Passive limb movement intervals results in repeated hyperemic responses in those with paraplegia

Study design Repeated measures. Objectives Reports suggest passive limb movement (PLM) could be used as a therapy to increase blood flow and tissue perfusion in the paralyzed lower limbs of those with spinal cord injuries. However, the hyperemic response to PLM appears to be transient, lasting only 30-45 s despite continued limb movement. The purpose of this investigation was to determine whether the hyperemic response is repeatable across multiple short bouts of passive limb movement. Setting Cleveland Veterans Affairs Medical Center. Methods Nine individuals with paraplegia 46 6 years of age, 17 12 years post injury (range: 3-33 years) with complete T3-T11 injuries were subject to 5 x 1 min bouts of passive knee extension/flexion at 1 Hz with a 1 min recovery period between each bout. Heart rate (HR), mean arterial pressure (MAP), femoral artery blood flow (FABF), skin blood flow (SBF), and tissue perfusion in the lower limb were recorded during baseline and throughout each bout of PLM. Results Despite no increase in HR (p >= 0.8) or MAP (p >= 0.40) across all four bouts of PLM, the average increase in FABF during each bout ranged from 71 +/- 87% to 88 +/- 93% greater than baseline (p <= 0.043). SBF also increased between 465 302% and 582 +/- 309% across the five bouts of PLM (p <= 0.005). Conclusions Repeated bouts of PLM in those with SCI while in an upright position resulted in a robust and steady increase in FABF and SBF which could have implications for improving vascular health and tissue perfusion in the lower limbs of those with paraplegia.