A pilot study of a novel pulsatile flow generator using large collapsible bladder

Abstract

Background: There are different experimental models avialable for generating pulsatile flow in laboratory and study their heamodynamic effects on blood vessels. We aim to produce a novel pulsatile flow generator utilizing a large collapsible rubber bladder and the phenomenon of fluid structure interactions occurring in a specially designed flexible tube arrangement. Mehtods: Water enters from a reservoir above into a large collapsible bladder made of rubber which opens into ‘U’ shaped tube made of flexible material and held by non rigid structures. As liquid starts flowing the distal end of collapsible bladder collapses under the negative atmospheric pressure generated inside closing the mouth of ‘U’ shaped tube and produces pulsatile flow. Resuts: The frequency of pulsations, pressure fluctuations and velocity profile resemble that of in vivo blood flow. As the flow entering into collapsible bladder increases the frequency of pulsatile flow decreases and also when height of the collapsible bladder from the ground was changed. The whole cycle of alternate collapse/expansion of collapsible bladder with generation of pulsatile flow continue indefinitely as long as there is enough water in reservoir and vertical gradient to sustain the flow. Conclusions: The pulsatile flow so produced has many of the characteristics of physiological blood flow and can be used to study mechanisms of various cardiovascular diseases in laboratory.