Charting new directions in education. Interview by Andrew Cole.
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Education, Nursing↗
Biomedical subjects
C Davies
Publications and source records attributed to C Davies.
Development of a magnetically operated artificial urethral sphincter. Chronic effects of compression on the skin structure and blood flow.
The artificial urethral sphincter (AUS) has been in clinical use for more than 20 years. Currently available AUS devices, however, are difficult to use and not entirely reliable. A magnetically operated AUS is currently under the development. Although the skin between the magnets will be compressed all day long, little information exists on the effects of chronic pressure on the skin structure and blood flow. In five miniature pigs, two internal magnets and one control metal disk were implanted subcutaneously at three different positions, and external magnets with differing magnetic forces were applied to the skin overlying the internal magnets for six weeks. In four pigs, the skin blood flow was measured by a laser Doppler flow meter applying different pressures. Compression of 10 mmHg preserved normal skin morphology in all but one animal where blood flow had not recovered 2 weeks after surgery. Compression of 20 mmHg for 6 weeks, however, produced pressure ulcers in all five cases (p < 0.05 vs. 10 mmHg group). The skin blood flow declined for pressures exceeding 20 mmHg (0 mmHg: 4.3 +/- 1.2, 10 mmHg: 4.3 +/- 3.3, 20 mmHg: 2.6 +/- 2.7 ml/min/100 g). We concluded that the magnetically operated AUS should use a magnetic coupling with a pressure less than 10 mmHg exerted on the interposing skin.
Animals↗
Effects of a total artificial heart right stroke volume limiter on left-right hemodynamic balance.
In a completely implantable total artificial heart (TAH), the left-right flow difference attributable to higher volumetric efficiency of the right pump and bronchial artery shunting has always been a significant problem. The automatic control of the Cleveland Clinic-Nimbus TAH accommodates for the left-right flow difference when the beat rate is below maximum (AUTO range). However, at its maximum beat rate (MAX), high left atrial pressure (LAP) (greater than 25 mmHg) with relatively low right atrial pressure (RAP) (less than 8 mmHg) were observed both in vitro and in vivo, suggesting the need for a stroke volume limiter (SVL) of the right pump. In vitro volume loading tests showed 10%, 15%, and 20% SVLs prevented a disproportionate increase of LAP. In vivo studies in five Holstein calves also showed a balanced LAP-RAP relationship with 10% and 15% SVLs at MAX. The left pump flow was not affected by this range of SVLs either in vitro or in vivo. Pulmonary function was maintained with either size SVL, with autopsies revealing absence of pulmonary congestion and minimal pleural effusions in two calves surviving for more than 1 month. Although additional studies are needed to determine the appropriate size of the SVL, both 10% and 15% SVLs were effective in maintaining left-right hemodynamic balance in this TAH.
Animals↗
Coronary artery luminal narrowing in the young with sudden unexpected death: a coroner's autopsy study in 350 subjects age 40 years and under.
OBJECTIVE: To describe the extent and distribution of coronary artery luminal narrowing in a Canadian population (aged 40 years and under) dying suddenly and unexpectedly. METHODS: From a coroner's autopsy population of 350 subjects whose mean age was 28.4 +/- 6.5 years and of whom 250 were male, percentage luminal narrowing was estimated in the four epicardial coronaries. The left main, left anterior descending, left circumflex and right major coronary arteries were sectioned at 5 mm intervals and percentage cross-sectional luminal narrowing from the internal elastic lamina of each segment was estimated microscopically and then graded into four categories: I, 0 to 25%; II, 26 to 50%; III, 51 to 75%; and IV, greater than 75%. A total of 14,611 5 mm segments were evaluated (mean 41.7 per case). The segments were classified as originating from males or females and into three age groups (less than 20, 20 to 29 and 30 to 40 years). RESULTS: For the entire population, virtually no luminal narrowing greater than 50% was found in patients less than age 20 years, but was found in 3% of segments in the group aged 20 to 29 years and in 8.4% of segments in the group aged 30 to 40 years. In the group aged 20 to 29 years, greater than 50% narrowing was found in 3.8% of segments in males and in 1.2% of segments in females (P < 0.001). In the group aged 30 to 40 years, the corresponding numbers were 10.5% for males and 2.2% in females (P < 0.0001). Eighty-six males (34.4%) had greater than 50% narrowing of at least one coronary artery versus 19 females (19%) (P < 0.01). Left main narrowing of greater than 50% was found in 17 subjects, of which 13 were males. Luminal narrowing was more prevalent in the left anterior descending than the right coronary artery or left circumflex coronary artery and more prevalent in the right coronary artery than the left circumflex coronary artery. CONCLUSIONS: In subjects less than age 20 years, luminal narrowing greater than 50% was virtually nonexistent. Its frequency progressed in both sexes after age 20 years and was significantly more pronounced in males. Narrowing of the left main coronary artery was more frequent than anticipated and was more common in males.
Adolescent↗
Cloaked in a tattered illusion.
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Female↗
A new vision of professionalism.
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Attitude of Health Personnel↗
Brain stem death and organ donation.
Our understanding of the concept and definition of death has changed over time. The British contribution to the body of knowledge on the diagnosis of brain steam death was the publication by the medical royal colleges (1976) of diagnostic criteria. Most literature and research which explores the knowledge and attitudes of nurses towards the concept of brain stem death is from the USA. Several issues which arise from the literature are discussed in relation to organ donation. Further UK-based research is required.
Attitude of Health Personnel↗
Knowledge and attitudes of nurses on a regional neurological intensive therapy unit towards brain stem death and organ donation.
The study aimed to explore nurses knowledge and attitudes towards brain stem death and organ donation. An ex post facto research design was used to determine relationships between variables. A 16 item questionnaire was used to collect data. Statistical analysis revealed one significant result. The limitations of the sample size is acknowledged and the conclusion suggests a larger study is required.
Adult↗