Elsevier

Applied Ergonomics

Volume 31, Issue 1, 4 January 2000, Pages 35-44
Applied Ergonomics

Psychophysical assessment of assistive devices for transferring patients/residents

https://doi.org/10.1016/S0003-6870(99)00023-XGet rights and content

Abstract

This article reports the psychophysical assessment of nine battery-powered lifts, a sliding board, a walking belt, and a baseline manual method for transferring nursing home patients/residents from a bed to a chair. A separate article reports the biomechanical evaluation of the same task and devices. The objectives of the psychophysical assessment were to investigate the effects of resident-transferring methods on the psychophysical stress to nursing assistants performing the transferring task, and to identify transfer methods that could reduce the psychophysical stress reported by nursing assistants. Nine nursing assistants served as test subjects. Two elderly persons participated as residents. The results indicated that the psychophysical stresses on nursing assistants were significantly lower when performing resident transfers with some of the assistive devices than when performing transfers with the baseline manual transfer method. The nursing assistants generally preferred the basket-sling lift and stand-up lift to other methods. The residents’ comfort and security ratings indicated the comfort and security with most of the assistive devices were greater than or equal to the baseline manual method. Most of the comments of the nursing assistants and residents on the assistive devices were favourable.

Introduction

Nursing home workers face the third highest rate of occupational injuries and illness among all US industries (US Department of Labor, 1994). Between 1980 and 1992, the injury and illness rate for nursing home workers increased from 10.7 to 18.2 per 100 workers among the nation's 1,506,000 nursing aides, orderlies, and attendants (US Department of Labor, 1994). A significant proportion of these are back injuries. Other studies have shown that nursing professionals have both a high prevalence rate of back pain (Biering-Sorensen, 1985) and a high incidence rate of workers’ compensation claims for back injuries (Klein et al., 1984; Jensen, 1987; Personick, 1990).

Patient/resident-handling tasks have been identified as one of the main causes of back injury among nursing personnel (Bell et al., 1979; Jensen et al., 1989; Owen, 1987; Owen et al., 1992; Stobbe et al., 1988; Leighton and Reilly, 1995). Stobbe et al. (1988) used four statistical procedures to test the possible relationship between frequency of patient lifting and risk of having at least one episode of back pain. The survival analysis by Stobbe et al. (1988) indicated that infrequent lifters survived longer than frequent lifters, i.e., worked for a longer time without back injury. Kumar (1990) reached a similar conclusion when he studied the cumulative spinal compressive load (a combination of the lifting frequency, the years of lifting exposure, and the posture related lifting forces) in health care personnel. He found that both cumulative spinal compressive load and cumulative generic load were predictive of low back pain. He also found that the longer a person worked in patient-handling activities, the more likely they were to experience low back pain.

Several researchers have suggested that assistive devices could reduce back stress for nursing personnel and may be effective in controlling back injury (Harber et al., 1985; Jensen, 1985; Owen, 1988; Stubbs et al., 1981; Stobbe et al., 1988; Owen et al., 1992). However, a laboratory study of six assistive devices revealed that only two assistive devices were helpful and four were not helpful in reducing nursing personnel's back stress (Garg et al., 1991). During the last 6 yr, many new assistive devices have become commercially available due to technological advances in lifting equipment (e.g., battery powered or ceiling mounted). A comprehensive evaluation of these resident-handling devices would be a practical undertaking for the research community and very valuable to the healthcare industry.

A laboratory study was conducted to perform biomechanical evaluation and psychophysical stress assessment of nine battery-powered lifts, a sliding board, a walking belt, and a baseline manual method for transferring nursing home residents from a bed to a chair. The objectives of the psychophysical assessment were: (1) to investigate the effects of resident-transferring methods on the psychophysical stress to nursing assistants performing the bed-to-chair transferring task, (2) to collect patient comfort and security data, and (3) to identify transfer methods that could reduce the psychophysical stress perceived by nursing assistants and residents. The transferring task was defined as transferring a resident from a supine position, i.e., lying on the back on a bed, to an upright seated position in a chair. The study hypothesized that the use of assistive devices would result in lower biomechanical and psychophysical stresses to nursing assistants when performing the resident-transferring task than the baseline manual method.

The results of the biomechanical evaluation are reported separately (Zhuang et al., 1999). This paper presents the results of the psychophysical assessment portion of this study.

Section snippets

Subjects

Nine nursing assistants (two males and seven females) were recruited from local nursing homes to participate as test subjects. The following criteria were established to select and protect the nursing assistants serving as research subjects in the study. Nursing assistants must: (1) perform resident-handling tasks as part of their work activity; (2) have no history of back injury or pain within the last year or chronic episodic back pain that was symptomatic within the last three years; and (3)

Ratings of perceived exertion

Ratings of perceived exertion (RPEs) for each method for the shoulders, upper back, lower back, and whole body are summarized in Table 1. The upper back received the lowest RPE ratings (9 of 12 sets) and the shoulders received the second lowest RPE ratings (5 of 12 sets). The walking belt, all four stand-up lifts, and basket-sling lift #3 received statistically significantly smaller ratings of perceived exertion than the baseline manual transfer method for the upper back, lower back, shoulders,

Discussion

In this study, the nursing assistants felt that the procedures for the walking belt and stand-up lifts were not complicated and using the walking belt and stand-up lifts was as easy as the baseline manual transfer method. Some devices received high stress ratings which may have been caused by the postural stresses which result from using the slings, and maneuvering and steering the lift to the chair. It could also be the result of the greater complexity of the activity; i.e., there are only a

Summary and conclusions

The perceived stresses by the nursing assistants were significantly lower when performing resident transfers with some of the assistive devices than when performing transfers with the baseline manual transfer method. The use of the sliding board and basket-sling lifts #1 and 4 did not reduce the perceived stresses to any body part or the whole body of the nursing assistants. The overhead lift only reduced the perceived stress to the shoulders of the nursing assistants. Basket-sling lift #2

Acknowledgements

The authors thank the nursing assistants and residents who participated in this laboratory study. Special thanks go to Mrs. Carolyn Lloyd of Monongalia County Vocational Education Centre for her help in understanding resident-handling procedures and acquiring a hospital bed for this study. The authors also wish to thank all the manufacturers for providing their devices and sending their representatives to train the research subjects. Mention of product names does not constitute endorsement by

References (23)

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