Assessment of patient support surfaces: principle, practice and limitations

Abstract

Pressure ulcers cause great pain and suffering to patients as well as unnecessary strain on nursing staff. Their treatment is both costly and time consuming. Every effort therefore should be directed towards their prevention. Understanding of the aetiology of pressure ulcers is still incomplete and assessment of devices aimed at prevention is difficult. Over the years, numerous parameters, including interface pressure and transcutaneous blood gas measurements, have been used to evaluate mattresses and cushions. However, the quality of the data gathered is variable and its clinical interpretation remains unsatisfactory. It could be said that the science of evaluation of support surfaces is still at a formative stage, as clinical validation of many of the approaches has yet to be carried out.

Preventing pressure ulcers by assessment of the microcirculation in tissue exposed to pressure

“…The manufacturers' promotional literature and manuals are often biased and might be of little help in the selection of a specific product for the individual in need (Rithalia, 2005). Efficacy of the product type and differences between products has always been difficult to demonstrate and only a few randomized clinical trials have been carried out (Clancy, 2013).…”

Evaluation of Repositioning in Pressure Ulcer Prevention

“…They measured the transcutaneous oxygen pressure (TcPO2), which requires heating of the skin up to 44 C and does not reflect normal heat accumulation. Furthermore, the TcPO2 sensors had a profile that undoubtedly interfered with the localized pressure and could, therefore, give false readings (Rithalia, 2005). The measurement probe used in this thesis was thin and flexible, and neither the silicon nor the light affect skin surface temperature (Hagblad, 2011).…”

Use of weight-bearing MRI for evaluating wheelchair cushions based on internal soft-tissue deformations under ischial tuberosities

“…Very few RCTs have focused specifically on wheelchair cushions, and even those were inconclusive for an ultimately superior cushion type [3,9,11]. A second approach is biomechanical studies of contact pressures using different cushions [10][11][12]24]. In light of recent literature Figure 4(a), assume that subject is sitting motionless on rigid support, which induces gluteal muscle tissue deformations of 72%.…”

“…Problems exist in isolating the effect of the cushion from other interfering clinical variables (e.g., comorbidities that are common in populations susceptible to pressure ulcers), environmental factors, and performance of the caregivers [9][10][11]. Various objective parameters, including contact pressures during sitting, buttocks skin temperatures, and humidity, have been used to evaluate the efficacy of cushions in preventing pressure ulcers [12], with contact pressure measurements being the most popular tool. However, no agreed threshold for the allowed sitting pressure exists in the literature, as explained in recent articles stating that internal anatomy and mechanical properties of tissues can cause substantial differences in internal tissue loading between individuals, even when their sitting pressures are similar [13][14][15].…”