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Biomedical subjects

F Rubens

Publications and source records attributed to F Rubens.

12 recordsLinked to original sources
PubMed2001

Evaluation of a decision aid for patients considering autologous blood donation before open-heart surgery.

BACKGROUND: Patients undergoing open-heart surgery frequently require one or more blood transfusions. Because of the risks of receiving blood from volunteer donors, some patients choose to donate their own blood before surgery. This reduces their risk of exposure to volunteer-donated blood, but it increases their chance of receiving any transfusion, either of self-donated or volunteer-donated blood. Also, preoperative hemoglobin levels tend to be lower in patients who donate their own blood, and surgeons may be more likely to give transfusions to patients with self-donated blood. To help patients decide whether to donate their blood before surgery, we designed a decision aid comprising a booklet and audiotape and assessed its effectiveness. METHODS: The 59 study subjects were a sample of consecutive patients referred to the Ottawa Heart Institute between Oct. 1, 1998, and Jan. 5, 1999, for future coronary artery bypass grafting, valve surgery or combined surgery. All were eligible to donate blood. Initial questionnaires were administered in the clinic by a physician or study nurse, and follow-up questionnaires were completed at home and mailed in after use of the decision aid. Outcome measures included patients' knowledge, values (importance ratings), preferences for transfusion methods, decisional conflict (the amount of uncertainty about the course of action to take), risk perception and acceptability of the decision aid. RESULTS: Mean knowledge scores on a 15-item test increased from 67% correct responses before the decision aid to 85% correct responses after use of the aid (p < 0.001); the effect was similar when the patients were divided into subgroups according to education level. The number of patients favouring donating their own blood increased from 41 (69%) before to 45 (76%) after use of the aid. Nine (64%) of 14 initially uncertain patients preferred autologous donation after use of the aid. The overall mean score for decisional conflict was unchanged, at 1.7, which indicated a low level of uncertainty. Risk perception improved, from 0%-14% correct responses on an 8-item test before the aid to 18%-60% correct responses after use of the aid. The decision aid was acceptable to the majority of patients, and 95% indicated that they would recommend it to others. INTERPRETATION: The decision aid improved knowledge and risk perceptions of blood donation and transfusion, and it helped uncertain patients to make choices.

Adolescent↗
PubMed2001

Prosthetic valve fungal endocarditis due to histoplasmosis.

Fungal endocarditis is associated with severe patient morbidity and mortality. Unfortunately, fungal endocarditis is difficult to diagnose because fungal pathogens are uncommonly isolated from routine blood cultures. Histopathological examination of surgically excised cardiac valves, peripheral emboli and systemic ulcers may be useful in identifying pathogens as etiological agents of culture-negative endocarditis. The authors describe a 63-year-old man who had culture-negative endocarditis. Multiple echocardiograms showed progression of the vegetations with valve stenosis despite treatment with multiple antimicrobials. He had multiple peripheral emboli before surgery. Disseminated histoplasmosis was diagnosed by bone marrow culture. Yeast organisms consistent with histoplasma were shown in the vegetations of his excised mitral valve prosthesis. The patient was treated with amphotericin and has been doing well in the two years since his surgery. The diagnosis and management of fungal endocarditis are emphasized.

Anti-Bacterial Agents↗
PubMed1999

A meta-analysis of the effectiveness of cell salvage to minimize perioperative allogeneic blood transfusion in cardiac and orthopedic surgery. International Study of Perioperative Transfusion (ISPOT) Investigators.

UNLABELLED: Concern about risks of allogeneic transfusion has led to an interest in methods for decreasing perioperative transfusion. To determine whether cell salvage reduces patient exposure to allogeneic blood, we performed meta-analyses of randomized trials, evaluating the effectiveness and safety of cell salvage in cardiac or orthopedic elective surgery. The primary outcome was the proportion of patients who received at least one perioperative allogeneic red cell transfusion. Twenty-seven studies were included in the meta-analyses. Cell salvage devices that do not wash salvaged blood were marginally effective in cardiac surgery patients when used postoperatively (relative risk [RR] = 0.85, 95% confidence interval [CI] = 0.79-0.92). Devices that wash or do not wash salvaged blood considerably decreased the proportion of orthopedic surgery patients who received allogeneic transfusion (RR = 0.39, 95% CI = 0.30-0.51 and RR = 0.35, 95% CI 0.26-0.46, respectively). No studies of cell savers that wash salvaged blood during cardiac surgery were included. Cell salvage did not appear to increase the frequency of adverse events. We conclude that cell salvage in orthopedic surgery decreases the risk of patients' exposure to allogeneic blood transfusion perioperatively. Postoperative cell salvage in cardiac surgery, with devices that do not wash the salvaged blood, is only marginally effective. IMPLICATIONS: This meta-analysis of all published randomized trials provides the best current estimate of the effectiveness of cell salvage and is useful in guiding clinical practice. We conclude that cell salvage in orthopedic surgery decreases the proportion of patients requiring allogeneic blood transfusion perioperatively, but postoperative cell salvage is only marginally effective in cardiac surgery.

Blood Transfusion↗
PubMed1999

Aortitis with multiple aneurysms mimicking infective endocarditis.

Aortitis usually produces aortic insufficiency by aortic root dilation. In rare cases the inflammation may involve the aortic valve cusps, causing valvular insufficiency. A patient in whom aortitis produced valvular masses, with aortic and peripheral arterial aneurysms, embolic episodes and aortic insufficiency is described. Valve replacement for suspected infective endocarditis was complicated by homograft dehiscence and multiple false aneurysms. Although immunosuppression was successful in decreasing the patient's vasculitis, he became infected and died of complications of aspergillus infection.

Adult↗
PubMed1993

Brachiocephalic fistula: a useful alternative for vascular access in chronic hemodialysis.

Construction of a Cimino-Brescia radiocephalic fistula is the current method of choice for vascular access in most patients on chronic hemodialysis. However, previous vascular access procedures, cephalic vein thrombosis or intrinsic arterial disease may render this procedure impracticable. The brachiocephalic fistula, which provides many advantages over the use of saphenous vein or prosthetic grafts for fistula access, is frequently overlooked as a surgical alternative in patients on chronic hemodialysis. Brachiocephalic fistula constructed directly between the brachial artery and cephalic vein at the level of the cubital fossa is associated with a 4.5-year patency rate of 80%. The incidence of complications is relatively low compared with that when interposition graft materials are used. However, two patients developed severe swelling of the upper extremity secondary to unrecognized preoperative subclavian vein thrombosis. The possibility of this complication should be suspected in any patient who has undergone previous percutaneous subclavian access.

Anastomosis, Surgical↗
PubMed1992

Interactions of thermally denatured fibrinogen on polyethylene with plasma proteins and platelets.

During the investigation of fibrin deposition onto hydrophobic polymers in contact with human blood, a model was developed in which fibrinogen was denatured and irreversibly coated onto a polyethylene surface by heating to 70 degrees C for 10 min. The denatured fibrinogen-polyethylene surface is resistant to fluid wall shear rates of up to 550 s-1 and the fibrinogen does not desorb in the presence of plasma proteins. Compared to uncoated polyethylene, little albumin or fibrinogen adsorbs to heat-denatured fibrinogen. Thrombin binds to the denatured fibrinogen-coated polyethylene with low affinity and also acts on the surface-bound denatured fibrinogen and cleaves fibrinopeptide A (FPA) quantitatively. Washed, 51Cr-labeled platelets do not adhere to the thermally denatured fibrinogen at either low or high shear rates compared to surfaces coated with undenatured fibrinogen (p < 0.01). These observations support the role of the D domain of fibrinogen in platelet adhesion because this is the region that is denatured by heating. In contrast, the E domain of fibrinogen is not altered by heating to 70 degrees C and hence remains susceptible to thrombin and/or plasmin cleavage. The characteristics of this surface are such that it can be used to develop fibrin-coated surfaces for use in studies of thrombus formation on artificial surfaces.

Absorption↗
PubMed1990

Popliteal artery injury after tibial osteotomy: report of two cases.

Operative injury to the popliteal artery after meniscal surgery on the knee has been described previously, but its occurrence after tibial osteotomy has not been reported. The authors describe two cases of the latter condition, both involving the formation of a false aneurysm at the site of injury. The pathogenesis of this condition, its clinical sequelae and its subsequent repair are discussed.

Adolescent↗
PubMed1989

Hoarseness secondary to left atrial myxoma.

A 62-year-old woman presented with a history of hoarseness. Although stable for ten years, she recently showed signs of deterioration. Investigations revealed left vocal cord paralysis and a large left atrial tumor displacing the left pulmonary artery under the arch of the aorta. The lesion was removed and the normal aortopulmonary window on computed tomography (CT) scan was restored. On review of the literature, this case appears to be the first to suggest that myxomas cause recurrent laryngeal nerve palsy through direct effects.

Female↗
PubMedDate not supplied

Surgical treatment of chronic thromboembolic pulmonary hypertension.

BACKGROUND: There are only limited treatment options for patients with chronic thromboembolic pulmonary hypertension in Canada. OBJECTIVE: To conduct a case-series study to assess the effectiveness of surgical endarterectomy of the pulmonary artery. DESIGN AND SETTING: Twenty-one patients with chronic thromboembolic pulmonary hypertension were admitted for surgery between July 1995 and October 1999. Clinical, laboratory and radiological data were collected for all patients who then underwent pulmonary thromboendarterectomy. MAIN RESULTS: Thirteen men and eight women between 22 and 71 years of age underwent surgery. The main presenting complaint was dyspnea on exertion. Pulmonary vascular resistance ranged from 382 to 1694 dynes s cm-5 with a mean of 765+/-372 dynes s cm-5 (normal is less than 180 dynes s cm-5) with a mean cardiac index of 2.2+/-0.9 L/min/m2. Two patients had concomitant tricuspid valve replacement and one patient had coronary bypass grafting. In three cases, the surgery involved a repeat sternotomy. After surgery, there was a significant drop in the pulmonary vascular resistance (208+/-92 dynes s cm-5, P<0.05) and a concomitant rise in the cardiac index to a mean of 3.1+/-0.6 L/min/m2 (P<0.05). There was one death in a patient who also had severe chronic obstructive pulmonary disease. Of the remaining patients, all but two showed significant clinical improvement. Spiral computed tomography postsurgery demonstrated improvement in pulmonary perfusion with either complete clearing or significant improvement in the mosaic perfusion pattern. Right ventricular function and pressure on echocardiogram improved in all but two patients. CONCLUSIONS: Pulmonary thromboendarterectomy provides effective treatment for chronic thromboembolic pulmonary hypertension.

Adult↗