Biomedical subjects

M L Dwyer

Publications and source records attributed to M L Dwyer.

7 recordsLinked to original sources

PubMed2000

Advanced practice nursing for children with HIV infection.

Children from any ethnic background and in any geographical location can be affected by HIV disease. Once acquired, HIV disease holds a devastating future for the infected child, his or her parents, and the entire family. As a multisystem disease, HIV affects every aspect of the child's growth and development. Management and prevention presents many challenges to the pediatric advanced practice nurse in the ambulatory care setting. This article reviews the epidemiology and transmission of HIV, as well as the clinical presentation of the HIV-infected child in the clinic.

Anti-HIV Agents↗

PubMed1998

Genetic research and ethical challenges: implications for nursing practice.

Careful consideration of the potential consequences of biomedical research involving human beings is an important advanced practice strategy. The presence of disease and the hope for a cure through genetic manipulation create a complex mix of ethical concerns. In this article, some of the actual and potential issues associated with genetic research and the implications for nursing practice are discussed. The principles of autonomy, beneficence, and justice provide a framework for the discussion.

Ethics, Nursing↗

PubMed1991

Intravascular ultrasound imaging of human coronary arteries in vivo. Analysis of tissue characterizations with comparison to in vitro histological specimens.

BACKGROUND: Intravascular ultrasound imaging was performed in 27 patients after coronary balloon angioplasty to quantify the lumen and atheroma cross-sectional areas. METHODS AND RESULTS: A 20-MHz ultrasound catheter was inserted through a 1.6-mm plastic introducer sheath across the dilated area to obtain real-time images at 30 times/sec. The ultrasound images distinguished the lumen from atheroma, calcification, and the muscular media. The presence of dissection between the media and the atheroma was well visualized. These observations of tissue characterization were compared with an in vitro study of 20 human atherosclerotic artery segments that correlated the ultrasound images to histological preparations. The results indicate that high-quality intravascular ultrasound images under controlled in vitro conditions can provide accurate microanatomic information about the histological characteristics of atherosclerotic plaques. Similar quality cross-sectional ultrasound images were also obtained in human coronary arteries in vivo. Quantitative analysis of the ultrasound images from the clinical studies revealed that the mean cross-sectional lumen area after balloon angioplasty was 5.0 +/- 2.0 mm2. The mean residual atheroma area at the level of the prior dilatation was 8.7 +/- 3.4 mm2, which corresponded to 63% of the available arterial cross-sectional area. At the segments of the coronary artery that appeared angiographically normal, the ultrasound images demonstrated the presence of atheroma involving 4.7 +/- 3.2 mm2, which was a mean of 35 +/- 23% of the available area bounded by the media. CONCLUSIONS: Intravascular ultrasound appears to be more sensitive than angiography for demonstrating the presence and extent of atherosclerosis and arterial calcification. Intracoronary imaging after balloon angioplasty reveals that a significant amount of atheroma is still present, which may partly explain why the incidence of restenosis is high after percutaneous transluminal coronary angioplasty.

Angiography↗

PubMed1990

Intravascular ultrasonic imaging.

Because conventional imaging methods are inadequate for evaluating human coronary arteries in vivo, an intravascular ultrasonic imaging catheter was developed that allows the arterial wall to be studied in cross-section from within the artery. The catheter incorporates a mechanically rotating 20-MHz transducer, which is designed so that the ringdown occurs within the catheter and imaging is permitted up to the catheter's surface. The device rotates at 1800-rpm within a plastic sleeve and provides real-time cross-sectional images at 30 frames/sec. Preliminary experimental and clinical studies indicate that the intravascular ultrasonic imaging catheter could play a valuable role in providing preoperative information concerning arterial wall thickness and tissue characteristics, in distinguishing normal from diseased arterial wall structures during therapeutic intervention, and in assessing the results of intervention.

Journal Article↗

PubMed1989

Quantitative regional contraction analysis of cineventriculography: reporting, filing, and retrieval functions using a personal computer.

A new method for the semiobjective evaluation of left ventricular wall contraction is proposed that uses a percent reduction of areas. The calculation model uses orthogonal coordinates, an internal reference system, and the concept of nonuniform reduction of the cavity, with its obliteration at the apex. From a normal patient population (ten males, four females; aged 45 +/- 13 years), a "normal reference curve" of contraction was obtained. A second patient group (56 males, two females, aged 56 +/- 7 years) with definite contraction abnormalities was then analyzed. A third group (eight males, one female, aged 56 +/- 10 years) was studied before and after nifedipine administration (1 mg over 2 min IV). Specific algorithms compare individual patient contraction curves with the normal reference curve and compute the score point system of contraction analysis. Data are automatically codified and filed during introduction. This saves time and allows a rapid retrieval of data grouped under different coded features. These features include the location and type of wall contraction abnormalities. This method of reading ventriculograms has been shown to be in accordance with the diagnosis of experienced observers and can detect small contraction changes that are induced pharmacologically. The method is proposed as a valuable tool for semiobjective evaluation of left ventricle wall contraction and to facilitate data collection in multicenter collaborative studies.

Algorithms↗

PubMed1989

Retrieval technique of a PTCA guidewire.

A report is made of a case study where a non-surgical technique was used to remove a broken floppy percutaneous transluminal coronary angioplasty (PTCA) guidewire. The technique involved the use of a "lasso" to successfully retrieve the broken wire from the left main artery and into the aorta.

Adult↗

PubMedDate not supplied

ECMO assisted angioplasty for cardiomyopathy patients with unstable angina.

Patients who are otherwise unsuitable candidates for coronary bypass surgery or standard coronary angioplasty (PTCA) may be successfully treated with PTCA during ECMO. Five patients (3 men, 2 women), with a mean age of 57 years, are reported on here. They were not considered good candidates for standard therapy because of poor left ventricular function (mean EF, 24; range, 16 to 28%). Patients were supported by percutaneous femoral bypass using a BARD CPS machine, and underwent successful PTCA of either two vessels (three patients) or three vessels (two patients); in addition, one patient had dilatation of a stenotic aortic valve. Patients were supported with ECMO for 26 to 140 (mean 104) minutes, and required transfusion with 0 to 4 (mean 2) units of blood during or after the procedure. Complications included groin hematoma in two patients. All were discharged within 4 days of the procedure. Follow-up of the patients has been completed (4-7 mo) with no further hospitalizations for unstable angina. All patients remain in NYHA Class II or III. These data suggest that ECMO-assisted angioplasty is a safe and effective method of palliation of unstable angina associated with cardiomyopathy.

Adult↗