PubMed Health⌕ Search

Biomedical subjects

J Benbassat

Publications and source records attributed to J Benbassat.

At least 19 recordsLinked to original sources
PubMed1992

Risk indicators after envenomation in humans by Echis coloratus (mid-east saw scaled viper).

To determine the frequency, severity and predictors of bleeding and azotemia after envenomation in humans by Echis coloratus, a retrospective survey of 68 cases in Israel between 1970 and 1989 was carried out. We used univariate and multivariate analyses of clinical variables on admission for the outcome variables of bleeding, hemoglobin and platelet levels, and blood urea. Within hours or days after envenomation, a major bleeding episode occurred in 18% of the victims, a drop in hemoglobin to 10 g/dliter or less in 14%, and an increase in blood urea to 9 mmole/liter or more in 15%. These complications correlated with time interval between envenomation and hospital admission, and the following admission variables: degree of bleeding, hemoglobin level, platelet and white blood cell counts, blood urea and proteinuria. Complications were unlikely in patients who were presented with all of the following: a hemoglobin level of 13 g/dliter or more, a platelet count of 100,000/mm3 or more, a blood urea level of 7 mmole/liter or less, no proteinuria and no bleeding. Treatment on admission with a specific monovalent antiserum was associated with a shorter duration of hemostatic failure and a reduced incidence of anemia and thrombopenia. Infusion of fresh frozen plasma on admission did not appear to be effective in preventing complications.

Adult↗
PubMed1992

The value of urinary red cell shape in the diagnosis of glomerular and post-glomerular haematuria. A meta-analysis.

The proportion of dysmorphic red cells (DRC) in the urinary sediment and their mean corpuscular volume (MCV) have been claimed to discriminate between glomerular and postglomerular sources of haematuria. To determine the diagnostic value of urinary DRC and MCV, we searched the literature and critically reviewed 21 published studies using a predetermined set of criteria for evaluation. All studies originated from referral centres. Interobserver variability in identifying urinary DRC was reported in four studies and found to be unacceptably large in one. Although reproducible over different samples of the same individual, urinary MCV was unreliable in cases of low-grade haematuria because of interfering debris. Weighted averages and 95% confidence limits of the sensitivity and specificity of the DRC proportion for glomerular disease were 0.88 (0.86-0.90) and 0.95 (0.93-0.97), respectively; those of a low MCV were 1.00 (0.98-1.00) for sensitivity and 0.87 (0.80-0.91) for specificity. Sensitivity and specificity values derived from in-patients were slightly higher than those in referred outpatients. No studies of urinary DRC or MCV in patients with incidentally detected microhaematuria in the primary care setting were found. We conclude that at present the diagnostic value of urinary DRC and MCV is limited. In referral centres, that is, in patients with a high probability of postglomerular haematuria, the test cannot rule out urological lesions, because its specificity for glomerular disease may be as low as 0.80. In the primary care setting, that is, in unselected patients with incidentally detected low-grade haematuria, the accuracy of the test has not been studied but may be even lower. The use of urinary DRC or MCV as an indicator of the source of haematuria is in need of further experimental development and confirmation.

Diagnosis, Differential↗
PubMed1991

Factors associated with leukocyturia in asymptomatic pilots.

We attempted to relate the prevalence of leukocyturia during annual examinations to recent activities and history data in 923 pilots. Urinary analysis was done and the results cross-tabulated with answers from a questionnaire and with a past history of leukocyturia obtained from the pilot's chart. The prevalence of 4 to 6 or more white blood cells (WBCs) in the urinary sediment was 5.3%. Leukocyturia was 35.7 times more common (odds ratio) in those with a previous history of leukocyturia and a concomitant history of urethritis (p less than 0.0001). Yet, a history of leukocyturia accounted for only 18.1% of the cases of leukocyturia. There was a trend for an association between jogging and leukocyturia. The prevalence of leukocyturia was not affected by smoking, other physical exercise, a history of nephrolithiasis, air duty in the preceding 24 h or a history of transient illness during the last 2 weeks. We conclude that there is an association between a history of both leukocyturia and urethritis and leukocyturia. In most cases, however none of the variables tested were found to be associated with leukocyturia.

Aerospace Medicine↗
PubMed1991

Can decision analysis help in the management of giant hemangioma of the liver?

We explore the trade-off between the risk and expected benefits from resection of giant liver hemangioma (GLH), one larger than 4 cm in diameter. We searched the English-language literature for studies of the postoperative mortality after resection of GLH and of the outcome of expectantly treated patients. The results of the data synthesis showed an operative mortality of 1.5% (90% confidence intervals, 0.1-3.0%) and an early surgical morbidity of up to 13%. Mortality among the 37 reported cases with ruptured GLH was 78%. There were no cases of spontaneous or traumatic rupture of unresected GLH during a follow-up of a total of 282 patient years. The main source of ambiguity regarding the management of GLH is the uncertain risk of its rupture. Rough estimates of this risk based on published data suggest that surgical resection is not justified in asymptomatic GLH. Yet, although rare, rupture of GLH does occur with disastrous consequences. Future research may attempt to define patient subsets whose GLHs are at higher risk of rupture, and in whom preventive resection may improve survival.

Adult↗
PubMed1990

The choice between splenectomy and medical treatment in patients with advanced agnogenic myeloid metaplasia.

The objective of the study was to explore the risks and benefits of splenectomy in advanced agnogenic myeloid metaplasia (AMM). We searched the literature (Medline, 1970-1987) for studies of postoperative survival, operative mortality and effects of splenectomy on painful splenomegaly, and portal hypertension or transfusion requirements in patients with AMM. We employed formal decision analysis to determine the relative value of medical and surgical treatment of advanced AMM. Results of data synthesis showed that splenectomy in AMM is associated with an operative mortality of 13.4% (95% confidence intervals (CI): 9.5-17.2%), an early morbidity of 45.3% (CI: 39.6-51.1%), and a late morbidity of 16.3% (CI: 9.9-22.5%). Almost all patients with portal hypertension and painful splenomegaly, but only about half of those with thrombopenia and anemia were reported to have experienced relief in their symptoms or signs after splenectomy. We found no evidence that splenectomy affects survival in AMM. We concluded that splenectomy in advanced AMM is a palliative procedure that carries a substantial risk. It may be considered for symptomatic patients after they have been informed about the operative mortality, morbidity, and chances of palliation. Decisions about treatment of advanced AMM should be guided predominantly by the patient's preferences.

Blood Transfusion↗
PubMed1990

Risk of gastric cancer after gastric surgery for benign disorders.

The objective of this review was to evaluate published evidence for the association between gastric resection for benign disorders and subsequent cancer of the gastric remnant. We searched the literature through Medline (1970 to 1988) and through the references of relevant articles. Fifty-eight studies consisting of case series, uncontrolled surveys, and case control or cohort analyses were identified and critically assessed using defined methodological criteria. There were no consistent differences between the expected and observed number of cancers occurring within 15 years after gastric resection. However, all case control studies and seven of the eight cohort analyses, in which the prevalence of cancer was stratified by time since gastric resection, indicated a twofold to fourfold increase in the risk of gastric cancer in patients who survived 15 or more years after gastric surgery. We conclude that most studies of the association of gastric surgery with subsequent gastric cancer have relatively weak designs. Still, the repetitive demonstration of this association by different investigators using different research designs supports the hypothesis that gastric resection increases the risk of cancer in the gastric remnant.

Case-Control Studies↗
PubMed1990

[The emergency room as a setting for clinical training].

The undergraduate medical curriculum does not include supervised training in emergency services. Medical students and residents are expected to acquire skills and experience related to emergency medicine during their clerkships in the clinical wards. Consequently, Israeli medical graduates often have difficulty in coping with common situations in primary care and emergency medicine. In response to the perceived need of emergency training, we modified the undergraduate teaching program of the clinical clerkship. During their medical clerkship, students spent several weeks in the emergency ward. Residents were similarly assigned to the emergency ward on a rotating basis for 3-month periods. Both the positive feedback of the trainees and the practical relevance of the program and its feasibility, suggest that it may be a worthwhile addition to the undergraduate and graduate clinical curriculum. However, we have no data for evaluating the outcome. We feel that all aspects of emergency medicine should be included in the teaching programs of the various clinical specialties, and suggest that the emergency room should be used as a teaching setting during the clinical clerkship, the internship and residency training.

Clinical Clerkship↗
PubMed1990

Blood pressure response to exercise in normotensive and hypertensive young men.

We attempted to determine the optimal cut-off value of blood pressure defining a hypertensive response to exercise testing in 90 asymptomatic Israeli candidates for flight training with casual resting blood pressure of 140/90 mm Hg or more, and 72 age-matched normotensive controls tested in the Israel Air Force Aeromedical Center. Exercise testing (Bruce protocol) was performed using a calibrated Quinton Treadmill and a Hewlett Packard 151711-A three-channel ECG recording system. Recordings were made at 3-min intervals. At 3 min of exercise 12/87 (14%) of the hypertensive subjects had a SBP of greater than or equal to 210, compared to only 1/71 (1%) of the control group (relative risk 14). At 12 min of exercise 27/51 (53%) of the hypertensives and 9/55 (16%) of the controls had similar elevations of SBP (relative risk 3.3). At 6 min of exercise 11/87 (13%) of hypertensives had SBP greater than or equal to 220, whereas none of the normal controls had SBPs elevated to that degree. We concluded that an increase in SBP to 210 mm Hg or more after 3 min or to 220 mm Hg after 6 min of exercise testing by the Bruce protocol best separates the hypertensive group from the control group. This occurs at the expense of sensitivity. Only appropriate longitudinal studies can compare the degree to which various definitions of the hypertensive response to exercise will predict future hypertension.

Adolescent↗
PubMed1989

Treatment of envenomation by Echis coloratus (mid-east saw scaled viper): a decision tree.

Envenomation by Echis coloratus causes a transient hemostatic failure. Systemic symptoms, hypotension and evident bleeding are rare, with only one reported fatality. In this paper, we examine the decision to treat victims of Echis coloratus by a specific horse antiserum. The decision model considers the mortality of treated and untreated envenomation, and the side effects of antiserum treatment: fatal anaphylaxis, serum sickness and increased risk of death after a possible repeated exposure to horse antiserum in the future. The results of the analysis are not sensitive to variations in the probability of side effects of antiserum treatment. They are sensitive to variations in the risk of bleeding after envenomation, in the degree of reduction of this risk by antiserum treatment and in the risk of dying after an event of bleeding. Prompt administration of antiserum appears to be the treatment of choice if it reduces the risk of bleeding from 23.6% to 20.3% and if 1.6% or more of the bleeding events are fatal. We conclude that presently available data support antiserum treatment of victims of Echis coloratus who present with hemostatic failure, even though the advantage imparted by this treatment appears to be small.

Adult↗
PubMed1989

Retirement of fighter pilots with incidentally detected illnesses: a decision analytic model.

Decisions regarding professional fitness after an incidental detection of a clinical disorder are often problematic. The added risk of an occupational error related to the detected disorder may be smaller than the risk of an error due to lack of experience if a veteran is replaced by a novice. In this paper, we examine the choice between grounding or granting a waiver to an experienced fighter pilot with an incidental finding of premature ventricular contractions. The decision considers the probability of sudden incapacitation during flight and of pilot error-related air accidents in novices and veterans. Although deliberately biased in favor of grounding the veteran, the analysis indicates that the risk of sudden death or incapacitation in an experienced fighter pilot with an incidentally detected illness should be increased ten-fold to 46-fold to justify his or her replacement by a novice. In the specific case considered, the analysis suggests that the risk of an air accident due to sudden death or incapacitation of a veteran with incidentally detected premature ventricular contractions is similar to the estimated added risk of an error-related air accident if she or he is grounded and replaced by a novice. When reliable data on the frequency of human error by age and experience become available, the proposed model may be applied to other situations in which trained professionals develop a potentially disabling disease.

Accidents, Aviation↗
PubMed1989

Variability in doctors' problem-solving as measured by open-ended written patient simulations.

The uncertain validity of written simulations could be due to the difficulty in setting criteria for optimal performance. Usually criteria are set by definition of a limited number of 'correct answers' by a panel of experts reached through an open discussion. This is an artificial situation which entails mutual influence and forces the participants to respond to the necessity to reach a consensus. In the present report we describe an attempt to set 'correct answers' by the independent performance of 15 board-certified internists on four written simulations. There was a marked variability in responses due to legitimate differences in approach, to obvious errors in interpretation of the provided data and to possible differences between the expert behaviour in a real life and in a simulated setting. We believe that the criteria for acceptable performance on written clinical simulations should be determined by independent experts, rather than by a group consensus. Students who receive after the examination a compiled list of options selected by experts in response to the same questions may obtain a more realistic insight into the complexity of clinical problem-solving.

Clinical Competence↗
PubMed1988

Air accidents, pilot experience, and disease-related inflight sudden incapacitation.

The epidemiology of sudden death, the etiology of inflight sudden incapacitation, and the influence of pilot age and experience on air accident rates are reviewed in order to determine the aeromedical emphasis needed to minimize accidents. Sudden deaths in men over age 35 are nearly all due to coronary artery disease, whereas in those under 35 years they are mostly due to hypertrophic cardiomyopathy. The incidence of fatal accidents from human error is, however, far greater than that from physical illness. Since inexperienced pilots have a 2-3 times increased incidence of mishaps due to pilot error, the estimated risk of disease related in-flight sudden incapacitation should be balanced by consideration of pilot experience. Therefore, it may be preferable to grant waivers to experienced pilots with an increased incidence of disease-related inflight sudden incapacitation than to replace them with novices. We conclude that overly strict medical criteria may paradoxically increase accident rates.

Accidents, Aviation↗
PubMed1987

Reliability of global rating scales in the assessment of clinical competence of medical students.

Undergraduate medical students of the Ben Gurion University were evaluated upon completion of their fourth- and sixth-year medical clerkships by a 17-item rating scale, a multiple choice question (MCQ) test and a patient-oriented oral examination by two academic staff members. Pearson's correlation coefficient between the fourth-and sixth-year global ratings was r = 0.44 (P less than or equal to 0.001), while that between the fourth- and sixth-year MCQ scores was r = 0.54 P less than or equal to 0.001). Pearson's coefficient between the global ratings and the MCQ scores in the sixth year was r = 0.25 (P less than or equal to 0.05). Stepwise regression analysis revealed that the ratings on the parameters 'reliability', 'knowledge', 'organization', 'diligence' and 'case presentation' were the most predictive of the overall global rating. It is concluded that the reproducibility of 'subjective' expert assessment of performance through global rating scales is comparable to that of 'objective' evaluation through written MCQ, even though these measures assess different domains of competence at different levels of simulations. It is recommended that the clinical performance of undergraduate medical students should be assessed by a combination of subjective and objective measures.

Clinical Clerkship↗
PubMed1987

Predictive value of sputum cytology.

A 60 year old woman non-smoker with bronchial asthma of 6 years' duration, treated with aminophylline, salbutamol, and oral corticosteroids, was admitted because of increasing dyspnoea and productive cough. On examination she was in moderate respiratory distress with inspiratory and expiratory wheezes. Her chest radiograph was interpreted as normal. Two consecutive sputum examinations requested by a junior doctor reveal "malignant" cells.

Adult↗