Evidence-based paramedic models of care to reduce unnecessary emergency department attendance--feasibility and safety

Machine learning based prediction models for analyzing risk factors in patients with acute abdominal pain: a retrospective study

Background

Acute abdominal pain (AAP) is a common symptom presented in the emergency department (ED), and it is crucial to have objective and accurate triage. This study aims to develop a machine learning-based prediction model for AAP triage. The goal is to identify triage indicators for critically ill patients and ensure the prompt availability of diagnostic and treatment resources.

Methods

In this study, we conducted a retrospective analysis of the medical records of patients admitted to the ED of Wuhan Puren Hospital with acute abdominal pain in 2019. To identify high-risk factors, univariate and multivariate logistic regression analyses were used with thirty-one predictor variables. Evaluation of eight machine learning triage prediction models was conducted using both test and validation cohorts to optimize the AAP triage prediction model.

Results

Eleven clinical indicators with statistical significance (p < 0.05) were identified, and they were found to be associated with the severity of acute abdominal pain. Among the eight machine learning models constructed from the training and test cohorts, the model based on the artificial neural network (ANN) demonstrated the best performance, achieving an accuracy of 0.9792 and an area under the curve (AUC) of 0.9972. Further optimization results indicate that the AUC value of the ANN model could reach 0.9832 by incorporating only seven variables: history of diabetes, history of stroke, pulse, blood pressure, pale appearance, bowel sounds, and location of the pain.

Conclusion

The ANN model is the most effective in predicting the triage of AAP. Furthermore, when only seven variables are considered, including history of diabetes, etc., the model still shows good predictive performance. This is helpful for the rapid clinical triage of AAP patients and the allocation of medical resources.

The paramedic-general practitioner relationship: a scoping review

BACKGROUND

Health services internationally are implementing programs that increase working ties between paramedics and general practitioners (GPs) to reduce unnecessary transport to emergency departments (EDs) and improve access to primary health care. As paramedic involvement in primary health care develops, there is increasing focus on the GP-paramedic collaborative relationship. Resulting issues regarding professional boundaries may occur, as paramedics practice in fields that were previously solely in the GP scope. An effective paramedic-GP working relationship will be an essential foundation to the success of future strategies.

METHODS

A search of three electronic databases was completed (Ovid MEDLINE, Embase Classic+ Embase and CINAHL Plus). Eligibility for inclusion required analysis of the relationship between paramedics and GPs. All processes were completed by two independent reviewers.

RESULTS

After removal of duplicates, 4995 titles were screened by title and/or abstract. After full-text review, 15 studies were included. Five themes were identified that contribute significantly to the strengths and weaknesses of the relationship - the importance of communication, understanding scope of practice, leadership roles, responsibility for patient care and interdisciplinary training. Issues identified included significant variation in the structure of different emergency medical services and varying standards of education requirements for paramedics worldwide.

CONCLUSIONS

There were no published Australian studies that had the primary aim of examining the paramedic-GP relationship. The depth of research on this topic is lacking, despite increased interest over the past decade. The relevance of the international literature to the Australian setting is questionable.

Emergency medical services: the next linking asset for public health approaches to palliative care?

Emergency medical services (EMS) are a unique workforce providing 24/7 emergency care across high-income countries (HICs) and low- and middle-income countries (LMICs). Although traditionally perceived as first responders to traumatic and medical emergencies, EMS scope of practice has evolved to respond to the changing needs of communities, including a growing demand for community-based palliative care. Public health provides a useful framework to conceptualise palliative and end-of-life care in community-based settings. However, countries lack public policy frameworks recognising the role EMS can play in initiating palliative approaches in the community, facilitating goals of care at end of life and transporting patients to preferred care settings. This article aims to explore the potential role of EMS in a public health palliative care approach in a critical discussion essay format by (1) discussing the utility of EMS within a public health palliative care approach, (2) identifying the current barriers preventing public health approaches to EMS palliative care provision and (3) outlining a way forward through priorities for future research, policy, education and practice. EMS facilitate equitable access, early provision, expert care and efficacious integration of community-based palliative care. However, numerous structural, cultural and practice barriers exist, appearing ubiquitous across both HICs and LMICs. A Public Health Palliative Care approach to EMS Framework highlights the opportunity for EMS to work as a linking asset to build capacity and capability to support palliative care in place; connect patients to health and community supports; integrate alternative pathways by engaging multidisciplinary teams of care; and reduce avoidable hospital admissions by facilitating home-based deaths. This article articulates a public health approach to EMS palliative and end-of-life care provision and offers a preliminary framework to illustrate the components of a potential implementation and policy strategy.

Quality Frameworks for Virtual Care: Expert Panel Recommendations

Given the significant advance of virtual care in the past year and half, it seems timely to focus on quality frameworks and how they have evolved collaboratively across health care organizations. Massachusetts General Hospital's (MGH) Center for TeleHealth and Mass General Brigham's (MGB) Virtual Care Program are committed to hosting annual symposia on key topics related to virtual care. Subject matter experts across the country, health care organizations, and academic medical centers are invited to participate. The inaugural MGH/MGB Virtual Care Symposium, which focused on rethinking curriculum, competency, and culture in the virtual care era, was held on September 2, 2020. The second MGH/MGB Virtual Care Symposium was held on November 2, 2021, and focused on virtual care quality frameworks. Resultant topics were (1) guiding principles necessary for the future of virtual care measurement; (2) best practices deployed to measure quality of virtual care and how they compare and align with in-person frameworks; (3) evolution of quality frameworks over time; (4) how increased adoption of virtual care has impacted patient access and experience and how it has been measured; (5) the pitfalls and barriers which have been encountered by organizations in developing virtual care quality frameworks; and (6) examples of how quality frameworks have been applied in various use cases. Common elements of a quality framework for virtual care programs among symposium participants included improving the patient and provider experience, a focus on achieving health equity, monitoring success rates and uptime of the technical elements of virtual care, financial stewardship, and clinical outcomes. Virtual care represents an evolution in the access to care paradigm that helps keep health care aligned with other modern industries in digital technology and systems adoption. With advances in health care delivery models, it is vitally important that the quality measurement systems be adapted to include virtual care encounters. New methods may be necessary for asynchronous transactions, but synchronous virtual visits and consults can likely be accommodated in traditional quality frameworks with minimal adjustments. Ultimately, quality frameworks for health care will adapt to hybrid in-person and virtual care practices.

Emergency Medical Services Demand: An Analysis of County-Level Social Determinants

OBJECTIVES

Variations in the demand for Emergency Medical Services (EMS) exist when observed at a local level. This unspecified heterogeneity leads to an investigation of social factors contributing to EMS demand.

METHODS

Data for this study were collected from publicly available EMS reports from Florida and Oklahoma for 2009 - 2015. Health and social data were gathered from County health rankings and roadmap reports. Data were combined into a single dataset, and pooled ordinary-least-squares models with time-fixed effects were utilized for tests of inference. EMS call volume was log-transformed to derive a semi-elasticity function.

RESULTS

A total of 874 county-year observations were analyzed. Increases in poor/fair health (95% CI: 0.6% - 3.9%), binge drinking (95% CI: 1.6% - 3.5%), teen birth rate (95% CI: 1.1% - 5.2%), unemployment rate (95% CI: 0.5% - 3.9%), and violent crime rate (95% CI: 1.0% - 3.0%) were associated with an increase in the EMS demand rate.

CONCLUSION

The data supports the notion that some community measures have an effect on EMS demand as counties with higher levels of poor health, binge drinking, teen births, unemployment, and violent crime saw higher EMS demand. These factors may have been treated as spurious, or overlooked by policy makers and EMS leadership.

Residential aged care residents and components of end of life care in an Australian hospital

Background

With ageing of Australians, the numbers of residential aged care (RAC) residents is rising. This places a spotlight on decisions about appropriate care for this population, including hospitalisation and end-of-life (EOL) care. The aim was to study a sample of RAC residents who attended and died in hospital, to quantify measurable components of EOL care so as to describe the extent of palliative care required.

Methods

A retrospective case-note review of hospital records was conducted in Adelaide, Australia. Participants were 109 RAC residents who attended from July 2013 to June 2014 and died in hospital.

Measurements were advance care planning, health care input from the RAC facilities to hospital and components of EOL care. Residents with and without advanced dementia were compared.

Results

Advance care directives (ACDs) were present from 11 to 50%, and advance care plans (ACPs) at 60%. There were more ACPs, resuscitation orders (for/against) and do-not-hospitalise orders in residents with advanced dementia than those without. General practitioner (GP) and extended care paramedic (ECP) input on decisions for hospital transfer were 30% and 1 %. Mean hospital stay to death was 5.2 days. For residents admitted under non-palliative care teams, specialist palliative care (SPC) was needed for phone advice in 5%, consultation in 45%, transfer to palliative care unit in 37%, and takeover by SPC team in 19%. Mean number of documented goals-of-care discussions with family/caregiver was 1.7. In the last 3 days of life, the mean daily number of doses of EOL medications was 4.2. Continuous subcutaneous infusion was commenced in 35%.

Conclusion

Staff in RAC need to be adequately resourced to make complex decisions about whether to transfer to hospital. RAC nurses are mainly making these decisions as GP and ECP input were suboptimal. Ways to support nurses and optimise decision-making are needed. Advance care planning can be improved, especially documentation of EOL wishes and hospitalisation orders.

By describing the components of EOL care, it is hoped providers and policy makers have more information to assist with making decisions about what is the most appropriate care for this population.

Paramedic literature search filters: optimised for clinicians and academics

Background

Search filters aid clinicians and academics to accurately locate literature. Despite this, there is no search filter or Medical Subject Headings (MeSH) term pertaining to paramedics. Therefore, the aim of this study was to create two filters to meet to different needs of paramedic clinicians and academics.

Methods

We created a gold standard from a reference set, which we measured against single terms and search filters. The words and phrases used stemmed from selective exclusion of terms from the previously published Prehospital Search Filter 2.0 as well as a Delphi session with an expert panel of paramedic researchers. Independent authors deemed articles paramedic-relevant or not following an agreed definition. We measured sensitivity, specificity, accuracy and number needed to read (NNR).

Results

We located 2102 articles of which 431 (20.5%) related to paramedics. The performance of single terms was on average of high specificity (97.1% (Standard Deviation 7.4%), but of poor sensitivity (12.0%, SD 18.7%). The NNR ranged from 1 to 8.6. The sensitivity-maximising search filter yielded 98.4% sensitivity, with a specificity of 74.3% and a NNR of 2. The specificity-maximising filter achieved 88.3% in specificity, which only lowered the sensitivity to 94.7%, and thus a NNR of 1.48.

Conclusions

We have created the first two paramedic specific search filters, one optimised for sensitivity and one optimised for specificity. The sensitivity-maximising search filter yielded 98.4% sensitivity, and a NNR of 2. The specificity-maximising filter achieved 88.3% in specificity, which only lowered the sensitivity to 94.7%, and a NNR of 1.48. A paramedic MeSH term is needed.

Electronic supplementary material

The online version of this article (10.1186/s12911-017-0544-z) contains supplementary material, which is available to authorized users.

The Event Chain of Survival in the Context of Music Festivals: A Framework for Improving Outcomes at Major Planned Events

Despite the best efforts of event producers and on-site medical teams, there are sometimes serious illnesses, life-threatening injuries, and fatalities related to music festival attendance. Producers, clinicians, and researchers are actively seeking ways to reduce the mortality and morbidity associated with these events. After analyzing the available literature on music festival health and safety, several major themes emerged. Principally, stakeholder groups planning in isolation from one another (ie, in silos) create fragmentation, gaps, and overlap in plans for major planned events (MPEs).

The authors hypothesized that one approach to minimizing this fragmentation may be to create a framework to “connect the dots,” or join together the many silos of professionals responsible for safety, security, health, and emergency planning at MPEs. Adapted from the well-established literature regarding the management of cardiac arrests, both in and out of hospital, the “chain of survival” concept is applied to the disparate groups providing services that support event safety in the context of music festivals. The authors propose this framework for describing, understanding, coordinating and planning around the integration of safety, security, health, and emergency service for events. The adapted Event Chain of Survival contains six interdependent links, including: (1) event producers; (2) police and security; (3) festival health; (4) on-site medical services; (5) ambulance services; and (6) off-site medical services.

The authors argue that adapting and applying this framework in the context of MPEs in general, and music festivals specifically, has the potential to break down the current disconnected approach to event safety, security, health, and emergency planning. It offers a means of shifting the focus from a purely reactive stance to a more proactive, collaborative, and integrated approach. Improving health outcomes for music festival attendees, reducing gaps in planning, promoting consistency, and improving efficiency by reducing duplication of services will ultimately require coordination and collaboration from the beginning of event production to post-event reporting.

LundA, TurrisSA. The Event Chain of Survival in the context of music festivals: a framework for improving outcomes at major planned events. Prehosp Disaster Med. 2017;32(4):437–443.

Telehealth-Enabled Emergency Medical Services Program Reduces Ambulance Transport to Urban Emergency Departments

INTRODUCTION

Emergency medical services (EMS) agencies transport a significant majority of patients with low acuity and non-emergent conditions to local emergency departments (ED), affecting the entire emergency care system's capacity and performance. Opportunities exist for alternative models that integrate technology, telehealth, and more appropriately aligned patient navigation. While a limited number of programs have evolved recently, no empirical evidence exists for their efficacy. This research describes the development and comparative effectiveness of one large urban program.

METHODS

The Houston Fire Department initiated the Emergency Telehealth and Navigation (ETHAN) program in 2014. ETHAN combines telehealth, social services, and alternative transportation to navigate primary care-related patients away from the ED where possible. Using a case-control study design, we describe the program and compare differences in effectiveness measures relative to the control group.

RESULTS

During the first 12 months, 5,570 patients participated in the telehealth-enabled program, which were compared against the same size control group. We found a 56% absolute reduction in ambulance transports to the ED with the intervention compared to the control group (18% vs. 74%, P<.001). EMS productivity (median time from EMS notification to unit back in service) was 44 minutes faster for the ETHAN group (39 vs. 83 minutes, median). There were no statistically significant differences in mortality or patient satisfaction.

CONCLUSION

We found that mobile technology-driven delivery models are effective at reducing unnecessary ED ambulance transports and increasing EMS unit productivity. This provides support for broader EMS mobile integrated health programs in other regions.

Which patients should be transported to the emergency department? A perpetual prehospital dilemma

OBJECTIVE

To examine the ability of paramedics to identify patients who could be managed in the community and to identify predictors that could be used to accurately identify patients who should be transported to EDs.

METHODS

Lower acuity patients who were assessed by paramedics in the Perth metropolitan area in 2013 were studied. Paramedics prospectively indicated on the patient care record if they considered that the patient could be treated in the community. The paramedic decisions were compared with actual disposition from the ED (discharge and admission), and the occurrence of subsequent events (ambulance request, ED visit, admission and death) for discharged patients at the scene was investigated. Decision tree analysis was used to identify predictors that were associated with hospital admission.

RESULTS

In total, 57 183 patients were transported to the ED, and 10 204 patients were discharged at the scene by paramedics. Paramedics identified 2717 patients who could potentially be treated in the community among those who were transported to the ED. Of these, 1455 patients (53.6%) were admitted to hospital. For patients discharged at the scene, those who were indicated as suitable for community care were more likely to experience subsequent events than those who were not. The decision tree found that two predictors (age and aetiology) were associated with hospital admission. Overall discriminative power of the decision tree was poor; the area under the receiver operating characteristic curve was 0.686.

CONCLUSION

Lower acuity patients who could be treated in the community were not accurately identified by paramedics. This process requires further evaluation.

A prediction model to identify patients without a concerning intraabdominal diagnosis

OBJECTIVE

Patients with abdominal diagnoses constitute 5% to 10% of all emergency department (ED) presentations. The goal of this study is to identify which of these patients will have a nonconcerning diagnosis based on demographic, physical examination, and basic laboratory testing.

METHODS

Consecutive patients from July 2013 to March 2014 discharged with a gastrointestinal (GI) diagnosis who presented to an urban, university-affiliated ED were identified. The cohort was split into a derivation set and a validation set. Using univariate and multivariable logistic regression analysis, a risk score was created based on the deviation data and then tested on the validation data.

RESULTS

There were 8852 patients with a GI diagnosis during the study period. A total of 7747 (87.5%) of them had a nonconcerning diagnosis. The logistic regression model identified 13 variables that predict a concerning GI diagnosis and created a scoring system ranging from 0 to 20. The area under the receiver operating characteristic was 0.81. When dichotomized at greater than or equal to 7 vs less than 7, the risk score has a sensitivity of 91% (95% confidence interval [CI], 88-94), specificity of 46% (95% CI, 44-48), positive predictive value of 17% (95% CI, 15-19) and negative predictive value of 98% (95% CI, 97-99).

CONCLUSION

One can determine with a high degree of certainty, based only on an initial evaluation and screening laboratory work (excluding radiology) whether a patient who presents with a GI-related complaint has a nonconcerning diagnosis. This model could be used as a tool to aid in quality assurance when reviewing patients discharged with GI complaints and with future study, as a secondary triage instrument in a crowded ED environment, and aid in resource allocation.

Paramedic Checklists do not Accurately Identify Post-ictal or Hypoglycaemic Patients Suitable for Discharge at the Scene

OBJECTIVES

The objective of this study was to assess the accuracy and safety of two pre-defined checklists to identify prehospital post-ictal or hypoglycemic patients who could be discharged at the scene.

METHODS

A retrospective cohort study of lower acuity, adult patients attended by paramedics in 2013, and who were either post-ictal or hypoglycemic, was conducted. Two self-care pathway assessment checklists (one each for post-ictal and hypoglycemia) designed as clinical decision tools for paramedics to identify patients suitable for discharge at the scene were used. The intention of the checklists was to provide paramedics with justification to not transport a patient if all checklist criteria were met. Actual patient destination (emergency department [ED] or discharge at the scene) and subsequent events (eg, ambulance requests) were compared between patients who did and did not fulfill the checklists. The performance of the checklists against the destination determined by paramedics was also assessed.

RESULTS

Totals of 629 post-ictal and 609 hypoglycemic patients were identified. Of these, 91 (14.5%) and 37 (6.1%) patients fulfilled the respective checklist. Among those who fulfilled the checklist, 25 (27.5%) post-ictal and 18 (48.6%) hypoglycemic patients were discharged at the scene, and 21 (23.1%) and seven (18.9%) were admitted to hospital after ED assessment. Amongst post-ictal patients, those fulfilling the checklist had more subsequent ambulance requests (P=.01) and ED attendances with seizure-related conditions (P=.04) within three days than those who did not. Amongst hypoglycemic patients, there were no significant differences in subsequent events between those who did and did not meet the criteria. Paramedics discharged five times more hypoglycemic patients at the scene than the checklist predicted with no significant differences in the rate of subsequent events. Four deaths (0.66%) occurred within seven days in the hypoglycemic cohort, and none of them were attributed directly to hypoglycemia.

CONCLUSIONS

The checklists did not accurately identify patients suitable for discharge at the scene within the Emergency Medical Service. Patients who fulfilled the post-ictal checklist made more subsequent health care service requests within three days than those who did not. Both checklists showed similar occurrence of subsequent events to paramedics' decision, but the hypoglycemia checklist identified fewer patients who could be discharged at the scene than paramedics actually discharged. Reliance on these checklists may increase transportations to ED and delay initiation of appropriate treatment at a hospital. Tohira H , Fatovich D , Williams TA , Bremner A , Arendts G , Rogers IR , Celenza A , Mountain D , Cameron P , Sprivulis P , Ahern T , Finn J . Paramedic checklists do not accurately identify post-ictal or hypoglycaemic patients suitable for discharge at the scene. Prehosp Disaster Med. 2016;31(3):282-293.

Acute abdominal pain in the emergency department of a university hospital in Italy

BACKGROUND

Acute abdominal pain (AAP) is one of the most common causes of referral to an emergency department (ED), but information about its impact is limited.

OBJECTIVES

The objectives of this article are to define the prevalence of AAP among ED visits in a large university hospital and analyze its main clinical features.

METHODS

All patients admitted at the Sant'Orsola, Malpighi University Hospital of Bologna ED on 12 a priori selected sample days in 2013 were included. General data were recorded for each patient. A total of 192 clinical variables were recorded for each patient with abdominal pain.

RESULTS

During the observation period the ED assisted 2623 patients with a daily admission rate of 219 ± 20 (mean ± SD). Of these, 239 patients complained of AAP as their chief complaint at entry (prevalence = 9.1%). AAP prevalence was significantly higher in females than in males (10.4% vs. 7.8%; OR = 1.37; p = 0.021) as well as in foreign over Italian patients (13.2% vs. 8.5%; OR = 1.64; p = 0.007). The most frequent ED operative diagnoses were non-specific abdominal pain (n = 86, 36.0%) and gastrointestinal (GI) tract-related pain (n = 79, 33.1%; n = 19 upper GI, n = 60 lower GI).

CONCLUSIONS

AAP is a common cause of referral at EDs. Despite technological advances, non-specific abdominal pain is still the main operative diagnosis.

Abdominal Computed Tomography Utilization and 30-day Revisitation in Emergency Department Patients Presenting With Abdominal Pain

OBJECTIVES

The objective was to explore which patient characteristics are associated with repeat emergency department (ED) visitation within 30 days of ED discharge for patients presenting with abdominal pain.

METHODS

A retrospective, observational study was conducted at a single, academic, urban ED with over 85,000 annual visits. A consecutive sample of adult patients with a chief complaint of abdominal pain from January 2010 through December 2010 who were discharged following ED evaluation were included in the analysis. A logistic regression model was used to determine which patient-level factors, including computed tomography (CT) utilization, were associated with the primary outcome of ED revisit within 30 days.

RESULTS

Of 80,619 total ED patient visits during the study period, 3,928 ED discharges with a chief complaint of abdominal pain were included. A total of 487 (12.4%) patients revisited the ED within 30 days. No deaths were recorded. CT imaging was associated with a lower 30-day revisit rate (odds ratio [OR] = 0.69, 95% confidence interval [CI] = 0.55 to 0.87) after controlling for multiple other patient-level factors associated with revisits. Increasing age (OR = 1.01, 95% CI = 1.00 to 1.02), increasing triage pain scores (OR = 1.13, 95% CI = 1.08 to 1.18), elevated triage heart rate (OR = 1.42, 95% CI = 1.07 to 1.89), low sodium levels (OR = 1.56, 95% CI = 1.07 to 2.23), and anemia (OR = 1.42, 95% CI = 1.04 to 1.95) were all associated with increased rate of return.

CONCLUSIONS

Performance of an abdominal CT was associated with fewer 30-day revisits, suggesting that future measures of "imaging appropriateness" and "ED overuse" consider downstream utilization of health care resources in addition to the index visit.

Relationship between intubation rate and continuous positive airway pressure therapy in the prehospital setting

BACKGROUND

To determine whether the prehospital use of continuous positive airway pressure (CPAP) therapy is associated with a reduced rate of endotracheal intubation in patients with an acute respiratory disorder brought to the emergency department (ED).

METHODS

We reviewed medical records of patients with acute respiratory distress who had been treated with CPAP in the Mobile Intensive Care Unit (MICU) from January 2010 to December 2011. These records were compared with those of patients who received standardized care without CPAP in the MICU from January 2004 to December 2004. Categorical variables were summarized as frequencies and compared between groups using Fisher's exact test or the Chi-square test. Continuous variables were summarized as medians (interquartile range), and comparison between the groups was made using Wilcoxon's rank-sum test. The relationship between CPAP and intubation rate was determined using multivariable logistic regression analysis of propensity scores. The results were presented as odds ratio (OR), 95% confidence interval (CI), and P value for test effect. The adequacy of the model was calibrated using Hosmer and Lemeshow's goodness-of-fit test. P<0.05 was considered statistically significant.

RESULTS

The records of 785 patients were reviewed. Of the 215 patients treated with CPAP in the MICU, 13% were intubated after admission. In contrast, of the 570 patients who did not receive CPAP, 28% were intubated after ED admission. Unadjusted logistic regression analysis showed that patients who had been treated with CPAP were less likely to be intubated than those without CPAP treatment (OR=0.37, 95%CI, 0.24-0.57, P<0.0001). With propensity scores adjusted, multivariate logistic regression analysis showed that CPAP treatment was associated with a 62% reduction of intubation (OR=0.384, 95%CI, 0.25-0.60, P<0.0001).

CONCLUSIONS

In patients with acute respiratory disorder, there was a relationship between CPAP therapy and the decreased intubation rate. CPAP therapy was feasible in prehospital management of patients with respiratory distress.

Blood coagulation induced by Iranian saw-scaled viper (echis carinatus) venom: identification, purification and characterization of a prothrombin activator

OBJECTIVE(S)

Echis carinatus is one of the venomous snakes in Iran. The venom of Iranian Echis carinatus is a rich source of protein with various factors affecting the plasma protein and blood coagulation factor. Some of these proteins exhibit types of enzymatic activities. However, other items are proteins with no enzymatic activity.

MATERIALS AND METHODS

In order to study the mechanism and effect of the venom on human plasma proteins, the present study has evaluated the effect of crude venom and all fractions. A procoagulant factor (prothrombin activator) was isolated from the venom of the Iranian snake Echis carinatus with a combination of gel filtration (Sephadex G-75), ion-exchange chromatography (DEAE- Sepharose) and reverse phase HPLC. Furthermore, proteolytic activity of the crude venom and all fractions on blood coagulation factors such as prothrombin time (PT) was studied.

RESULTS

In the present study, the PT test was reduced from 13.4 s to 8.6 s when human plasma was treated with crude venom (concentraion of venom was 1 mg/ml). The purified procoagulant factor revealed a single protein band in SDS polyacrylamide electrophoresis under reducing conditions and its molecular weight was estimated at about 65 kDa. A single-band protein showed fragment patterns similar to those generated by the group A prothrombin activators, which convert prothrombin into meizothrombin independent of the prothrombinase complex.

CONCLUSION

This study showed that the fraction which separated from Iranian snake Echis carinatus venom can be a prothrombin activators. It can be concluded that this fraction is a procoagulant factor.