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Biomedical subjects

S D Horn

Publications and source records attributed to S D Horn.

At least 19 recordsLinked to original sources
PubMed1999

Calf-thigh sequential pneumatic compression compared with plantar venous pneumatic compression to prevent deep-vein thrombosis after non-lower extremity trauma.

OBJECTIVE: To compare the effectiveness of calf-thigh sequential pneumatic compression devices with the effectiveness of plantar venous intermittent pneumatic compression devices in prevention of venous thrombosis after major trauma. SUBJECTS AND METHODS: We evaluated 181 consecutive patients after major trauma without lower extremity injuries that precluded the use of pneumatic compression devices. We randomly assigned 149 patients to either calf-thigh sequential pneumatic compression or plantar venous pneumatic compression. After blinding the observers to the method of prophylaxis against deep-vein thrombosis, we performed bilateral compression ultrasonography on or before day 8 after randomization. RESULTS: Among 149 randomized patients, 62 who received calf-thigh sequential pneumatic compression and 62 who received plantar venous intermittent pneumatic compression devices completed the trial. Thirteen patients randomized to plantar venous intermittent pneumatic compression (21.0%) and 4 patients randomized to calf-thigh sequential pneumatic compression (6.5%) had deep-vein thrombosis (p = 0.009). Seven of 13 patients with deep-vein thrombosis after prophylaxis with plantar venous intermittent pneumatic compression had bilateral deep-vein thromboses, whereas all 4 patients with deep-vein thrombosis after prophylaxis with calf-thigh sequential pneumatic compression had unilateral deep-vein thrombosis. CONCLUSION: Calf-thigh sequential pneumatic compression prevents deep-vein thrombosis more effectively than plantar venous intermittent pneumatic compression after major trauma without lower extremity injuries.

Adult↗
PubMed1998

Formulary limitations and the elderly: results from the Managed Care Outcomes Project.

OBJECTIVE: To examine whether restrictive formularies are associated with differences in healthcare resource utilization, including number of office visits, prescriptions, and hospitalizations, and whether this association varies by age. STUDY DESIGN: Cross-sectional, longitudinal study. PATIENTS AND METHODS: Patients enrolled in one of six health maintenance organizations in six different states, three in the eastern and three in the western United States, were eligible for the study. Data from between 1309 and 3938 patients were available for analysis for each of the five diseases studied, for a total of 12,997 patients across all study diseases. Healthcare utilization by patients in the study included more than 99,000 office visits, 1000 hospitalizations, and 240,000 prescriptions. We used severity-adjusted prescription counts, prescription costs, office visit counts, and measures of inpatient hospital utilization to assess the effects of formulary limitations. RESULTS: We found positive, significant associations between the independent variable formulary limitations in drug class and the dependent variables measuring resource utilization. These associations were sometimes significantly greater for elderly patients after controlling for severity of illness and other variables. CONCLUSIONS: Common strategies for decreasing drug expenditures may be associated with higher severity-adjusted resource utilization. In specific areas, this association is more pronounced in the elderly.

Aged↗
PubMed1997

A comparison of the accuracy and reproducibility of digital three-dimensional coronary artery reconstructions using edge detection or videodensitometry.

Global quantitative three-dimensional measurements of coronary arteries may be helpful in determining the functional significance of various forms of coronary pathology. A computerized system has been developed that is capable of performing 3-D reconstruction of digitized images obtained from multiple coronary angiographic views using either automated edge detection (AED) or videodensitometric (VD) techniques. To compare the accuracy and reproducibility of measurements obtained from this system using either technique, stationary and moving coronary aluminum 3-D phantoms, each with 13 branches (diameter 0.58-6.35 mm, length 21.5-64.5 mm), were imaged and reconstructed 10 separate times each. Individual branch lengths and diameters were calculated and compared to each other and to known values. Diameter measurements were compared using either AED or VD. Intraclass correlation coefficients between observed values (ICC) for vessel length were r = 0.89 for the stationary and r = 0.97 for the moving phantom. ICCs for vessel diameter were r = 0.93 (AED) and r = 0.95 (VD) for the stationary and r = 0.98 (AED) and r = 0.97 (VD) for the moving phantom. Mean differences (+/-SD) between true and observed values [MDTO(+/-SD)] for vessel length were -1.0 +/- 3.9 mm for the stationary and -3.5 +/- 3.2 mm for the moving phantom. MDTO(+/-SD) for vessel diameter were -0.10 +/- 0.52 mm (AED) and +0.03 +/- 0.30 mm (VD) for the stationary and -0.21 +/- 0. 44 mm (AED) and -0.12 +/- 0.33 (VD) for the moving phantom. We conclude that the quantitative accuracy and reproducibility of measurements obtained by computerized 3-D reconstruction of coronary model phantoms is of high enough quality to warrant further clinical evaluation. VD appears to be more accurate than AED for measuring vessel diameter.

Aluminum↗
PubMed1997

Overcoming obstacles to effective treatment: use of clinical practice improvement methodology.

Clinical practice improvement (CPI) is a method for examining the steps of a care process to determine how to achieve the best medical outcomes at the least necessary cost over the continuum of a patient's care. This methodology includes tracking of medical care process factors (management strategies, interventions, medications), patient factors (physiologic severity of illness and psychosocial deviations at each visit), and outcomes and furnishes information that presents distinct advantages over information furnished by outcomes research or clinical trials in the designing of management protocols. The Managed Care Outcomes Project, a large-scale CPI study, examined the effects of health maintenance organization (HMO) cost-containment strategies on patient outcome and utilization of care. Approximately 13,000 patients with otitis media, arthritis, hypertension, asthma, or ulcer disease were analyzed; since all patient diagnoses and medication use were captured in the CPI model, my colleagues and I were able to assess factors in psychiatric illness diagnosis, treatment, and outcome. Among the findings were the following: (1) the majority of patients receiving psychiatric drugs do not have a specific psychiatric diagnosis; (2) a significant proportion of patients with a specific diagnosis of major depression do not receive antidepressant medication; (3) cost-containment strategies appeared to markedly limit psychiatric referral and frequency of visits and use of serotonin selective reuptake inhibitor treatment; and (4) severity of the primary illness in the study population was markedly increased in patients with a psychiatric diagnosis. Further analysis of data from this study may help to determine which processes of care for depression were associated with better outcomes.

Antidepressive Agents↗
PubMed1996

The clinical practice improvement (CPI) model and how it is used to examine the availability of pharmaceuticals and the utilisation of ambulatory healthcare services in HMOs. Results from the Managed Care Outcomes Project (MCOP).

Many American healthcare facilities have come to understand that quality controls cost. Clinical practice improvement (CPI) is a methodology that creates a clinical laboratory, built into the everyday practice setting, to find and test best practices. A CPI study is an analysis of the content and timing of individual steps in a medical care process aimed at producing better clinical outcomes for the least necessary cost over the continuum of a patient's care. Statistical regression analyses are used to determine whether and how much a particular step actually improves medical outcomes. Systematic determination of individual process steps that improve medical outcomes is the best way to develop demonstrably better care and practice. Combining CPI methodology and a data monitor creates a dynamic environment in which all patient encounters potentially contribute to improving the process of care. We describe a recent multisite study: the Managed Care Outcomes Project (MCOP). The MCOP study design permits us to compare the effects of various pharmaceutical treatments on resource utilisation in actual practice in managed-care organisations. The MCOP database is an important resource for developing information required to design systems-based disease management programmes.

Ambulatory Care↗
PubMed1996

A cohort analysis of pre-menopausal women with dysfunctional uterine bleeding.

OBJECTIVE: To examine the clinical and cost outcomes of patients with dysfunctional uterine bleeding (DUB) who are treated with hysterectomy or not. DESIGN: A retrospective analysis of DUB patients over 30 months of treatment after initial diagnosis. SETTING: Patients with DUB from an HMO with over 200,000 enrollees. PARTICIPANTS: Study patients, all women with an initial diagnosis of DUB, were divided into two cohorts. Cohort 1 was women who had a hysterectomy (not for cancer); Cohort 2 was women who did not have a hysterectomy. MAIN OUTCOME MEASURES: Visit counts and costs, prescription counts and costs, hospital costs, and procedure counts. RESULTS: Hysterectomy patients in our dataset tend to have more prescriptions, higher prescription costs, more visits overall, higher visit costs, higher hospitalization costs, and higher total costs per member per month (PMPM) than non-hysterectomy patients. After surgery, the hysterectomy patients' costs and utilization PMPM are higher than those for the non-hysterectomy patients. CONCLUSIONS: There is wide variation in the treatment of patients with DUB. Clinical practice improvement studies are needed to determine the appropriate treatments based on patient characteristics to achieve better outcomes for lower costs.

Adult↗
PubMed1995

International comparison of waiting times for selected cardiovascular procedures.

OBJECTIVES: This study was designed to compare waiting times for cardiovascular procedures in five different health care delivery/financing systems. BACKGROUND: A recurrent criticism of national health care systems is long waiting times, or "queues," for high technology procedures. However, no objective data exist comparing waiting times in the United States with those in other systems. METHODS: Directors of cardiac catheterization laboratories, directors of cardiac surgery in the United States, U.S. Department of Veterans Affairs (VA) system, Canada and the United Kingdom and directors of cardiology clinics in Sweden were asked to respond to a mailed questionnaire as to how long it would take to obtain coronary angiography or coronary artery bypass surgery, or both, for specified case scenarios at their institutions. RESULTS: Significant differences in waiting times (p < 0.00001) were found among the systems for all four scenarios (elective and urgent angiography, elective and urgent bypass surgery). Compared with non-VA hospitals in the United States, waiting times were significantly longer in all systems, with the exception of waiting times for urgent surgery in the U.S. VA hospitals (p = 0.9). The longest waiting times for all four procedures were reported in the United Kingdom, Sweden and Canada, with some waiting times for elective procedures > 9 months. CONCLUSIONS: Physicians report that patients treated in health care systems structured differently from the non-VA hospital system in the United States wait significantly longer for cardiac catheterization and coronary artery bypass surgery.

Canada↗
PubMed1995

Effect of patient factors on hospital costs for major bowel surgery: implications for managed health care.

BACKGROUND: We examined the effects of patient factors on hospital resource consumption for patients who had undergone major bowel operation (diagnosis-related groups [DRGs] 148 and 149) at an urban, university hospital. METHODS: We performed cross-sectional analysis of computerized hospital discharge abstracts and charts of 491 consecutive discharges in these DRGs. Total hospital charges and length of stay were dependent variables. Independent variables included admission status, admission service, previous admissions, payer type, service type, diagnosis, reoperation, and death. RESULTS: Patient factors accounted for significant variability in resource consumption. By univariate analysis all of the above variables significantly affected total charges, and all but service type significantly affected length of stay. By multivariate analysis DRGs 148/149 alone explained 4.2% of the variance, whereas all the variables together increased R2 to 52.1%. Logistic regression of reoperation and of death as dependent variables suggested that patient factors also accounted for significant variance in these outcomes. CONCLUSIONS: Because patient factors may not be directly controllable by hospitals or physicians, differences among hospitals in costs and in "quality" may relate more to differences in patient mix than to efficiency. DRGs alone are not a sufficient management tool, and additional measures are needed to adequately measure both efficiency and quality.

Age Factors↗
PubMed1995

CPI (clinical practice improvement): improving quality and decreasing cost in managed care.

The focus on quality has never been greater. As a result, a new concept, clinical practice improvement (CPI), is emerging. Clinical practice improvement is the application of the scientific method to the day-to-day practice of medicine and can be employed in all health care settings: inpatient or ambulatory, large or small. According to the author, CPI has proved to be effective in reducing costs and improving outcomes because it requires the committed support of clinicians who are involved directly in the process of designing studies, analyzing data, and developing more efficient forms of treatment in their own organizations.

Asthma↗
PubMed1995

Quantitative volumetric analysis of brain MR: normative database spanning 5 decades of life.

PURPOSE: To present a normative volumetric database, spanning 5 decades of life, of cerebrospinal fluid, subarachnoid cerebrospinal fluid, total brain volume, total ventricular volume (component ventricular volumes of lateral, temporal horn, and third and fourth ventricles) and estimates of white and gray matter, based on a multispectral segmentation of brain MR. This database is presented as a reference for future studies comparing pathologic states. METHOD: One hundred ninety-four healthy subjects, ranging in age from 16 to 65 years, received standard axial intermediate- and T2-weighted spin-echo MR images. Multispectral segmentation and volume analysis were performed using ANALYZE. RESULTS: Normative volumetric estimates, both uncorrected and corrected for differences in total intracranial volume, were obtained for all subjects and presented by decade and sex. Age-related cerebrospinal fluid changes were evident for both male and female subjects. Most gender differences were eliminated by correction for differences in total intracranial volume. Standard and fast spin-echo acquisition methods gave comparable volume estimates. Total brain volume measurements from MR compare favorably with data from large autopsy series. CONCLUSION: Although there may be limitations to generalizations, these normative data tables can provide a comparison index for contrasting pathologic groups with a normative sample.

Adolescent↗
PubMed1994

Comparison of signal-averaging electrocardiographic systems using device specific criteria in 104 normal subjects.

UNLABELLED: The advent of several signal-averaged electrocardiogram (SAECG) systems for late potential (LP) assessment warrants comparisons to assess intersystem reproducibility and variability. Simultaneous SAECGs on two systems, Arrhythmia Research Technology (ART) and Marquette (MEI), were performed on 104 normal volunteers (53 males, age 44 +/- 14 years), and analyzed filtered QRS duration (TFQRS), root mean square voltage (RMS40), and low amplitude signal duration (LAS40), filtered at 40-250 Hz. The Gomes criteria (TfQRS > 114 msec, RMS40 < 20 microV and LAS40 > 38 msec) were used as criteria for LP. The data was also analyzed using the recently proposed system specific criteria for MEI (TFQRS > 120 msec, RMS40 < 20 microV and LAS40 > 38 msec). Where appropriate, statistical analysis was performed using simple linear and Spearman's rank correlation, analysis of variance, Finn's R and McNemar's test. RESULTS: The means +/- SD for ART and MEI were: TFQRS: 97.2 +/- 8.9 vs 108.2 +/- 7.2 msec (R = 0.76), RMS40: 31.8 +/- 17.8 vs 45.3 +/- 19.9 microV (R = 0.53), and LAS40: 32.2 +/- 8.4 vs 30 +/- 7.4 (R = 0.54). When the Gomes criteria were applied, the number of subjects identified by each system as abnormal were: TFQRS = 3 vs 22 (P < 0.001), RMS40 = 20 vs 8 (P = 0.004), LAS40 = 21 vs 9 (P = 0.004), TFQRS/RMS40 = 3 vs 6 (P = 0.38), TFQRS/LAS40 = 3 vs 7 (P = 0.22), RMS40/LAS40 40 = 17 vs 8 (P = 0.02), and all three criteria = 3 vs 6 (P = 0.38) for ART vs MEI, respectively. Percent agreement was 81.7% for TFQRS and 84.6% for RMS40 and LAS40 when single criteria were applied. Agreement improved when combined criteria were utilized (87.5%-95.2% for any two criteria and 95.2% for all three criteria). The intersystem agreement that was not due to chance was 0.63-0.69 for single criteria and 0.75-0.90 for combined criteria. Disagreement was highly significant for the three criteria when used singly and for RMS40 and LAS40 combined. Disagreement was not significant when TFQRS was used in combination with > or = one other criteria. When the MEI criteria were applied, there was a decrease in the number of subjects identified by the MEI system as abnormal, using the TFQRS criteria singly or in combination. Percent agreement for system specific TFQRS measurements was 94.2% for single criteria and 97.1% for combined criteria. The intersystem agreement that was not due to chance improved (88-0.94). Disagreement between system specific criteria for TFQRS was not significant (P > 0.05). CONCLUSION: Our data indicate that although there is a general correlation between ART and MEI measurements, variability is substantial, leading to significant differences when the criteria for LP are applied, especially for single parameter determinations. Thus, there is a need to establish system specific normal ranges and more accurate criteria for LP parameters.

Adult↗
PubMed1994

Preventing adverse drug events in hospitalized patients.

OBJECTIVE: To use computerized adverse drug event (ADE) surveillance to help identify methods to reduce the number of ADEs in hospitalized patients. DESIGN: Prospective study of 79,719 hospitalized patients during a 44-month period. SETTING: LDS Hospital, a 520-bed tertiary care center affiliated with the University of Utah School of Medicine, Salt Lake City. INTERVENTION: Sequential study periods of at least one year each were compared. In the first period, data were collected but not reported to physicians, pharmacists, or nurses. In the subsequent study periods, three interventions (computerized alerts of drug allergies, standardized antibiotic administration rates, and timely physician notification of all ADEs) were made to reduce the number of type B (allergic or idiosyncratic reactions) and severe ADEs. RESULTS: In the first study period, we identified 56 type B ADEs during 120,213 patient days. During two subsequent study periods that included alerts to physicians of known drug allergies and standardized antibiotic administration rates, 8 type B events were identified during 113,237 patient days and 18 during 107,868 patient days, respectively (p < 0.002). Early notification of physicians of all confirmed ADEs regardless of severity was associated with a significant reduction of ADEs classified as severe from 41 during 113,859 patient days in the first study period to 12 during 103,071 patient days and 15 during 108,320 patient days in two subsequent study periods, respectively (p < 0.001). CONCLUSIONS: Prospective surveillance of computer-based medical records for known drug allergies and appropriate drug administration rates can reduce the number of type B ADEs. Early ADE detection and notification of physicians permit drug and dosage changes that reduce the progression of mild and moderate ADEs to more severe conditions.

Adverse Drug Reaction Reporting Systems↗
PubMed1992

The timing of prophylactic administration of antibiotics and the risk of surgical-wound infection.

BACKGROUND: Randomized, controlled trials have shown that prophylactic antibiotics are effective in preventing surgical-wound infections. However, it is uncertain how the timing of antibiotic administration affects the risk of surgical-wound infection in actual clinical practice. METHODS: We prospectively monitored the timing of antibiotic prophylaxis and studied the occurrence of surgical-wound infections in 2847 patients undergoing elective clean or "clean-contaminated" surgical procedures at a large community hospital. The administration of antibiotics 2 to 24 hours before the surgical incision was defined as early; that during the 2 hours before the incision, as preoperative; that during the 3 hours after the incision, as perioperative; and that more than 3 but less than 24 hours after the incision, as postoperative. RESULTS: Of the 1708 patients who received the prophylactic antibiotics preoperatively, 10 (0.6 percent) subsequently had surgical-wound infections. Of the 282 patients who received the antibiotics perioperatively, 4 (1.4 percent) had such infections (P = 0.12; relative risk as compared with the preoperatively treated group, 2.4; 95 percent confidence interval, 0.9 to 7.9). Of 488 patients who received the antibiotics postoperatively, 16 (3.3 percent) had wound infections (P less than 0.0001; relative risk, 5.8; 95 percent confidence interval, 2.6 to 12.3). Finally, of 369 patients who had antibiotics administered early, 14 (3.8 percent) had wound infections (P less than 0.0001; relative risk, 6.7; 95 percent confidence interval, 2.9 to 14.7). Stepwise logistic-regression analysis confirmed that the administration of antibiotics in the preoperative period was associated with the lowest risk of surgical-wound infection. CONCLUSIONS: We conclude that in surgical practice there is considerable variation in the timing of prophylactic administration of antibiotics and that administration in the two hours before surgery reduces the risk of wound infection.

Adult↗
PubMed1992

Neurovirulence tests of type 3 oral poliovirus vaccine manufactured by Lederle Laboratories, 1964-1988.

Oral poliovirus vaccine (OPV) is tested for safety by evaluation of neurovirulence in rhesus and cynomolgus macaques. After intraspinal or intrathalamic injection of varying doses of vaccine, monkeys are followed for 17-21 days, killed, and a histopathological evaluation is made of the severity of poliomyelitis lesions in the spinal cord and brainstem. Each production lot of vaccine is compared with a type 1 OPV reference virus tested by the same method. Records of neurovirulence tests on production lots of type 3 OPV manufactured by Lederle Laboratories, during the period 1964-1988, have recently become available, together with the corresponding tests on type 1 reference vaccine. The cumulative data were collated, using a system under which each monkey was given a single grade according to the severity and spread of neuropathological poliomyelitis lesions. These raw data were assembled into frequency distributions ('neurovirulence profiles'), and used to compare type 3 OPV with the reference vaccine. These comparisons included monkeys injected by intraspinal injection (three vaccine dose levels) and intrathalamic injection (one vaccine dose level), and comprised independent tests conducted by the Food and Drug Administration and by the vaccine manufacturer. A total of 13 different comparisons were made, each one consisting of a pair of profiles, on type 3 OPV and reference vaccine, respectively. In total, these comparisons represented tests on more than 12,000 monkeys. Based on these neurovirulence profiles, the type 3 OPV appeared to be no more virulent than the reference vaccine.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗