Augmentation of venous, arterial and microvascular blood supply in the leg by isometric neuromuscular stimulation via the peroneal nerve

Abstract

Background: Deep vein thrombosis (DVT) is the formation of a blood clot within the deep veins. During periods of sitting, blood flow is decreased and this contributes to an increased risk of DVT. Trials have shown that 5% to 10% of passengers undertaking long-haul flights develop asymptomatic calf DVT.

Aim: To investigate the safety and efficacy of a novel neuromuscular device that augments peripheral blood flow.

Methods: Thirty healthy volunteers were assessed while seated. Each subject had one leg connected to the stimulator and the other leg immobile acting as control. Fifteen sequential electrical stimulations were applied for 5 min each followed by a 10 min recovery phase. The following noninvasive measurements were performed before, during and after the stimulation programs: photoplethysmography, strain gauge plethysmography, laser Doppler fluxmetry, transcutaneous oxygen tension, pulse oximetry, superficial femoral vein blood flow and vessel diameter (ultrasound); discomfort questionnaires were also administered.

Results: During neuromuscular stimulation, significant increases in blood volume flow and velocity and skin capillary blood flow were found; transdermal skin oxygen levels were maintained. No changes were observed in heart rate, blood pressure, oxygen saturation or femoral vein vessel diameter.

Conclusions: Using a newly developed device, electrical nerve stimulation of the lower leg significantly increased blood flow; the device in the present study is, therefore, a promising tool for the development of a novel DVT prevention device. Because this method of electrical nerve stimulation is virtually pain free, the present study has significant implications for the prevention of DVT in hospitals, outpatient settings and community care settings, as well as in preventing travel-related thrombosis.

Figure 1)

Electrode application on the common peroneal nerve. Illustration of the nerves of the right lower extremity in posterior view adjusted from reference

Figure 2)

Photoplethysmography (PPG) measurements showing venous emptying response versus stimulation current, by frequency, compared with full flexion. Data presented as mean ± standard error of the difference

Figure 3)

Strain gauge plethysmography (SPG) measurements showing percentage of calf circumference change at 15 different stimulation programs versus foot flexion. Data presented as mean ± standard error of the difference

Figure 4)

Ultrasonography measurements showing venous volume flow at 15 different stimulation programs versus baseline. Data presented as mean ± standard error of the difference

Figure 5)

Mean peak venous velocity at 15 different stimulation programs versus baseline. Data presented as mean ± standard error of the difference

Figure 6)

Laser Doppler fluxmetry (LDF) measurements of micro-circulatory flux on the dorsum of the foot bilaterally for each stimulation setting as a percentage of baseline. Data presented as mean ± standard error of the difference

Figure 7)

Transcutaneous oxygen tension on the dorsum of the foot versus stimulation program as a percentage of baseline. Data presented as mean ± standard error of the difference

Figure 8)

Verbal rating scale (VRS) scores for discomfort, by stimulation settings. Data presented as mean ± standard error of the difference