Hemodynamic effects of habituation to a week-long program of neuromuscular electricalstimulation.
Electrical & Electronic Engineering, School of Engineering & Informatics, NUI Galway, University Rd, Galway, Ireland; Bioelectronics Research Cluster, National Centre for Biomedical Engineering Science, NUI Galway, University Rd, Galway, Ireland.
Neuromuscular electrical stimulation (NMES) of the calf muscles has been shown to cause instantaneous increases in venous outflow from the lower leg and could be used as an adjunct to current gold-standard compression therapies for the prevention of venous stasis and its related pathologies. However, little is known about the effects of NMES in combination with compression therapies on subject comfort, compliance and popliteal venous blood flow over the course of a week-long NMES protocol. This study aimed to assess the effects of a NMES and compression protocol for the prevention of venous stasis on the compliance, comfort and venous blood flow of healthy volunteers over the course of seven days.
Twenty-four healthy subjects were assigned to either a stimulation or control group. The stimulation group received 1.5h of NMES daily while the control group received none. Daily measures of popliteal venous blood flow, subject compliance and comfort were recorded over 7 days.
Ejected blood flow volumes and peak velocities in the popliteal vein during NMES were sustained over a 30-min stimulationsession and increased by approximately 100% over the course of seven days. Mean stimulation intensities increased progressively throughout the week, while perceived pain during NMES decreased significantly. Mean compliance to the 7-day protocol was 100%.
User habituation to a combined NMES and compression protocol resulted in significant increases in ejected venous volume and peak velocity over the course of 7 days. This resulted in the highest ejected venous volume reported from a single NMES induced contraction of the calf muscles to date which was twice the magnitude of values previously reported in the literature. These findings suggest that NMES based protocols applied over an extended period of days, weeks or months may provide greater hemodynamic effect for the prevention of venous stasis than previously observed during NMES sessions lasting less than a few hours.