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Biomedical subjects

J R Wheeler

Publications and source records attributed to J R Wheeler.

At least 73 records · Page 4Linked to original sources
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.

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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↗
PubMed1989

Accounting based risk measures for not-for-profit hospitals.

This paper discusses the issues involved with determining an appropriate discount rate for not-for-profit hospitals and develops a method for computing measures of systematic risk based on a hospital's own accounting data. Data on four hospital management companies are used to demonstrate the method. Results indicate the need for sensitivity analysis in the selection of estimation methods and in the final determination of a discount rate.

Accounting↗
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↗
PubMed1988

The Kensey catheter: preliminary results with a transluminal atherectomy tool.

The Kensey dynamic angioplasty instrument is an atherectomy device approved by the Food and Drug Administration that uses a rotating cam tip housed within a flexible polyurethane catheter to recanalize obstructed and stenotic arteries. Twenty patients with significant femoral arteriosclerotic occlusive disease underwent attempted transluminal endarterectomy of 23 extremities with the Kensey catheter. Significant improvements of superficial femoral artery luminal diameter was achieved in 10 of 13 patients with stenosis and passage of the spinning catheter tip at 60,000 to 90,000 rpm through areas of complete occlusion was successful in 4 of 10 cases. Balloon dilatation was used as an adjunct to increase the diameter of the superficial femoral artery lumen in 11 of 14 successful cases. This preliminary report provides technical data and short-term follow-up of this new innovative vascular tool.

Angioplasty, Balloon↗
PubMed1988

Absolute ethanol embolization for peripheral arteriovenous malformation: report of two cures.

We have reported two patients in whom absolute ethanol was used to sclerose arteriovenous malformations. Because of its low viscosity, liquid form, and devastating effect when injected intra-arterially, absolute ethanol is effective in treating AVMs, and it has been proven to have curative potential. For these same reasons it is also potentially harmful, particularly to nerves and possibly to skin.

Adult↗
PubMed1988

An assessment of hospital acquisition prices.

Although much has been written about hospital acquisitions by investor-owned systems, little attention has been paid to how the systems determine the prices they are willing to pay for acquired hospitals. In this study, we attempted to ascertain whether certain market and management variables explain the purchase price of 37 hospitals acquired by investor-owned systems during the period 1978-1984. Our findings suggest that the systems were willing to pay a higher price per bed for more highly utilized facilities in high-income community settings, but paid less for older, aging facilities that were more likely to require major capital improvements after acquisition.

Bed Occupancy↗
PubMed1987

Comparison of packed column and capillary column supercritical fluid chromatography and high-performance liquid chromatography using representative herbicides and pesticides as typical moderate polarity and molecular weight range molecules.

The role of supercritical fluid chromatography (SFC) as a viable technique for analyzing agricultural products has been investigated using packed and capillary column methodology. The goal was to question the strengths and weaknesses of each of the techniques as possible approaches to separation strategies for thermally labile compounds as compared to the currently used high-performance liquid chromatography methodology. Representative herbicides have been examined with the techniques to compare such factors as linearity of response, limit of detection and reproducibility. In the literature so far, a direct numerical comparison of these three techniques for the analysis of real samples has not been presented. Results indicate that faster analyses, lower detection limits and greater injection to injection reproducibility are obtainable with packed column SFC. No appreciable difference in the linearity of response between the three techniques was noted. It has been well documented that the capillary SFC affords greater efficiencies and higher resolution [H. E. Schwartz, LC.GC, Mag. Liq. Gas Chromatogr., 5 (1987) 14]. Capillary SFC can also be interfaced to a variety of detectors not as easily accomplished with packed column SFC. Capillary SFC therefore still has a viable position in the analysis of low and moderate molecular weight and polarity molecules.

Chromatography, High Pressure Liquid↗
PubMed1987

Arterialization of reversed autogenous vein grafts: quantitative light and electron microscopy of canine jugular vein grafts harvested and implanted by standard or improved techniques.

To provide sequential, quantitative analysis of the cellular events occurring in reversed autogenous vein grafts after implantation and potential modifications of these events, two groups of veins were evaluated. Veins prepared by standard techniques of unmonitored pressure distension with cold heparinized saline solution, tributary ligation adjacent to the wall, and storage at 4 degrees C were morphometrically compared with veins harvested by means of a modified protocol of papaverine irrigation, tributary ligation away from the graft wall, pressure distension to 100 mm Hg with heparinized blood containing papaverine at body temperature, storage in identical solution at 4 degrees C, and implantation while distended. Unilateral jugular veins harvested from dogs with the modified technique (IRJV,N = 9) or standard technique (SRJV,N = 9) were implanted into carotid arteries, retrieved at 30 minutes, 2 days, and 10 days postoperatively along with the contralateral control vein after perfusion fixation in situ, and examined microscopically to quantitate intimal-medial thickness and endothelial damage (denudation and ultrastructural alterations). All IRJVs remained endothelialized, whereas SRJVs had 19% and 40% endothelial denudation at 30 minutes and 2 days, respectively, as well as massive neutrophil, platelet, and monocyte involvement. In contrast, IRJVs had only a modest infiltration of monocytes beginning early after implantation and culminating in their localization beneath endothelial cells; these endothelial cells increased in number during the 10-day period. Although SRJVs exhibited nearly complete reendothelialization over the luminal surface of macrophages by 10 days, endothelial damage was consistently higher than that of IRJVs at all periods and intimal-medial thickness was significantly greater at 10 days (65 +/- 0 vs. 57 +/- 0 micron, respectively; p less than 0.001). These findings suggest that endothelial preservation with improved harvesting techniques inhibits thrombosis and limits wall thickening and also that macrophages may play a protective role by promoting endothelial proliferation.

Animals↗
PubMed1987

Switching and the definition of modality in end-stage renal disease treatment.

End-stage renal disease treatment expenditures have increased greatly in recent years. Modality of treatment is a very important factor in determining costs as well as outcome and quality of life. Using quarterly observations on treatments received by ESRD patients, this paper presents a definition of modality based on type of treatment received and setting in which treatment is received. This paper also documents the magnitude of switching among defined modalities. Because many patients switch modality, selection of one modality is really a selection of a probable course of treatment by several modalities. The careful definition of modality and recognition that switching occurs are important first steps in conducting cost-effectiveness type analyses of ESRD treatment.

Hemodialysis Units, Hospital↗
PubMed1987

Freshly harvested cadaveric venous homografts as arterial conduits in infected fields.

Six patients with patent multilevel prosthetic grafts (three axillofemoral-femoral grafts, an aortobifemoral graft, an axillofemoral and femoral-anterior tibial graft, and an axillofemoral and femoral-popliteal graft) that demonstrated overt infection involving both the proximal inflow (one infrarenal aorta, five axillary arteries) and groin anastomoses required complete graft excision. Cadaveric inferior vena cava, common and external iliac, common and superficial femoral, and greater saphenous veins were harvested in conjunction with multiple organ donor procedures. Identical anatomic reconstruction within the infected fields was accomplished, with patency and distal perfusion maintained for intervals sufficient to achieve complete resolution of infection in all cases. This interval of revascularization with a venous homograft has served as a temporizing maneuver, which permitted eradication of infection and allowed subsequent reimplantation of prosthetic graft material without associated reinfection in the two instances in which it was required. Use of freshly harvested large-caliber caval, iliac, and femoral homograft veins as arterial substitutes in infected fields has not been previously reported. Case histories and a review of the venous homografting literature are included.

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