Biomedical subjects
M D Nettleman
Publications and source records attributed to M D Nettleman.
Epidemiology of isolation precautions.
OBJECTIVE: To investigate compliance with isolation precautions. DESIGN: A prospective observational study carried out during ten weeks of 1989. Participants were unaware of the study. SETTING: The isolation bay of a 24-bed surgical intensive care unit in a 900-bed university tertiary care facility. PARTICIPANTS: Study participants included any healthcare worker or visitor entering the patient room during designated 15-minute intervals. RESULTS: We observed 467 subjects entering patient rooms. Compliance with strict isolation (65%) was better than with wound/skin (40%) or excretion/secretion (36%) isolation (p less than .01). Visitors were more compliant than healthcare workers (88% versus 41%; p less than .01). Spending more time in the room was associated with improved compliance (p less than .01). Compliance was higher for subjects entering with a group compared with those entering alone (51% versus 41%; p less than .05). The compliance rate for nurses improved as the nurse/patient ratio improved (p = .14). Compliance was independent of severity of illness. Multivariate analysis revealed that the amount of time spent in the room, being a visitor, and use of strict isolation were independent predictors of compliance. CONCLUSIONS: Noncompliance was widespread. When increased demands are placed on the time of physicians and nurses in the name of cost containment, unperceived consequences, such as those resulting from decreased compliance, must be considered.
Biological warfare and infection control.
Though many agents have been proposed as potential biological weapons, the feasibility of biological warfare is largely a matter of conjecture. The unpredictable and indiscriminate devastation caused by natural epidemics during wartime should warn us of the dangers of employing microbes as weapons.
Cholera, travel, and infection control.
The spread of cholera is a testimony to our inability to provide a consistently decent standard of living to the peoples of the world. Simply separating human sewage from potable water sources would curtail, if not eliminate, the disease. Even persons who acquire cholera would not die if they were given access to rehydration. American travelers should follow sensible food and water precautions, but need not curtail their travels to countries that have cholera.
Health advice for travelers from embassies and consulates.
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Emporiatrics: diarrhea in travelers.
The degree of discomfort and inconvenience caused by travelers' diarrhea highlights the need to prepare the international traveler thoroughly. In addition to observing food and water precautions, most travelers should carry antibiotics and antimotility agents to be started if diarrhea occurs. Used judiciously, these precautions may prevent an unplanned tour of bathrooms and outhouses in foreign countries.
Emporiatrics: the study of diseases in travelers.
Travel to developing countries is exhilarating and, for the most part, safe. However, the unwary traveler may encounter unexpected tropical diseases, many of which are preventable. Additionally, infected travelers may return with exotic diseases that pose special problems for ICPs.
Using decision analysis to assess the quality of quality assurance.
Quality assurance is rapidly encroaching on the fields of epidemiology and infection control. If we are to lead this most recent revolution in medical care, we must ensure that our approach is structured, that we reassess our goals and methods regularly and that we achieve the maximal benefit from the resources we consume. According to Colloton, "Unless refined or replaced, the unsophisticated methodologies now emerging on several fronts will be used, with or without our endorsement, to assess the quality of care rendered within all of medical practice."
Emporiatrics: protecting travelers from malaria.
Travelers to malarious areas of the world should take precautions against mosquito bites and take medications to prevent the disease. Chloroquine is the prophylactic agent of choice in areas where malaria remains sensitive. If no contraindications exist, mefloquine is recommended in areas where chloroquine resistance occurs. Alternative regimens would include doxycycline taken as the sole prophylactic agent, or weekly chloroquine with a treatment dose of Fansidar to be taken if symptoms compatible with malaria occur.
Nosocomial infections: validation of surveillance and computer modeling to identify patients at risk.
To estimate the accuracy of routine hospital-wide surveillance for nosocomial infection, the authors performed a validation study at the University of Iowa Hospitals and Clinics, a 900-bed tertiary care institution, by daily concurrent surveys of all patients' charts. The study extended over a 10-month period from January to October 1987. The sensitivity and specificity of the reported data were 80.7% (95% confidence interval (CI) 72.2-89.2) and 97.5% (95% CI 96.4-98.5), respectively. The predictive values of positive or negative reports of an infection were 75.3% (95% CI 66.3-84.2) and 98.1% (95% CI 97.3-99.1), respectively. In a separate analysis, the data entry system was reviewed for eight descriptive variables among all patients with infections (n = 443) identified over a 2-month period. The data entry was found to be 94-99% accurate. To improve the efficiency of current surveillance, the authors used data gathered during the study to develop a computer model for the identification of patients with a high probability of having a nosocomial infection. The use of stepwise logistic regression identified five variables which independently predicted infection: age of the patient (years), days of antibiotics, days of hospitalization, and the number of days on which urine and/or wound cultures were obtained. Optimal sensitivity and specificity (81.6% and 72.5%, respectively) were found when the model examined patients with an 8% or higher a priori probability of infection; this figure corresponded to a review of 33% of the patients' charts. Increasing the a priori probability would progressively increase specificity and reduce both sensitivity and the number of charts needed for review. If it is prospectively validated, the model may provide a more efficient mechanism by which to conduct hospital-wide surveillance.
Smallpox vaccination for investigators using vaccinia recombinants.
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Outcome measurements in decision analysis: life versus quality of life.
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Game theory: for adults only.
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Cost-effectiveness of screening women at moderate risk for genital infections caused by Chlamydia trachomatis.
We evaluated the cost-effectiveness of screening women at moderate (prevalence, 7.9%) risk for urogenital infections with Chlamydia trachomatis. The characteristics of culture and direct antigen tests were based on published values. Those of serology were based on a comparative study in 434 college women. Three serological tests were evaluated: microimmunofluorescence, an indirect fluorescent antibody assay, and an enzyme-linked immunoassay. Their sensitivities and specificities were 97% and 64%, 87% and 64%, and 84% and 51%, respectively, compared with culture. Screening all patients with a direct antigen test costing less than $12 was more cost-effective than neither testing nor treating patients, although only 53% of patients with positive test results would actually be infected. The use of culture alone or as a confirmatory test was less cost-effective but had high positive predictive values. Seropositivity was not highly predictive of active infection. Chlamydial screening can be cost-effective in moderate-risk women.
The effectiveness of medical care.
One skill required of the modern physician is the ability to provide effective care while spending a minimal amount of money. As outcomes become more complex, it is important to have a structured approach to the evaluation of effectiveness. Decision analysis provides the tools to quantitate and compare the utilities of alternate strategies.
Decision analysis: a tool for infection control.
The medical world would seem to be one of increasing technology and shrinking financial resources. New tests and therapies constantly appear on the market. Most have been examined for efficacy and side effects. The real question is: where does the new test or therapy fit in with all previous products? Decision analysis is a mathematical tool adapted to assess the relative cost-effectiveness of complex diagnostic and therapeutic strategies.
Practical applications of decision analysis.
The number and complexity of available tests and therapies is expanding and financial resources are shrinking. Clinicians must now consider how to give the best care while limiting health expenses. Decision analysis is a tool used to guide clinicians in the practice of medicine, and to supplement and enhance intuitive decision making based on clinical experience.
Receiver operator characteristic (ROC) curves.
Receiver operator characteristic curves describe the trade-off between appropriate diagnoses of true disease and inappropriate positive diagnoses in healthy persons. ROC curves may be used to compare the accuracy of two or more tests, diagnostic algorithms, or the performance of diagnosticians.