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Biomedical subjects

I David

Publications and source records attributed to I David.

51 records · Page 3Linked to original sources
PubMed1981

Pericardial tamponade and its effect on cardiac performance in absence of the pulmonic valve.

A controlled study was undertaken to quantitate and compare the amount of accumulated pericardial fluid causing acute pericardial tamponade in animals with or without an intact pulmonary valve. In 13 mongrel dogs, acute pericardial tamponade was induced by gradual loading of the pericardial cavity with fluid (mean 21.3 cc/m2). In 10 dogs (Group A) the pulmonic valve was completely excised under caval occlusion and the pericardium resealed. In Group B, the control group (n = 3), caval occlusion was performed for the same period of time but the pulmonary valve was left intact. Reloading of the pericardium with fluid in both groups revealed that whereas in the Control Group B a similar volume of fluid was required (mean 213 cc/m2) to cause critical tamponade, in Group A a much smaller volume (mean 132 cc/m2) (40% decrease) now produced tamponade (p less than 0.001). The results of the study may have important practical implications in patients having cardiac operations in which the pulmonary valve is left incompetent, such as after complete repair of tetralogy of Fallot.

Animals↗
PubMedDate not supplied

A time-dependent stopping problem with application to live organ transplants.

We consider a time-dependent stopping problem and its application to the decision-making process associated with transplanting a live organ. "Offers" (e.g., kidneys for transplant) become available from time to time. The values of the offers constitute a sequence of independent identically distributed positive random variables. When an offer arrives, a decision is made whether to accept it. If it is accepted, the process terminates. Otherwise, the offer is lost and the process continues until the next arrival, or until a moment when the process terminates by itself. Self-termination depends on an underlying lifetime distribution (which in the application corresponds to that of the candidate for a transplant). When the underlying process has an increasing failure rate, and the arrivals form a renewal process, we show that the control-limit type policy that maximizes the expected reward is a nonincreasing function of time. For non-homogeneous Poisson arrivals, we derive a first-order differential equation for the control-limit function. This equation is explicitly solved for the case of discrete-valued offers, homogeneous Poisson arrivals, and Gamma distributed lifetime. We use the solution to analyze a detailed numerical example based on actual kidney transplant data.

Decision Making↗
PubMedDate not supplied

Assessment of hypertension levels control and management (hypertension "AUDIT" project). Study in a population of workers.

The hypertension AUDIT project (WHO) was used for the study of large populations of workers in two Romanian industrial centers, Slatina and Sibiu, constituted into two main groups. The objects of the study were: the detection of new cases of arterial hypertension (AH) and of their proportion as compared with older cases, the assessment of the quality of diagnosis control and treatment methodology as well as the estimation of the patient's attitude regarding the conditions of treatment and of the physician's knowledge and attitude regarding AH. Group I (Slatina) included 22,839 workers and the program was applied in 15,740 randomly chosen subjects. Group II (Sibiu) included 14,874 workers of whom 2,838 were randomly chosen for study. From a total of 606 (6.20%) subjects aged 35 to 64 years with AH in both groups, 494 (81.51%) were older cases and 112 (18.48%) were newly detected. The prevalence of AH was found to increase with age and to be higher in women aged 55 to 64 years. The treatment in older cases from both groups was considered effective in 232 cases (46.96%) (of which 26 (11.2%) with overtreatment) and insufficient in 262 (53%). The reasons alleged by the patients for the late detection of AH were the absence of symptoms and a casual interest for their state of health. The risk factors were systematically checked. Smoking was found in 30.36% of the subjects in group I and in 31% of those in group II. The use of diagnostic laboratory procedures was corresponding to the present recommendations. The nonpharmaceutic therapy was frequently recommended, especially reduction of salt consumption. Besides that, pharmaceutic treatment was indicated in most of the patients (63% in group I and 90% in group II). Diuretics (41.26% in group I and 75% in group II), and beta blocking drugs (35.3% in group I and 70% in group II) were the most frequently administered and in a lesser proportion vasodilators with central or peripheral action, calcium blockers, Rauwolfia and angiotensin conversion enzyme inhibitors. The consumer inquiry showed satisfactory compliance of patients, most of them took their tablets regularly, were satisfied with the medical assistance and preferred to consult the same physician. The data of the physician inquiry regarding diagnosis treatment of AH and professional training also proved satisfactory. The use of the AUDIT project has allowed a complex estimation of AH in the groups studied and will prove useful for a more efficient control of AH in the whole population.

Adolescent↗