Haemodynamic Effects of Different Mechanical Compression Devices and Neuromuscular Stimulation in the Lower Limb

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.