Pressure-reducing cushions: perceptions of comfort from the wheelchair users' perspective using interface pressure, temperature and humidity measurements.

INTRODUCTION: There are many static pressure-reducing cushions commercially available consisting of foams, gels, air or a combination of these. There is, however, little evidence available on their effectiveness to guide prescription. In practice, comfort tends to be a major factor in determining whether a pressure-reducing cushion will continue to be used, although it is unclear as to what determines comfort. The aim of this study was to assess if perceptions of comfort could be associated with the measurable parameters of interface pressure and temperature. This pilot study was undertaken in the community with individuals who were totally reliant upon a wheelchair for their mobility who each used a series of four different cushions for up to 7 days. METHOD: The temperature and humidity characteristics of four commercially available pressure-reducing cushions of differing mediums were measured using data loggers for a continuous period of up to 7 days. Snap-shot interface pressure measurements were taken and perceptions of comfort were obtained via specifically designed questionnaires. RESULTS: The cushions that wheelchair users found to be the most comfortable for them were not necessarily those, which provided them with the lowest interface pressures. If a cushion was discontinued by the wheelchair user, it was invariably a "softer" medium. Wheelchair users tended to acknowledge discomfort only after 2 days continuous use. CONCLUSION: There are potential implications for clinical practice with respect to how cushions are issued to wheelchair-reliant individuals. Findings support the undertaking of a larger study.

Physiological response of the heel tissue on pressure relief between three alternating pressure air mattresses.

Heels have substantially higher tissue interface pressures and are prone to ulceration compared to other bony prominences. Although many different types of alternating pressure air mattresses (APAMs) are used for the prevention and treatment of pressure ulcers, a few high-quality randomised controlled trials (RCTs) are available on which to base purchasing decisions. Faced with this situation, physiological measurements are increasingly being used as a surrogate. A time-based technique, which calculates pressure relief index (PRI), has been previously reported for analysing the ability of such systems. This technique has demonstrated that different designs produce variable results in this regard. The aim of the present study is to investigate the performance of three APAMs using PRI and blood perfusion measurements. Eleven able-bodied adult volunteers (6 males and 5 females) participated in the study. Their age, weight, height and body mass index (BMI) were (mean +/- s.d.) 23.9 +/- 2.1 years, 65.6 +/- 12.4 kg, 1.76 +/- 0.84 m and 21.0 +/- 2.4 kg/m2, respectively. There was no statistically significant difference in maximum interface pressure for the three mattresses. However, the AUTOlogic produced a statistically significant lower minimum interface pressure (Duo Care Plus, p < 0.0001 and higher pressure relief index below 30 mmHg than either the Duo Care Plus, p = 0.002 or Proficare, p < 0.0001. The AUTOlogic also gave a statistically significant enhanced perfusion per cycle when compared to other two mattresses (Duo Care Plus, p = 0.03 or Proficare, p = 0.01).

Transverse rotation and longitudinal translation during prosthetic gait--a literature review.

Improved technology allows for more accurate gait analysis to increase awareness of nonoptimized prosthetic gait patterns and for the manufacture of sophisticated prosthetic components to improve nonoptimized gait patterns. However, prescriptions are often based on intuition rather than rigorous research findings for evidence-based practice. The number of studies found in the literature that are based on prosthetic research regarding transverse rotation and longitudinal translation is small when compared to topics regarding other types of movements. Some design criteria for prosthetic components described in those studies that permit transverse rotation and longitudinal translation can be found in current designs. However, little research has been conducted to establish their effectiveness on the gait parameters and residual limb. This literature review is an investigation into these motions between the socket and the prosthetic foot, with particular reference to gait characteristics and prosthetic design criteria.

Evaluation of alternating pressure air mattresses: one laboratory-based strategy.

Although many different type of alternating pressure air mattresses (APAMs) are used for the prevention and treatment of pressure ulcers, few high quality randomised controlled trials are available on which to base purchasing decisions. Faced with this situation, physiological measurements are increasingly being used as a surrogate. Laboratory evaluation techniques have centred largely on interface pressure (IP) measurement, typically analysing discrete maximum and minimum levels, or average pressure. However, since pressure relief is time varying, a time-based analysis technique may be more suitable for performance assessment. Measurements of IP, mattress air cell pressure (AP), skin tissue perfusion using laser Doppler fluxmetry (LDF), transcutaneous oxygen (tcPO2) and carbon dioxide (tcPCO2) were taken simultaneously on the sacrum, heels, trochanters and buttock over at least two alternating cycles. Duration of IP below three thresholds (30, 20, and 10 mmHg) as well as the area under the tcPO2, tcPCO2 and LDF curves were calculated automatically. Ten healthy volunteers were recruited to evaluate the pressure-relieving characteristics of two different designs of APAMs. Results indicated significant differences between the products. During the deflation phase of the cycle contact pressures on the heel were significantly lower (p < 0.0001) on the device whose inflation pressure was significantly higher, although there was no significant difference in deflation pressure. Therefore, it is important to note that low APs do not necessarily produce lower IPs under the heel, contrary to the intuitive classical notion. These techniques could assist in the selection of alternating or dynamic surfaces of any description confirmed by further clinical validation.

Evaluation of intermittent pneumatic compression systems.

The operational characteristics of eight intermittent pneumatic compression systems were evaluated. Considerable differences between the pressure/time curves were found when different pumps were compared. The pressure attained in the garments varied from 6 to 124 mmHg and the rate of inflation from less than 1 to 9 mmHg per second.

Randomized clinical trial comparing 2 support surfaces: results of the Prevention of Pressure Ulcers Study.

OBJECTIVE: To determine whether a viscoelastic polymer (energy absorbing) foam mattress was superior to a standard hospital mattress for pressure ulcer prevention and to analyze the cost-effectiveness in comparison with standard hospital mattresses. DESIGN: Unblinded, randomized, prospective trial. SETTING: Elderly acute care, rehabilitation, and orthopedic wards at 3 hospitals in the United Kingdom. PARTICIPANTS: 1168 patients at risk of developing pressure ulcers (Waterlow score, 15 to 20), with a median age of 83 years (25th to 75th percentile range, 79-87). INTERVENTIONS: Participants were allocated to either the experimental equipment (CONFOR-Med mattress/cushion combination) or a standard mattress/cushion combination; all were given standard nursing care. Pressure areas were observed daily. MAIN OUTCOME MEASURE: Development of nonblanching erythema. RESULTS: A significant decrease in the incidence of blanching erythema (26.3% to 19.9%; P =.004) and a nonsignificant decrease in the incidence of nonblanching erythema occurred in participants allocated to the experimental equipment. However, when the survival curve plots were analyzed at 7 days, both categories showed statistically significant decreases (P =.0015 and P =.042, respectively). Participants on standard equipment had a relative odds ratio of 1.36 (95% confidence interval [CI], 1.10-1.69) for developing blanching erythema or worse and 1.46 (95% CI, 0.90-1.82) for developing nonblanching erythema or worse. To prevent nonblanching erythema, the number needed to treat (NNT) was 41.9 (95% CI, -82.6-15.3). To prevent any erythema (blanching or nonblanching), the NNT was 11.5 (95% CI, 41.6-9.3). Participants with blanching or nonblanching erythema were significantly less mobile than participants with normal skin and more likely to have worsening mobility (P <.001). For participants with similar pressure ulcer status, mattress type was not associated with difference in mobility. CONCLUSIONS: Regardless of prevention routine, pressure ulcers occur. In this study, the experimental equipment showed statistical significance to standard equipment for prevention of blanching erythema; significance was not achieved for nonblanching erythema. Trend and survival analysis show that a larger study is required to determine whether this nonsignificant difference is genuine.