Pilot study of strap-based custom wheelchair seating system in persons with spinal cord injury

Exploring pressures, tissue reperfusion and body positioning: a pilot evaluation

OBJECTIVE

To assess the relationship in healthy adults and critically ill patients between: patient position, body mass index (BMI), patient body temperature, interface pressure (IP) and tissue reperfusion (TR). Also to determine the relationship in critically ill patients between: Sequential Organ Failure Assessment (SOFA) score, Braden Scale score for predicting pressure injury risk, Acute Physiology and Chronic Health Evaluation II (APACHE II) severity of disease classification score, IP and TR.

METHODS

This study took place in a 27-bed intensive care unit (ICU) of an Australian tertiary hospital. IP and TR outcomes were measured at the sacrum and greater trochanter. Repeated measures analyses of variance (ANOVAs) and doubly multivariate repeated measures ANOVAs were conducted using peak pressure index (PPI), peak time (PT), settled time constant (STC) and normalised hyperaemic area (NHA) measures of TR as outcomes. Participant type, body mass index (BMI), Braden and APACHE II scores and patient body temperature were considered as between-groups factors and covariates.

RESULTS

We recruited 23 low- and high-acuity ICU patients and nine healthy adult volunteers. Not all IP readings could be obtained from ICU patients. TR readings were collected from all recruited patients, but not all TR measurements were mutually uncorrelated. Controlling for age, PPI readings differed between participant types (p=0.093), with the highest values associated with high-acuity patients and the lowest with healthy adults; the association was not substantive when controlling for age and BMI. Age was a significant variable (p=0.008), with older participants having higher scores than younger ones. No statistically significant associations between any measured parameter and TR variables were observed. However, temperature was revealed to be related to TR (p=0.091).

CONCLUSIONS

Although not powered to detect significant effects, this pilot analysis has determined several associations of importance, with differences in outcomes observed between low- and high-acuity ICU patients; and between ICU patients and healthy volunteers.

Microclimate evaluation of strap-based wheelchair seating systems for persons with spinal cord injury: A pilot study

STUDY PURPOSE

The purpose of this pilot study was to assess microclimate characteristics of two versions of a strap-based wheelchair seating system (perforated and solid straps) and to conduct preliminary microclimate comparisons of subjects' current wheelchair seating systems.

MATERIALS AND METHODS

In this pilot study, the microclimate properties of two variations (solid and perforated) of a strap-based seating system were compared with two commonly used seating systems. Six subjects sat on three different seating systems each for 100-min test periods, while temperature and relative humidity were measured with a single sensor adjacent to the skin-seat interface. Additionally, thermal images of the seat interface were collected before and after each test period.

RESULTS

The thermal images revealed that the maximum surface temperature of the solid-strap-based seating system was significantly lower than the other seating systems, -1.21 °C. (95% CI -2.11 to -0.30, p = 0.02), immediately following transfer out of the seat. Five minutes after transferring out of the seat, the perforated-strap seat was significantly cooler than the other seats -0.94 °C. (95% CI -1.59 to -0.30), p = 0.01, as was the solid-strap-based seat, -1.66 °C. (95% CI -2.69 to -0.63), p = 0.01. There were no significant differences in interface temperature or relative humidity measured with the single sensor near the skin-seat interface.

CONCLUSION

This pilot study offers preliminary evidence regarding the microclimate of the strap-based seating systems compared with other common seating systems. Clinically, the strap-based seating system may offer another option for those who struggle with microclimate management.