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Case Study 1. Questions the University of California, San Diego Medical Center Encountered While Developing Its Venous Thromboembolism Protocol

Preventing Hospital-Acquired Venous Thromboembolism

Should intermittent pneumatic compression (IPC) be a first-line, appropriate choice for patients at moderate risk of VTE?

At the University of California, San Diego (UCSD) Medical Center, a 300-bed referral center, the team originally wanted to keep IPC as an option for patients at moderate risk for VTE, despite the lack of solid evidence in the literature for medical patients. Team audits revealed about 55 percent compliance with IPC, however, and the UCSD team adapted the approach of the American College of Chest Physicians Conference on Antithrombotic and Thrombolytic Therapy, which relegates IPC to patients with contraindications for pharmacologic prophylaxis or as a secondary method to enhance the effectiveness of pharmacologic prophylaxis.

Which patients need IPC in addition to pharmacologic prophylaxis?

At UCSD, the team decided the very high-risk patient must have it, while other patients could have it.

Which patients should have 5,000 units of heparin every 12 hours as an option versus 5,000 units of heparin every 8 hours?

UCSD initially had four levels of VTE risk. They allowed 5,000 units of heparin every 12 hours as a choice for patients at moderate VTE risk (which described many medical ward patients), but advocated the higher-frequency 5,000 units of heparin every 8 hours for high-risk patients (which typified sicker medical and critical care patients).

Eventually UCSD collapsed its moderate and high-risk categories into a single category because:

  • Poor compliance with IPC eliminated that as a viable first-line method.
  • Many patients on 5,000 units of heparin every 12 hours were still developing VTE.
  • It would greatly simplify the risk assessment tool and order sets if 5,000 units of heparin every 12 hours were eliminated as an option for all patients unless they weighed 50 kilograms (110 pounds) or less.

Other teams may make logical alternative choices based on local factors.

Should 7,500 units of unfractionated heparin (UFH) every 12 hours be offered as an option?

At first glance, this is an attractive choice. It retains dosing at every 12 hours and pharmacodynamically should deliver the same protection as offered by the clinical-trial-proven regimen of 5,000 units of UFH every 8 hours. Unfortunately, UCSD found that its pharmacy or nurses had to draw up 7,500-unit doses on special order, while the 5,000-unit doses came prepackaged from the distributor. For UCSD, the 7,500-unit dose carried too many labor, cost, and potential safety issues.

Should low molecular weight heparin (LMWH) or UFH be the recommended choice for VTE prophylaxis in moderate to high-risk patients?

This is a difficult decision for many institutions. The team should make a decision that is best for patients and nurses while still being fiscally responsible. To make an informed decision, consider:

  • Pharmacy cost.
  • Cost of administration (e.g., every 8 hours versus every day).
  • Patient and nursing satisfaction.
  • Lower incidence of heparin-induced thrombocytopenia with LMWH.
  • The danger of using LMWH as default. For example, will staff forget to use UFH in patients with renal insufficiency, or will there be a reminder process in place for these situations?
  • Roughly equivalent performance. Some would argue a slight edge exists for LMWH, especially in critically ill patients.

At UCSD, they found the following:

Protocol UsedPharmacy costAdmin time/costTotal cost
LMWH every day$1610 mins/$5.33$21.33
UFH every 8 hours$130 mins/$16$17
The pharmacy costs above are based on actual pharmacy purchase costs at UCSD, not the retail cost to the customer. Admin time/cost is based on GRASP® Methodology estimates of nursing time to administer UFH every 8 hours versus LMWH every day, estimated as 10 minutes per injection, multiplied by the average registered nurse rate of $32 per hour. This does not mean that the institution actually reaps the savings of 20 minutes of nursing time per day, but rather that it represents an opportunity cost (i.e., the nurse is freed up for 20 minutes for other responsibilities). While there was only a $4.33 difference in cost per patient day between these two options, and the every day dosing of LMWH is attractive to patients and nurses, UCSD decided to allow for either 5,000 units of UFH every 8 hours or 40 mg of enoxaparin every day as first options for patients at intermediate VTE risk. The UCSD team thought it was important to retain an UFH choice in patients with end-stage renal disease and had no valid reason to exclude it as an option in the intermediate-VTE-risk population. Other teams should make these decisions based on their local environment.
Current as of August 2008
Internet Citation: Case Study 1. Questions the University of California, San Diego Medical Center Encountered While Developing Its Venous Thromboembolism Protocol: Preventing Hospital-Acquired Venous Thromboembolism. August 2008. Agency for Healthcare Research and Quality, Rockville, MD. http://www.ahrq.gov/professionals/quality-patient-safety/patient-safety-resources/resources/vtguide/vtguidecase1.html