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Biomedical subjects

M Hunt

Publications and source records attributed to M Hunt.

At least 109 records · Page 6Linked to original sources

Indium-111 platelet scintigraphy and two-dimensional echocardiography for detection of left ventricular thrombus: influence of clot size and age.

Two-dimensional echocardiography and indium-111 platelet scintigraphy were performed on 50 dogs to determine the influence of clot age and size on the detection of experimentally induced left ventricular mural thrombus. Thrombus was induced by apical infarction and injection of a sclerosing agent and thrombin. The animals were classified into four groups according to the time of indium-111 platelet injection after thrombus induction: Group I (17 dogs, 1/2 hour after induction; 3 dogs, before induction), Group II (12 dogs, 24 hours after induction) and Group III (12 dogs, 1 week after induction). In Group IV (six control dogs) apical infarction was produced, but thrombin was not injected; indium-111 platelets were injected 1/2 to 1 hour after infarction. The dogs were studied by indium-111 platelet scintigraphy and by two-dimensional echocardiography 1/2 to 5 hours (Group I) and 1 to 5 and up to 72 hours (Groups II to IV) after platelet administration and before death was induced. Two-dimensional echocardiography showed the best overall sensitivity for detection of acute thrombus (97%; 29 of 30). The sensitivity of indium-111 platelet scintigraphy was 86% (18 of 21) for clots greater than or equal to 0.08 ml in size, and 67% (20 of 30) for detection of all clots. Thrombus did not form in 14 dogs of Groups I to III and in 6 of 6 control dogs. The specificity of scintigraphy was 100% (20 of 20) compared with 80% (16 of 20) for echocardiography. Echocardiography was more sensitive than scintigraphy for detecting very small clots in this experimental model.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Platelets↗

The process of translating research findings into nursing practice.

Action research studies are described which involved nurse teachers, ward sisters and nurse managers in the processes of: nursing practice problem identification and the search for relevant research literature; the evaluation and synthesis of the collected literature; the identification of the need to change practice and the translation of the research synthesis into practice if warranted. The processes engaged in by the groups in each of the three phases in relation to the management of mouth care and preoperative fasting are analysed. The findings suggest that the demands of these processes are beyond the capacity of any one individual nurse and require systematic organizational approaches such as that proposed by quality assurance programmes. The need is emphasized for as much status and resources to be expended on the utilization of existing information as is given to the generation of new knowledge.

Education, Nursing↗

Can localised brain impairment be simulated on neuropsychological test profiles?

We asked 28 registered nurses with varying degrees of experience in working with neurological and neurosurgical patients to fake results on 10 neuropsychological tests in such a way as to be congruent with a history of trauma to the left fronto-temporal cortex. We compared these data to those obtained from 21 patients who had been referred with verified cerebral injury and who had a diagnosis of left fronto-temporal dysfunction. The overall hit rate of classification for the two groups was 85.7% and 89.8%, depending on the way in which test scores were combined. Results showed that a knowledgeable group of informed fakers had great difficulty reproducing the test performance of individuals with left fronto-temporal impairment.

Adult↗

High frequency epicardial echocardiography for coronary artery evaluation: in vitro and in vivo validation of arterial lumen and wall thickness measurements.

The purpose of this study was to determine the accuracy of a new high frequency echocardiographic technique for the quantitative assessment of coronary artery luminal and wall dimensions. In 32 open chest animals, high frequency echocardiographic measurements (echo) of luminal diameter correlated well with in vitro histologic measurements (Histo) (r = 0.86; high frequency echo = 0.89 Histo + 0.79) (range 1.7 to 5.8 mm). Similar results were found in the evaluation of five human autopsy hearts studied in vitro. Coronary artery wall thickness measurements in human autopsy hearts showed a good correlation with high frequency echocardiographic measurements (r = 0.86; high frequency echo = 0.65 Histo + 0.24) (range 0.3 to 0.8 mm). In eight open chest calves, high frequency echocardiographic measurements of total vessel diameter correlated well with sonomicrometer measurements (Sono) (r = 0.94; high frequency echo = 1.03 Sono + 0.4) (range 2.1 to 5.3 mm). Inter- and intraobserver variability measurements of high frequency echocardiographic measurements demonstrated excellent reproducibility (r = 0.95, interobserver variability for wall thickness; r = 0.97, interobserver variability for luminal diameter; n = 10 postmortem human coronary arteries). In conclusion, high frequency echocardiography is an accurate and reproducible method of measuring coronary luminal and wall geometry and may be a potentially useful tool for in vivo coronary artery evaluation in patients.

Animals↗

Effect of lidocaine and bretylium on energy requirements for transthoracic defibrillation: experimental studies.

The purpose of this study was to determine the effect of the antiarrhythmic drugs lidocaine and bretylium on the minimal energy requirement for transthoracic defibrillation--the defibrillation threshold. Closed chest dogs were anesthetized with chloralose or pentobarbital; lidocaine was administered at varying rates for 2 hours and defibrillation threshold periodically redetermined. Similar protocols were followed for bretylium. Serum lidocaine levels from therapeutic to toxic ranges were obtained, and up to a 60% (p less than 0.05) increase in defibrillation threshold in the pentobarbital-anesthetized dogs was demonstrated. In chloralose-anesthetized dogs the lidocaine effect was modest, with only a 10 to 20% rise in defibrillation threshold (p = NS) despite similar increases in serum lidocaine levels. Thus, lidocaine increases the minimal energy requirements for transthoracic defibrillation, but this effect is in part anesthesia-related, indicating a lidocaine-pentobarbital interaction. When phentolamine was administered to chloralose-anesthetized dogs receiving lidocaine, defibrillation threshold rose 13% (p less than 0.05); this suggests that alpha-adrenergic receptor blockade is at least in part the mechanism of the pentobarbital-lidocaine interaction on defibrillation threshold. Bretylium with either anesthetic had no significant effect on defibrillation threshold.

Animals↗

Intraoperative evaluation of coronary artery bypass graft anastomoses with high-frequency epicardial echocardiography: experimental validation and initial patient studies.

There is currently no accepted approach for intraoperative evaluation of the technical adequacy of coronary artery bypass graft anastomoses. High-frequency epicardial echocardiography performed intraoperatively could assess coronary artery bypass graft anastomoses by providing on-line short-axis (cross-sectional) and longitudinal two-dimensional images of the vessels. To validate measurements of anastomoses with high-frequency epicardial echocardiography, luminal diameter determined by high-frequency epicardial echocardiography was compared with that determined histologically after perfusion fixation in 12 dogs studied after coronary artery bypass grafting. Technical errors were deliberately created in some grafts. The results of these animal validation studies showed that maximum luminal diameter of the anastomosis by high-frequency epicardial echocardiography correlated well with histologic measurements (r = .92; high-frequency epicardial echocardiography = 0.8 histology + 0.3). All deliberately created technical errors were detected by an independent observer using high-frequency epicardial echocardiography. After completion of the animal studies, we demonstrated the clinical applicability of this approach in 12 patients. Fifteen coronary artery bypass graft anastomoses were examined intraoperatively with high-frequency epicardial echocardiography. The measured maximum luminal diameter of the anastomosis was greater than the maximum luminal diameter of the native artery, as expected, in all end-to-side anastomoses. However, the maximum luminal diameter of the side-to-side anastomoses was equal to or slightly less than that of the native artery. In this initial patient group, minor technical errors were noted in two of 15 graft anastomoses. In conclusion, high-frequency epicardial echocardiography can accurately measure coronary arterial bypass graft anastomoses and has potential for intraoperative detection of technical errors and inadequacies.

Animals↗

Managed care in the 1990s.

The demand for managed care is growing at a phenomenal rate, and insurance and hospital corporations are now entering the market. With this influx of new providers, however, price-based competition will intensify and cost containment will become key to survival. This article traces the growing demand for managed care through the development of HMOs and PPOs that can maintain their market share in a competitive environment.

Cost Control↗

[Not Available].

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History, Modern 1601-↗

Missed opportunities for early diagnosis of cancer of the cervix.

In a low-income community, 52% of new invasive cancer of the cervix arose in women who had no previous Pap smear, while 62% arose in women with no smear within five years. In the previous five years, 73% of the unscreened women had received ambulatory medical care (including 41% who had regular care for chronic conditions), while 16% were hospitalized. Much of the unscreened low-income population could be reached by routine screening in regular ambulatory health services and hospitals.

Ambulatory Care↗