Skin Blood Flow Response to Weight Bearing in People with Acute and Chronic Spinal Cord Injuries

Research Objectives: To compare skin blood flow (SBF) response at the ischial tuberosity during seated weight bearing for people with acute and chronic spinal cord injury (SCI).

Design: Cross-sectional study with mixed design: within participant comparison between weight bearing and non-weight bearing, and between participants with acute and chronic SCI. SBF was collected using laser Doppler flowmetry at one of the ischial tuberosities (random selection) on all participants with and without weight bearing for up to 30 minutes each. Participants lay on their side for non-weight bearing and sat in their prescribed wheelchair cushions for weight bearing. Freidman’s tests were computed for within participant comparisons: mean SBF during 1) non-weight bearing, 2) first two minutes, and 3) last two minutes of weight bearing. Mann-Whitney U tests were computed for comparisons between participants with acute and chronic SCI on changes in SBF from non-weight bearing to 1) first two minutes, and 2) last two minutes of weight bearing.

Setting: Laboratory.

Participants: Thirty-two participants with SCI: 12 acute (one year of SCI).

Interventions: N/A.

Main Outcome Measures: Skin blood flow using laser Doppler flowmetry.

Results: In participants with acute SCI, there was no statistically significant within-participant difference in SBF. However there was a trend (p=0.097) in increase in SBF from non-weight bearing to the first two minutes of weight bearing (r=0.407) and from the first to last two minutes of weight bearing (r=0.362) with medium effect size. No difference in SBF was observed within participant with chronic SCI (p=0.951). Between participants with acute and chronic SCI, there was no difference in changes in SBF from non-weight bearing to either first (p=0.408, r=0.151) or last two minutes of weight bearing (p=0.632, r=0.089).

Conclusions: An individual with SCI is unlikely to experience significant sustained decrease in SBF during seated weight bearing when seated in a well-fitted wheelchair with a prescribed seat cushion for pressure redistribution. Subtle changes in SBF across weight bearing conditions suggested some vascular response adjustment during the acute stage of SCI, however this change appears negligible during chronic stage of SCI.

Author(s) Disclosures: None.