ABSTRACT
Objective To compare the impacts of sustained and intermittent gradient pressure on perfusion disorders and myofiber injuries and to explore the mechanism by which intermittent gradient pressure helps treat deep tissue injury (DTI). MethodsTwenty Sprague-Dawley rats 10-12 weeks old were randomly divided into an experimental group and a control group.The tibialis anterior muscles of the experimental group received intermittent fluctuating pressure at 8.0-21.3 kPa while the control group received sustained pressure at 13.3 kPa.The contralateral notpressed muscles served as healthy controls.The experiment was terminated after 3 cycles of compression where each cycle involved 2 h of compression and 30 min of conpression release.The general condition of the rats'skin and muscles in the compressed region were observed and laser doppler perfusion imaging was used to detect blood perfusion of the skin of the compressed leg after 3 cycles of compression.Any pathomorphological changes in the tibialis anterior muscles of the compressed region were observed by phosphotungstic acid hematoxylin (PTAH) staining. Results Blood perfusion of the skin and muscle in the control group was significantly less than in the experimental group after compression,and blood flow velocity increased with time in both groups.However,perfusion was significantly more extensive in the experimental group.PTAH staining showed that muscle injury in the experimental group was significantly less severe than in the control group. ConclusionCompared to the sustained pressure,intermittent pressure cause significantly less severe DTI by reducing compression-induced ischemia and hypoxia.