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Biomedical subjects

J R Wheeler

Publications and source records attributed to J R Wheeler.

At least 19 recordsLinked to original sources
PubMed1992

Duplex scanning for the intraoperative assessment of infrainguinal arterial reconstruction: a useful tool?

Duplex scan, arteriography, and graft flow rates were used intraoperatively to assess 56 infrainguinal arterial reconstructions for technical error. Intraoperative duplex scan identified a technical defect or low graft flow velocity in 22 of 56 (39%) grafts. Eleven of the defects were judged to be clinically significant and were corrected. Four of these defects were missed by the completion arteriogram. One technical defect identified by completion arteriography was missed by duplex scan. Fifty percent (5/10) of grafts with an abnormal intraoperative duplex scan which were not corrected occluded within 30 days. Graft flow rates measured by the electromagnetic flowmeter were neither predictive of technical defect nor early graft outcome. Although the sensitivity of arteriography and duplex scan (88% sensitivity for both) were both high for predicting early graft occlusion, the combination of duplex scan and completion arteriography was significantly more accurate (p less than .0001) in predicting early graft outcome than either study alone. Duplex scan identified significant graft defects which were not detected by completion arteriography or graft flow rate measurement. The duplex scan also provided hemodynamic information which was predictive of early graft outcome. The duplex scan can be an important adjunct to completion arteriography for the intraoperative assessment of infrainguinal arterial reconstruction.

Adult↗
PubMed1992

The ischemic window: a method for the objective quantitation of the training effect in exercise therapy for intermittent claudication.

Twenty-two patients with intermittent claudication were prospectively enrolled in a 12-week program of supervised, graded treadmill exercise therapy. Severity and distribution of arterial occlusive disease were ascertained by noninvasive determination of segmental lower extremity blood pressures and waveforms. No attempt was made to modify risk factors for atherosclerotic occlusive disease. The exercise-induced reduction of the ankle pressure and its recovery were recorded over time, and the area under this curve, the "ischemic window," represents the severity of the ischemic deficit. Absolute systolic ankle pressure, ankle-brachial index, maximum walking time, claudication pain time, and the ischemic window were measured before and after exercise training in all subjects. Maximum walking time and claudication pain time increased 659% and 846%, respectively, among the 19 patients completing the 12-week program (p = 0.001; p = 0.0002). These patients underwent a mean reduction of 58.7% in the ischemic window after a standardized workload (p less than 0.05), and this correlated with the degree of symptomatic improvement. Absolute ankle pressure and ankle-brachial index were unchanged after exercise training. This study confirms the utility of supervised exercise therapy in the treatment of intermittent claudication. The ischemic window is a useful method for quantifying the ischemic deficit produced by exercise and provides a reproducible means of documenting functional improvement in patients undergoing exercise training.

Aged↗
PubMed1992

Ownership and performance of outpatient substance abuse treatment centers.

BACKGROUND: Little is known about the organization and performance of outpatient substance abuse treatment (OSAT) centers. We examine several performance measures of OSAT units, including clients treated, services provided, revenue sources, financial performance, and access to care, in relation to ownership of the center. METHODS: Data were drawn from a national random sample of 575 OSAT centers (85.8% response rate) participating in a telephone survey conducted in 1988. Analysis of variance by ownership was conducted on each performance measure, with differences subjected to tests of statistical significance. RESULTS: Descriptive results show that major funding sources differ by ownership. Private for-profit centers generate higher profits, charge higher prices, and achieve higher levels of financial performance than public and not-for-profit centers. Public centers provide better access to care for persons who are unable to pay. CONCLUSIONS: There appear to be substantial and interrelated differences by ownership type in the financing and operation of OSAT units.

Financing, Organized↗
PubMed1991

Thoracic aortic ectasia in a patient with Takayasu's disease.

Arterial aneurysm formation occurs in 15 to 20% of patients with Takayasu's disease. The timing of surgical intervention of these aneurysms is controversial. A case of ectasia of the descending thoracic aorta in a patient with Takayasu's disease is presented. The diagnosis and timing of surgical intervention of aneurysms associated with Takayasu's disease are discussed.

Adult↗
PubMed1991

Spontaneous carotid dissection: duplex scanning in diagnosis and management.

The clinical, duplex, and angiographic findings in six patients with seven spontaneous extracranial carotid artery dissections are reported. Four dissections resulted in internal carotid artery occlusion. These patients complained of ipsilateral headache followed by contralateral hemiplegia. The other three dissections involved the common carotid artery and resulted in dual (one true and one false) lumens. Two of these dissections were asymptomatic. All dissections were treated nonoperatively with anticoagulant therapy. Neurologic deficits improved or disappeared in all symptomatic patients. On follow-up studies, one of the four internal carotid occlusions completely resolved with normalization of the duplex examination. All three dual lumen dissections remained patent on serial studies. Diagnostic duplex characteristics, both conclusive and supportive, of carotid dissections are described. Duplex scanning is shown to be accurate in diagnosing and ideally suited for serially following spontaneous carotid dissections.

Adult↗
PubMed1991

Experience with laser-assisted balloon angioplasty and a rotary angioplasty instrument: lessons learned.

Favorable early results with mechanical angioplasty devices and laser-assisted balloon angioplasty have resulted in aggressive marketing and a rapid increase in the use of these devices for the treatment of femoropopliteal occlusive disease. Recent reports, however, have questioned the durability of these less invasive procedures. Since 1986 we have been involved in the clinical investigation of the Kensey dynamic angioplasty instrument and laser-assisted balloon angioplasty. One hundred two balloon angioplasty procedures assisted by the Nd:YAG laser (n = 56) and the Kensey dynamic angioplasty instrument (n = 46) were performed for the treatment of femoropopliteal occlusive lesions. Both Kensey dynamic angioplasty instrument and laser-assisted balloon angioplasty groups were similar with regard to age, operative indication, preoperative ankle-brachial index, lesion length, and distal runoff. Mean follow-up was 19 months in the Kensey dynamic angioplasty instrument group and 15 months in the laser-assisted balloon angioplasty group. Technically successful recanalization was achieved in 67% of Kensey dynamic angioplasty instrument-assisted balloon angioplasty procedures and 82% of laser-assisted balloon angioplasty procedures. Early hemodynamic and clinical improvement was obtained in 59% of Kensey dynamic angioplasty instrument-assisted balloon angioplasty procedures and 57% of laser-assisted balloon angioplasty procedures. Two-year clinical success by life-table analysis was 37% in the Kensey dynamic angioplasty instrument group and 19% in the laser-assisted balloon angioplasty group. The level of subsequent surgical revascularization was not altered in any patient by Kensey dynamic angioplasty instrument-assisted balloon angioplasty or laser-assisted balloon angioplasty.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Have hospital inpatient cost containment programs contributed to the growth in outpatient expenditures? Analysis of the substitution effect associated with hospital utilization review.

The rapid increase in outpatient expenditures has been the focus of growing attention in recent years. This increase has corresponded with public and private efforts to contain hospital inpatient costs, prompting some analysts to suggest that outpatient expenditure growth is the result of a substitution effect; that is, the substitution of outpatient for inpatient care associated with hospital cost containment programs. Claims data on 43 privately insured groups that adopted utilization review (UR) during the latter part of 1984 or early 1985 were analyzed, comparing outpatient expenditures before and after adoption of hospital inpatient UR to quantify the substitution effect associated with UR. UR was not associated with higher physician office expenditures nor with higher outpatient diagnostic expenditures. UR was related to significantly higher hospital outpatient department expenditures. On average, these expenditures were approximately 20% higher (P = 0.01) after the adoption of UR. However, outpatient department expenditures of the groups analyzed represented a fairly small percentage of total medical expenditures; hence, the absolute expenditure increase was quite modest, on the order of $9 per insured person per year. This analysis, admittedly limited in scope, suggests that UR is associated with a measurable substitution effect. It is likely that inpatient hospital cost containment programs have resulted in some substitution of outpatient for inpatient care and thus have played a role in fostering outpatient expenditure growth during recent years.

Cost Control↗
PubMed1990

Initial results and subsequent outcome of laser thermal-assisted balloon angioplasty of 56 consecutive femoropopliteal lesions.

Laser thermal-assisted balloon angioplasty (LABA) was prospectively applied in the treatment of 56 atherosclerotic femoropopliteal occlusive lesions in 51 consecutive patients. All procedures were performed in the operating room using a neodynium:yttrium-aluminum-garnet (Nd:YAG) laser source, and patients were evaluated for immediate and long-term hemodynamic and clinical improvement. Technically successful recanalization was achieved in 82% of cases, with 57% of all patients (32 of 56) obtaining early hemodynamic and clinical improvement. Long-term clinical success (by life-table analysis) was obtained by only 22.5% at 6 months, and only 13.5% at 12 months. Patients presenting with intermittent claudication did significantly better than those presenting for limb salvage (p = 0.01), and trends toward improved outcome were noted for short versus long lesions as well as for patients with "good" versus "poor" distal runoff (NS). Procedure-related morbidity occurred in 14%, and there was one peri-procedural mortality (1.8%). We conclude that the use of LABA is associated with long-term clinical success in only a small proportion of patients, and that widespread clinical application of this technique is not indicated at the present time.

Adult↗
PubMed1990

Increased infection rate in double-lumen versus single-lumen Hickman catheters in cancer patients.

Over the 48-month period from January 1983 through December 1986, 51 single-lumen (SL) and 94 double-lumen (DL) indwelling central venous (Hickman) catheters were placed in 118 patients with malignant disease. We reviewed these cases retrospectively to determine the types and frequency of complications requiring catheter removal. The catheters were in place a total of 18,397 days. Overall, 14% (7/51) of SL and 21% (20/94) of DL catheters were removed due to infection. Of those catheters becoming infected, DL catheters were infected earlier. SL catheters that became infected averaged 213 days of use before removal, whereas DL catheters becoming infected averaged only 78 days before removal (P less than or equal to .02). The infection rate was significantly less in SL (one infection per 1,210 days) than in DL catheters (one infection per 496 days) (P less than or equal to .02). Thus because of its significantly reduced risk of infection, the single-lumen Hickman may be the preferred catheter for long-term venous access in many patients.

Adult↗
PubMed1990

Reducing hospital use and expenditures through utilization review. Findings from an outcome evaluation.

Utilization review (UR) has become a prominent approach to cost containment now used by almost 65% of private group insurance plans. Although insurers have increasingly relied on UR to contain health care costs, until recently little was known about the effects of this cost containment approach. This article reviews some of the key findings of a UR evaluation, based on analysis of claims data on 223 insured groups for the years 1984 through 1986. The evaluation found that UR reduced admissions by 12%, inpatient expenditures by 8%, and total expenditures by 6%. It was estimated that UR generated net savings of $115 per employee per year. Groups adopting UR with high baseline rates of hospital use had larger expenditure reductions and greater net savings. It appears that UR can play an important role in private cost containment and help improve medical care resource consumption.

Cost Control↗
PubMed1990

Relating health care market characteristics to the effectiveness of utilization review programs.

This paper presents an exploratory analysis of the relationships between several health care market characteristics and the effectiveness of utilization review programs directed at controlling hospital use and expenditures. The analysis is based on claims data from 223 insured groups over 12 quarters. Results indicate that UR is associated with larger reductions in utilization and expenditures in markets with low HMO enrollment, high admissions per capita, and low hospital occupancy rates. These results suggest that health care market conditions that permit unnecessary use are the ones under which UR programs can be most effective.

Cost-Benefit Analysis↗
PubMed1990

The use of composite grafts in femorocrural bypasses performed for limb salvage: a review of 108 consecutive cases and comparison with 57 in situ saphenous vein bypasses.

We retrospectively reviewed the results of 108 consecutive femorocrural bypasses performed with prosthetic/autogenous composite graft material and compared these with the results of 57 crural bypasses using greater saphenous vein by the in situ technique. Indication for operation in all cases was the salvage of an otherwise imminently threatened limb. Polytetrafluoroethylene-composite grafts (n = 87) and human umbilical vein-composite grafts (n = 21) were placed only in patients lacking suitable autogenous material for in-line reconstruction. Patient groups were similar with respect to mean age, prevalence of arterial disease risk factors, quality of the distal runoff, and location of the distal anastomosis. Cumulative patency rates at 1 year by life-table analysis were 81.9%, 34.6%, and 12.1% for the in situ, polytetrafluoroethylene-composite and human umbilical vein-composite groups, respectively. At 2 years these were 63.9%, 29.9%, and 6.0%, respectively (p less than 0.025). Cumulative limb salvage at 1 year was 70.6%, 62.3%, and 32.7%, respectively. Wound-related complications occurred in 52.4% of human umbilical vein-composite, 38.6% of in situ, and 18.3% of polytetrafluoroethylene-composite bypasses (p less than 0.05). On the basis of these results, we conclude that femorocrural bypass with polytetrafluoroethylene-composite graft is an acceptable form of distal reconstruction for limb salvage in patients lacking sufficient lengths of autogenous vein. We no longer use human umbilical vein for composite construction.

Aged↗
PubMed1989

Does utilization review reduce unnecessary hospital care and contain costs?

Research indicates that approximately one in five hospital admissions is unnecessary or inappropriate, based on accepted clinical criteria. Various cost-containment approaches have been initiated to reduce unnecessary hospital care. Among these approaches, hospital utilization review (UR) has shown promise as a cost-containment strategy. Although third party payers are increasingly relying on UR and similar approaches to contain health care expenditures, little is known about the effects of these efforts. This study analyzes insurance claims data on 223 insured groups for 1984 through 1986 to determine the effects of a UR program instituted by a commercial insurance company. It was found that UR had a significant negative effect on both utilization and expenditures, even after controlling for a large number of factors. Specifically, UR reduced admissions by 13%, inpatient days by 11%, expenditures on routine hospital inpatient services by 7%, expenditures on hospital ancillary services by 9%, and total medical expenditures by 6%. Even though UR reduced the level of utilization and expenditures, it did not appear to influence the rate of change in these areas over time. These findings suggest that hospital UR programs can reduce utilization and expenditures and generate cost savings, thereby helping to improve the efficiency of medical care resources consumption.

Cost Control↗
PubMed1988

Private cost containment. The effects of utilization review programs on health care use and expenditures.

Utilization review has been regarded as one of the most promising approaches to the containment of health care costs. We analyzed insurance claims data on 222 groups of employees and dependents for 1984 and 1985 to evaluate the effects of utilization review programs instituted by a large private insurance carrier. The utilization review programs we studied were compulsory; patients who did not follow established utilization review procedures were subject to financial penalties. Controlling for employee characteristics, health care market area factors, and benefit-plan features, we found that utilization review reduced admissions by 12.3 percent, inpatient days by 8.0 percent, hospital expenditures by 11.9 percent, and total medical expenditures by 8.3 percent. When only groups that had relatively high admission rates before adopting utilization review were analyzed, it was found that they had a 34 percent reduction in patient days and a 30 percent reduction in hospital expenditures. The savings-to-cost ratio of utilization review for groups overall was highly favorable--approximately 8 to 1. Private utilization review programs of the type we studied appear to be effective in reducing hospital use and decreasing medical expenditures. This study did not address the possible effects of such programs on the health status of patients.

Cost Control↗
PubMed1988

Supercritical fluid extraction coupled with supercritical fluid chromatography for the separation of sulfonylurea herbicides and their metabolites from complex matrices.

Supercritical fluid chromatography and supercritical fluid extraction have been coupled to provide on-line evaluation of a dynamic extraction procedure. The simultaneous removal and analysis of representative sulfonylureas, their precursors and metabolites from complex matrices was accomplished with this configuration. The matrices examined include soil, plant materials and a cell culture medium. The simplicity and current applicability of this design to the agricultural products industry is demonstrated.

Chromatography, Liquid↗
PubMed1988

A comparison of charges for continuous ambulatory peritoneal dialysis and center hemodialysis.

Use of continuous ambulatory peritoneal dialysis (CAPD) is increasing, and it is being promoted as a less expensive alternative to center hemodialysis (CHD). The debate over the relative charges for CAPD and CHD cannot generally be answered without considering the relationship between modality selection and patient characteristics. When selection and patient characteristics are accounted for, the difference between annual charges for CAPD and CHD patients is insignificant, in part because of the current payment system. The analysis suggests that patients using CHD may have lower charges than if they were using CAPD; similarly, patients using CAPD may have lower charges than if they were using CHD. Charges during CAPD training are lower than CHD or CAPD charges. Charges during the transition between CHD and CAPD tend to be higher than either CHD or CAPD due to additional hospitalizations. Estimated results suggest that encouraging current CHD patients to transfer to CAPD (or vice versa) may not have the desired effect of reducing charges.

Fees and Charges↗