Date on Master's Thesis/Doctoral Dissertation

12-2008

Document Type

Master's Thesis

Degree Name

M.S.

Department

Mechanical Engineering

Committee Chair

Sharp, Michael Keith

Subject

Viscoelasticity; Blood; Children--Physiology

Abstract

The performance of pediatric circulatory support devices depends on the properties of pediatric blood. This study reports the measurement of the viscoelastic properties of pediatric blood at 37°C [body temperature]. The results were compared with adult viscoelastic properties at the same temperature and also to pediatric viscoelastic properties analyzed at 22°C [room temperature]. The measurements were made using a viscoelasticity analyzer Vilastic-3 on the blood at the hematocrit at which it was drawn. Each test produced results for viscoelastic parameters versus shear rate [stretch test] at a frequency of 2 Hz. Samples were obtained with informed consent from 11 pediatric patients at Kosair Children's Hospital with body weight of 12.72 ± 9.85 kg [3.60 kg to 34.8 kg] and age of 2.72 ± 3.42 years [0.0301 years to 11.83 years]. The average spun hematocrit was 40.2 ± 7.38% [30% to 51.5%] and the average density was 1.053 ± 0.00492 [1.047 to 1.060]. Mean viscosity values were 0.091 ± 0.022 poise [0.2 strain], 0.08 ± 0.021 poise [1 strain] and 0.0696 ± 0.016 poise [5 strain]. Mean elasticity values were 0.056 ± 0.028 poise [0.2 strain], 0.053 ± 0.024 poise [1 strain] and 0.021 ± 0.007 poise [5 strain]. The results obtained by 2 way - ANOVA comparison showed significant variation (p < 0.05) between the adult and pediatric data at 37°C. The comparison of the pediatric data at body temperature and room temperature showed dissimilar values in viscoelasticity with a significant variation (p < 0.05). The results from this study can be used as base data for pediatric blood at normal body temperature for design of implants for pediatric patients.

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