• Nick J Koning, Fellery de Lange, Alexander B A Vonk, Yunus Ahmed, Charissa E van den Brom, Sylvia Bogaards, Matijs van Meurs, Rianne M Jongman, Casper G Schalkwijk, Mark P V Begieneman, Hans W Niessen, Christophe Baufreton, and Christa Boer.
• Department of Anesthesiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands; Department of Integrated Neurovascular Biology, INSERM U1083, CNRS UMR 6214, LUNAM University, Université d'Angers, Angers, France n.koning@vumc.nl.
• Am. J. Physiol. Heart Circ. Physiol. 2016 Mar 1; 310 (5): H550-8.

AbstractAlthough hemodilution is attributed as the main cause of microcirculatory impairment during cardiopulmonary bypass (CPB), this relationship has never been investigated. We investigated the distinct effects of hemodilution with or without CPB on microvascular perfusion and subsequent renal tissue injury in a rat model. Male Wistar rats (375-425 g) were anesthetized, prepared for cremaster muscle intravital microscopy, and subjected to CPB (n = 9), hemodilution alone (n = 9), or a sham procedure (n = 6). Microcirculatory recordings were performed at multiple time points and analyzed for perfusion characteristics. Kidney and lung tissue were investigated for mRNA expression for genes regulating inflammation and endothelial adhesion molecule expression. Renal injury was assessed with immunohistochemistry. Hematocrit levels dropped to 0.24 ± 0.03 l/l and 0.22 ± 0.02 l/l after onset of hemodilution with or without CPB. Microcirculatory perfusion remained unaltered in sham rats. Hemodilution alone induced a 13% decrease in perfused capillaries, after which recovery was observed. Onset of CPB reduced the perfused capillaries by 40% (9.2 ± 0.9 to 5.5 ± 1.5 perfused capillaries per microscope field; P < 0.001), and this reduction persisted throughout the experiment. Endothelial and inflammatory activation and renal histological injury were increased after CPB compared with hemodilution or sham procedure. Hemodilution leads to minor and transient disturbances in microcirculatory perfusion, which cannot fully explain impaired microcirculation following cardiopulmonary bypass. CPB led to increased renal injury and endothelial adhesion molecule expression in the kidney and lung compared with hemodilution. Our findings suggest that microcirculatory impairment during CPB may play a role in the development of kidney injury. Copyright © 2016 the American Physiological Society.

45 keywords...

hide…