Muscle contractions induced by calf low-intensity neuromuscular electrical stimulation (C-LI-NMES) can increase venous return and may reduce venous thromboembolism. This study aimed to compare the effect of different C-LI-NMES frequencies and plateau times on hemodynamics, discomfort and energy efficiency, when applied via sock-integrated transverse textile electrodes.
Fifteen healthy participants were stimulated via two 3x3cm transverse textile electrodes integrated in a sock, with ten different combinations of frequency (1Hz or 36Hz) and plateau times (0.5/1.5/3/5/7s), with gradually increasing NMES-intensity until plantar flexion-induction. At this point, popliteal peak venous velocity (PVV), time-averaged mean velocity (TAMV) and ejection volume (EV) were assessed by Doppler-ultrasound, discomfort by a numerical rating scale (NRS, 0-10) and values for current amplitude and energy were calculated based on the NMES-device´s intensity level. Values expressed with median (interquartile range), significance set to p\<0.05.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
15
Neuromuscular electrical stimulation (NMES) was applied with a device called Chattanooga Physio (DJO), testing 10 different combinations of parameter-settings. The parameter-settings that were varied and combined were frequency (1Hz and 36Hz) and plateau times (0.5s, 1.5s, 3s, 5s, 7s). The NMES was applied to the calf of the participants via transversally placed textile electrodes (3x3 cm) integrated in a sock starting with very low current amplitude followed by gradual small increases in current amplitude until induction of ankle plantar flexion, at which time-point the outcomes where measured.
Karolinska university Hospital
Stockholm, Sweden
Peak venous velocity (PVV)
Peak venous velocity (centimeters per second) will be assesed by Doppler ultrasound of in the popliteal vein
Time frame: Day 1 at rest (baseline, no intervention) and when ankle plantar flexion was induced by the intervention
Time averaged mean velocity (TAMV)
Time averaged mean velocity will be assesed by Doppler ultrasound in the popliteal vein (centimeters per second)
Time frame: Day 1 at rest (baseline, no intervention) and when ankle plantar flexion was induced by the intervention
Average duration of blood pulse (ADBP)
Average duration of blood pulse will be assesed by Doppler ultrasound in the popliteal vein (seconds)
Time frame: Day 1 at rest (baseline, no intervention) and when ankle plantar flexion was induced by the intervention
Ejection volume (EV)
Ejection volume of blood will be assesed by Doppler ultrasound in the popliteal vein (milliliters)
Time frame: Day 1 at rest (baseline, no intervention) and when ankle plantar flexion was induced by the intervention
Numerical rating scale (NRS)
Discomfort estimated using a numerical rating scale from 0 (no pain) to 10 (worst pain)
Time frame: Day 1 during ankle plantar flexion was induced by the intervention
Current amplitude
Current amplitude in milliampere (mA) will be assessed by using stepwise increases (typically 1mA) on the NMES device until a plantar flexion is induced
Time frame: Day 1 during ankle plantar flexion was induced by the intervention
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Energy
Energy per stimulation cycle in millijoule (mJ) will be assessed by using stepwise increases (typically 1mA) on the NMES device until a plantar flexion is induced, at which point the energy consumption (mJ) is calculated.
Time frame: Day 1 during ankle plantar flexion was induced by the intervention