Biomedical subjects

J G Stevenson

Publications and source records attributed to J G Stevenson.

116 records · Page 7Linked to original sources

PubMedDate not supplied

Two-dimensional color Doppler estimation of the severity of atrioventricular valve regurgitation: important effects of instrument gain setting, pulse repetition frequency, and carrier frequency.

Literature reports of good correlation between two-dimensional color Doppler and ventriculography for estimation of the severity of atrioventricular valve regurgitation have appeared. Local experience has been variable. The purpose of this study was to evaluate three factors for their effect on two-dimensional color Doppler display of the apparent area of regurgitant flow. The factors studied were instrument gain setting, pulse repetition frequency (PRF), and carrier frequency. Sixteen regurgitant valves were examined with high quality commercial instrumentation from two manufacturers. Electrocardiographic-triggered image gating was used for recording and planimetry of maximal imaged flow area (IFA). Examinations were performed at two gain settings with constant carrier frequency and PRF, at three carrier frequencies (2.5, 3.5, and 5 MHz) at constant gain, and at differing PRF (3.0 to 12 kHz). Reduction in gain setting made little difference in asthetic quality of regurgitant jets, but their areas decreased by 29%. Carrier frequency was found to greatly affect IFA, with each higher carrier frequency giving significantly smaller IFAs. PRF also affected IFA consistently, with progressively smaller IFAs at each higher PRF. There was no useful correlation between IFA of a single jet evaluated on the two instruments at generally similar settings. It is concluded that instrument gain setting, PRF, and carrier frequency each significantly affects the size of IFA within a single instrument and between different instruments. Given the variety of instruments and settings employed within the cardiology community, it is unlikely that even moderately accurate grading of severity of regurgitation based on IFA can be done unless instrument settings are specified and standardized. There is a clear need for annotation of instrument settings during color Doppler examinations and a need for concensus regarding "optimal" settings. Finally, the consistency of reduction in IFA with increasing carrier frequency and PRF within each of the instruments tested suggests investigation of "normalization" of IFA displays.

Adolescent↗

PubMedDate not supplied

Comparison of several noninvasive methods for estimation of pulmonary artery pressure.

Noninvasive estimation of pulmonary artery pressure is an important component of cardiac ultrasound studies. A number of methods are available for estimation of pulmonary pressure, each with varying degrees of reported accuracy. To assess feasibility and accuracy, noninvasive pulmonary artery pressure estimates were performed in infants and children at the time of catheterization. Patients were examined prospectively until there were 50 patients, in whom each of six methods for estimation of pulmonary pressure had been accomplished. All patients had tricuspid and pulmonary regurgitation of less than severe degree and no structural, flow, or electrocardiographic abnormality known to compromise the six methods. Systolic pressure was estimated by the Burstin method and also from peak tricuspid regurgitation velocity. Mean pressure was estimated by acceleration time divided by ejection time from waveforms obtained from the right ventricular outflow tract and main pulmonary artery. Diastolic pressure was estimated by systolic time intervals and from end-diastolic pulmonary regurgitation velocity. Noninvasive estimates were compared with simultaneous or nearly simultaneous catheterization measurements. For systolic pressure Burstin estimates were accomplished in 89% with high accuracy (r = 0.97). Tricuspid regurgitation velocities were recorded in 82%, also with high accuracy (r = 0.96). Waveforms for mean pressure estimation were recorded in 98% to 100% of patients. Those from the right ventricular outflow tract corresponded well with catheterization pressures (r = 0.94), whereas those recorded from the main pulmonary artery offered poor prediction of pulmonary pressure (r = 0.63). Systolic time interval measurements were accomplished in only 65% and did not correlate highly with catheterization (r = 0.84). Diastolic pressure estimates based on pulmonary regurgitation velocity were recorded in 98% of subjects with high accuracy (r = 0.96). Each method had advantages and disadvantages. The Burstin method was accurate but technically demanding and is reported to be limited by heart rate and significant right-sided regurgitation. Peak tricuspid velocities proved unexpectedly difficult to record in some patients but when successful, provided excellent prediction of pressure. Recording of waveforms for ratios of acceleration time to ejection time proved easy, but accuracy was high only for outflow tract waveforms. Peculiarities of main pulmonary artery flow may have led to poor accuracy for ratios measured from that site. For diastolic pressure estimation, systolic time interval records were the most difficult to obtain and did not provide useful accuracy. In contrast, pulmonary regurgitation velocities were easily obtained and provided high accuracy results. This is a selected pediatric series, evaluating methods in nearly ideal circumstances.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

PubMedDate not supplied

A conceptual framework for achieving high-quality care in nursing homes.

Nursing home care accounts for 12% of healthcare expenditures in the United States, yet serious concerns remain about the quality of care provided in these settings. This article describes a comprehensive systems model that views organizational environments as consisting of four interacting dimensions: organizing arrangements, social factors, technology, and physical setting. This model is then used as a conceptual framework (vis-à-vis an extensive literature review) to identify factors that contribute to poor-quality care in nursing homes and to highlight previous research efforts. The literature review also provides a useful framework to guide nursing home administrators and healthcare quality professionals in their implementation of quality improvement processes and serves to help direct future research in this very important arena.

Facility Design and Construction↗

PubMedDate not supplied

Apparent rupture of the ventricular septum after myocardial infarction in an infant with congenital heart disease.

Clinical and angiocardiographic simulation of rupture of the interventricular septum, in an infant with an endocardial cushion defect and documented myocardial infarction is reported. Close straddling of a proven congenital muscular apical ventricular septal defect by trabeculae carne is believed to have led to the angiocardiographic simulation of a post-infarction apical ventricular septal defect. In the surgical approach to post-infarction ventricular septal defects, the implication of such a simulation could be important.

Heart Rupture↗

PubMedDate not supplied

A computerized system to improve documentation and reporting of pharmacists' clinical interventions, cost savings, and workload activities.

A major factor in delivering patient care is documenting activities by pharmacists. This documentation is not only essential to sustain existing programs but necessary to justify future growth of resources. A computerized documentation system for clinical interventions and workload activities was developed in a 340-bed university teaching hospital. With the expansion of its pharmaceutical care model, the department reworked its distribution process to allocate more pharmacist time for patient care. Manual documentation of these services, however, soon was identified as an obstacle. A software program was developed to alleviate the problems inherent with manual documentation. This "user-friendly" program tracks clinical recommendations and interventions by pharmacists, and calculates cost savings/avoidance. It also facilitates monthly and annual reporting for department managers.

Clinical Pharmacy Information Systems↗

PubMedDate not supplied

A pharmacoeconomic analysis of neuromuscular blocking agents in the operating room.

A cost-minimization analysis was performed to compare the direct costs of various neuromuscular blocking agents (NMBAs) in procedures of specific durations. Secondary objectives were to review the role of the NMBAs studied with respect to their place on our hospital formulary, and to develop a pharmacoeconomic methodology to be applied to other formulary decisions. Patients were stratified according to estimated length of surgical procedure; group 1 (55 patients) included surgeries estimated to take less than 2 hours, and group 2 (55 patients) included those estimated to be 2-4 hours long. Patients were then randomized to one of three intermediate-acting NMBAs: atracurium, vecuronium, or rocuronium. Anesthesia records were used to obtain all anesthetic agents administered in the operating room, and drug costs were calculated from hospital drug acquisition costs as of December 1994. Postanesthesia care unit (PACU) costs were estimated from patient charges and converted to costs using our hospital's cost-to-charge ratio. Costs that were common to all study treatments or unrelated to the use of NMBAs were excluded from the analysis. Two time-adjusted costs were calculated to determine the cost of neuromuscular blockade/hour and the total anesthesia drug costs/hour. In group 1 there were no statistical differences in NMBA cost/hour, anesthesia cost/hour, or PACU times or costs. In group 2, a significant difference was found in NMBA cost/case between atracurium ($54.23 +/- 41.26, mean +/- SD) and vecuronium ($31.95 +/- 15.33, p = 0.046). Atracurium was also significantly more costly than either vecuronium or recuronium/hour ($21.95 +/- 7.42 vs $14.39 +/- 7.02 and $16.07 +/- 8.15, respectively, p = 0.011) and anesthesia cost/hour ($28.77 +/- 7.43 vs $ 22.82 +/- 7.46 and $23.32 +/- 6.54, respectively, p = 0.03). There were no differences in PACU times or costs. Based on these results, vecuronium or rocuronium is preferred over atracurium in procedures with an estimated duration of 2-4 hours. In the patient population evaluated, there were no significant cost differences among the three NMBAs in surgeries with an estimated duration of less than 2 hours.

Adult↗

PubMedDate not supplied

Thromboembolic prophylaxis in moderate-risk patients undergoing elective abdominal surgery: decision and cost-effectiveness analyses.

We conducted a retrospective, literature-based decision analysis to compare the cost-effectiveness of conventional low-dose heparin, dalteparin, and intermittent pneumatic compression (IPC) as thromboembolic prophylaxis to a no-prophylaxis option in patients at moderate risk of developing thromboembolic complications after major elective abdominal surgery. The analysis was conducted through an institutional perspective. Probability and incidence rate data were summarized from the literature. Cost data were obtained from the Detroit Medical Center's cost accounting systems and from national diagnosis-related group estimates. Mortality and complications avoided were the main outcome measures on which cost-effectiveness was based. Overall costs associated with conventional low-dose heparin, dalteparin, intermittent pneumatic compression, and no prophylaxis were $84, $122, $102, and $112, respectively in the primary analysis, which included costs of labor. Corresponding cost-effectiveness ratios in terms of costs/complication-free patient were $86, $124, $103, and $118, respectively. Compared with no prophylaxis, incremental cost-effectiveness analysis in terms of cost/mortality avoided involved savings of $6087 and $3125 with conventional low-dose heparin and IPC, respectively, and expenses of $2857 with dalteparin. A secondary analysis excluding costs of labor showed similar results. The results of the study consistently showed conventional low-dose heparin to provide the most cost-effective thromboembolic prophylaxis of the methods considered in terms of reducing both morbidity and mortality in the patient population studied.

Cost-Benefit Analysis↗

PubMedDate not supplied

A pharmacist-initiated program of intravenous to oral antibiotic conversion.

A prospective program to convert patients from parenteral to oral antibiotics was evaluated over 12 months to determine its pharmacoeconomic impact on antibiotic acquisition and length of hospital stay. Physicians of patients meeting predetermined clinical criteria for mild and moderate infections were contacted to discuss potential oral alternative therapy. Clinical end points and economic data were followed in 242 patients (200 converted and 42 not converted but meeting criteria). No significant differences were noted between the groups with regard to demographic data, infection diagnosis, clinical outcome, or adverse effects. The average number of days of therapy for patients converted was 1.53 days shorter than that of patients who were not converted to oral therapy (p < 0.003). Cost savings for drug acquisition and length of stay were $15,149.24 and $161,071.88, respectively. The intervention program appeared to provide a cost-effective conversion from parenteral to oral antimicrobial administration without compromising patient care. It is anticipated that expansion of the program to include additional antibiotics will result in even greater cost savings for the institution.

Administration, Oral↗