Factors contributing to frailty: literature review.

AIM: This paper presents a review of theoretical and research literature in order to identify the factors contributing to frailty. BACKGROUND: Frailty is a multifaceted gerontological concept that lacks a clear definition, but may result from an identifiable homogeneous cluster of bio-psycho-social-spiritual factors. METHOD: A total of 134 articles were identified through a search of the MEDLINE (1966 to July 2004), CINAHL (1982 to July 2004), PsychInfo (1985 to July 2004) and Ageline (1995 to July 2004) databases. Each article was reviewed to determine its fit with inclusion/exclusion criteria. Seven research and 11 theoretical articles were retained and further reviewed for methodological quality using a validity tool. FINDINGS: Seventeen different definitions of frailty were identified. Regardless of the differing definitions, common contributing factors could be identified. Physical, cognitive/psychological, nutritional and social factors, as well as ageing and disease, were evident in both the theoretical and research literature. CONCLUSIONS: Although there is strong agreement that a relationship exists between a cluster of factors and frailty, designation of the factors as contributors or outcomes of frailty differs. Without a clear explanatory theory of the path from contributors to frailty to outcomes, research will continue to produce confusing results. A theoretical framework that includes bio-psycho-social-spiritual factors as contributors to frailty is recommended as the most useful framework for gerontological nursing.

Implementing nursing practice guidelines: a complex undertaking.

Clinical practice guidelines have been proposed to significantly reduce the gap between available scientific evidence and clinical practice. Evidence-based guidelines are also being produced at an ever-increasing pace. However, guidelines do not implement themselves, and the research to support implementation does not provide straightforward answers. What works in one setting does not necessarily work in another. In short, guideline implementation and change of practice is complex and messy. The purpose of this article is to discuss the implementation of clinical practice guidelines using the Promoting Action on Research Implementation in Health Services framework. More specifically, 3 key components are highlighted: (1) the evidence base for guideline recommendations, (2) the clinical context where guidelines are to be implemented, and (3) the nature of facilitation needed to ensure a successful change process. An overview of the literature in the field is provided, and the authors' experiences are shared, and a few recommendations are tentatively provided.

Sources of practice knowledge among nurses.

Several studies have been published listing sources of practice knowledge used by nurses. However, the authors located no studies that asked clinicians to describe comprehensively and categorize the kinds of knowledge needed to practice or in which the researchers attempted to understand how clinicians privilege various knowledge sources. In this article, the authors report findings from two large ethnographic case studies in which sources of practice knowledge was a subsidiary theme. They draw on data from individual and card sort interviews, as well as participant observations, to identify nurses' sources of practice knowledge. Their findings demonstrate that nurses categorize their sources of practice knowledge into four broad groupings: social interactions, experiential knowledge, documents, and a priori knowledge. The insights gained add new understanding about sources of knowledge used by nurses and challenge the disproportionate weight that proponents of the evidence-based movement ascribe to research knowledge.

Structural equation model testing and the quality of natural killer cell activity measurements.

BACKGROUND: Browne et al. [Browne, MacCallum, Kim, Andersen, Glaser: When fit indices and residuals are incompatible. Psychol Methods 2002] employed a structural equation model of measurements of target cell lysing by natural killer cells as an example purportedly demonstrating that small but statistically significant ill model fit can be dismissed as "negligible from a practical point of view". METHODS: Reanalysis of the natural killer cell data reveals that the supposedly negligible ill fit obscured important, systematic, and substantial causal misspecifications. RESULTS: A clean-fitting structural equation model indicates that measurements employing higher natural-killer-cell to target-cell ratios are more strongly influenced by a progressively intrusive factor, whether or not the natural killer cell activity is activated by recombinant interferon gamma (rIFN gamma). The progressive influence may reflect independent rate limiting steps in cell recognition and attachment, spatial competition for cell attachment points, or the simultaneous lysings of single target cells by multiple natural killer cells. CONCLUSIONS: If the progressively influential factor is ultimately identified as a mere procedural impediment, the substantive conclusion will be that measurements of natural killer cell activity made at lower effector to target ratios are more valid. Alternatively, if the individual variations in the progressively influential factor are modifiable, this may presage a new therapeutic route to enhancing natural killer cell activity. The methodological conclusion is that, when using structural equation models, researchers should attend to significant model ill fit even if the degree of covariance ill fit is small, because small covariance residuals do not imply that the underlying model misspecifications are correspondingly small or inconsequential.