Clinical studySkin response to sustained loading: A clinical explorative study
Introduction
Acute severe illnesses, disability, functional limitations or advanced care dependency are often associated with mobility and activity impairments. Patients or care receivers are confined to beds or chairs and are unable to move themselves and change positions. Maintaining body positions over longer periods of time leads to sustained deformation of soft tissues in contact with the underlying support surface especially over bony prominences [1]. If the duration and intensity of the loading exceeds the structural and functional capacity of the deformed cells and tissues pressure ulcers (PUs) may develop [2]. PUs are localized injuries to the skin and/or underlying tissue as a results of long enduring pressure and shear [1].
Worldwide PU prevalence and incidence are high ranging from 1 to 12% in hospital and acute care settings [3], [4], [5], [6], [7] to 20% in institutional long term and geriatric care [8], [9], [10]. Although PUs do occur in all age groups it is especially a condition of the aged [11]. PUs are associated with pain, reduced quality of life [12] and PU treatment is burdensome and expensive. Among 15 selected common skin conditions in the latest Global Burden of Disease report PUs were regarded as the most severe dermatological diseases contributing to a substantial health loss [13]. Furthermore PU development is regarded as an unintended adverse event and it is therefore a widely accepted indicator for the quality and safety of care [14], [15]. Consequently, efficient PU prevention and maintaining skin integrity are major goals in health care [16].
During the last years the knowledge about PU aetiology increased substantially. It could be shown that strains within deeper tissues especially near bony curvatures are much higher compared to the skin surface [17], [18] and that there is a time depended increase of muscle cell death during sustained deformation [19]. Ischemia, reperfusion damage, and impaired lymphatic functions further contribute to necrosis development in muscle and/or subcutaneous fat tissues [20], [21] leading to so called deep tissue injuries [10], [22], [23]. While this inside-out mechanism of PU development is widely accepted today the distinct role of the skin under sustained deformation has gained less attention. Above all little is known about the role of the epidermis and the stratum corneum (SC), the upper most skin layers, which are in direct contact to the support surface and which contribute to mechanical strength of the skin [24].
Results of previous experimental ex vivo and animal studies indicate that sustained loading or deformation alter or even damage epidermal and dermal layers [25], [26], [27] and that there are associations between temperature and moisture content and biophysical properties of the SC [28], [29] and the whole skin [30]. However, little is known about the functional skin barrier characteristics in vivo under ‘real world’ clinical conditions especially in aged individuals. Based on increased transepidermal water loss (TEWL) values Angelova-Fischer et al. recently showed skin barrier impairments in early stages of chronic venous insufficiency compared to healthy controls [31]. Whether such subclinical epidermal changes also occur prior to early PU development is unknown. Therefore the aim of this investigation was to explore possible effects of long enduring loading on the skin under clinical conditions.
Section snippets
Study design, setting and participants
Between March and June 2013 an explorative clinical study was conducted. The study followed a protocol to simulate immobilization while lying in bed. Healthy volunteers were invited to participate meeting the following eligibility criteria: age 60–80 years, absence of skin diseases, absence of acute diseases, ability to move independently and to maintain supine and prone positions. We included only female subjects at this stage because in aged populations females are generally overrepresented
Results
Demographic characteristics of the included 20 females are shown in Table 2. Mean age was 70 years and the BMI of subjects was comparable. The mean skin temperature, TEWL, SCH and erythema indices are shown in Table 3. Baseline skin temperature was comparable at the sternal and sacral skin (32 °C) and slightly lower at the heel skin (29 °C). After both loading times the skin surface temperature increased but remained nearly stable at the control area. The behaviour of the TEWL was similar. TEWL
Discussion
This is the first study investigating skin barrier changes of the two most important PU predilection sites during loading in vivo in humans. We observed loading and site dependent changes for skin temperature, TEWL, and erythema. SCH seemed to be unaffected by loading.
An increase in skin temperature during prolonged loading is well known. The direct contact of the skin with the linen and mattress reduces air convection leading to a local accumulation of heat [30], [36]. In addition local
Conclusion
Based on the study results we conclude that skin functions change during prolonged loading at the sacral and heel skin in aged individuals on a standard hospital mattress. Accumulation of heat and hyperaemia seem to be primarily responsible for increasing skin temperature and erythema which are associated with PU development. For the first time we showed that the TEWL increases at the heels after loading indicating subclinical damage to the SC. TEWL remained stable at the sacral skin indicating
Conflicts of interest
None.
Funding sources
This study was supported by the Clinical Research Center for Hair and Skin Science and the Charité-Universitätsmedizin Berlin.
Acknowledgements
This research was supported by the Clinical Research Center for Hair and Skin Science and the Hair and Skin Research Foundation.
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2022, Journal of Tissue ViabilityCitation Excerpt :This occlusive effect seems to be particular strong on standard hospital matresses compared to special surfaces used in PU prevention [21]. Increasing values of TEWL and SCH during loading could have been shown previously in supine position at the sacral and heel skin, as well as on the gluteal area during sitting [20,38]. At the heel skin, changes of both parameters were substantially higher compared to the sacral skin area in the present investigation, as well as in previous research.
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Recipient of the Hans Schaefer Young Researcher Grant, www.hairskinberlin.com.