An evaluation of dermal microcirculatory occlusion under repeated mechanical loads: Implication of lymphatic impairment in pressure ulcers

Abstract

Objective Pressure ulcers are caused by prolonged mechanical loads deforming the underlying soft tissues. However, the mechanical loads for microcirculatory occlusion are unknown. The present study was designed to characterize the simultaneous response of microvascular and lymphatic structures under repeated mechanical loading. Methods The effects of two distinct loading/unloading cycles involving (a) incremental pressures 30, 60, and 90 mmHg and (b) three repeated cycles of 30 mmHg were evaluated on a cohort of able‐bodied volunteers. Microvascular response involved the monitoring of transcutaneous gas tensions, while dermal lymphatic activity was estimated from near‐infrared imaging. Responses were compared during each load and recovery cycle. Results Changes in microvascular response were dependent on the load magnitudes, with 30 mmHg resulting in a reduction in oxygen tension only, while 90 mmHg affected both oxygen and carbon dioxide values in most cases (54%). By contrast, lymphatics revealed near total occlusion at 30 mmHg. Although there were intersubject differences, temporal trends consistently revealed partial or full impairment under load, with recovery during off‐loading. Conclusions The pressure required to cause microcirculatory occlusion differed between individuals, with lymphatic impairment occurring at a lower pressure to that of microvascular vessels. This highlights the need for personalized care strategies and regular off‐loading of vulnerable tissues.

Myoglobin-derived iron causes wound enlargement and impaired regeneration in pressure injuries of muscle

“…In normal injuries, DAMPs and waste products exit via veins and lymphatic vessels. However, lymph vessels are occluded at very low pressure, and impaired lymphatic flow can persist after pressure is removed (79). Proper drainage of myoglobin is capable of causing toxicity for kidney (i.e., rhabdomyolysis), but the failure of drainage is what we believe caused iron toxicity at the site of the mPI wound.…”

“…Pressure has been reported to cause disruption to arterial supply, venous clearance, and lymphatic drainage (4, 51, 52), although not always (81). Lymph vessels are occluded at very low pressure, and impaired lymphatic flow can persist after pressure is removed (82). Impaired circulation and/or impaired drainage likely caused waste factors to accumulate in the mPI, including iron.…”

An evaluation of the effects of localised skin cooling on microvascular, inflammatory, structural, and perceptual responses to sustained mechanical loading of the sacrum: A study protocol

“…prosthetics or respiratory masks [3,4]. Internal tissue deformations will occur as a result of sustained pressure and shear forces that can lead to changes in the physiology of skin and sub-dermal tissue, including ischemia in the blood vasculature, lymphatic impairment, and direct deformation damage [5]. When load is removed, ischemia reperfusion injury may also occur due to the onset of post-occlusive reactive hyperaemia [6].…”

Thermal modulation of skin friction at the fingertip

“…The associated pressure and shear forces acting on the skin induce internal tissue deformations, causing changes to the physiology of skin and sub-dermal tissue. The negative impacts of the deformation include ischemia in the blood vasculature, lymphatic impairment, and direct deformation damage [3]. In addition, the moisture level, and the temperature within and around skin tissues strongly influence skin tolerance to mechanical loading.…”