Volume 17 Supplement 2

33rd International Symposium on Intensive Care and Emergency Medicine

Open Access

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

  • T Clark1,
  • S Jewell2,
  • M Sair1,
  • P Petrov2 and
  • P Winlove2
Critical Care201317(Suppl 2):P12

DOI: 10.1186/cc11950

Published: 19 March 2013

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

Patient

A1

A2

A3

A4

A5

A6

A7

B8

B9

B10

B11

B12

B13

B14

B15

Post CPB

+0.1

-0.4

-0.1

-0.5

-0.1

-0.2

-0.1

+0.5

0

+0.4

+0.1

+0.2

0

+0.2

+0.1

Day 1

0

0

+0.1

-0.1

-0.1

+0.1

+0.1

0

+0.5

+0.4

+0.7

+0.4

+0.6

+0.5

+0.7

Day 2

-0.2

+0.1

0

NA

NA

0

NA

+0.5

-0.1

+0.4

NA

+0.1

NA

NA

NA

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.

Authors’ Affiliations

(1)
Derriford Hospital
(2)
University of Exeter

References

  1. Lindmark , et al.: J Thoracic Cardiovasc Surg. 2002, 123: 381-383. 10.1067/mtc.2002.118270View ArticleGoogle Scholar

Copyright

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

This article is published under license to 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.

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