Autoregulation remains intact during stable xenon inhalation in the baboon.
To test the possible effect of 32% end-tidal Xe concentration upon autoregulation, 5 baboons, Papio anubis/cynocephalus, were anesthetized/paralyzed with propranolol 0.02, diazepam 0.1, morphine sulfate 0.1, and pancuronium 0.2 (mg/(h.kg)). The animals were subjected to a servocontrolled blood infusion-withdrawal program to control central aortic blood pressure (CAP). PaCO2 was held to 30 to 35 torr, with individual variation less than 3 torr by control of ventilation and by including CO2 in the Xe/O2 mixture. Three to six CBF measurements were made in each subject over the above range. In four animals the CAP was varied between 18 and 150 torr, with corresponding CBF measurements. The CAP range was extended to 196 torr in the 5th animal by IV administration of phenylephrine. Significant lowering of global blood flow did not occur above 40 torr mean CAP. While regulated flow persists to about 150 torr at the high end, there is a breakaway between 150 and 190 torr where flow increased 90%. A 4th order polynomial fit of the data has the characteristic appearance of the familiar autoregulation curve. We conclude that autoregulation is preserved even in the presence of FIXe of 32% in the breathing mixture.
Wolfson
S K
SK
Montefiore Hospital, Department of Neurological Surgery, University of Pittsburgh, PA.
Yonas
H
H
Gur
D
D
Cook
E E
EE
Greenberg
J
J
Brenner
R P
RP
D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D006706:Homeostasis / Q000502:physiology*; D010215:Papio / Q000502:physiology*; D014057:Tomography, X-Ray Computed; D014978:Xenon
D014978:Xenon