Hospital Básico de Jipijapa (Manabí-Ecuador). Resultados: del total de 78 pacientes, 61 (78,2%) recibieron suero antiofídico (SAO) y 17 pacientes (21,8%) no recibieron. No se encontró relación entre los días de hospitalización y el hecho de haber o no recibido SAO (p= 0,8), ni tampoco entre la prueba de coagulación positiva o negativa con el tiempo de hospitalización (p= 0,7). Se encontró una correlación baja entre la variable prueba de coagulación y el grado de mordedura, siendo estadísticamente significativo (p= 0,04). Se observó incremento de mordeduras en ciertos meses, en relación con los hábitos migratorios y reproductivos de las serpientes. Conclusiones: existió dificultad en la aplicación de protocolos de atención para accidente ofídico y si bien esto no repercutió en la morbilidad y mortalidad, puede afectar en la optimización de los recursos disponibles.

Introduction: ophidian accident is the clinical picture caused by the bite of a venomous snake. Forty one species of poisonous snakes are described in Ecuador Objective: to describe clinically and epidemiologically the ophidian accident in patients of the Basic Hospital of Jipijapa (Manabí-Ecuador). Methods: a retrospective observational, descriptive study, based on medical records of hospitalized patients with a diagnosis of snake bite in Internal Medicine Basic Hospital, Jipijapa (Manabí-Ecuador) during January 2008 - April 2012 was done. Results: of the total 78 patients, 61 (78.2%) received antivenin and 17 patients (21.8%) did not receive. There was no relationship between days of hospitalization and the fact of having or not received antivenin, p=Ns (0.8) nor between test positive or negative coagulation time found hospitalization p=Ns (0.7). A low correlation was found between the coagulation test variable and the degree of bite, being statistically significant (p = 0.04). An increase of bites in certain months, in relation to the migratory and reproductive habits of the snakes was observed. Conclusions: there was difficulty in applying protocols of care for ophidian accidents and although this did not affect morbidity and mortality, it can affect the optimization of available resources.