Biomedical subjects

Mary E Hardwick

Publications and source records attributed to Mary E Hardwick.

7 recordsLinked to original sources

PubMed2006

Rationale for low-molecular-weight heparin prophylaxis after total knee arthroplasty.

Low-molecular-weight heparin has been studied extensively in total knee arthroplasty (TKA) and provides highly effective and safe prophylaxis against deep venous thrombosis (DVT). Low-molecular-weight heparin received the highest rating (A1) in the American College of Chest Physicians recommendations for DVT prophylaxis after elective TKA. Prevalence of DVT with low-molecular-weight heparin prophylaxis was 33% in TKA data pooled from six randomized studies, with a proximal DVT rate of 7.1%. A metaanalysis reported a 2.4% rate of major bleeding with low-molecular-weight heparin. Low-molecular-weight heparin, given by subcutaneous injection, can be started before surgery or after surgery. A synthetic pentasaccharide (fondaparinux), which received an A1 rating in the American College of Chest Physicians recommendations, also is available. As with all treatments, the benefit must be considered against the risk when using these anticoagulants.

Arthroplasty, Replacement, Knee↗

PubMed2005

Patient compliance with outpatient prophylaxis: an observational study.

The need for prophylaxis against venous thromboembolic disease following lower-extremity joint replacement is well documented and accepted. Although low molecular weight heparin is approved for inpatient and extended prophylaxis beyond the hospital environment, orthopedic surgeons must determine the duration of injectable low molecular weight heparin based on the period of venous thromboembolic disease risk and on patient compliance with self-administration of medication at home. Lack of confidence in patients' ability to self-administer injections may contribute to hesitancy in prescribing injectable prophylaxis. This observational study evaluated the effectiveness of a self-injection education program. Findings demonstrate that when properly instructed, patients safely and efficaciously self-administer low molecular weight heparin at home. With shorter hospital stays, self-administration of low molecular weight heparin may optimize the clinical outcomes of orthopedic patients.

Adult↗

PubMed2004

Two-dose epoetin alfa reduces blood transfusions compared with autologous donation.

This study evaluated whether patients receiving a two-dose regime of epoetin alfa received less allogeneic blood than patients donating autologous blood before primary hip arthroplasty. Consenting patients with a hemoglobin level between 12 and 15 g/dL were randomly assigned to a two-dose administration of epoetin alfa (19 patients) or autologous donation (21 patients). Sixteen percent of the patients in the epoetin alfa group and 52% of the patients in the autologous donation group received transfusions, with a mean volume of 90 cc per patient in the epoetin alfa group and 340 cc in the autologous donation group. Hemoglobin was similar at screening; however, the epoetin alfa group achieved a higher hemoglobin (14.6 g/dL) than the autologous donation group (12.6 g/dL) before surgery. Hemoglobin remained significantly higher in the epoetin alfa group for 3 days after surgery. Administration of two doses of epoetin alfa provided patients with effective and safe reduction of allogeneic blood transfusions and decreased the necessity and difficulty of autologous donation before total hip arthroplasty.

Adolescent↗

PubMed2004

The efficacy of a single daily dose of enoxaparin for deep vein thrombosis prophylaxis following total knee arthroplasty.

Deep vein thrombosis (DVT) is a major risk following total knee arthroplasty (TKA). This prospective outcomes study evaluates the efficacy of enoxaparin 40 mg once daily for 7 days after TKA, by documenting symptomatic and asymptomatic outcomes using bilateral lower extremity duplex ultrasound upon hospital discharge and on postoperative day 21 (+/-2). In 60 extremities, duplex ultrasound demonstrated a DVT prevalence of 16.7% (10) on the day of discharge and of 11.7% (7) on postoperative day 21. No new DVT or propagation of distal to proximal DVT were noted. For this small cohort, enoxaparin 40 mg daily demonstrates effective prophylaxis for DVT in TKA patients.

Adult↗

PubMed2004

Advances in DVT prophylaxis and management in major orthopaedic surgery.

Every year, approximately 2 million people experience a deep venous thrombosis (DVT). Approximately 600,000 of these people are diagnosed with a pulmonary embolism and about 10% of these die. It has been established that surgery, anesthesia, and bed rest increase the risk of DVT, and therefore, patients who undergo a major lower-extremity procedure should receive prophylaxis. During the past 10 years, the choices of pharmacological and mechanical prophylaxis have increased greatly. Warfarin is probably the most widely used prophylactic method in the U.S., but low-molecular-weight heparin (LMWH) use has increased. Also available is a synthetic pentasaccharide that acts as an anti-Xa inhibitor to decrease DVT without increase in bleeding. All but warfarin are given by subcutaneous injection and require no laboratory management to adjust the medication. Another drug in clinical trials is a direct thrombin inhibitor taken orally in a fixed dose that does not require monitoring. Non-pharmacological prophylaxis and/or stacked modalities, although used, have not shown the efficacy of pharmacological prophylaxis. With the incidence of DVT reported in the range of 41% to 85% without prophylaxis in joint replacement and hip-fracture surgery, prophylaxis is warranted in all lower-extremity joint replacement and hip-fracture patients.

Anticoagulants↗

PubMed2002

Erythrocyte viability in blood salvaged during total joint arthroplasty with cement.

BACKGROUND: Erythrocyte salvage, the collection of a patient's blood shed from the surgical wound, is one aspect of blood management. Previous investigators have examined salvaged blood for content; however, to our knowledge, none have examined the viability of erythrocytes after exposure to the chemical and thermal reactions produced by motorized instruments and polymethylmethacrylate during surgery. The purpose of this study was to determine the viability of salvaged erythrocytes from patients undergoing primary total joint arthroplasty with cement. METHODS: Erythrocyte viability studies were performed on specimens from three subjects with use of a double isotope-labeling technique employing chromium-51 and technetium-99m. With use of a fresh blood specimen obtained prior to surgery and a specimen of salvaged blood that had been recycled, washed, and filtered with use of the Cell Saver, the viability of the Cell-Saver-processed erythrocytes, labeled with chromium-51, was calculated on the basis of the technetium-99m-labeled red blood-cell mass. RESULTS: The mean erythrocyte viability (and standard deviation) in blood salvaged with use of the Cell Saver was 88.0% +/- 3.8%. The standard of the American Association of Blood Banks for minimum erythrocyte viability in adequately cross-matched allogeneic blood or predeposited autologous blood is 70%. CONCLUSIONS: The high rate of viability of the erythrocytes in this study shows that the Cell Saver is a valuable adjunct to other blood management techniques for patients having total joint arthroplasty. We believe that the very high mean rate of erythrocyte viability and the extremely small standard deviation in our three subjects, as compared with the standards of the American Association of Blood Banks, made additional study subjects unnecessary.

Arthroplasty, Replacement↗

PubMedDate not supplied

e-Knee: the electronic knee prosthesis.

Tibiofemoral forces determine polyethylene wear and affect the longevity of total knee prostheses. Previously, investigators relied on theoretic data from mathematical models to predict mechanical forces in the knee. Predictions of tibiofemoral forces are highly variable because of the complex interplay of the muscles involved in activities. Ideally, knee forces should be directly measured. An electronic total knee prosthesis (e-Knee) was developed to directly measure tibiofemoral compressive and tensile forces in vivo. After 13 years of research and development, the e-Knee was implanted into a patient in 2004. Tibiofemoral force data were collected intraoperatively and throughout the postoperative period during activities of daily living and during exercise. Direct measurement of knee forces can lead to a better understanding of the stresses seen following total knee arthroplasty. Information generated by the e-Knee will aid in the improvement of implant design and patient care.

Activities of Daily Living↗