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Biomedical subjects

M J Barry

Publications and source records attributed to M J Barry.

At least 127 records · Page 7Linked to original sources
PubMed1990

True emergency coronary artery bypass surgery.

Previous reports of emergency coronary artery bypass grafting often included cases that were not true surgical emergencies, thereby creating inappropriately favorable results. To accurately investigate this important subgroup of patients, we analyzed our recent experience with truly emergent coronary artery bypass grafting. From January 1984 to January 1989, 117 patients underwent true emergency bypass grafting for acute refractory coronary artery ischemia. Clinical deterioration was associated with failure of percutaneous angioplasty in 37 patients and instability during diagnostic catheterization in 13 patients. Refractory ischemia developed in the remaining patients while on the ward or in the intensive care unit. All operations were performed within four hours of surgical consultation, most within one hour. Overall in-hospital operative mortality was 14.5% (17/117), and 76.5% of deaths (13/17) were due to cardiac-related causes. Major morbidity occurred in 35.9% (42/117). Univariate analysis isolated ejection fraction, extent of coronary artery disease, previous myocardial infarction, hypertension, need for inotropic support, use of an intraaortic balloon pump, and cardiopulmonary resuscitation as risk factors for operative mortality. Stepwise multivariate analysis confirmed that previous myocardial infarction, hypertension, cardiopulmonary resuscitation, and reoperation were independently significant risk factors. Age, sex, diabetes, left main disease, and peripheral vascular disease had no significant impact on the prognosis. The 4% operative mortality (2/50) for patients taken directly to the operating room from the catheterization suite was significantly lower than the 22.4% mortality (15/67) associated with emergencies arising on the ward or intensive care unit (p less than 0.01). A logistic risk equation developed from this population accurately modeled operative mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Further study of the increased mortality following transurethral prostatectomy: a chart-based analysis.

Previous studies using large administrative databases found an elevated relative risk of reoperation and death after transurethral resection of the prostate compared to open prostatectomy. To investigate whether differences in case-mix unmeasured by administrative data explained this finding, we reviewed the charts of 485 patients who had undergone prostatectomy (236 open and 249 transurethral) at the Health Science Centre, Winnipeg, Manitoba, Canada between 1974 and 1980. Data from patient histories, physical examinations and laboratory evaluations were abstracted and used to control for case-mix in models comparing the rates of reoperation and mortality after transurethral versus open prostatectomy. Several models were specified. In all models the relative risk of dying after transurethral prostatectomy remained elevated (1.36 to 1.89), as did the risk for reoperation (3.62). A prospective trial is needed to establish the relative safety and effectiveness of transurethral and open prostatectomy.

Aged↗
PubMed1990

Computerized tomography in the evaluation of myasthenia gravis.

Thymomas occur in 10% to 15% of patients with myasthenia gravis. Since not all patients are referred for thymectomy, a test that could reliably predict the presence or absence of a thymoma would be of great assistance in the management of these patients. We studied all patients referred for thymectomy at Walter Reed Army Medical Center from 1983 to 1989. Complete records were available for 13 patients. Computerized tomography (CT) correctly predicted the presence of a thymoma in one patient and falsely predicted a thymoma in a patient with a thymic cyst; it accurately predicted the absence of a thymoma in the remaining 11 patients. The sensitivity of CT scanning was 100%, the specificity was 92%, and the accuracy was 92%, results that are in agreement with previously published data. Compared to conventional chest roentgenography, CT scanning provided a more precise anatomic localization, and accurately predicted local invasion. We recommend a CT scan of the mediastinum in all patients with myasthenia gravis to avoid delayed diagnosis of thymoma in patients who normally would not be referred for thymectomy.

Adult↗
PubMed1990

Epidemiology and natural history of benign prostatic hyperplasia.

Benign prostatic hyperplasia (BPH) afflicts the majority of elderly men, and if current rates of surgery persist, the average 40-year-old man in the United States will have a 30 to 40 per cent chance of undergoing a prostatectomy if he survives to age 80. Age is by the far the most important determinant of BPH occurrence. Symptomatic BPH has a waxing and waning course, and a few men may have long-term remission. Surprisingly, the natural history of BPH is poorly defined, particularly with regard to the magnitude of the risks of its complications.

Aging↗
PubMed1989

Coronary artery bypass in idiopathic thrombocytopenia without splenectomy.

A patient with coronary artery disease and idiopathic thrombocytopenia purpura underwent coronary artery bypass grafting without splenectomy. Our experience indicates that use of cardiopulmonary bypass in patients with idiopathic thrombocytopenic purpura does not invariably mandate splenectomy.

Coronary Artery Bypass↗
PubMed1989

Use of artificial intelligence for the preoperative diagnosis of pulmonary lesions.

The relatively new field of artificial intelligence has spawned a variety of techniques associated with computer-assisted diagnosis. These techniques have been applied to the diagnosis of pulmonary lesions, but previous reports have focused on medical rather than surgical populations and the results have been evaluated using only retrospective patient surveys. We used a Bayesian algorithm to develop a diagnostic computer model for prospectively evaluating patients undergoing thoracotomy for suspected pulmonary malignancy. Patients who had a preoperative diagnosis were not included. Preoperative clinical and radiographic parameters for 100 consecutive patients were prospectively entered into the diagnostic model, which then categorized the lesion as benign or malignant. The computer predictions agreed with the final histological diagnosis in 95 of the 100 patients. The sensitivity was 96% and the specificity was 89% for this prospective series. These results indicate that the computer-assisted diagnosis of pulmonary lesions may have a role in this clinical setting.

Adult↗
PubMed1989

Medical diagnostic technology in the home.

This article studies the issues surrounding the assessment of several home diagnostic tests. First, the authors review the current data and proper use of fecal occult blood and pregnancy tests. Second, they evaluate the roles of blood and urine glucose monitoring in the management of diabetes mellitus and home pressure monitoring in the management of hypertension. The authors conclude that while home measurement of blood pressure or blood sugar can be recommended to improve compliance with medical programs, home fecal occult blood testing, while helpful, has not been fully investigated.

Blood Pressure Determination↗
PubMed1989

The influence of early surface thromboreactivity on long-term arterial graft patency.

The influence of early graft surface thromboreactivity on long-term arterial polyester (Dacron) graft patency was investigated with separate ex vivo and in vivo animal models. First, parallel, flow-regulated external aortocaval fistulae were created in five pigs with use of paired 8 mm X 35 cm crimped, warp-knitted, low-profile filamentous velour Dacron tubes: one tube preclotted with autologous blood, the other autoclaved after being soaked in human albumin. Autologous radiolabeled platelets, red cells, and radiolabeled human fibrinogen were injected at initiation of graft flow, with timed graft samples submitted for isotope gamma well-counting. Flow surface accumulation of radiolabeled blood elements was greater on the preclotted graft limb at-all time intervals studied, greatest after 5 minutes of flow initiation with RBC accumulation on the preclotted limb 5.19 +/- 0.84 (x +/- S.E.), platelet accumulation 5.57 +/- 1.00, and fibrinogen accumulation 1.82 +/- 0.14 times greater than that on the albumin-treated limb. Second, bilateral iliofemoral artery bypass grafts were placed in 12 mongrel dogs using 6 mm X 10 cm externally supported, noncrimped, warp-knitted, low-profile filamentous Dacron tubes. Before implant in each dog, one graft limb was clotted with autologous blood and the other was autoclaved after being soaked in 25% human albumin. Fresh autologous radiolabeled platelets were injected after wound closure in seven of these dogs. Postimplant graft imaging at 24 and 72 hours showed radiolabeled platelet accumulation to be 1.43 +/- 0.21 and 2.05 +/- 0.18 times greater on the preclotted graft limb. Six of 12 preclotted graft limbs and 7 of 12 albumin-treated graft limbs were patent when animals were killed 5 to 6 months after implant (not significant). Heat-denatured albumin-coated Dacron surfaces have a reduced early thromboreactivity but do not appear to greatly potentiate long-term arterial graft patency.

Albumins↗
PubMed1988

Watchful waiting vs immediate transurethral resection for symptomatic prostatism. The importance of patients' preferences.

The rate of resection for benign prostatic hypertrophy shows considerable variability among small geographic areas. To help inform the decision to recommend prostatectomy to men with prostatism without signs of chronic retention, we performed a decision analysis to compare the expected outcomes with immediate transurethral resection and watchful waiting. Data used in the model originated from the medical literature, Medicare claims data, and patient interview studies. In our base-case analysis for 70-year-old men, immediate surgery resulted in the loss of 1.01 months of life expectancy, but when adjustments were made for quality of life, immediate surgery was favored with a net utility benefit of 2.94 quality-adjusted life-months. However, the analysis was particularly sensitive to the degree of disutility attributed to the index symptoms of prostatism. We conclude that patient preferences should be the dominant factor in the decision whether to recommend prostatectomy.

Age Factors↗
PubMed1988

Symptom status and quality of life following prostatectomy.

When prostatectomy is proposed as treatment for the symptoms of prostatism, the decision to operate should depend on how patients evaluate their symptoms and on objective information about the outcomes. We undertook a health interview study to determine the probabilities for symptom relief, improvement in the quality of life, and complications following surgery and to evaluate patient concern about the symptoms of prostatism. The operation was effective in reducing symptoms: 93% of severely and 79% of moderately symptomatic patients experienced improvement; however, a statistically significant improvement in indices of quality of life occurred only among patients with acute retention or severe symptoms prior to surgery. Short-term complications of varying severity occurred in 24% of patients; in addition, 4% reported persistent incontinence and 5%, impotence. Patients with similar symptoms reported considerable difference in the degree to which they were bothered by their symptoms. The result emphasizes the importance of patient participation in the decision to undergo prostatectomy.

Aged↗
PubMed1988

Use of a Bayesian statistical model for risk assessment in coronary artery surgery.

A computerized statistical model based on the theorem of Bayes was developed to predict mortality after coronary artery bypass grafting. From January, 1984, to April, 1987, at our hospital, 700 patients underwent isolated coronary artery bypass grafting. The presence or absence of 20 risk factors was determined for each patient. The first 300 patients formed the initial database of the Bayesian predictive model, and the remaining 400 patients were prospectively evaluated in four groups of 100 each. Each group was prospectively evaluated and then incorporated into the database to update the model. There was good agreement between predicted and observed results. Bayesian theory is particularly suited to this task because it (1) accommodates multiple risk factors, (2) is tailored to one's specific practice, (3) determines individual, rather than group, prognosis, and (4) can be updated with time to compensate for a changing patient population. These flexible attributes are especially valuable in light of recent changes in the coronary artery bypass graft patient profile.

Aged↗
PubMed1987

The effects of excitatory amino acids and their antagonists on the generation of motor activity in the isolated chick spinal cord.

We have investigated the action of excitatory amino acids and their antagonists on spontaneous motor activity produced by an isolated preparation of the chick lumbosacral cord. Bath application of N-methyl-DL-aspartic acid (NMDA) or D-glutamate increased the occurrence and duration of spontaneous episodes of motor activity. Both NMDA-induced and spontaneous activity were reversibly inhibited by several excitatory amino acid antagonists including 2-amino-5-phosphono valeric acid and gamma-D-glutamyl glycine in a dose-dependent manner. These results suggest that motor activity in the chick spinal cord may be regulated by the release of endogenous excitatory amino acids from spinal interneurons.

2-Amino-5-phosphonovalerate↗
PubMed1987

Compulsory premarital screening for the human immunodeficiency virus. Technical and public health considerations.

The effectiveness of a mandatory premarital screening program was examined as a means of curtailing the spread of the human immunodeficiency virus (HIV) infection in the United States. The epidemiology of the HIV, the technical characteristics of tests for antibodies to HIV, and the logistic, economic, and legal implications of such a program were considered. In one year, universal premarital screening in the United States currently would detect fewer than one tenth of 1% of HIV-infected individuals at a cost of substantially more than +100 million. More than 100 infected individuals would be told that they were probably not infected, and there would likely be more than 350 false-positive results. Public education, counseling of individuals, and discretionary testing can be important tools in reducing the spread of HIV infection, but mandatory premarital screening in a population with a low prevalence of infection is a relatively ineffective and inefficient use of resources.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Effect of workup strategy on the cost-effectiveness of fecal occult blood screening for colorectal cancer.

Physicians respond to a positive fecal occult blood test with a variety of workup strategies. To study the effect of the choice of strategy on the net costs and health benefits of colorectal cancer screening using this test, we used a decision analysis model to compare seven strategies that physicians might choose to examine a positive "screenee." Strategies using rigid or flexible sigmoidoscopy alone are not only insensitive, but also have high cost-effectiveness ratios. The strategy of air contrast barium enema alone had the lowest cost-effectiveness ratio. Rigid sigmoidoscopy combined with barium enema had a lower cost-effectiveness ratio than primary colonoscopy, but the strategy of primary colonoscopy could have an equal or better ratio depending on assumptions about test costs and the benefit of removing benign polyps. The primary colonoscopy strategy is both more effective and less costly than the combination of flexible sigmoidoscopy and barium enema. The optimal strategy will vary with local factors, and with the perspective of the decision-maker.

Aged↗
PubMed1986

Bioprosthetic heart valve rupture associated with trauma.

Disruption of a bovine pericardial bioprosthetic aortic heart valve occurred in a motor vehicle accident, and was treated by valve replacement for progressive aortic insufficiency. Leaflet rupture was through areas of noninflammatory tissue degeneration, corresponding to regions of repeated mechanical stress and trauma that occur during the normal function of tissue valves. Patients with bioprosthetic heart valves may be predisposed to traumatic valve injury. Early diagnosis and replacement of these disrupted valves should be accomplished to avoid sudden, unpredictable heart failure.

Accidents, Traffic↗