Document Detail


Altered cerebrovascular responses after exposure to venoarterial extracorporeal membrane oxygenation: role of the nitric oxide pathway.
MedLine Citation:
PMID:  16738508     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Previous studies in our laboratory on newborn lambs have shown cerebral autoregulation impairment after exposure to venoarterial extracorporeal membrane oxygenation (VA ECMO), with additional studies showing an altered cerebrovascular response to NG-nitro-L-arginine methyl ester in lamb cerebral vessels in this same model. OBJECTIVE: To further study the mechanisms involved in altered cerebrovascular responses in vessels exposed to VA ECMO. DESIGN: Prospective study. SETTING: Research Animal Facility at Children's National Medical Center, Washington, DC. SUBJECT: Newborn lambs, 1-7 days of age, 4.76 +/- 0.8 kg (n = 10). METHODS: Animals randomly assigned two groups, control and VA ECMO, were anesthetized, ventilated, heparinized, and kept in a normal physiologic condition. Control animals were continued on ventilatory support, whereas animals in the VA ECMO groups were placed on VA ECMO, with bypass flows maintained between 120 and 200 mL x kg x min(-1) for 2.5 hrs. Isolated third-order branches of the middle cerebral arteries were studied for myotonic reactivity to increasing intraluminal pressure changes, response to acetylcholine, an endothelium-dependent vasodilator, 3-morpholinyl-sydnoneimine chloride, an endothelium-independent vasodilator, and serotonin, a direct vascular vasoconstrictor. Arterial caliber was monitored using video microscopy. RESULTS: Myogenic constriction response was significantly decreased in the VA ECMO group compared with the control group (p = .03). Intraluminal acetylcholine caused concentration-dependent arterial dilation in the control group, whereas it resulted in vasoconstriction in the VA ECMO group (p = .008). There were no significant differences in dilation responses to 3-morpholinyl-sydnoneimine chloride and contractile responses to serotonin among the groups. CONCLUSION: Cerebral arteries exposed to VA ECMO had impaired myogenic responses combined with altered endothelial function. The endothelial alteration seems to be mediated through the nitric oxide pathway, with recovery noted after addition of a nitric oxide donor. It can be postulated that these changes may reflect the mechanisms for the impairment of cerebral autoregulation previously reported in this lamb model.
Authors:
Ma Ingyinn; Khodayar Rais-Bahrami; Mohan Viswanathan; Billie L Short
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies     Volume:  7     ISSN:  1529-7535     ISO Abbreviation:  Pediatr Crit Care Med     Publication Date:  2006 Jul 
Date Detail:
Created Date:  2006-08-10     Completed Date:  2006-09-21     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  100954653     Medline TA:  Pediatr Crit Care Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  368-73     Citation Subset:  IM    
Affiliation:
Department of Neonatology, Children's National Medical Center, Washington, DC, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Animals, Newborn
Brain / metabolism*
Cerebrovascular Disorders / etiology,  physiopathology*
Endothelium, Vascular / drug effects
Extracorporeal Membrane Oxygenation / adverse effects*,  methods
Homeostasis*
NG-Nitroarginine Methyl Ester / pharmacology
Nitric Oxide / metabolism*
Random Allocation
Sheep
Chemical
Reg. No./Substance:
10102-43-9/Nitric Oxide; 50903-99-6/NG-Nitroarginine Methyl Ester

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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