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Annual Volume (annual + volume)

Distribution by Scientific Domains

Medical Sciences	83%

Selected Abstracts

The Relationship between Hospital Volume and Mortality in Mechanical Ventilation: An Instrumental Variable Analysis

HEALTH SERVICES RESEARCH, Issue 3 2009
Jeremy M. Kahn
Objective. To examine the relationship between hospital volume and mortality for nonsurgical patients receiving mechanical ventilation. Data Sources. Pennsylvania state discharge records from July 1, 2004, to June 30, 2006, linked to the Pennsylvania Department of Health death records and the 2000 United States Census. Study Design. We categorized all general acute care hospitals in Pennsylvania (n=169) by the annual number of nonsurgical, mechanically ventilated discharges according to previous criteria. To estimate the relationship between annual volume and 30-day mortality, we fit linear probability models using administrative risk adjustment, clinical risk adjustment, and an instrumental variable approach. Principle Findings. Using a clinical measure of risk adjustment, we observed a significant reduction in the probability of 30-day mortality at higher volume hospitals (,300 admissions per year) compared with lower volume hospitals (<300 patients per year; absolute risk reduction: 3.4%, p=.04). No significant volume,outcome relationship was observed using only administrative risk adjustment. Using the distance from the patient's home to the nearest higher volume hospital as an instrument, the volume,outcome relationship was greater than observed using clinical risk adjustment (absolute risk reduction: 7.0%, p=.01). Conclusions. Care in higher volume hospitals is independently associated with a reduction in mortality for patients receiving mechanical ventilation. Adequate risk adjustment is essential in order to obtained unbiased estimates of the volume,outcome relationship. [source]

Water Use by Thermoelectric Power Plants in the United States,

JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 1 2007
Xiaoying Yang
Abstract:, Thermoelectric power generation is responsible for the largest annual volume of water withdrawals in the United States although it is only a distant third after irrigation and industrial sectors in consumptive use. The substantial water withdrawals by thermoelectric power plants can have significant impacts on local surface and ground water sources, especially in arid regions. However, there are few studies of the determinants of water use in thermoelectric generation. Analysis of thermoelectric water use data in existing steam thermoelectric power plants shows that there is wide variability in unitary thermoelectric water use (in cubic decimeters per 1 kWh) within and among different types of cooling systems. Multiple-regression models of unit thermoelectric water use were developed to identify significant determinants of unit thermoelectric water use. The high variability of unit usage rates indicates that there is a significant potential for water conservation in existing thermoelectric power plants. [source]

Transplant Center Volume and Outcomes After Liver Retransplantation

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 2 2009
P. P. Reese
Liver retransplantation surgery has a high rate of allograft failure due to patient comorbidities and technical demands of the procedure. Success of liver retransplantation could depend on surgeon experience and processes of care that relate to center volume. We performed a retrospective cohort study of adult liver retransplantation procedures performed from January 1, 1996 through December 31, 2005 using registry data from the Organ Procurement Transplantation Network. The primary outcome was 1-year allograft failure. Liver transplant centers were categorized as small, intermediate or high volume by dividing overall liver transplants into three tertiles of approximately equal size. Mean annual volume of overall liver transplants was <50 for low-volume centers, 50,88 for intermediate-volume centers and >88 for high-volume centers. The primary analysis consisted of 3977 liver retransplantation patients. The unadjusted risk of 1-year allograft failure was 37.8%. In multivariable logistic regression, the risk of 1-year allograft failure was not significantly different between low- (reference), intermediate- (OR 0.86, CI 0.72,1.03, p = 0.11) and high-volume centers (OR 0.88, CI 0.74,1.04, p = 0.14). Results were similar when the analysis was limited to retransplantation performed >160 days after initial transplantation. Center volume is an imprecise surrogate measure for 1-year outcomes after liver retransplantation. [source]

Hypospadias surgery: when, what and by whom?

BJU INTERNATIONAL, Issue 8 2004
Gianantonio Manzoni
Summary Hypospadias is repaired by paediatric surgeons, paediatric urologists, adult reconstructive urologists and plastic surgeons. This review is unique in representing all four specialities, to provide a unified policy on the management of hypospadias. The surgeon of whichever speciality should have a dedicated interest in this challenging work, ideally having an annual volume of at least 40,50 cases. The ideal time for primary repair is at 6,12 months old, although when this is not practicable there is another opportunity at 3,4 years old. A surgical protocol is presented which emphasises both functional and cosmetic refinement. Using a logical progression of a very few related procedures allows the reliable correction of almost any hypospadias deformity. A one-stage repair is used when the urethral plate does not require transection and its axial integrity can be maintained. Occasionally, when the plate is of adequate width and depth, it can be tubularized directly using the second stage of the two-stage repair. When (usually) the urethral plate is not adequately developed and requires augmentation before it can be tubularized, then that second-stage procedure is modified by adding a dorsal releasing incision ± a graft (alias Snodgrass and ,Snodgraft' procedures). The two-stage repair offers the most reliable and refined solution for those patients who require transection of the urethral plate and a full circumferential substitution urethroplasty. From available evidence this protocol combines excellent function and cosmesis with optimum reliability. Nevertheless, it would be complacent to assume that these gratifying results will be maintained into adult life. We therefore recommend that there is still a need for active follow-up through to genital maturity. [source]

A Survey of the Practice of Lead Extraction in the United States

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 6 2010
CHARLES A. HENRIKSON M.D.
Background:,Endovascular lead extraction is an important component of the management of patients with chronically implanted arrhythmia control devices. Although it is associated with the potential for significant morbidity and mortality, there is little information about its scope and practice. Methods:,We surveyed 1,000 physician members of the Heart Rhythm Society via e-mail solicitation. Results:,Of the 252 respondents (25%), 221 (88%) reported either performing extractions themselves (63%), or having privileges at a hospital where extractions are performed (25%). Electrophysiologists perform extractions at most sites (83%) but cardiac surgeons perform endovascular lead extraction at a significant minority of sites (20%). Most respondents report low annual volumes of extractions at their site: 15% reported <10 procedures/year, 42% 10,25 procedures/year, 23% 26,50 procedure/year, and only 19% reported >50 procedures/year. Thirty-six percent of respondents reported that extractions were done in the operating room (OR) with surgeon present or immediately available, 39% in the electrophysiology (EP) lab with surgeon and OR identified and available, and 25% in EP lab without a surgeon or OR identified. The overall risks of lead extraction were felt to be 1,5% of major complication and 0.5,1% of mortality, roughly in line with published data. Conclusions:,While there is agreement as to the risk of major complication and death from lead extraction, the degree of surgical availability varies considerably. The new guidelines document recommends the ability to promptly initiate an emergent surgical procedure, and this should be an important goal for all extractionists. (PACE 2010; 33:721,726) [source]

Long-term trends in cancer mortality in the United States, 1930,1998,

CANCER, Issue S12 2003
M.S., Phyllis A. Wingo Ph.D.
Abstract BACKGROUND Progress against cancer can be examined by analyzing long-term trends in cancer incidence and mortality. The recent directive from the U.S. Department of Health and Human Services to adopt the 2000 U.S. standard population for the age adjustment of death rates prompted the American Cancer Society to update historical cancer mortality statistics using the new standard. METHODS Mortality data were abstracted by race, gender, year, and age at death for 1930 through 1959 from annual volumes of Vital Statistics of the United States. For 1960 through 1998, these data were obtained from data tapes provided by the National Center for Health Statistics. Two U.S. standard million populations (1970 and 2000) were used to calculate age-adjusted rates. Average annual percent change was estimated for each decade by site, gender, and age, and the statistical significance of the change was assessed at p < 0.05. RESULTS After long-term increases or mostly level trends that date from the 1930s for some sites, death rates for cancers of the lung (in males), prostate, female breast, colon-rectum, pancreas, leukemia, and ovary were decreasing in the 1990s. Liver cancer death rates were increasing in the 1990s. Throughout the study period, death rates for female lung cancer increased, while death rates for stomach and uterine cancers declined. CONCLUSIONS The trends of decreasing cancer death rates for the leading cancer sites in the 1990s are encouraging. However, surveillance researchers must continue to monitor these declines to assess whether the progress seen in this decade persists. Efforts also must be made to study the sites with increasing trends and identify potential underlying causes. Cancer 2003;97(12 Suppl):3133,3275. Published 2003 by the American Cancer Society. DOI 10.1002/cncr.11380 [source]