Comparison of skin perfusion response with alternating and constant pressures in people with spinal cord injury

Abstract

Study design: Two-way factorial mixed design, the between-subjects factor as the spinal cord injury (SCI) status (SCI and non-SCI) and the within-subjects factor as the pressure pattern (alternating and constant pressures). Objectives: To compare the effects of alternating and constant pressures on weight-bearing tissue perfusion in people with SCI, with application for improving alternating pressure support surface usage. Setting: University research laboratory. Subjects: A total of 28 participants were studied, 7 participants with cervical injury, 7 participants with injury below T6 and 14 healthy controls. Methods: Sacral skin perfusion was continuously measured using laser Doppler flowmetry under 10 min preloading, 20 min loading (alternating or constant pressures) and 10 min postloading. Alternating pressure was applied with low-interface pressure at 0 mm Hg and high-interface pressure at 60 mm Hg with a cycle time of 5 min; constant pressure was applied with interface pressure at 30 mm Hg. Results: The results showed that pressure pattern affects skin perfusion responses in weight-bearing tissues (Po0.01). Alternating pressure stimulates an increase in skin perfusion (1.21 ± 0.08 au) as compared with constant pressure (0.74±0.07 au) in people with SCI (Po0.01). There was no overall difference in the skin perfusion responses of patients with SCI as compared with non-SCI patients (P40.05). Conclusion: This study has shown that alternating pressure enhances the skin perfusion of weightbearing tissues as compared with constant pressure in people with SCI. The protocol tested in this study may be used to guide the selection of parameters of commercial alternating pressure support surfaces for preventing pressure ulcers in people with SCI.

Investigation of Peak Pressure Index Parameters for People with Spinal Cord Injury Using Wheelchair Tilt-in-Space and Recline: Methodology and Preliminary Report

“…Empirically, there is evidence linking increased mechanical loading with increased pressure ulcer incidence in elderly wheelchair users [12]. Clinically, best-practice guidelines recommend routinely performing pressure-relieving maneuvers to further manage pressure ulcer risk [13–15]. …”

Using multifractal detrended fluctuation analysis to assess sacral skin blood flow oscillations in people with spinal cord injury

“…Hagisawa et al showed that people with SCI take longer to reach peak hyperemia after removal of loading pressure [29]. Jan et al showed that pressure loadings (alternating and constant pressures) induce different skin blood flow response between people with SCI and nondisabled controls [28]. Nicotra et al observed a lower ratio of the first peak to baseline blood flow at the level below the lesion in people with complete high-level SCI (cervical 6 to thoracic 5) as compared with people with low-level SCI (thoracic 6 to 11) [26].…”

“…The finding may contribute to our long-term goal of using BFO patterns for the early detection of pressure ulcers in people with SCI [7,9,18]. Vasodilatory function could be used to quantify risk for pressure ulcers in people with SCI [25][26][27]; people with SCI who fail to increase skin blood in response to a causative factor of pressure ulcers (pressure, shear, or heating) are susceptible to pressure ulcers [27][28]. Schubert and Fagrell demonstrated that people with SCI have impaired vasodilatory response to either local heating or local pressure [27].…”

Synchronization of sacral skin blood flow oscillations in response to local heating

“…The study of skin microcirculation has been shown to be useful to assess risk for pressure ulcers [1–4]. Recently, skin blood flow response to local heat has been used to assess microvascular regulation using wavelet analysis [2, 5, 6].…”