Preventing the spread of vancomycin-resistant enterococci in a long-term care facility.

OBJECTIVES: To test the hypothesis that infection control practices can prevent the spread of vancomycin-resistant enterococci (VRE) to residents of a long-term care facility (LCF) from an affiliated acute care facility with a high endemic rate of colonization. DESIGN: Point prevalence study of the rate of rectal colonization. SETTING: A state-supported veterans nursing home and an acute care veterans hospital. PARTICIPANTS: Residents in a state veterans home. INTERVENTIONS: Identification of patients with rectal colonization by VRE before transfer to the state veterans home, contact isolation for colonized veterans, use of oral bacitracin to eliminate colonization. MEASUREMENTS: Rectal swab and culture for VRE, review of clinical records and recording of presumptive risk factors for VRE colonization. The risk factors were age, gender, length of stay at nursing home, treatment with vancomycin or oral antibiotics, prior hospitalization at the acute care facility during the prior year, use of indwelling urethral catheters, presence of diarrhea, and fecal or urinary incontinence. RESULTS: Sixty-nine of 200 residents were cultured in the first study (1996) and 130 of 230 residents were cultured in the second study (1998). Residents who consented to culture differed from those who did not only with regards to gender (2 vs 7, P = .012). In neither study were any residents found to be colonized with VRE who had not already been identified as positive on admission. CONCLUSIONS: Adherence to infection control practices by the patient care staff of the LTCF was associated with the absence of transmission of VRE colonization among its residents. The presence of rectal colonization with VRE in an acute care patient should not be a barrier to acceptance in a nursing home.

Dysthyroid orbitopathy: invasive treatment and the value of radiotherapy.

In this retrospective review of 29 patients with severe dysthyroid orbitopathy, the authors compare 3 invasive therapeutic modalities corticosteroids, radiotherapy and surgical orbital decompression) with special emphasis on the role of radiotherapy.

Effects of aging on sensation of respiratory force and displacement.

The psychophysical technique of magnitude production was used to evaluate the sensation of inspiratory force and inspired volume in young and older subjects. Inspiratory force was generated during a static inspiratory maneuver against a closed airway. The exponent of the power function relationship between airway pressure and sensation intensity during force scaling was not significantly different between young and older subjects. In contrast, the exponents for the magnitude production of inspired volume were significantly greater in the older compared with the young group. We also assessed the effects of age on the relative importance of force and displacement signals on the sensation of inspired volume. Subjects attempted to reproduce a control tidal volume while breathing against a series of inspiratory resistive and elastic loads. In both groups error in tidal volume reproduction increased progressively as the severity of the load increased. During moderate and severe loading the error in the older subjects was significantly greater than in the young group. Correspondingly, the peak inspiratory airway pressures at tidal volume reproduction against these loads were significantly smaller in the older compared with the young subjects. The results suggest that in older subjects cues related to respiratory muscle force are more important than volume in the sensation of lung volume changes. In young subjects the sensation of lung volume changes is based to a greater degree on signals of volume or displacement.

Effect of aging on the perception of resistive ventilatory loads.

We have shown previously, using the technique of magnitude estimation, that the change in sensation level for a given change in elastic loading is less in elderly than in young subjects. In the present study, we used the same technique to compare the perception of added inspiratory and expiratory resistive loads in 40 young (18 to 30 yr of age) and 19 elderly (60 yr of age and older) subjects. Two different ranges of loads were studied and the relation between load magnitude and sensation intensity (the exponent for magnitude estimation) was determined. The study showed that the exponent for both inspiratory and expiratory loads is less in the older group. Because peak airway pressure and the inspiratory and expiratory times while breathing against the added loads were the same in both age groups, the difference in exponents in the two groups was not caused by differences in the forces generated during breathing. Age-related changes in sensory perception may affect behavioral responses to impaired respiratory mechanics.

Effect of aging on respiratory responses to CO2 and inspiratory resistive loads.

We studied 10 elderly individuals over 60 years of age and 18 individuals less than 30 years to determine whether aging affects the response of the respiratory control system to chemical stimuli or to altered mechanical conditions. Both groups consisted of males and females who were nonsmokers. Ventilation and the isometric force developed by the inspiratory muscles (occlusion pressure) was assessed during hypercapnia while the subjects breathed under control conditions or through a load at the mouth that increased inspiratory resistance. Ventilation responses to progressively increasing CO2 were lower but not significantly so in the older group. There were significant differences in ventilatory pattern in the two groups. However, occlusion pressure responses to hypercapnia and to resistive loads were the same. The results suggest that aging has little or no adverse effect on respiratory control.

Effect of aging on respiratory sensations produced by elastic loads.

We compared the effects of graded elastic loads on respiratory sensations in 19 healthy subjects greater than 60 yr of age to 21 healthy subjects less than 30 yr old. The magnitude of the respiratory sensation was quantitated by two well-established psychophysical techniques. In the magnitude-estimation method, subjects indicated the intensity of the sensation experienced with numbers; in the cross-modality method, the level of sensation was signaled with a dynamometer activated by thumb pressure. In addition, the effects of nonrespiratory stimuli were compared in the two groups. With both methods, the logarithm of the response to elastic loads was linearly related to the logarithms of the stimulus. The slope of the line relating the log of the response to the log of the stimulus (beta) was significantly greater in the younger group than in the older group using the magnitude-estimation method but not with the cross-modality matching test. There were no differences in the ability of the two groups to assign numbers to line length. However, the older group had a lower beta for magnitude estimation of thumb force than the younger group. The results suggest 1) that respiratory sensation follows Steven's law and grows exponentially with the stimulus; 2) that the growth of sensations produced by elastic loading is less in older than in younger individuals; and 3) differences in the perception of the mode used for matching in the cross-modality test may obscure significant differences in the sensations elicited by respiratory stimuli.