Optic nerve vasomotor effects of arterial blood gases.
OBJECTIVE
The purpose of this study was to examine the vasomotor effects of blood gases on the anterior optic nerve vascular bed. The microvasculature of the optic nerve was examined with intraluminal microvascular corrosion castings in six rabbits.


METHODS
The blood gases were varied by manipulating the ventilation rate for each rabbit prior to the intraluminal injection of the casting medium. The correlation between arterial blood gases (pO2, pCO2) and vasoconstriction of the arterioles supplying the anterior optic nerve was analyzed.


RESULTS
Relative constriction values of a total of 88 arterioles supplying the optic nerve of the six rabbits were obtained. A regression analysis provided a high and significant correlation between pCO2 and the average relative arteriolar constriction values for each rabbit (R = 0.86; t = -4.95; p = 0.008). The correlation between the arterial oxygen saturation and the average relative arteriolar constriction values was of borderline significance (R = 0.64; t = 2.65; p = 0.057).


CONCLUSIONS
A strong interrelationship between arterial pCO2 and anterior optic nerve arteriolar constriction has been demonstrated.
Orgül
S
S
Devers Eye Institute/Good Samaritan Hospital and Medical Center Portland, Oregon, U.S.A.
Cioffi
G A
GA
Bacon
D R
DR
Onda
E
E
Van Buskirk
E M
EM