Viscoelasticity of Pediatric Blood and its Implications for the Testing of a Pulsatile Pediatric Blood Pump

Long, Jennifer A.; Ündar, Akif; Manning, Keefe B.; Deutsch, Steven

doi:10.1097/01.mat.0000180353.12963.f2

Cited by 76 publications

(64 citation statements)

References 6 publications

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“…However, the present result is comparable with the previous result, in the point of dependency on hematocrit. 28 In other words, viscosity and elasticity of blood have higher values at higher hematocrits, even in narrow microfluidic channels (P < 0.05). In conclusion, this proposed method is capable of simultaneously measuring viscosity and elasticity of various blood samples, depending on varying hematocrits that range from 20% to 50%.…”

Section: Resultsmentioning

confidence: 97%

“…This increasing tendency of blood viscosity is also shown in the previous study. 28 In addition, the characteristic time gradually decreased with respect to hematocrit. The blood elasticity (G Blood ) was identified using the relaxation formula (k Blood ¼ l Blood /G Blood ).…”

Section: Resultsmentioning

confidence: 99%

“…2, the left lower side channel filled with blood is modeled by elasticity element (G Blood ) and viscosity element (l Blood ) connected in series. 28 Using the linear viscoelasticity model, a governing equation for the blood viscoelasticity in the left lower side channel is derived as…”

Section: B Analytical Regression Formulae Based On the Linear Viscoementioning

confidence: 99%

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Blood viscoelasticity measurement using steady and transient flow controls of blood in a microfluidic analogue of Wheastone-bridge channel

Kang

Lee

2013

Biomicrofluidics

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Accurate measurement of blood viscoelasticity including viscosity and elasticity is essential in estimating blood flows in arteries, arterials, and capillaries and in investigating sub-lethal damage of RBCs. Furthermore, the blood viscoelasticity could be clinically used as key indices in monitoring patients with cardiovascular diseases. In this study, we propose a new method to simultaneously measure the viscosity and elasticity of blood by simply controlling the steady and transient blood flows in a microfluidic analogue of Wheastone-bridge channel, without fully integrated sensors and labelling operations. The microfluidic device is designed to have two inlets and outlets, two side channels, and one bridge channel connecting the two side channels. Blood and PBS solution are simultaneously delivered into the microfluidic device as test fluid and reference fluid, respectively. Using a fluidic-circuit model for the microfluidic device, the analytical formula is derived by applying the linear viscoelasticity model for rheological representation of blood. First, in the steady blood flow, the relationship between the viscosity of blood and that of PBS solution (l Blood /l PBS ) is obtained by monitoring the reverse flows in the bridge channel at a specific flow-rate rate (Q PBS SS /Q Blood L ). Next, in the transient blood flow, a sudden increase in the blood flow-rate induces the transient behaviors of the blood flow in the bridge channel. Here, the elasticity (or characteristic time) of blood can be quantitatively measured by analyzing the dynamic movement of blood in the bridge channel. The regression formulais selected based on the pressure difference (DP ¼ P A À P B ) at each junction (A, B) of both side channels. The characteristic time of blood (k Blood ) is measured by analyzing the area (A Blood ) filled with blood in the bridge channel by selecting an appropriate detection window in the microscopic images captured by a high-speed camera (frame rate ¼ 200 Hz, total measurement time ¼ 7 s). The elasticity of blood (G Blood ) is identified using the relationship between the characteristic time and the viscosity of blood. For practical demonstrations, the proposed method is successfully applied to evaluate the variations in viscosity and elasticity of various blood samples: (a) various hematocrits form 20% to 50%, (b) thermal-induced treatment (50 C for 30 min), (c) flow-induced shear stress (53 6 0.5 mL/h for 120 min), and (d) normal rat versus spontaneously hypertensive rat. Based on these experimental demonstrations, the proposed method can be effectively used to monitor variations in viscosity and elasticity of bloods, even with the absence of fully integrated sensors, tedious labeling and calibrations. V C 2013 AIP Publishing LLC.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

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Blood viscoelasticity measurement using steady and transient flow controls of blood in a microfluidic analogue of Wheastone-bridge channel

Kang

Lee

2013

Biomicrofluidics

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“…The experimental result is comparable with the previous result, in terms of dependency on hematocrit. 31 In addition, at a fixed pumping speed of 2 (i.e., x ¼ 2), the flow rate of blood is consistently identified as 5 mL/h regardless of hematocrits. This indicates that the peristaltic pump provides a constant flow rate, independent of fluidic resistance variation.…”

Section: Blood Viscosity Measurement For Unknown Flow Ratementioning

confidence: 92%

A microfluidic device for simultaneous measurement of viscosity and flow rate of blood in a complex fluidic network

2013

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Blood viscosity has been considered as one of important biophysical parameters for effectively monitoring variations in physiological and pathological conditions of circulatory disorders. Standard previous methods make it difficult to evaluate variations of blood viscosity under cardiopulmonary bypass procedures or hemodialysis. In this study, we proposed a unique microfluidic device for simultaneously measuring viscosity and flow rate of whole blood circulating in a complex fluidic network including a rat, a reservoir, a pinch valve, and a peristaltic pump. To demonstrate the proposed method, a twin-shaped microfluidic device, which is composed of two half-circular chambers, two side channels with multiple indicating channels, and one bridge channel, was carefully designed. Based on the microfluidic device, three sequential flow controls were applied to identify viscosity and flow rate of blood, with label-free and sensorless detection. The half-circular chamber was employed to achieve mechanical membrane compliance for flow stabilization in the microfluidic device. To quantify the effect of flow stabilization on flow fluctuations, a formula of pulsation index (PI) was analytically derived using a discrete fluidic circuit model. Using the PI formula, the time constant contributed by the half-circular chamber is estimated to be 8 s. Furthermore, flow fluctuations resulting from the peristaltic pumps are completely removed, especially under periodic flow conditions within short periods (T < 10 s). For performance demonstrations, the proposed method was applied to evaluate blood viscosity with respect to varying flow rate conditions [(a) known blood flow rate via a syringe pump, (b) unknown blood flow rate via a peristaltic pump]. As a result, the flow rate and viscosity of blood can be simultaneously measured with satisfactory accuracy. In addition, the proposed method was successfully applied to identify the viscosity of rat blood, which circulates in a complex fluidic network. These observations confirm that the proposed method can be used for simultaneous measurement of viscosity and flow rate of whole blood circulating in the complex fluid network, with sensorless and label-free detection. Furthermore, the proposed method will be used in evaluating variations in the viscosity of human blood during cardiopulmonary bypass procedures or hemodialysis.

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“…The pediatric data used for comparison was obtained from Penn State University [Long, et al 2005]. The data set is from 10 patients tested at 22°C.…”

Section: Pediatric Data Analysismentioning

confidence: 99%

Viscoelastic properties of pediatric blood

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Viscoelasticity of Pediatric Blood and its Implications for the Testing of a Pulsatile Pediatric Blood Pump

Cited by 76 publications

References 6 publications

Blood viscoelasticity measurement using steady and transient flow controls of blood in a microfluidic analogue of Wheastone-bridge channel

Blood viscoelasticity measurement using steady and transient flow controls of blood in a microfluidic analogue of Wheastone-bridge channel

A microfluidic device for simultaneous measurement of viscosity and flow rate of blood in a complex fluidic network

Viscoelastic properties of pediatric blood

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