An Evidence-­Based Tool for V.T.E. Observation

Venous thromboembolism is a significant cause of preventable harm; it is the most common cause of preventable death in hospitalized patients, and more than half of all venous thromboembolic events are hospital-acquired.(1-8) VTE is thought to be preventable in up to 65 percent of cases, and providing VTE prophylaxis to at-risk patients improves patient safety.(9-14) Patients at risk of VTE however are inconsistently prescribed appropriate prophylaxis.(15-19) The Centers for Medicare and Medicaid Services has deemed VTE a “never event” — an occurrence that should never happen in the inpatient setting.(20)

The “Two-Midnight Rule,” coupled with other pressures in health policy to reduce avoidable inpatient admissions, has led to greater frequency and duration of observation service use in recent years.(21,22) The management of patients requiring OS in dedicated observation units is a best practice; patients managed in OUs traditionally had a length of stay of 24 hours, with approximately 20 percent requiring admission to inpatient status for ongoing care.(23,24) With the advent of CMS’s “Two-Midnight Rule,” a time-based guideline intended to determine appropriateness for inpatient status, length of observation stay might now reach up to 48 hours before patients qualify for inpatient status.(25)

Because patients receiving observation care generally are classified as outpatients and are often ambulatory, there is a paucity of literature describing an evidence-based approach for VTE prophylaxis in this population.(26) But, patients lying in hospital beds accrue the same risk of VTE during their hospitalization regardless of their administrative classification (e.g., observation versus inpatient). Therefore, VTE risk might be under-recognized in observation patients overall, and especially in observation patients converted to inpatient status if VTE prophylaxis is not initiated at the onset of hospitalization. But neither did we want to over-administer prophylaxis, which also has been demonstrated in previous studies.(27)

The objective of this report is to describe the impact on patient risk stratification for VTE resulting from the use of a novel VTE risk stratification and management guideline for patients receiving observation care.

Methods

• Study setting and population: The facility, the identity of which has been suppressed here for purposes of blinding, is an urban, tertiary care academic medical center. Its observation unit is a geographically dedicated, ED-run OU, delivering evidence-based, protocol-driven care with a dedicated, multidisciplinary team of physicians, physician assistants, nurses, care managers and social workers. Placement into the OU results from a collaborative decision made by emergency department and OU providers and care managers.
  Data for this study was drawn from all patients dispositioned to the OU at the facility from the period of May 1, 2015, through Oct. 13, 2016. The guidelines were implemented on Oct. 13, 2015. The data were stratified into pre- and post-intervention periods accordingly (pre-VTE risk stratification tool period of May 1-Oct. 12, 2015; post-VTE risk stratification tool period of April 13-Oct. 13, 2016). The authors determined the post-intervention period should exclude the first six months immediately following implementation to account for the “time investment” barrier to knowledge uptake.(28) Thus, the post-intervention period used for comparison was designated as six months after the implementation date, when the electronic medical record officially was updated and the education process began.

• Study design: This manuscript represents a descriptive study of the implementation of a novel, evidence-based risk stratification tool for the prophylaxis of venous thromboembolic disease patients in a single site, dedicated, protocol-driven ED OU. The conduct of this study was approved by the facility’s institutional review board, in the Office of Science and Research. A waiver of consent and authorization was granted for this study.

• Needs assessment: Before the intervention, OU providers were surveyed regarding their practices in VTE risk assessment and management. The authors concluded no standard approach to VTE risk stratification was in use for this population. OU providers did not have access to evidence-based VTE prophylaxis guidelines specific to OU patients that could be used at the point of clinical decision-making. In addition, the EMR offered no decision support to OU providers regarding VTE prophylaxis.

• Intervention: To develop a novel VTE risk stratification and management guideline, the authors conducted a literature review (including PubMed, Web of Science and Google Scholar), searching for existing models of VTE risk stratification in other observation clinical models, using combinations of the search terms “venous thromboembolism,” “prophylaxis,” and “observation unit.” This search yielded no relevant results. The authors then reviewed existing evidence-based guidelines for VTE risk assessment and management used by other departments within the facility’s system and, on the basis of a review of the literature and the consensus expertise from emergency medicine, internal medicine, surgery, neurology, ob/gyn and orthopedic surgery, identified clinical risk factors for development of VTE that when present, warranted implementation of VTE prophylaxis.(29-34) The guideline was then assembled with input from content-matter experts from emergency medicine, internal medicine, surgery, cardiology and neurology services (see Figure 1).

Figure 1. VTE risk stratification and management guidelines

The VTE risk stratification and management guidelines help providers determine if prophylaxis is necessary, and, if so, whether chemoprophylaxis or mechanical prophylaxis is indicated. The guidelines include both absolute contraindications, indicating a patient should never receive chemoprophylaxis, and relative contraindications, indicating factors that should be taken into consideration before deciding to administer chemoprophylaxis.

The VTE prophylaxis protocol was introduced to clinicians, incorporating the risk-stratification and management guidelines and streamlining the ordering process. Clinicians were introduced to the VTE prophylaxis protocol through monthly departmental meetings, weekly electronic communications, and daily provider-specific emails. All communications included the guidelines for reference, and daily provider-specific emails informed providers if and how they deviated from the guidelines. Risk stratification for VTE was introduced at the beginning of the ordering process for every patient presenting to the observation unit, and patients that were and were not at risk for VTE were variably assessed for prophylaxis.

To facilitate compliance, the EMR (Epic Version 2014 IU1CP39BL44, Epic Systems Corp., Madison, Wisconsin) was enhanced by the institution’s clinical information technology department with clinical decision support to include a text prompt in the history and physical documentation, a visual prompt in the order set, and an “interruption” alert requiring providers to screen for VTE prophylaxis. EMR OU arrival order sets were streamlined to cue providers to review the need for VTE prophylaxis for new patients. Real-time audits were completed at the beginning of the change strategy, and real-time feedback was given to providers on a case-by-case basis. Appropriate VTE prophylaxis was monitored electronically and reported in regular intervals to the clinical leadership team.

• Analysis: A random sample of patient encounters occurring before and after implementation of the VTE prophylaxis guidelines was reviewed to compare the VTE prophylaxis strategy to nonstandardized clinical judgment. One hundred charts from the pre-intervention period and 100 charts from the post-intervention period were randomly selected by use of an automated, web-based randomization service (random.org).(35) Charts from the pre-intervention period were analyzed to determine if the patient received prophylaxis during the visit, indicating the patient was determined as at risk for developing VTE by the use of nonstandardized clinical judgment.

These encounters were then analyzed to determine if these same patients would be stratified as at risk for VTE using the VTE prophylaxis guidelines, to determine if the guideline-based strategy identified additional patients as at risk for VTE. Encounters in the post-intervention period were examined to determine if patients were at risk for VTE using the risk stratification and management guideline, and then analyzed to determine if patients were appropriately risk-stratified, indicating compliance with the guidelines.

In both the pre- and the post-intervention period, patients were considered appropriately risk-stratified if they were determined as at risk for VTE by the guidelines and received the appropriate prophylaxis, or if they were considered as not at risk by the guidelines and did not receive prophylaxis. Patients were considered as not appropriately risk-stratified if they were considered as at risk by the guidelines and did not receive the appropriate prophylaxis, or if they were considered as not at risk by the guidelines and received prophylaxis. Three OU providers independently performed the chart review analysis. Charts were divided among reviewers and all reviewers used the same method for chart analysis (see Figure 2).

Figure 2. Guideline for determination of appropriate prophylaxis

Reviewers then separately reviewed patient charts in accordance with the risk stratification and management guidelines. Patients who received chemoprophylaxis (including heparin and warfarin), mechanical prophylaxis (sequential compression device), those already receiving systemic anticoagulation, and those with orders specifically stating “ambulate patient three times daily” were considered as receiving VTE prophylaxis. Patients lacking these criteria were considered as not receiving VTE prophylaxis.

VTE and iatrogenic bleeding events occurring in the hospital were monitored through regular surveillance of twice-daily shift reports, specific clinical case reviews, and institutional patient safety databases (such as United Hospital Consortium Patient Safety Intelligence software).

We did not track VTE events that occur after patient discharge.

A chi-squared test with a significance level of a = 0.05 was used to perform the power analysis for this study. Statistical analysis for this study was performed in R (version 3.5.1), a free software environment for statistical computing and graphics.

Results

Demographic characteristics of the study population, OU volume, and rate of patient conversion to inpatient status are presented in Table 1. The top 10 OU clinical protocols for all patients in the study period are presented in Table 2.

In the pre-intervention period, 44 of the 100 patients were determined as at risk of VTE by the guidelines and 21 of such patients received the appropriate prophylaxis. Fifty-six patients were determined as not at risk of VTE by the guidelines and appropriately did not receive prophylaxis, resulting in an appropriate risk-stratification rate of 77 percent. In the post-intervention period, 45 patients were determined as at risk by the guidelines and 37 such patients received the appropriate prophylaxis.

Fifty-five patients were determined to not be at risk of VTE by the guidelines, and one of these patients received prophylaxis, leading to an appropriate risk stratification rate of 91 percent and an increase of 14 percent in appropriate risk stratification overall. Findings suggest that the intervention was effective in appropriately categorizing and treating patients at-risk of VTE (p-value equals 0.002875, power equals 0.874686). The observed difference between pre- and post-intervention suggests that only 0.29 percent of that difference was because of chance.

The comparison of appropriate risk stratification rates can be found in Table 3. A breakdown of types of prophylaxis distributed to patients can be found in Table 4.

In the pre-intervention period, the VTE prophylaxis guidelines identified twice as many patients at risk for VTE as were determined by nonstandardized clinical judgment.

No adverse patient outcomes related to bleeding or development of VTE in patients receiving VTE prophylaxis per the VTE guidelines occurred.

Discussion

The development and implementation of a standardized VTE risk management guideline for patients receiving observation care led to an increase in the identification and prophylaxis of patients determined to be at risk for VTE. We successfully transitioned from a nonstandardized approach to VTE prophylaxis in patients receiving OU care to the consistent use of evidence-based guidelines designed to cover a broader range of scenarios, as encountered in an observation unit, than do inpatient guidelines. We experienced no pushback from providers while implementing our guidelines, and many providers noted that they appreciated having access to a more clearly delineated approach to risk stratification and prophylaxis.

Reducing the incidence of VTE presents an opportunity for enormous savings across the health care system. A 2011 review estimated the average annual cost of a deep vein thrombosis to be $19,692 a patient and the average annual cost of a pulmonary embolism to be $37,185 a patient when combining the estimated cost of treatment and costs incurred from lost productivity.(36) The same study estimated the annual national costs incurred by preventable cases of DVT and PE to be as high as $4.3 billion and $9.9 billion, respectively.(37)

The continually expanding evidence base supporting the use of dedicated, protocol-driven OUs as the best practice model for short-term hospitalization, coupled with increasing pressures to reduce avoidable inpatient admissions, suggests that current trends in OS use should be expected.(22,37) Traditional “inpatient” quality measures, such as VTE prophylaxis, will need to be further validated for their risk/benefit profile for patients treated in an OU care model.

Our work has several limitations. Individual chart reviews for each patient would have been excessively onerous, so we used random sampling instead. We recorded only VTE events that occurred during the hospital stay and were unable to measure any potential longer-term impacts on patients following their discharge from the hospital. However, no patients who were managed using this tool developed VTE or developed iatrogenic bleeding during their hospital stays. We operated under the expectation that all OU patients were assessed for need of VTE prophylaxis regardless of their anticipated length of stay. Patients who were discharged in less than 24 hours but received pharmacologic VTE prophylaxis may have been exposed to unnecessary risks associated with prophylaxis (such as bleeding). However, we have not experienced any adverse outcome related to prophylaxis administration related to our guidelines.

Conclusion

This work demonstrates that risk stratification and management guidelines for VTE prophylaxis in a dedicated emergency department observation unit can be implemented safely and in accordance with evidence-based guidelines. Further work is necessary to determine if VTE prophylaxis actually prevents VTE events in observation patients.

References

1. Shojania KG, Duncan BW, McDonald KM, et al. Making health care safer: a critical analysis of patient safety practices. Evid Rep Technol Assess 2001;43: i-x, 1-668.

2. Heit JA, O’Fallon WM, Petterson TM, et al. Relative impact of risk factors for deep vein thrombosis and pulmonary embolism: a population-based study. Arch Intern Med 2002; 162(11):1245-8.

3. Anderson FA, Jr., Zayaruzny M, Heit JA, et al. Estimated annual numbers of US acute-care hospital patients at risk for venous thromboembolism. Am J Hematol 2007;82(9): 777-82.

4. Heit JA, on behalf of the VTE Impact Assessment Group. Estimated annual number of incident and recurrent, non-fatal and fatal venous thromboembolism (VTE) events in the US. Blood (ASH Annual Meeting Abstracts) 2005; 106: Abstract 910.

5. Cohen AT, Agnelli G, Anderson FA, et al. Venous thromboembolism (VTE) in Europe. The number of VTE events and associated morbidity and mortality. Thromb Haemost 2007;98(4):756-64.

6. Spencer FA, Emery C, Lessard D, et al. The Worcester Venous Thromboembolism study: a population-based study of the clinical epidemiology of venous thromboembolism. J Gen Intern Med 2006;21(7):722-7.

7. Spencer FA, Lessard D, Emery C, et al. Venous thromboembolism in the outpatient setting. Arch Intern Med 2007;167(14):1471-5.

8. Goldhaber SZ, Tapson VF. A prospective registry of 5,451 patients with ultrasound-confirmed deep vein thrombosis. Am J Cardiol 2004;93(2):259-62.

9. Geerts WH, Bergqvist D, Pineo GF, et al. Prevention of venous thromboembolism: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest 2008;133(Suppl 6):381S-453S.

10. Collins R, Scrimgeour A, Yusuf S, Peto R. Reduction in fatal pulmonary embolism and venous thrombosis by perioperative administration of subcutaneous heparin. Overview of results of randomized trials in general, orthopedic, and urologic surgery. N Engl J Med 1988;318(18):1162-73.

11. Mismetti P, Laporte S, Darmon JY, et al. Meta-analysis of low molecular weight heparin in the prevention of venous thromboembolism in general surgery. Br J Surg 2001;88(7):913-30.

12. Arnold DM, Kahn SR, Shrier I. Missed opportunities for prevention of venous thromboembolism: an evaluation of the use of thromboprophylaxis guidelines. Chest 2001;120(6):1964-71.

13. Shackford SR, Rogers FB, Terrien CM, et al. 10-year analysis of venous thromboembolism on the surgical service: the effect of practice guidelines for prophylaxis. Surgery 2008;144(1):3-11.

14. Goldhaber SZ. Venous thromboembolism risk among hospitalized patients: magnitude of the risk is staggering. Am J Hematol. 2007;82(9):775-6.

15. Tapson VF, Deconusus H, Pini M, et al. Venous thromboembolism prophylaxis in acutely ill hospitalized medical patients: findings from the International Medical Prevention Registry on Venous Thromboembolism. Chest. 2007;132(3):936-45.

16. Cohen AT, Tapson VF, Bergmann JF, Goldhaber SZ, Kakkar AK, Deslandes B, et al. Venous thromboembolism risk and prophylaxis in the acute hospital care setting (ENDORSE study): a multinational cross-sectional study. Lancet. 2008;371(9610):387-94.

17. Yu H, Dylan ML, Lin J, Dubois RW. Hospitals compliance with prophylaxis guidelines for venous thromboembolism. Am J Health Syst Pharm 2007;64(1):69-76.

18. Rothberg MB, Lahti M, Pekow PS, Lindenauer PK. Venous thromboembolism prophylaxis among medical patients at US hospitals. J. Gen. Intern. Med. 2010;25(6):489-94

19. Dentali F, Douketis JD, Gianni M, et al. Meta-analysis: anticoagulant prophylaxis to prevent symptomatic venous thromboembolism in hospitalized medical patients. Ann Intern Med. 2007;146(4):278-88.

20. Centers for Medicare & Medicaid Services. Medicare and Medicaid move aggressively to encourage greater patient safety in hospitals and reduce never events. 2008. [Accessed August 27, 2008]. Available at: https://www.cms.gov/newsroom/press-releases/medicare-and-medicaid-move-aggressively-encourage-greater-patient-safety-hospitals-and-reduce-never .

21. Feng Z, Wright B, Mor V. Sharp rise in Medicare enrollees being held in hospitals for observation raises concerns about causes and consequences. Health Aff. 2012;31(6):1251-9

22. Hockenberry JM, Mutter R, Barret M, et al. Factors associated with prolonged observation services stays and the impact of long stays on patient cost. Health Serv Res 2014;49(3):893-909.

23. ACEP College of Medical Directors. Emergency Department Observation Services. October 2015. www.acep.org/patient-care/policy-statements/emergency-department-observation-services/#sm.0001hzpumjcukdcswpn1fkk1cpfc8 . Accessed Jan. 20, 2018.

24. Ross MA, Hockenberry JM, Mutter R, et al. Protocol driven emergency department observation units offer savings, shorter stays, and reduced admissions. Health Aff 2013:32(12):2149-56.

25. Center for Medicare & Medicaid Services. Fact sheet: two midnight rule. Available at https://www.cms.gov/newsroom/fact-sheets/fact-sheet-two-midnight-rule-0 .

26. Sattler S, Baugh C. Venous thromboembolism prophylaxis in ED observation units-Is it time? Am. J. Emerg. Med. 2016;34(1):2238-40.

27. Grant PJ, Conlon A, Chopra V, et al. Use of venous thromboembolism prophylaxis in hospitalized patients. JAMA Intern Med. 2018 178(8):1122-4. doi: 0.1001/jamainternmed.2018.2022. DOI: 10.1001/jamainternmed.2018.2022

28. Lang E, Wyer P, Haynes R. Knowledge translation: closing the evidence-to-practice gap. Ann Emerg Med. 2007;49(3):355-63.Epub2006Nov3.DOI: 10.1016/j.annemergmed.2006.08.022

29. American Congress of Obstetricians and Gynecologists. Maternal Safety Bundle for Venous Thromboembolism. Safe Motherhood Initiative. Nov. 2015. Available at: https://www.acog.org/-/media/Districts/District-II/Public/SMI/v2/VTESlideSetNov2015Update052317.pdf?dmc=1&ts=20170620T0835529890

30. Balk EM, Ellis AG, Di M, et al. Venous thromboembolism prophylaxis in major orthopedic surgery: systematic review update. Rockville (MD): Agency for Healthcare Research and Quality (US); 2017 Jun. Comparative Effectiveness Reviews, No. 191. Available from: https://www.ncbi.nlm.nih.gov/books/NBK476632/ .

31. O’Donnell M, Weitz JI. Thromboprophylaxis in surgical patients. Canadian Journal of Surgery. 2003;46(2):129-35.

32. Bajenaru O, Antochi F, Balasa R., et al. Assessment of venous thromboembolism prophylaxis in neurological patients with restricted mobility –VTE- NEURO Study. Maedica. 2014;9(1):6-14.

33. Mejilla A, Guirguis M, Koshman S, Bungard TJ. Venous thromboembolism prophylaxis on general internal medicine units: are patients well served by current practice? The Canadian Journal of Hospital Pharmacy. 2017;70(3):200-6.

34. Levine RL, Hergenroeder GW, Miller CC, Davies A. Venous thromboembolism prophylaxis in emergency department admissions. J Hosp Med. 2007;2(2):79-85 DOI: 10.1002/jhm.171

35. Haahr M. Random.org:True Random Number Service. 1998. Accessed April 26, 2018. Available at: www.random.org .

36. Mahan CE, Borrego ME, Woersching AL, et al. Venous thromboembolism: annualised United States models for total, hospital acquired and preventable costs utilizing long-term attack rates. Thromb Haemost. 2012:108(2):291-302.

37. Ross MA, Aurora T, Graff L, et al. State of the art: emergency department observation units. Crit Pathw Cardiol. 2012;11(3):128-38.