Value of the infectious diseases specialist.
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Biomedical subjects
Publications and source records attributed to R P Wenzel.
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In the absence of detailed and specific data on outcomes, specialists are thought to contribute excessively to the cost of care. Infectious diseases physicians are at further risk of heavy utilization of medical resources because their patients often are those with serious complications or expensive underlying diseases (e.g., AIDS). By using readily available information in a sophisticated computer database, we examined the crude economic impact of an inpatient infectious diseases consultation and identified important matching variables for more refined analysis. The study was performed at LDS Hospital (Salt Lake City), a tertiary care facility with four full-time infectious diseases physicians. A total of 496 cases (patients who were seen by an infectious diseases consultant) were matched with 3,117 controls (patients who were not seen by an infectious diseases consultant). Matching was performed on the basis of age, sex, exact discharge diagnosis-related group, minimum length of hospital stay equal to the interval from admission to consultation for cases, and measures of the severity of illness (nursing acuity score and the number of secondary diagnoses). Cases had longer lengths of hospital stays, longer intensive care unit lengths of stays, and higher antibiotic costs than did matched controls, and if the consultation occurred in the last one-third of hospitalization, cases had shorter lengths of hospital stay and lower antibiotic costs than did controls.
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The outcomes of cardiovascular care for individual patients are known to be better when treatment is provided in hospitals where the volume of such care is greater. We examined the impact of establishing safe volume thresholds on hospitals now performing such procedures in the state of Iowa by analysing the relationship between various volume thresholds and the number of hospitals that would continue to provide the service if the thresholds were enforced. Four procedures performed in hospitals in Iowa in 1990 were studied: coronary artery bypass graft surgery, vascular surgery, cardiac valve surgery, and cardiac catheterization. The analysis was conducted assuming current per capita procedure rates and repeated assuming reduced procedure rates. The study finds that the 12 hospitals now performing coronary artery bypass graft surgery in Iowa could be reduced to two, providers of vascular surgery could be reduced to as low as four from the current 33, the 10 providers of cardiac valve surgery might be reduced to one, and catheterization could be provided at two rather than 22 hospitals.
Included in a 3-year population-based study were all patients (n = 64,281) admitted to a single tertiary care hospital (902 beds) using prospective hospital-wide surveillance for nosocomial infections. The objective of the study was to identify patients at risk for nosocomial bloodstream infection by using readily available hospital admission variables. After identifying potential risk factors for infection by univariate analyses, we derived multivariate models for predicting bloodstream infection by using logistical regression procedures. A total of 931 patients (1.45 per 100 admissions) developed a nosocomial bloodstream infection (2.2 episodes per 1000 patient-days) between 1 July 1987, and 30 June 1990. The crude mortality among infected patients was 34%, and the 319 deaths represented 22% of the total in-hospital mortality. Independent predictors of bloodstream infection were age, gender, primary diagnosis, and admission to a critical care unit. The sensitivity and specificity of the models for classifying patients as infected or noninfected were 81% and 81% for infants (1-11 months old) and 72% and 72% for adults, respectively. The negative predictive value of both models exceeded 99%. Applied to all patients on admission, the models we developed allowed us to survey only 28% of patients to identify more than 70% of those who will develop a nosocomial bloodstream infection.
Selected issues for hospital epidemiology are presented. The issues of infection control, employee health and quality assessment cross the traditional department and reporting lines and require a multidisciplinary approach utilizing the epidemiological method. Programs seeking enhanced value--high quality outcomes per dollar cost--will likely support such an approach.
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Given the dramatic increase in the incidence of vancomycin resistance among the enterococci and experimental evidence for the transfer of vancomycin resistance from enterococci to Staphylococcus aureus, there is concern that strains of S. aureus will emerge that are resistant to vancomycin. The result would be a highly virulent pathogen for which effective antimicrobial therapy would not be available. To prevent the nosocomial transmission of such an organism, stringent infection control policies need to be developed and implemented. We offer proposals that are based on the limited data available on the transmission and control of S. aureus and that may be used as starting points for the development of formal guidelines for the isolation of colonized and infected patients and for microbiology laboratory precautions.
OBJECTIVE: To provide hospital leaders with strategic goals or actions likely to have a significant impact on antimicrobial resistance, outline outcome and process measures for evaluating progress toward each goal, describe potential barriers to success, and suggest countermeasures and novel improvement strategies. PARTICIPANTS: A multidisciplinary group of experts was drawn from the following areas: hospital epidemiology and infection control, infectious diseases (including graduate training programs), clinical practice (including nursing, surgery, internal medicine, and pediatrics), pharmacy, administration, quality improvement, appropriateness evaluation, behavior modification, practice guideline development, medical informatics, and outcomes research. Representatives from appropriate federal agencies, the Joint Commission on Accreditation of Healthcare Organizations, and the pharmaceutical industry also participated. EVIDENCE: Published literature, guidelines, expert opinion, and practical experience regarding efforts to improve antibiotic utilization and prevent and control the emergence and dissemination of antimicrobial-resistant microorganisms in hospitals. CONSENSUS PROCESS: Participants were divided into two quality improvement teams: one focusing on improving antimicrobial usage and the other on preventing and controlling transmission of resistant microorganisms. The teams modeled the process a hospital might use to develop and implement a strategic plan to combat antimicrobial resistance. CONCLUSIONS: Ten strategic goals and related process and outcome measures were agreed on. The five strategic goals to optimize antimicrobial use were as follows: optimizing antimicrobial prophylaxis for operative procedures; optimizing choice and duration of empiric therapy; improving antimicrobial prescribing by educational and administrative means; monitoring and providing feedback regarding antibiotic resistance; and defining and implementing health care delivery system guidelines for important types of antimicrobial use. The five strategic goals to detect, report, and prevent transmission of antimicrobial resistant organisms were as follows: to develop a system to recognize and report trends in antimicrobial resistance within the institution; develop a system to rapidly detect and report resistant microorganisms in individual patients and ensure a rapid response by caregivers; increase adherence to basic infection control policies and procedures; incorporate the detection, prevention, and control of antimicrobial resistance into institutional strategic goals and provide the required resources; and develop a plan for identifying, transferring, discharging, and readmitting patients colonized with specific antimicrobial-resistant pathogens.
Ribotyping and macrorestriction analysis of chromosomal DNA using pulsed-field gel electrophoresis (PFGE) are among the more useful molecular epidemiologic typing methods. Because these techniques are labor intensive, automation of one or more steps may allow clinical laboratories to apply molecular typing methods. We compared the recently developed automated ribotyping system, the RiboPrinter Microbial Characterization System (DuPont), with PFGE as a means of typing clinical isolates of E. coli and P. aeruginosa. A total of 22 E. coli and 24 P. aeruginosa were typed by both PFGE and the RiboPrinter. When compared with PFGE typing of E. coli and P. aeruginosa, the RiboPrinter was less sensitive in identifying different strains, particularly among the isolates of P. aeruginosa. The RiboPrinter was completely automated and allowed up to 32 isolates to be typed within an 8-hour period. The pattern of results obtained in this study suggests that a heirarchical approach to molecular typing using the RiboPrinter Microbial Characterization System plus PFGE might be feasible. The RiboPrinter Microbial Characterization System promises to be a very useful addition to the expanding molecular typing armamentarium.
PURPOSE: A sharp increase of Acanthamoeba keratitis from two cases per year to 30 cases per year at our institution prompted this study to determine whether there was a change in the clinical characteristics, basic epidemiology, and outcome of this disease. METHODS: We reviewed all cases of Acanthamoeba keratitis diagnosed at the University of Iowa Hospitals and Clinics from mid-1993 through 1994. RESULTS: We screened 217 patients with keratitis by tandem scanning confocal microscopy and suspected Acanthamoeba in 51 patients. Diagnosis was confirmed by cytology in 43 patients (48 eyes). There were no positive cultures. Patients examined within four weeks of onset of symptoms were younger (mean age, 32.6 +/- 15.4 years) and wore contact lenses (11 of 18 patients), and infrequently herpes simplex keratitis (four of 18 patients) was diagnosed. Patients examined after four weeks were older (mean age, 54.0 +/- 19.5 years), infrequently wore contact lenses (six of 25 patients), and often had herpes simplex keratitis (12 of 25 patients). CONCLUSIONS: Corneal examination with tandem scanning confocal microscopy was associated with a marked increase in the detection of Acanthamoeba, strongly suggesting that the disease is more prevalent than suspected. Acanthamoeba may account for many cases of clinically presumed herpes simplex keratitis, the leading cause of corneal blindness in the United States. Acanthamoeba should be considered in the differential diagnosis of any unexplained keratitis, even those of short duration.
Hospital epidemiologists translate their expertise into institutional policy and gain the support of administrators through the infection control committee. Committee members have the important task of helping to disseminate information to all important hospital constituencies. The infection control team can facilitate its goals by properly preparing committee members for the meeting. A well-educated committee will approve policies efficiently. The committee periodically should reassess its accomplishments and goals. This article will explore the workings of the infection control committee and will suggest strategies that the hospital epidemiologist can use to make the committee an asset rather than a hindrance. an asset rather than a hindrance.
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The number of nosocomial bloodstream infections due to Candida species in critically ill newborns is increasing. This pathogen may be vertically transmitted from the mother or nosocomially acquired in the nursery. The goal of this study was to identify the route of transmission of unique Candida species and strains from mothers to their preterm offspring. Specimens from mothers for fungal cultures were obtained before delivery, and specimens from infants for sequential fungal cultures were obtained at defined intervals. Candida species were identified by standard methods and were typed by electrophoretic karyotyping (EK) and restriction endonuclease analysis of genomic DNA (REAG) with pulsed-field gel electrophoresis. Antifungal susceptibility testing was performed on all isolates. Fungal cultures were positive for Candida species in 12 (63%) of 19 mothers' specimens and in seven (33%) of 21 infants' specimens. EK and REAG revealed that both the mother and the infant in three (14%) of 21 mother-infant pairs were colonized with the identical strain of Candida albicans. C. albicans was most commonly transmitted vertically. Candida parapsilosis colonized other infants and could not be accounted for by a maternal reservoir.
Previous studies have shown that bacteremia due to vancomycin-resistant Enterococcus species (VRE) is associated with mortality of 17%-100%, but comorbid conditions may have confounded the estimates. We designed a historical cohort study to determine the mortality attributable to VRE bacteremia. Twenty-seven patients with VRE bacteremia were identified as cases. Within 7 days of the onset of bacteremia, severe sepsis developed in 12 patients (44%) and septic shock developed in 10 (37%). Case patients were closely matched to control patients without VRE bacteremia (1:1) by time of hospitalization, duration of exposure, underlying disease, age, gender, and surgical procedure. The mortality was 67% among cases and 30% among matched controls (P = 0.1). Thus, the mortality attributable to VRE bacteremia was 37% (95% confidence interval [CI], 10%-64%) and the risk ratio for death was 2.3 [CI, 1.2-4.1). We conclude that VRE bacteremia is associated with high rates of severe sepsis and septic shock. The attributable mortality approaches 40%, and patients who have VRE bacteremia are twice as likely to die than closely matched controls.
The prognosis in patients with sepsis depends on severity of acute illness, underlying chronic diseases, and complications associated with infection. Adjusting for these factors is essential for evaluation of new therapies. The purpose of the present study was to determine variables readily identifiable at the bedside that predict mortality in intensive care unit (ICU) patients with sepsis and positive blood cultures. For a 5-yr period, all patients of a surgical ICU presenting with positive blood cultures and sepsis were systematically analyzed for clinical variables and organ dysfunctions at the day of onset of sepsis and bacteremia and during the subsequent clinical course. The prognostic value of these variables was determined using logistic regression procedures. Of the 5,457 admissions to the ICU, 176 patients developed sepsis with positive blood cultures (3.2 per 100 admissions). The fatality rate was 35% at 28 days after the onset of sepsis; in-hospital mortality was 43%. Independent predictors of mortality at onset of sepsis were previous antibiotic therapy (odds ratio [OR], 2.40; 95% confidence interval [CI95], 1.59 to 3.62; p = 0.034), hypothermia (OR, 1.43; CI95, 1.04 to 2.44; p = 0.030), requirement for mechanical ventilation (OR, 2.97; CI95, 1.96 to 4.51; p = 0.009), and onset-of-sepsis APACHE II score (OR, 1.21; CI95, 1.13 to 1.29; p < 0.001). Vital organ dysfunctions developing after the onset of sepsis influenced outcome markedly. The best two independent prognostic factors were the APACHE II score at the onset of sepsis (OR, 1.13 per unit; CI95, 1.08 to 1.17; p = 0.0016) and the number of organ dysfunctions developing thereafter (OR, 2.39; CI95, 2.02 to 2.82; p < 0.001). In ICU patients with sepsis and positive blood cultures, outcome can be predicted by the severity of illness at onset of sepsis and the number of vital organ dysfunctions developing subsequently. These variables are easily assessed at the bedside and should be included in the evaluation of new therapeutic strategies.
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OBJECTIVE: To determine the long-term (> 3 months) survival of septic patients, to develop mathematical models that predict patients likely to survive long-term, and to measure the health and functional status of surviving patients. SETTING: A large tertiary care university hospital and an associated Veterans Affairs Medical Center. DESIGN: From December 1986 to December 1990, a total of 103 patients with suspected gram-negative sepsis entered a double-blind, placebo-controlled efficacy trial of monoclonal antiendotoxin antibody. Of these, we followed up 100 patients for 7667 patient-months. Beginning in May 1992, we reviewed hospital records and contacted all known survivors. We measured the health status of all surviving patients. MAIN OUTCOME MEASURES: The determinants of long-term survival (up to 6 years) were identified through two Cox proportional hazard regression models: one that included patient characteristics identified at the time of sepsis (bedside model) and another that included bedside, infection-related, and treatment characteristics (overall model). RESULTS: Of the 60 patients in the cohort who died at a median interval of 30.5 days after sepsis, 32 died within the first month of the septic episode, seven died within 3 months, and four more died within 6 months. In the bedside multivariate model constructed to predict long-term survival, large hazard ratios (HRs) were associated with severity of underlying illness as classified by McCabe and Jackson criteria (for rapidly fatal disease, HR = 30.4, P < .001; for ultimately fatal disease, HR = 7.6, P < .001) and the use of vasopressors (HR = 2.5; P = .001). In the overall model for long-term survival, severity of underlying illness (rapidly fatal disease, HR = 23.7, P < .001; ultimately fatal disease, HR = 6.5, P < .001), number of active comorbid illnesses (HR = 1.3; P = .04), use of vasopressors at the time of sepsis (HR = 2.0; P = .02), and development of adult respiratory distress syndrome (HR = 2.3; P = .02) predicted patients most likely to die. The Acute Physiology and Chronic Health Evaluation II score was not a significant predictor of outcome when either model included the simpler McCabe and Jackson classification of underlying disease severity. We compared the health status scores with norms for the general population and found that patients with resolved sepsis reported more physical dysfunction (P < .001), including problems with work and activities of daily living (P = .02), and more poorly perceived general health (P < .01). In contrast, patients' scores for perceived emotional health were higher than those in the general population (P = .004). The mean Barthel score of our patients was 85 (100 = total independence) and the mean Eastern Cooperative Oncology Group score was 0.7 (0 = normal, 4 = 100% bedridden), suggesting that the patients' physical function was not normal. CONCLUSIONS: At the onset of suspected gram-negative sepsis, severity of underlying illness and in-hospital use of vasopressors are strong and consistent predictors of short- and long-term survival. Our data validate the McCabe and Jackson severity of illness scoring system for predicting long-term survival after sepsis. Physical dysfunction and more poorly perceived general health occur commonly after sepsis.