Pulsatile flow

About: Pulsatile flow is a research topic. Over the lifetime, 6278 publications have been published within this topic receiving 149638 citations.

Pulsatile entrance flow in a curved pipe

Abstract: An experimental investitition was made of the entry flow in a curved pipe under conditions wherein a pulsatile component of flow was superimposed on a steady mean flow. Two experiments were conducted, one in a pipe of curvature ratio for αw = 12·5 and κ = 372. Laser-velocimetry measurements of the axial and secondary velocities were made throughout the cross-section at different instants of time within the cycle and at several axial locations downstream from the pipe entrance.The flow in the first experiment was found to be quasisteady, with axial and secondary velocities varying in time at the several axial stations proportionally to the instantaneous mean velocity, but essentially the same in character as low-Dean-number steady entry flow. The flow in the second experiment was more complex, with separation of the axial flow appearing at the inner bend during deceleration, starting downstream and propagating upstream toward the pipe entrance. Helical motions imbedded within the Dean circulation were also observed, and during certain portions of the cycle the secondary motions within the central core took on a jet-like structure.It suggested that the classifications employed by Smith to describe the different regimes of fully-developed pulsatile flow in curved pipes may also be useful to distinguish between different entry-flow regimes.

Right ventricular-pulmonary arterial interactions.

Abstract: The application of pulsatile models to hemodynamic data has made possible a more complete understanding of the relationship of pulmonary pressure and flow To review the genesis of these concepts, the unique characteristics of the pulmonary artery and right ventricle are outlined as a basis for understanding why differences in their pulsatile properties from the systemic circuit must exist The pulmonary impedance spectrum is introduced and the concept of optimal right ventricular-pulmonary artery coupling is explored based on a review of extensive experimental data Finally, available studies of normal pulmonary impedance in man and abnormal impedance in human disease states are reviewed, with emphasis on disturbances in optimal ventricular-vascular coupling The important implications of these concepts for understanding and treatment of cardiovascular disease are developed

Apparatus for aiding and improving the blood flow in patients

Abstract: Improved blood pumping apparatus is disclosed which includes a smooth avalvular deflatable section through which blood flows, said section mounted within a rigid avalvular airtight housing, gas being introduced and withdrawn from the housing by suitable control means, the action of the gas causing the blood chamber to inflate and deflate with consequent non-traumatic pulsatile ejection of blood from said chamber. The apparatus is simple, reliable, inexpensive and can aid the blood pumping function in many ways. For example, apparatus is disclosed to provide pulsatile flow to the blood being pumped by a heart-lung machine, or to provide pulsatile flow to the coronary arteries during coronary artery perfusion, or to be utilized as an arterio-venous fistula to decrease the afterload of the left ventricle and preserve the systemic diastolic pressure while increasing coronary perfusion. In addition, apparatus is disclosed which can, with slight modification, function as counterpulsation apparatus to, for example, support a patient's systemic circulation by left heart counterpulsation, or wean a patient off a heart-lung machine when the patient's heart has resumed beating, or support the right heart by pulmonary artery counterpulsation, or provide counterpulsation when other types of counterpulsation, such as intra-aortic balloon pump counterpulsation, are impractical.