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Biomedical subjects

E Larson

Publications and source records attributed to E Larson.

At least 73 records · Page 4Linked to original sources

Phenytoin and acute mountain sickness on Mount Everest.

Twenty-one climbers who were members of the American Ultima Thule Everest Expedition participated in a double-blind, randomized clinical trial of phenytoin prophylaxis for acute mountain sickness during the approach to the northeast ridge of Mount Everest. The study was carried out between Beijing and base camp at 16,800 feet. Time spent ascending from Beijing to base camp averaged 13 days. High-altitude symptom questionnaires were filled out beginning in Lhasa at 11,800 feet and in Xigatse at 12,000 feet, in Xegar at 14,000 feet, and at base camp. Computer analysis of the questionnaire answers performed by an impartial analyst revealed that climbers who took phenytoin were less likely to have headaches at base camp. No other statistically significant differences were observed, but the power of the sample size was low.

Acute Disease

Physiologic, microbiologic, and seasonal effects of handwashing on the skin of health care personnel.

The handwashing practices of 22 personnel on an oncology unit in an urban medical center were studied for 2 months. During 891 person-hours of observation, 986 handwashes were observed. Subjects washed a mean of 1.1 times an hour for a mean of 13.2 seconds. Reported and observed handwashing behavior was only moderately correlated (p = 0.05 for frequency, 0.30 for duration of handwashing). Physicians washed significantly less often (p less than 0.001), but more thoroughly (p less than 0.001), than did nurses. Nurses washed more often after minimal or no patient contact than did physicians (p less than 0.001). Individuals were very consistent in their handwashing technique. A total of 558 isolates were recovered from 158 hand cultures. The mean log count was 4.88, with no significant difference between physicians and nurses. Coagulase-negative staphylococci isolated from hands of physicians and nurses were significantly more resistant to antimicrobial agents than those of personnel with minimal patient contact (p less than 0.01). Subjects had more skin damage in winter than in summer, as indicated by increased shedding of skin squames (p less than 0.05). We conclude that handwashing practices vary significantly by profession and that reporting of handwashing practices by personnel is inaccurate.

Drug Resistance, Microbial

Certification: philosophy, goals, and methods, with application to the discipline of infection control practice.

The philosophy, goals, and methods of certification are complex and need to be understood in general before they can be applied to a specific practice discipline. This article is intended to provide background information about certification, summarize the history of credentialing for health occupations, and briefly describe methods for test design and construction. Philosophy, goals, methods, and preparation for certification are then applied to the discipline of infection control practice, with specific reference to the Infection Control Certification Examination, offered for the first time in November 1983 and in each subsequent year.

Certification

Physiologic and microbiologic changes in skin related to frequent handwashing.

Handwashing practices may be adversely influenced by the detrimental effects of handwashing on skin. A protocol was developed to assess the physiologic and microbiologic effects of frequent handwashing. Fifty-two female volunteers washed their hands 24 times per day for 5 days. Five agents were tested: water alone, non-medicated bar soap, a chlorhexidine-containing antiseptic, and two agents containing povidone-iodine (one currently available on the market and one being tested for possible marketing). Some damage to the outer membrane of skin, the stratum corneum, occurred in all groups. There were significant changes in the amount of evaporation water loss (p = .001) and in self assessments of skin condition (p = .005) from pre-to-post test for the entire group. Skin damage was also assessed by visualizing desquamating stratum corneum cells, which are shed in large aggregates when detergents injure skin. Significantly less such shedding occurred in subjects using water alone, bar soap, and the chlorhexidine formulation (p = .02). Greater antimicrobial activity of an agent was not correlated with increased skin trauma. We have quantitated, using objective physiologic parameter, the skin damage that occurs during even a short period of frequent handwashing. We recommend that further studies using the methods described be conducted to quantitate skin damage over longer periods of time, more closely resembling handwashing practices of health care personnel.

Adolescent

An approach for selection of health care personnel handwashing agents.

Given the wide range of available health care personnel handwashing agents, selection of an appropriate product may be difficult. This decision may be made on the basis of user preference, cost, or other factors unrelated to product effectiveness. Four criteria--efficacy, safety, cost, and acceptability--are appropriate for systematic evaluation of handwashing products. These criteria are applied to para-chloro-meta-xylenol (PCMX), a compound used with increasing frequency in health care personnel handwashing agents. Published data regarding the biochemical properties, efficacy, and safety of PCMX are summarized. We conclude that the substance appears to be safe and efficacious. However, the activity of PCMX is highly formula-dependent and many of the studies available in scientific literature have been conducted in Europe using a variety of testing conditions and formulations different from those currently available in the US. Clinical studies of marketed formulations are beginning to appear in the literature. Such studies will provide the data needed for adequate product evaluation.

Animals

Evaluation of the sterility of thermodilution room-temperature injectate preparations.

This study assessed the bacteriologic safety of room-temperature injectate used for cardiac output measurement in a surgical ICU, and compared its cost/benefit relationship to that of prefilled packaged syringes and a closed-loop injectate system. Ninety-five samples of injectate were obtained at four time intervals from staff-prepared syringes, and cultured for microbiologic growth. About 29% (27/95) of samples yielded bacterial growth, ranging from two colony-forming units to those too numerous to count. All positive samples contained skin flora, including coagulase-negative staphylococci and coryneforms. Additionally, five plates contained colonies of Gram-negative bacteria. Extended storage time increased the risk of contamination: 16.2% were contaminated within the first 24 h, whereas 45% were contaminated when stored for more than 72 h. Switching to a closed injectate system significantly (p less than .001) decreased the incidence of contamination by 1.2%, and also allowed a cost savings of $1.52/patient.

Bacteriological Techniques

Dementia of the Alzheimer's type and depression.

This retrospective review of medical records was designed to address three questions: 1) Can the depression seen in some patients with Dementia of the Alzheimer's Type (DAT) be successfully treated? 2) Does this treatment lead to any long-term improvement in the patient's cognitive status? and 3) Do patients with coexisting DAT and depression have a different long-term clinical course than nondepressed DAT patients? In the authors' sample of 131 DAT subjects, 41 (31%) also met DMS-III criteria for a major affective disorder. Of those DAT plus depression patients whose records reflected treatment (usually with a tricyclic antidepressant), 85% (17 of 20) showed clear evidence of improvement in mood, vegetative signs, or activities of daily living (ADLs) based on review of the medical record. An analysis of change in cognitive function (measured by the Folstein Mini-Mental State) and five global measures failed to reveal any differences between the depressed and nondepressed groups after a mean interval of 17 months. The depression that occurs in approximately one-quarter to one-third of DAT patients appears to respond to appropriate therapy. These patients often show improvement in their mood and ADLs but remain demented.

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