Therapeutic interchange of darbepoetin alfa for epoetin alfa in a multiinstitution health care system.
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Anemia↗
Biomedical subjects
Robert Adamson
Publications and source records attributed to Robert Adamson.
Evaluation of a computational model used to predict the patellofemoral contact pressure distribution.
One possible cause of patellofemoral pain syndrome is excessive lateral force acting on the patella. Although several treatment methods focus on decreasing the lateral force acting on the patella, the relationship between the lateral force and the patellofemoral contact pressure distribution is unclear. A computational model has been developed to determine how loading variations alter the patellofemoral force and pressure distributions for individual knees. The model allows variation in the quadriceps and patella tendon forces, and calculates the predicted contact pressure distribution using the discrete element analysis technique. To characterize the accuracy of the model, four cadaver knees were flexed on a knee simulator with three initial Q-angles, while recording the force and pressure distributions with a pressure sensor. A model of each knee was created from CT data. Using the external force applied to the knee, the geometry of the knee, and the quadriceps origin as input, the pressure distribution was calculated during flexion. Similar trends were noted for the computational and experimental results. The percentage of the total force applied to the lateral cartilage increased with the Q-angle. The maximum contact pressure increased during flexion. The maximum lateral contact pressure increased with the Q-angle for three knees. For the other knee, increasing the Q-angle decreased the maximum lateral pressure. The maximum medial contact pressure decreased as the Q-angle increased. By characterizing the influence of patellofemoral loading on the force and pressure distributions, the computational model could be used to evaluate treatment methods prescribed for patellofemoral pain.
Cadaver↗
The Human Tissue Bill.
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Human Experimentation↗
A multicenter retrospective cohort study of practice patterns and clinical outcomes of the use of darbepoetin alfa and epoetin alfa for chemotherapy-induced anemia.
BACKGROUND: Darbepoetin alfa is the second erythropoietic protein to be approved for the treatment of chemotherapy-induced anemia (CIA). In the clinical setting, darbepoetin alfa can be administered less frequently than epoetin alfa with similar efficacy. Practice patterns and outcomes associated with the use of darbepoetin alfa and epoetin alfa in the clinical setting have not been reported. OBJECTIVE: This study compared practice patterns and clinical outcomes of the use of darbepoetin alfa and epoetin alfa for CIA at oncology practices in the United States. METHODS: This was a multicenter retrospective cohort study. Data were abstracted from the medical charts of consecutive patients who began darbepoetin alfa treatment between August 1 and October 4, 2002, or epoetin alfa treatment between April 1 and July 31, 2002, and were receiving concurrent chemotherapy. These data were used to determine the initial dose and dosing schedule, dose changes, and changes in hemoglobin concentrations after 4, 8, and 12 weeks of treatment, adjusted for red blood cell (RBC) transfusions, and the incidence of RBC transfusions over time. To minimize potential bias, the study protocol defined specific end points and prespecified analytic techniques for assessing clinical outcomes with the 2 agents. RESULTS: The records of 1391 patients from 16 community and hospital outpatient oncology clinics were abstracted. Of these, 1293 patients (93.0%) received only 1 erythropoietic agent (darbepoetin alfa, 735 [56.8%]; epoetin alfa, 558 [43.2%]); the remainder received both agents. In the patients who received darbepoetin alfa, most (553 [75.2%]) received an initial dosage of 200 microg q2wk. A similar proportion (414 [74.2%]) received epoetin alfa at an initial dosage of 40,000 U qwk. As these were the regimens for the majority of patients whose records were abstracted, the results reported here are for these patients. The dose was increased in 63 darbepoetin alfa recipients (11.4%) and 58 epoetin alfa recipients (14.0%) at a median of 7 weeks. After 12 weeks, the 2 groups had an identical mean imputed change from baseline in hemoglobin concentration (1.0 g/dL), and the incidence of RBC transfusions during treatment was also similar between groups (darbepoetin alfa, 44553 [8.0%]; epoetin alfa, 39414 [9.4%]). CONCLUSIONS: Darbepoetin alfa 200 microg q2wk was used as a standard regimen for CIA at the 16 US oncology practices participating in this study. It appeared to be as effective as epoetin alfa 40,000 U qwk, with a reduced frequency of dosing.
Aged↗
Prescribing patterns and outcomes of enoxaparin for anticoagulation of atrial fibrillation.
STUDY OBJECTIVE: To determine prescribing patterns and clinical outcomes of enoxaparin for anticoagulation of atrial fibrillation. DESIGN: Retrospective analysis. SETTING: A 650-bed, tertiary care, community teaching hospital. SUBJECTS: Two hundred thirteen patients who received enoxaparin for thromboprophylaxis during an episode of atrial fibrillation. Intervention. Data collection on demographics, antithrombotic usage, and thrombotic and bleeding episodes from January-June 2001. MEASUREMENTS AND MAIN RESULTS: Patients were characterized as having acute (51.6%) or chronic (48.4%) atrial fibrillation and were categorized according to stroke risk. Three enoxaparin dosing strategies had been prescribed: therapeutic, prophylactic, or adjusted. Prescribed regimens did not reflect stroke risk or type of atrial fibrillation but did reflect the degree of renal impairment. No episodes of stroke occurred with therapeutic enoxaparin dosages, but five strokes occurred among patients receiving prophylactic or adjusted dosages. Bleeding was similar with all dosing strategies in patients with adequate renal function and appeared to be more frequent in those with renal impairment. CONCLUSION: At a single hospital, wide variation in enoxaparin prescribing patterns existed. Further study is necessary to elucidate more fully the appropriate dosing strategy for this agent in the treatment of atrial fibrillation.
Aged↗
Left ventricular outflow tract obstruction associated with chronic ventricular assist device support.
Favorable long-term patient outcome after insertion of a left ventricular assist device (LVAD) as a bridge to recovery or destination therapy for the treatment of end-stage cardiomyopathy is adversely affected by pathophysiologic changes affecting the heart. Alterations in the native aortic valve apparatus, specifically aortic valve cusp fusion, is an example of such a phenomenon and may especially affect patients in cases of bridge to recovery, a rare but reported event. A retrospective review of the last 33 LVAD placements at our institution was conducted, including reviews of operative reports and pathologic examinations of the native hearts. Seven hearts were found to have varying degrees of aortic valve cusp fusion after chronic LVAD support (63-1, 339 days). Five of these patients had native aortic valves, and two had bioprosthetic valves. The left ventricular outflow tracts in two patients were surgically occluded at the time of LVAD insertion. Aortic valve cusp fusion occurs in roughly 25% of patients on chronic LVAD support. This phenomenon may prove to be clinically significant by creating a potential source of emboli and infection. In addition, in the case of myocardial recovery, left ventricular outflow tract obstruction could limit parallel flow and produce suprasystemic ventricular pressures that in turn would elevate left ventricular end diastolic pressures. The latter may contribute to further myocardial injury, ultimately limiting the ability of an otherwise recovered heart to be weaned from LVAD support.
Adult↗
Case series: clinical management of persistent mechanical assist device driveline drainage using vacuum-assisted closure therapy.
Percutaneous driveline lead and pocket sites are potential sources of drainage that can lead to infection. Some patients experience a slower closure of tissue growth into the driveline. The management of chronically open and or draining driveline wounds is a challenge. The KCI vacuum-assisted closure (VAC) device is a noninvasive negative-pressure therapy that promotes the healing of wounds not responding to conventional treatment. Vacuum-assisted closure therapy has proven safe, effective, and cost efficient by decreasing the number of dressing changes and length of stay. The left ventricular assist device (LVAD) team initiated VAC therapy in 3 patients. The tunneling method allowed the wound to heal from the inside out. The dressing was changed every 3 days, and the size and depth of the wound was monitored. Patients may be sent home using a portable VAC device until wound closure is obtained, which decreases the hospital length of stay. Our experience with three patients suggests the VAC device can be used for draining and tunneling LVAD driveline-site wounds and may prevent fistula formation. It is especially useful for patients with ascites that may be draining along the driveline tract. The sites showed increased granulation, decreased drainage, and a reduced bacterial burden after having the device in place.
Adult↗