Response on near-infrared spectroscopy and of cerebral blood flow to hypoxemia induced by N2 and CO2 in young rabbits.
Cerebral blood oxyhemoglobin (HbO2), deoxyhemoglobin (HbR) and total hemoglobin (Hb) were examined in N2 and CO2 induced hypoxemia by near-infrared spectroscopy and compared with CBF examined by the H2 clearance method. HbO2 and HbR changed more sensitively than total Hb, reflecting the blood volume. Low CO2-loading showed marked increase in CBF with little change of blood volume, and higher CO2-induced hypoxemia was less increased and followed by a crossed after-reaction, probably because of persistent arterial dilatation due to the marked hypercarbia and acidosis. Neck venous compression showed a specific pattern of increased total Hb and HbR with little change in CBF. Thus, for near-infrared spectroscopy the intracranial blood volume may be affected mainly by arterial dilatation with an increase in CBF and venous dilatation with congestion. And Hb fractions of HbO2 and HbR may be influenced by cerebral blood oxygenation as well as the arteriovenous blood volume.
Mito
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T
Division of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, NCNP, Tokyo, Japan.
Koyama
K
K
Houdou
S
S
Takashima
S
S
Suzuki
S
S
D000818:Animals; D002245:Carbon Dioxide / Q000633:toxicity; D002560:Cerebrovascular Circulation; D005260:Female; D006452:Hemoglobinometry / Q000379:methods*; D006454:Hemoglobins / Q000032:analysis*; D000860:Hypoxia / Q000097:blood / Q000139:chemically induced / Q000503:physiopathology*; D009584:Nitrogen / Q000633:toxicity; D010108:Oxyhemoglobins / Q000032:analysis; D011817:Rabbits; D013055:Spectrophotometry, Infrared
D006454:Hemoglobins; D010108:Oxyhemoglobins; D002245:Carbon Dioxide; D009584:Nitrogen