Blood Flow Stimulation in the Lower Limbs by Application of Different External Devices

Not Applicable

Completed

Interventions: Device: Slow calf IPC
Device: Foot IPC
Device: Rapid calf IPC
Device: Calf NMES

Brief Summary: In this study, four different devices which stimulate the blood in the lower extremities are used in ten healthy persons while measuring the blood flow with ultrasound. The aim is to study the haemodynamic effects in the lower extremities of each modality and also to compare those effects between the four modalities in order to identify those which most effective than the others.

Detailed Description: Three Intermittent Pneumatic Compression (IPC) devices were selected: Foot-IPC, rapid Calf-IPC and a slow, sequential Calf-IPC. A Neuromuscular Electrical Stimulation (NMES) device was also used in the calf. Blood flow measurements in the right popliteal vein of ten healthy individuals were performed using Doppler ultrasound before (control) and while using IPC or NMES. The blood flow parameters measured where: peak systolic velocity (cm/s), time-averaged mean velocity (cm/sec), volume flow (ml/min) and ejected volume per individual stimulus (ml). The tolerability of each device was also assessed using an analogue scale from zero to ten. Differences between modalities regarding the pattern as well as the absolute values of velocity and volume are being assessed. Power calculation: Recent studies showed that the peak venous velocity (PV) at baseline is around 11 cm/s and after applying foot-IPC the PV rises to 50 cm/s with a maximum standard deviation of 15 (Broderick et all, 2014). Thus, three patients per group would be required to detect a difference of 39 cm/s in PV (two-sided type-I error rate = 5%; power = 80%). To reach an even higher power we choose to include 10 patients in study, which resulted in a power of 99.7% for the above calculation.

Recruitment & Eligibility

Inclusion Criteria

Exclusion Criteria

Arm && Interventions

Group	Intervention	Description
Slow calf IPC	Slow calf IPC	Intermittent pneumatic compression in the calf using the Kendall SCD™ 700, Covidien, Medtronic, USA
Foot IPC	Foot IPC	Intermittent pneumatic compression in the foot using the A-V Impulse™, Covidien®, New Haven, CT, USA
Rapid calf IPC	Rapid calf IPC	Intermittent pneumatic compression in the calf using the VenaFlow® Elite, DJO Global, USA
Calf NMES	Calf NMES	Neuromuscular electrical stimulation in the calf using the DJO,TM, CefarCompex Mi-Theta 500 stimulator

Primary Outcome Measures

Name	Time	Method
Blood Flow - Peak Systolic Velocity (cm/Sec)	up to one hour in total	With the use of Doppler Ultrasound Peak systolic velocity (cm/sec) is assessed in the popliteal vein.
Blood Flow - Ejected Volume Per Individual Stimulus (ml)	up to one hour in total	With the use of Doppler Ultrasound Ejected volume per individual stimulus (ml) is assessed in the popliteal vein.
Blood Flow - Time-averaged Mean Velocity (cm/Sec)	up to one hour in total	With the use of Doppler Ultrasound Time-averaged mean velocity (cm/sec) is assessed in the popliteal vein.
Blood Flow - Volume Flow (ml/Min)	up to one hour in total	With the use of Doppler Ultrasound Volume flow (ml/min), is assessed in the popliteal vein.

Secondary Outcome Measures

Name	Time	Method
Tolerability to IPC and NMES According to Visual Analogue Scale 0-10	one minute	All subjects will be asked to subjectively grade each modality according to how comfortable or uncomfortable it felt under the time was applied to the subject according to Visual Analogue Scale 0-10. The following description will be given to the subjects: 0 denotes the the modality was totally intolerable, 10 denotes that the modality is very pleasant to use and 5 denotes neither pleasant nor unpleasant feeling.