Document Detail

Transient hyperoxia and residual cerebrovascular effects in the newborn rat.
MedLine Citation:
PMID:  14681497     Owner:  NLM     Status:  MEDLINE    
Unrestricted use of oxygen in the delivery room after preterm birth has been associated with reduced cerebral blood flow (CBF) 2 h later. To further investigate residual cerebrovascular effects of transient hyperoxia, we developed a newborn rat model in which laser-Doppler flowmetry (LDF) and near-infrared spectroscopy (NIRS) were used to monitor changes in cerebral perfusion. The hypothesis to be tested was that hyperoxic exposure limits cerebral vasodilation in response to increase in carbon dioxide tension (Pco(2)). Twenty-four 3- to 5-d-old rats were kept on spontaneous breathing with doxapram under light isoflurane anesthesia, randomized into two groups, and exposed to either room air or 100% oxygen for 30 min. Then, after 15 min of stabilization in normoxia, 8% CO(2) was given for 5 min. No significant differences in CO(2) responses were observed between the two groups: mean CBF-CO(2) reactivity as measured by NIRS was 13.3 +/- 3.9 %/kPa in the normoxia-group versus 8.8 +/- 4.1 %/kPa in the hyperoxia group (NS). The oxygenation index [(HbO(2) - Hb)/2] increased by 0.67 +/- 0.17 micromol/L/kPa in the normoxia group compared with 1.18 +/- 0.19 micromol/L/kPa in the hyperoxia group (NS). Cortical perfusion, monitored by LDF, increased by 7.3 +/- 1.5 %/kPa versus 6.8 +/- 1.8 %/kPa in the normoxia and hyperoxia groups, respectively (NS). We conclude that in newborn rats the CBF-CO(2) reactivity remains intact after 30 min of oxygen exposure.
Monica Fumagalli; Fabio Mosca; Gitte Moos Knudsen; Gorm Greisen
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2003-12-17
Journal Detail:
Title:  Pediatric research     Volume:  55     ISSN:  0031-3998     ISO Abbreviation:  Pediatr. Res.     Publication Date:  2004 Mar 
Date Detail:
Created Date:  2004-02-25     Completed Date:  2004-09-28     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0100714     Medline TA:  Pediatr Res     Country:  United States    
Other Details:
Languages:  eng     Pagination:  380-4     Citation Subset:  IM    
Department of Neonatology, Clinica Mangiagalli-I.C.P. Milan, Via Commenda, 12, 20122 Milan, Italy.
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MeSH Terms
Animals, Newborn
Cerebrovascular Circulation*
Hyperoxia / complications*
Laser-Doppler Flowmetry
Spectroscopy, Near-Infrared

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