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Biomedical subjects

W C Dunagan

Publications and source records attributed to W C Dunagan.

31 records · Page 2Linked to original sources
PubMed1993

Symptomatic cytomegalovirus infection in renal transplant recipients given either Minnesota antilymphoblast globulin (MALG) or OKT3 for rejection prophylaxis.

To compare the impact of using Minnesota antilymphoblast globulin (MALG) versus the monoclonal antibody, OKT3, on the development of symptomatic cytomegalovirus (CMV) infection, we reviewed a cohort of 130 cadaveric renal transplant recipients enrolled in a prospective comparison of MALG versus OKT3 for rejection prophylaxis. Among the 112 patients at risk for CMV, prophylactic MALG was associated with an increased risk of symptomatic infection (relative hazard [rh] = 3.31; 95% confidence interval CI], 1.50 to 7.30; P = 0.003). Transplantation of kidneys from CMV-seropositive donors into CMV-seronegative recipients (rh = 5.22; 95% CI, 2.34 to 11.63; P = 0.00004), first transplantation (rh = 4.76; 95% CI, 1.06 to 21.3; P = 0.039), and acute rejection therapy (rh = 2.03; 95% CI, 0.98 to 4.21; P = 0.055) were also associated with an increased risk. Prophylactic MALG followed by treatment with any agent for acute rejection was strongly correlated with symptomatic CMV infection (rh = 4.46; 95% CI, 3.71 to 5.21; P = 0.00006). Symptomatic CMV infection was not only more frequent, but more severe in recipients of prophylactic MALG, and more MALG recipients were treated with ganciclovir. There was no difference in rejection rate for the two rejection prophylaxis regimens (P = 0.625). Prophylactic OKT3 results in less risk of symptomatic CMV infection than prophylactic MALG in cadaveric renal transplant recipients who are seropositive for CMV or whose donors are seropositive for CMV.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Evaluation of rooms with negative pressure ventilation used for respiratory isolation in seven midwestern hospitals.

OBJECTIVE: To determine the number and efficacy of respiratory isolation facilities in St. Louis hospitals and to assess the mechanisms in place for evaluating function of hospital ventilation systems. DESIGN: A prospective multi-hospital surveillance study using direct observation and a standardized questionnaire. SETTING: Seven hospitals (including university-affiliated large teaching, private community, private teaching, and private nonteaching adult hospitals, and one pediatric teaching hospital) in St. Louis, Missouri. MEASUREMENTS: Actual direction of airflow in rooms designated for respiratory isolation was measured using smokesticks. Hospital demographic information, respiratory isolation policies, and frequency of ventilation tests were provided by infection control personnel. RESULTS: One hundred twenty-one (3.4%) of 3,574 hospital rooms were designed to have negative pressure ventilation suitable for respiratory isolation. The percentage of isolation rooms in each institution ranged from 0.4% (92 of 486) to 93% (39 of 42). Only three (43%) of seven hospitals had intensive care respiratory isolation rooms, and none had isolation rooms in the emergency department. No hospital had tested routinely the efficacy of the negative pressure ventilation, and two (28%) of seven had tested airflow for the first time in the past year. We tested 115 (95%) of 121 isolation rooms. With the doors closed, 52 (45%) of 115 designated negative pressure rooms actually had positive airflow to the corridor. The number of negative pressure rooms and the presence or absence of anterooms did not predict correct direction of airflow. There was a significant difference among hospitals in the percentage of designated isolation rooms that had truly negative pressure (P < 0.0001). Hospital age, size, and type correlated with correct direction of airflow (P < 0.0001). CONCLUSION: In the hospitals studied, only a small number of rooms were designated for respiratory isolation, and the performance of these was not tested routinely. High-risk areas including intensive care units and emergency rooms were not equipped to provide respiratory isolation. The direction of airflow in respiratory isolation rooms was not always correct and should be evaluated frequently.

Cross Infection↗
PubMed1993

An expert system for culture-based infection control surveillance.

Hospital-acquired infections represent a significant cause of prolonged inpatient days and additional hospital charges. We describe an expert system, called GERMWATCHER, which applies the Centers for Disease Control's National Nosocomial Infection Surveillance culture-based criteria for detecting nosocomial infections. GERMWATCHER has been deployed at Barnes Hospital, a large tertiary-care teaching hospital, since February 1993. We describe the Barnes Hospital infection control environment, the expert system design, and a predeployment performance evaluation. We then compare our system to other efforts in computer-based infection control.

Cells, Cultured↗
PubMed1992

Candidemia in a tertiary care hospital: epidemiology, risk factors, and predictors of mortality.

Demographic information, risk factors, therapy, and outcome for all patients who had candidemia at Barnes Hospital, St. Louis, between 1 September 1988 and 1 September 1989 were retrospectively reviewed. One hundred six candidemic patients were identified, representing 0.5% of all medical and surgical discharges and 0.33% of total patient discharges. These percentages represent a 20-fold increase in the incidence of candidemia at our hospital in comparison with that during 1976-1979. Candida albicans was the most frequently isolated species (63%), followed by Candida tropicalis (17%), Candida glabrata (13%), Candida parapsilosis (6.5%), and Candida krusei (0.9%). Overall mortality was 57%, and 14 (23%) of 60 deaths occurred within 48 hours of the detection of candidemia. Mortality was associated with higher APACHE II scores (25 for nonsurvivors vs. 16 for survivors; P = .0001), the presence of a rapidly fatal underlying illness (P = .0009), and sustained positivity of blood cultures (P = .02). In cases of sustained candidemia, the isolation of non-albicans Candida species also correlated with increased mortality (8 of 8 vs. 10 of 21; P = .005). Thirty candidemic patients (28%) did not receive any antifungal therapy, and 19 (63%) of these untreated patients died. Eleven untreated patients (37%) survived without sequelae. There has been a marked increase in the incidence of candidemia in our institution that is associated with a high overall mortality. Candidemia lasting less than 24 hours was associated with a lower mortality than was that of longer duration. Severity of illness and duration of candidemia should be used as stratifying factors in prospective studies to determine optimum therapy.

Adolescent↗
PubMed1990

Mycobacterial infection and HIV disease.

Mycobacteria infections are a common cause of morbidity among patients infected with the human immunodeficiency virus (HIV). The author presents an overview of the most common infections and suggests several treatment options and drug regimens.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Antimicrobial misuse in patients with positive blood cultures.

PURPOSE: Inappropriate antimicrobial use was examined among a randomly and prospectively selected cohort of patients with at least one positive result of blood cultures. This misuse was then analyzed with respect to hospital charges and length of stay (LOS). PATIENTS AND METHODS: The study consisted of 70 patients (average age, 58.5 years) who had not undergone bone marrow transplantation. Patient charts were reviewed daily for the following information: clinical signs and symptoms of infection, pertinent laboratory data, culture results, detailed data on each antimicrobial in every antimicrobial regimen and their appropriateness, hospital charges, LOS, diagnostic and procedure codes, and discharge status. Three severity of illness variables were generated. Inappropriate antimicrobial use was described according to one of 12 categories. RESULTS: The percent of antimicrobial misuse, defined as the proportion of days of administration of antimicrobials on which one or more antimicrobials were judged inappropriate, was found to be 22.3%. After adjustment for severity of illness and diagnosis, this average inappropriateness correlated with 4.2 additional hospitalization days and $5,368 additional hospital charges. CONCLUSION: Our results cannot distinguish among several possible reasons for these associations, including direct causality (e.g., toxicity and prolonged hospitalization for antimicrobial use) and indirect links such as inappropriate utilization of other resources and influences of severity of illness on antimicrobial use not accounted for in our equations. Nevertheless, the magnitude of the association gives import to the desirability of further studies.

Anti-Infective Agents↗
PubMedDate not supplied

Formulary control of antimicrobial usage. What price freedom?

Formulary controls are the most common and probably the most effective method for controlling abuse of antimicrobial agents in hospitalized patients. Such programs may include restriction of both the number of agents available and the way these agents may be used. These programs have been demonstrated to control pharmacy expenditures. Other potential advantages include reductions in the incidence of adverse drug reactions and the antimicrobial resistance among the hospital flora, and improvements in the overall quality of prescribing of antimicrobials. There are few data to document such benefits, however. Potential disadvantages are also poorly documented but include inconvenience for prescribing physicians, increased administrative costs, prescribing errors, and increased antimicrobial resistance. Antimicrobial control programs will likely remain common, but the availability of new information technologies should enable a transition to systems based on concurrent assessment of antimicrobial appropriateness with immediate feedback to the prescribing physician.

Anti-Bacterial Agents↗
PubMedDate not supplied

Anaerobic culture yield in interventional radiologic drainage procedures.

PURPOSE: This study was designed to determine the yield of anaerobic cultures from percutaneous radiologic drainage procedures. PATIENTS AND METHODS: Anaerobic culture results in 317 patients from June 1992 to May 1994 were retrospectively examined. Anaerobic specimens were placed in specially designed anaerobic culture tubes and not blood culture media. Patients had undergone the following procedures: percutaneous nephrostomy (105 patients), biliary drainage (65 patients), and abdominal abscess drainage (147 patients). Aerobic culture results were tabulated in those patients with positive anaerobic cultures. RESULTS: Overall, 10% of patients (n = 32) had positive anaerobic cultures (Bacteroides species, n = 25; Clostridium, n = 6; other organisms, n = 4). Anaerobes were isolated in 13% (n = 19) of abdominal abscess drainages, 8% (n = 8) of nephrostomy drainages, and 8% (n = 5) of biliary drainages. Aerobic isolates were present in 78% (n = 25) of patients with anaerobic infection. CONCLUSION: The yield for anaerobic cultures varies for different types of percutaneous drainage procedures from 8% to 13%. When isolated, anaerobic bacteria are frequently mixed with aerobic bacteria. Anaerobic culture usage is recommended with abdominal abscess and biliary drainages. Anaerobic bacterial cultures are not recommended for percutaneous nephrostomy unless the patient has a urinary tract malignancy or has undergone urinary instrumentation.

Abdominal Abscess↗
PubMedDate not supplied

Antibiotic misuse in two clinical situations: positive blood culture and administration of aminoglycosides.

Antibiotic use was examined among randomly and prospectively selected cohorts of 79 patients with a positive blood culture and 88 patients given aminoglycosides for a variety of reasons. Appropriateness of antibiotic use was judged daily for each agent according to specific criteria of misuse. For patients with a positive blood culture, 14.3% of antibiotic-days were judged inappropriate in some regard, while for patients given aminoglycosides, 10.2% of antibiotic-days were thought to be inappropriate. The patterns of misuse were similar for the two groups despite disparate selection criteria. The unnecessary use of antibiotics was the single most common type of misuse in both groups, but errors in dosing collectively accounted for nearly one-half of antibiotic misuse. These results suggest that a variety of factors are responsible for misuse of antibiotics. Although the data presented do not allow conclusions about the optimal methods for control of antibiotic misuse, they imply that a multifaceted approach is probably required.

Ampicillin↗
PubMedDate not supplied

Monitoring expert system performance using continuous user feedback.

OBJECTIVE: To evaluate the applicability of metrics collected during routine use to monitor the performance of a deployed expert system. METHODS: Two extensive formal evaluations of the GermWatcher (Washington University School of Medicine) expert system were performed approximately six months apart. Deficiencies noted during the first evaluation were corrected via a series of interim changes to the expert system rules, even though the expert system was in routine use. As part of their daily work routine, infection control nurses reviewed expert system output and changed the output results with which they disagreed. The rate of nurse disagreement with expert system output was used as an indirect or surrogate metric of expert system performance between formal evaluations. The results of the second evaluation were used to validate the disagreement rate as an indirect performance measure. Based on continued monitoring of user feedback, expert system changes incorporated after the second formal evaluation have resulted in additional improvements in performance. RESULTS: The rate of nurse disagreement with GermWatcher output decreased consistently after each change to the program. The second formal evaluation confirmed a marked improvement in the program's performance, justifying the use of the nurses' disagreement rate as an indirect performance metric. CONCLUSIONS: Metrics collected during the routine use of the GermWatcher expert system can be used to monitor the performance of the expert system. The impact of improvements to the program can be followed using continuous user feedback without requiring extensive formal evaluations after each modification. When possible, the design of an expert system should incorporate measures of system performance that can be collected and monitored during the routine use of the system.

Expert Systems↗
PubMedDate not supplied

Statistical process control methods for expert system performance monitoring.

The literature on the performance evaluation of medical expert system is extensive, yet most of the techniques used in the early stages of system development are inappropriate for deployed expert systems. Because extensive clinical and informatics expertise and resources are required to perform evaluations, efficient yet effective methods of monitoring performance during the long-term maintenance phase of the expert system life cycle must be devised. Statistical process control techniques provide a well-established methodology that can be used to define policies and procedures for continuous, concurrent performance evaluation. Although the field of statistical process control has been developed for monitoring industrial processes, its tools, techniques, and theory are easily transferred to the evaluation of expert systems. Statistical process tools provide convenient visual methods and heuristic guidelines for detecting meaningful changes in expert system performance. The underlying statistical theory provides estimates of the detection capabilities of alternative evaluation strategies. This paper describes a set of statistical process control tools that can be used to monitor the performance of a number of deployed medical expert systems. It describes how p-charts are used in practice to monitor the GermWatcher expert system. The case volume and error rate of GermWatcher are then used to demonstrate how different inspection strategies would perform.

Evaluation Studies as Topic↗
PubMedDate not supplied

A randomized, prospective evaluation of an interventional program to discontinue intravenous antibiotics at two tertiary care teaching institutions.

To evaluate a program to discontinue intravenous antibiotics at two teaching hospitals, 102 inpatients meeting eligibility criteria were randomly assigned to two groups. In one group, patients' physicians were contacted by pharmacists with recommendations to discontinue intravenous antibiotic therapy; in the other, patients were simply observed. Measured outcomes were antibiotic costs, length of stay, need to restart intravenous antibiotics, in-hospital mortality, and 30-day readmissions. The intervention significantly reduced mean antibiotic costs per patient ($19.82 vs $35.84, p = 0.03), but related labor costs exceeded this benefit. Readmissions were significantly more frequent in the intervention group than in the control group (29% vs 9.8% p = 0.02), but they were not infection related. No impact was demonstrated on the other measured outcomes. Institutions considering such programs or with one in place should conduct similar evaluations.

Administration, Oral↗