Effect of active and passive techniques used in thromboembolic prophylaxis on venous flow velocity in the post-procedure period

Introduction

Studies have shown that using mechanical thromboembolic prophylaxis methods speeds up venous flow and decreases stasis. These studies examine the post-intervention period of 1-10 min. The length of the effect of procedures to raise venous flow velocity cannot be determined by clinical trials. To apply mathematical techniques to estimate how long mechanical thromboembolism prophylaxis procedures will increase venous flow rate.

Methods

In the survey, we examined 25 persons (poststroke patients), with an average age of 57.2 ± 6.3 years. Regarding the proportion of genders, 13 (52%) participants were male and 12 (48%) female. The peak venous blood flow velocity was measured with a HADECO BIDOP ES-100V II type Doppler ultrasound device, using an 8 MHz head, in the femoral vein, at the level of the hip joint. We estimated the change of the venous blood flow velocity from the available sampled data using the method of least squares. For the calculations, we used Microsoft Excel, version Mac Excel 2019.

Results

The decrease in peak venous flow velocity can be approximated by a logarithm function. Mathematical calculations show that after active thromboembolic prophylaxis interventions, resting venous flow velocity is restored at 26.8 min on the intact limb and 85.1 min on the hemiparetic side. Resting flow velocity is restored in 131.9 min after passive mobilization of the hemiparetic side and in 137.7 min after the consensual effect.

Discussion

An elementary mathematical function can be used to estimate the time to recovery of peak venous flow velocity to resting state from measurements taken 15 min after the intervention. Active and passive mechanical thromboembolic prophylaxis after the intervention has a longer-term effect on venous flow velocity.

Wearable Neuromuscular Electrical Stimulation on Quadriceps Muscle Can Increase Venous Flow

Neuromuscular electrical stimulation (NMES) of the quadriceps (Q) may increase venous blood flow to reduce the risk of venous thromboembolism. This study assessed whether Q-NMES pants could increase peak venous velocity (PVV) in the femoral vein using Doppler ultrasound and minimize discomfort. On 15 healthy subjects, Q-NMES using textile electrodes integrated in pants was applied with increasing intensity (mA) until the first visible muscle contraction [measurement level (ML)-I] and with an additional increase of six NMES levels (ML II). Discomfort using a numeric rating scale (NRS, 0-10) and PVV were used to assess different NMES parameters: frequency (1, 36, 66 Hz), ramp-up/-down time (RUD) (0, 1 s), plateau time (1.5, 4, and 6 s), and on:off duty cycle (1:1, 1:2, 1:3, 1:4). Q-NMES pants significantly increased PVV from baseline with 93% at ML I and 173% at ML II. Frequencies 36 Hz and 66 Hz and no RUD resulted in significantly higher PVV at both MLs compared to 1 Hz and 1 s RUD, respectively. Plateau time, and duty cycle did not significantly change PVV. Discomfort was only significantly higher with increasing intensity and frequency. Q-NMES pants produces intensity-dependent 2-3-fold increases of venous blood flow with minimal discomfort. The superior NMES parameters were a frequency of 36 Hz, 0 s RUD, and intensity at ML II. Textile-based NMES wearables are promising for non-episodic venous thromboembolism prevention.

Effects on hemodynamic enhancement and discomfort of a new textile electrode integrated in a sock during calf neuromuscular electrical stimulation

PURPOSE

To compare fixed transverse textile electrodes (TTE) knitted into a sock versus motor point placed standard gel electrodes (MPE) on peak venous velocity (PVV) and discomfort, during calf neuromuscular electrical stimulation (calf-NMES).

METHODS

Ten healthy participants received calf-NMES with increasing intensity until plantar flexion (measurement level I = ML I), and an additional mean 4 mA intensity (ML II), utilizing TTE and MPE. PVV was measured with Doppler ultrasound in the popliteal and femoral veins at baseline, ML I and II. Discomfort was assessed with a numerical rating scale (NRS, 0-10). Significance was set to p < 0.05.

RESULTS

TTE and MPE both induced significant increases in PVV from baseline to ML I and significantly higher increases to ML II, in both the popliteal and femoral veins (all p < 0.001). The popliteal increases of PVV from baseline to both ML I and II were significantly higher with TTE versus MPE (p < 0.05). The femoral increases of PVV from baseline to both ML I and II were not significantly different between TTE and MPE. TTE versus MPE resulted at ML I in higher mA and NRS (p < 0.001), and at ML II in higher mA (p = 0.005) while NRS was not significantly different.

CONCLUSION

TTE integrated in a sock produces intensity-dependent increases of popliteal and femoral hemodynamics comparable to MPE, but results in more discomfort at plantar flexion due to higher current required. TTE exhibits in the popliteal vein higher increases of PVV compared to MPE.

TRIAL REGISTRATION

Trial_ID: ISRCTN49260430. Date: 11/01/2022. Retrospectively registered.

A novel device for lower leg intermittent pneumatic compression synchronized with active ankle exercise for prevention of deep vein thrombosis

Objective

Intermittent pneumatic compression devices (IPCDs) and active ankle exercises have been shown to be efficacious in preventing venous thromboembolism (VTE) by increasing venous flow velocity and volume. However, IPCDs are expensive and require electricity; therefore, they cannot be used in the event of power loss. We developed a non-powered device that provides lower leg intermittent pneumatic compression synchronized with AAEs (LISA) and compared its efficacy with AAEs alone in increasing the peak velocity in the femoral vein.

Methods

The study population consisted of 20 healthy younger men and 20 healthy older men who performed AAE every 2 s in a sitting posture under four conditions: AAE with LISA (AAE+LISA), AAE alone (AAE), AAE with IPCD, and AAE with a graduated compression stocking.

Results

The PVs under all conditions were significantly higher than those at rest. The PVs in the AAE+LISA condition were significantly higher than those in the AAE alone condition in both younger and older groups (both p < .001).

Conclusions

AAE with LISA significantly increased the PV, suggesting that LISA might be useful for preventing DVT.

Effects of intermittent pneumatic compression on femoral vein peak venous velocity during active ankle exercise

INTRODUCTION

The risk of developing deep vein thrombosis (DVT) is high even after the period of bed rest following major general surgery including total joint arthroplasty (TJA). Mobile intermittent pneumatic compression (IPC) devices allow the application of IPC during postoperative exercise. Although ambulation included ankle movement, no reports have been made regarding the effects of IPC during exercise, including active ankle exercise (AAE), on venous flow. This study was performed to examine whether using a mobile IPC device can effectively augment the AAE-induced increase in peak velocity (PV).

METHODS

PV was measured by Doppler ultrasonography in the superficial femoral vein at rest, during AAE alone, during IPC alone, and during AAE with IPC in 20 healthy subjects in the sitting position. PV in AAE with IPC was measured with a mobile IPC device during AAE in the strong compression phase. AAE was interrupted from the end of the strong compression phase to minimize lower limb fatigue.

RESULTS

AAE with IPC (76.2 cm/s [95%CI, 69.0-83.4]) resulted in a significant increase in PV compared to either AAE or IPC alone (47.1 cm/s [95%CI, 38.7-55.6], p < 0.001 and 48.1 cm/s [95%CI, 43.7-52.4], p < 0.001, respectively).

DISCUSSION

Reduced calf muscle pump activity due to the decline in ambulation ability reduced venous flow. Therefore, use of a mobile IPC device during postoperative rehabilitation in hospital and activity including self-training in an inpatient ward may promote venous flow compared to postoperative exercise without IPC.

CONCLUSION

Use of a mobile IPC device significantly increased the PV during AAE, and simultaneous AAE with IPC could be useful evidence for the prevention of DVT in clinical settings, including after TJA.