Patient Self-Testing of Prothrombin Time After Hip Arthroplasty

C. Anderson Engh, Jr., MD, William J. Culpepper II, MA, Patricia A. Charette, RN and Rachel Brown, from the Anderson Orthopaedic Research Institute, Alexandria, Va.

J South Orthop Assoc. 2001;10(3) 

In This Article

Abstract and Introduction

We determined whether total hip arthroplasty (THA) patients could test their own prothrombin time reliably over 6 weeks of anticoagulation prophylaxis with a portable device that measures prothrombin time and whether self-testing would improve or maintain the quality of care at a lower cost than our standard procedure. Forty-six THA patients participated in the study and were compared with a matched group managed with our standard protocol using a home health-care nurse. Seven patients (15%) could not be trained to obtain the blood sample, and others required multiple finger sticks to obtain valid results. However, the results from the 29 patients completing the study showed high reliability when compared with results obtained through standard protocol. Self-testing saved about $260 per patient over the cost of venipuncture. Patient self-testing of prothrombin time using the device in this study is reliable and cost-effective for monitoring the anticoagulation status after THA in a select group of elderly patients.

Deep venous thrombosis (DVT) is a common complication associated with THA. If left untreated, DVT can lead to potentially life-threatening pulmonary emboli.[1,2,3] Prophylactic anticoagulation therapy is highly effective in preventing DVT and pulmonary emboli,[1,3,4,5] and low-dose warfarin (Coumadin) has become an accepted prophylactic agent for decreasing the incidence of DVT after THA.[5,6,7,8] Its major drawbacks have been the risk of bleeding and the need to monitor the patient's prothrombin International Normalization Ratio (INR) and maintain it between 1.5 and 2.5.[8]

Current postdischarge monitoring most commonly involves venipuncture at home. Generally, patients with hip replacements are incapable of traveling to an outpatient anticoagulation clinic for testing for 6 weeks. At this institution, a home health nurse draws the blood sample during the weekly assessment at the patient's home and then delivers the blood sample to the laboratory. The laboratory reports the result to the physician.

Recent studies have shown that patients receiving long-term anticoagulation therapy can safely and effectively manage their anticoagulation medication with a device that enables them to test their own prothrombin time.[9,10,11,12] Such a device offers several advantages, including elimination of venous access problems, improved communication between the patient and the medical staff, improved patient satisfaction, more frequent testing, and potential cost savings.[13] This study evaluated whether patients could reliably test their own prothrombin time during the 6-week period of anticoagulation prophylaxis after total hip replacement. Additionally, this study group was compared with a matched group of patients whose prothrombin time was monitored with conventional home venipuncture laboratory testing. Our hypothesis was that patient self-testing would improve or maintain the quality of care at a lower cost than our standard for monitoring patient anticoagulation status procedure (using the home nurse and laboratory tests).


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