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Biomedical subjects

M M Berezin

Publications and source records attributed to M M Berezin.

5 recordsLinked to original sources

Effectiveness of a prehospital medical control system: an analysis of the interaction between emergency room physician and paramedic.

Medical control for paramedics by means of radio and ECG telemetry is costly, time consuming, and of unproved value. We assessed the interaction between emergency room physicians and paramedics during ambulance transport of "seriously ill" cardiac patients (cardiac arrest, acute myocardial infarction, or new onset of crescendo angina pectoris) with paramedics in service. Thirty-five percent of all arrhythmias and 35% of potentially life-threatening arrhythmias were misclassified. Correct treatment was rendered in 74% of the cases, although only 65% were correctly diagnosed (p < 0.01). The principal predictive variable for misdiagnosing or incorrectly treating a patient was the presence of a potentially life-threatening arrhythmia, precisely the condition for which medical control and the paramedic system has the most to offer. Only 39% of patients with life-threatening arrhythmias were correctly diagnosed and correctly treated, whereas 64% of patients without life-threatening arrhythmias were correctly diagnosed and correctly treated (p < 0.001). Mortality reflected correct diagnosis and treatment. In-hospital and overall mortalities were 12% and 33%, respectively, for patients who were correctly diagnosed and treated (p < 0.06), compared with 20% and 43%, respectively, for patients who were incorrectly diagnosed or incorrectly treated (p < 0.04). More rigorous medical control is needed to improve the quality of patient care and outcome and to further integrate the advanced life support program into the health care system.

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Implications of alternative sampling strategies for emergency medical service evaluation.

Evaluations of emergency medical service (EMS) programs have been ambiguous, due in part, to problems of sample definition. Four different sampling strategies were studied: 1) all patients in cardiac arrest; 2) patients with a final diagnosis of myocardial infarction (MI); 3) patients with an emergency room diagnosis of "rule out MI"; and 4) patients identified by the ambulance team as a possible MI. Using a regional data base of all ambulance runs, we created study samples based on each of these strategies and measured the error that may be introduced as a result of sample selection. Bias was measured along three parameters of EMS system performance: 1) observed incidence of MI in the ambulance system; 2) condition recognition--the ability of the ambulance team to correctly identify acute cardiac patients; and 3) emergency room and hospital mortality rates. The emergency room diagnosis strategy systematically excludes all false-positives, while samples based on the ambulance team's assessment omit all false-negatives. The final diagnosis strategy yields significant underestimates of cardiac mortality. Samples restricted to cardiac arrests result in biased estimates of both the incidence of MI and the number of deaths.

Ambulances↗

An assessment of emergency medical technicians' performance as related to seasonal population influx.

The periodic influx of large numbers of people into resort areas substantially increases the use of emergency medical services. This investigation assesses the effects of such a threefold increase in the summer population of the Cape Cod area upon the accuracy of emergency medical technicians' diagnoses and treatments. The technicians' diagnoses for ambulance patients were evaluated against those given by the emergency room physicians during the months of August 1975 and February 1976. The distribution of conditions was similar for both months and the observed frequency of correct diagnoses for common conditions was more than 90% in both months. The overdiagnosis rate of 25% to 50% for common conditions and the correct treatment rate for suspected myocardial infarction of 65% did not vary significantly between summer and winter. Thus, a large influx in population does not seem to affect adversely EMT diagnosis rates. Although misdiagnoses were uncommon, a failure to follow through with a correct treatment for patients with suspected myocardial infarctions, thus indicating the need for better quality control on EMT performance.

Allied Health Personnel↗

Ambulance utilization by patients with acute myocardial infarction.

Fifty-five per cent (73/133) of myocardial infarction (MI) patients on Cape Cod during a three-month period reached the hospital by ambulance. the 45 per cent (60/133) not using ambulances were compared to users to identify a subpopulation to which public health programs might be directed to increase appropriate use of cardiac ambulances. Univariate analyses showed a distnce of more than ten miles from the hospital, and a prior history of MI distinguished ambulance users from non-users. Demographic/economic status, delay in seeking care, presenting symptoms, Killip class, and in-hospital mortality rates were not signigicantly different. Step-wise discriminant analysis identified four predictive variables in rank order: distance from the hospital, past history of MI, symptoms of fainting, and negative history for hypertension which correctly classified 72 per cent of our population with respect to ambulance utilization.

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