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Retinal blood velocities during carbogen breathing using scanning laser ophthalmoscopy
Author(s) -
Arend Oliver,
Harris Alon,
Martin Bruce J.,
Holin Mary,
Wolf Sebastian
Publication year - 1994
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.1994.tb02768.x
Subject(s) - retinal , hyperoxia , carbogen , perfusion , medicine , blood flow , oxygenation , blood pressure , room air distribution , arterial blood , hypercapnia , fluorescein angiography , retinal artery , anesthesia , cardiology , ophthalmology , lung , acidosis , physics , thermodynamics
. Hyperoxic‐hypercapnic gas mixture (‘carbogen’: 6% CO 2 ‐94% O 2 ) is widely used clinically. Its influence on retinal perfusion remains unclear, since past work suggests that high O 2 may reduce and high CO 2 may increase retinal blood flow. To examine the changes in retinal blood velocity during ‘hyperoxic‐hypercapnic’ gax mixture breathing, we quantified retinal blood velocity indices. Twenty‐eight healthy subjects were studied using scanning laser video fluorescein angiograms at baseline and after gas inhalation. Retinal arteriovenous passage time and mean arterial dye velocity were measured by means of a digital image processing system. Arterial diameter measurements showed no change (4%) during carbogen breathing. Increased arterial Pco 2 and Po 2 resulted in small but statistically significant increases in systolic and diastolic blood pressure and heart rate (each c. 8%, p < 0.05), and a dramatic increase in mean dye velocity (27%, p < 0.01), with parallel reduction in arteriovenous passage time (40%, p < 0.01). The substantial acceleration of retinal dye velocity and transit under combined hyperoxia and hypercapnia strongly suggests that this clinically standard gas mixture may indeed improve oxygenation without reducing retinal perfusion.