[Duplex ultrasound examinations of retinal circulation after inhalation of various mixed respiratory gases].
BACKGROUND
Hyperoxic-hypercapnic inhalation is a therapeutic option in vascular disorders of the retina. The effect of hyperoxic and/or hypercapnic inhalation on the perfusion of the retina was examined.


METHODS
Twenty-five young adults between 18 and 35 years were investigated in a prospective study. They inhaled one of three different mixtures of breathing gases: (1) 100% O2, (2) Carbogen 240 (95% O2 and 5% CO2), (3) 92% O2 with 8% CO2 and were examined by color Doppler imaging of the CRA and OA before and after inhalation. The resistance index (RI) was calculated.


RESULTS
The majority of the subjects showed an Increase in the RI in both ophthalmic vessels after inhalation of pure O2, a decrease after breathing in 92% O2 and 8% CO2 and it remained almost constant with inhalation of 95% O2 and 5% CO2.


CONCLUSIONS
Inhalation of 92% O2 and 8% CO2 is a possibility for decreasing the peripheral resistance of OA and CRA. No change in blood flow was observed with Carbogen 240.
Schüttauf
F
F
Universitäts-Augenklinik, Halle/Saale.
Cobet
U
U
Klemenz
A
A
Krause
A
A
D000293:Adolescent; D000328:Adult; D001783:Blood Flow Velocity / Q000187:drug effects; D002245:Carbon Dioxide; D005260:Female; D006801:Humans; D008297:Male; D010100:Oxygen; D010102:Oxygen Inhalation Therapy; D011446:Prospective Studies; D012171:Retinal Vessels / Q000000981:diagnostic imaging* / Q000187:drug effects; D018615:Ultrasonography, Doppler, Color; D014655:Vascular Resistance / Q000187:drug effects
D002245:Carbon Dioxide; C011700:carbogen; D010100:Oxygen
Duplexsonographische Untersuchungen zur retinalen Durchblutung nach Inhalation verschiedener Atemgasgemische.