Inflammatory stimuli and/or mechanical stresses associated with hypothermic cardiopulmonary bypass (HCPB) could potentially impair cerebrovascular function resulting in inadequate cerebral perfusion. We hypothesize that HCPB is associated with endothelial and/or vascular smooth muscle dysfunction and associated cerebral hypoperfusion. Therefore, we studied the cerebrovascular response to endothelium-dependent vasodilator, acetylcholine (ACh), endothelium-independent nitric oxide donor, sodium nitroprusside (SNP), and vasoactive amine, serotonin, in newborn lambs undergoing HCPB (nasopharygeal temperature = 18°C). Studies were performed on thirteen newborn lambs equipped with a closed cranial window allowing for direct visualization of surface pial arterioles. Six animals were studied while undergoing HCPB while seven served as nonbypass, warm (37°C) controls. Pial arteriolar caliber(range = 111 to 316 μm diameter) was monitored using video microscopy. Topical application of ACh caused dose-dependent increase in arteriolar diameter in the control group (18±6%; 163±22 μm to 190±18 μm) that was absent in animals undergoing HCPB. HCPB did not alter the vasodilation in response to SNP (19±7%; 173±26 μm to 202±21 μm). Furthermore, the contractile response to serotonin(26±4%; 172±14 μm to 124±9 μm) was fully expressed during HCPB. The specific loss of ACh-induced vasodilation suggests endothelial cell dysfunction rather than impaired ability of vascular smooth muscle to respond to nitric oxide. It is speculated that loss of endothelium-dependent regulatory factors in the cerebral microcirculation during HCPB may enhance vasoconstriction and impaired cerebrovascular function may be a basis for associated neurological injury during or following HCPB.
Author information
Authors and Affiliations
Additional information
Supported by a grant from Allegheny Singer Research Institute
Rights and permissions
About this article
Cite this article
Wagerle, L., Russo, P., Dahdah, N. et al. Endothelial Dysfunction in Cerebral Microcirculation During Hypothermic Cardiopulmonary Bypass in Newborn Lambs † 1908. Pediatr Res 43 (Suppl 4), 325 (1998). https://doi.org/10.1203/00006450-199804001-01931
Issue Date:
DOI: https://doi.org/10.1203/00006450-199804001-01931