The Effect of Pulsatile Versus Nonpulsatile Blood Flow on Viscoelasticity and Red Blood Cell Aggregation in Extracorporeal Circulation

Abstract

BackgroundExtracorporeal circulation (ECC) can induce alterations in blood viscoelasticity and cause red blood cell (RBC) aggregation. In this study, the authors evaluated the effects of pump flow pulsatility on blood viscoelasticity and RBC aggregation.MethodsMongrel dogs were randomly assigned to two groups: a nonpulsatile pump group (n=6) or a pulsatile pump group (n=6). After ECC was started at a pump flow rate of 80 mL/kg/min, cardiac fibrillation was induced. Blood sampling was performed before and at 1, 2, and 3 hours after ECC commencement. To eliminate bias induced by hematocrit and plasma, all blood samples were adjusted to a hematocrit of 45% using baseline plasma. Blood viscoelasticity, plasma viscosity, hematocrit, arterial blood gas analysis, central venous O2 saturation, and lactate were measured.ResultsThe blood viscosity and aggregation index decreased abruptly 1 hour after ECC and then remained low during ECC in both groups, but blood elasticity did not change during ECC. Blood viscosity, blood elasticity, plasma viscosity, and the aggregation index were not significantly different in the groups at any time. Hematocrit decreased abruptly 1 hour after ECC in both groups due to dilution by the priming solution used.ConclusionAfter ECC, blood viscoelasticity and RBC aggregation were not different in the pulsatile and nonpulsatile groups in the adult dog model. Furthermore, pulsatile flow did not have a more harmful effect on blood viscoelasticity or RBC aggregation than nonpulsatile flow.

Microfluidic-Based Biosensor for Sequential Measurement of Blood Pressure and RBC Aggregation Over Continuously Varying Blood Flows

“…Because the number of RBCs (red blood cells) is significantly higher than the other cells (platelet, white blood cell), hemorheological properties of blood are dominantly determined by those of the RBCs [5,6]. Hemorheological properties including haematocrit [7,8,9,10], blood viscosity [11,12,13,14], RBC aggregation [15,16,17,18,19,20,21,22], and RBC deformability [14,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38] have been proposed for the early detection of CVDs [39,40]. RBC aggregation leads to altering the hemorheological property, especially in lower blood flows of post-capillary venules [5,41].…”

Microfluidic-Based Measurement Method of Red Blood Cell Aggregation under Hematocrit Variations

“…For this reason, biochemical analyses, such as biomarkers in cardiovascular diseases and disorders [ 4 ] or DNA [ 5 ], do not show sufficient promise for the early detection of cardiovascular diseases [ 6 ]. Since the associations between coronary heart diseases and blood rheology have been sufficiently investigated [ 3 , 7 , 8 ], several biophysical properties such as the viscosity [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ], erythrocyte sedimentation rate (ESR) [ 17 , 18 , 19 , 20 , 21 , 22 ], hematocrit [ 23 , 24 , 25 ], aggregation [ 26 , 27 , 28 , 29 , 30 , 31 , 32 ], and deformability [ 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ] are employed to detect variations in blood samples. Among them, blood viscosity varies depending on several factors, such as the plasma viscosity, hematocrit, red blood cell (RBC) aggregation, and deformability.…”

Use of a Virtual Mock Loop model to evaluate a new left ventricular assist device for transapical insertion

“…Pulsatile flow improves microcirculatory blood flow and tissue oxygen saturation compared with non-pulsatile flow. Ahn et al 5 showed that the effects of pulsatile flow on blood viscoelasticity and red blood cell aggregation were decreased compared to the effects of non-pulsatile flow. While these advantages have prompted the development of pulsatile flow pumps, the efficiency of the non-pulsatile flow pump has recently been reconsidered.…”

“…Left ventricular assist devices (LVADs) play a crucial role for patients with end-stage heart failure (HF). Various types of LVADs are being developed, [1][2][3][4][5][6] including a miniaturized device configured for transapical insertion that we are developing (Perfusion Solution, Inc., South Euclid, OH, USA; Figure 1). This pump has a smaller diameter than any equally durable device with theoretically equal flow output, thereby more easily fitting a higher percentage of patients.…”