Response of vertebral and carotid blood flow to isocapnic changes in end-tidal oxygen tension.
The response of the vertebral and carotid blood flow to isocapnic hypoxia was measured in 9 cats anaesthetized with chloralose-urethane using perivascular electromagnetic flow probes. The carotid flow was already significantly increased when going from hyperoxia (PETO2 55 kPa) to normoxia. For the vertebral blood flow a significant increase compared to hyperoxia was observed at a moderate level of hypoxia (PETO2 9 kPa). The time course of the response of the blood flow to isocapnic step-like changes in PETO2 was fitted with a first order model. The mean time constant (+/- SD) for steps into hypoxia for the carotid flow was 35 +/- 38 sec(8 cats) and for the vertebral flow, 44 +/- 37 sec (5 cats). The mean time constant (+/- SD) for steps out of hypoxia was significantly smaller and found to be 23 +/- 22 sec (8 cats) and 19 +/- 18 sec (4 cats), respectively. We argue that a major part of the changes in vertebral and carotid blood flow to steps into hypoxia goes to brain tissue.
Van Beek
J H
JH
Berkenbosch
A
A
De Goede
J
J
Olievier
C N
CN
D000818:Animals; D001794:Blood Pressure; D002245:Carbon Dioxide / Q000032:analysis* / Q000097:blood; D002339:Carotid Arteries / Q000502:physiology*; D002415:Cats; D005260:Female; D006339:Heart Rate; D000860:Hypoxia / Q000097:blood; D008297:Male; D010100:Oxygen / Q000032:analysis / Q000097:blood; D010313:Partial Pressure; D012039:Regional Blood Flow; D013131:Spine / Q000098:blood supply*; D014132:Trachea
D002245:Carbon Dioxide; D010100:Oxygen