Monitoring contractile dermal lymphatic activity following uniaxial mechanical loading

Abstract

a b s t r a c tIt is proposed that direct mechanical loading can impair dermal lymphatic function, contributing to the causal pathway of pressure ulcers. The present study aims to investigate the effects of loading on human dermal lymphatic vessels.Ten participants were recruited with ages ranging from 24 to 61 years. Participants had intradermal Indocyanine Green injections administrated between left finger digits. Fluorescence was imaged for 5 min sequences with an infra-red camera prior to lymph vessel loading, immediately after axial loading (60 mmHg) and following a recovery period. Image processing was employed to defined transient lymph packets and compare lymph function between each test phase.The results revealed that between 1-8 transient events (median = 4) occurred at baseline, with a median velocity of 8.1 mm/sec (range 4.1-20.1 mm/sec). Immediately post-loading, there was a significant ( p < 0.05) reduction in velocity (median = 6.4, range 2.2-13.5 mm/sec), although the number of transient lymph packages varied between participants. During the recovery period the number (range 1-7) and velocity (recovery median = 9.6 mm/sec) of transient packets were largely restored to basal values.The present study revealed that some individuals present with impaired dermal lymphatic function immediately after uniaxial mechanical loading. More research is needed to investigate the effects of pressure and shear on lymphatic vessel patency.

Wearable Electrical Stimulation to Improve Lymphatic Function

“…shows the lymphatic behaviour varied at baseline, with normative values similar to that in the published literature[19][20].…”

“…Lymphatic activity was characterised using a standardized technique involving near-infrared fluorescence lymphatic imaging (NIRFLI). An Indocyanine Green (ICG) contrast agent was injected to help visualise dermal lymphatic vessels [19][20]. To review briefly, ICG was diluted in a saline solution to achieve the required dose for testing (50μL, 0.05% w/v).…”

“…Proprietary image processing code enabled the lymphatic activity to be extracted quantitatively from the NIR video data. Lymph packets were identified as bright regions on video frames, and tracked in subsequent frames to measure the number of lymph packets and their movement using a droplet morphometry and velocimetry (DMV) approach [19]. Here image subtraction, binary conversion, and centroid tracking provided the basis to identify and measure each transient lymph packet captured within the 5-minute video sequences.…”

Device-related pressure ulcers: SECURE prevention

“…47 In ammatory mediators 48 secreted from damaged and nearby immune cells lead to progressive in ammatory oedema, which increases interstitial pressures, the mechanical distortions of cells and tissues, and the growing obstructions within the vasculature and lymphatics. 49 Damage may be ampli ed in ischaemic tissue after reperfusion through the release of reactive oxygen species (ROS), termed reperfusion injury.…”

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

“…However, this approach does not account for the damage mechanisms associated with the majority of PUs involving small tissue strains in superficial dermal tissues. Indeed, in this case, researchers have used biophysical and imaging techniques to assess the response of superficial skin tissues under representative loads 12–15 . These studies revealed that due to microvascular compromise, tissue ischemia can occur in both able‐bodied and patient cohorts during periods of lying and sitting postures.…”