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This article is part of the supplement: 33rd International Symposium on Intensive Care and Emergency Medicine

Poster presentation

Do erythrocytes subjected to cardiopulmonary bypass exhibit changes in their membrane mechanical properties?

T Clark1*, S Jewell2, M Sair1, P Petrov2 and P Winlove2

  • * Corresponding author: T Clark

Author Affiliations

1 Derriford Hospital, Plymouth, UK

2 University of Exeter, UK

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Critical Care 2013, 17(Suppl 2):P12  doi:10.1186/cc11950

The electronic version of this article is the complete one and can be found online at: http://ccforum.com/content/17/S2/P12


Published:19 March 2013

© 2013 Clark et al.; licensee BioMed Central Ltd.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Introduction

Whole blood experiments suggest that cardiopulmonary bypass (CPB) causes red blood cell (RBC) trauma and changes in deformability that may contribute to postoperative microcirculatory dysfunction. We used a novel fluctuation microscopy technique to quantify the effects of CPB on RBC elasticity at a cellular level.

Methods

We collected blood samples from elective cardiac surgery patients pre (at induction) and post (immediately, each day until CICU discharge) CPB. Thermal fluctuations of individual RBCs were recorded using a high-frame-rate camera allowing a complete analysis of RBC shape variation over time. Mean elasticity of the cell membrane was then quantified for each sample collected.

Results

Fifteen patients were recruited. Table 1 displays the results. RBC thermal fluctuation is measured relative to pre-bypass values. An increase in RBC fluctuation marks a decrease in stiffness. CPB caused two distinct changes in RBC elasticity; pre fix A indicates samples where stiffness increases or shows no change, B those where stiffness decreases. Data on day 2 were not collected in patients discharged from the CICU. CPB type or time had no apparent impact on RBC response to CPB.

Table 1. Change in RBC thermal fluctuation relative to baseline: two distinct groups seen

Conclusion

RBC thermal fluctuation analysis quanties the impact of CPB on erythrocyte membrane elasticity. We clearly identified two separate RBC elasticity responses to CPB. This finding is contrary to traditional flow measurement techniques that suggest CPB impairs whole blood flow and reduces RBC deformability.

References

  1. Lindmark , et al.:

    J Thoracic Cardiovasc Surg. 2002, 123:381-383. Publisher Full Text OpenURL