Retinal arteriolar diameter, blood velocity, and blood flow response to an isocapnic hyperoxic provocation
Retinal arteriolar diameter, blood velocity, and blood flow response to an isocapnic hyperoxic provocation
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DOI：
10.1152/ajpheart.01037.2004
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发表时间：
2005-06-01
影响因子：
4.8
通讯作者：
Fisher, J
中科院分区：
文献类型：
--
作者：
Gilmore, ED;Hudson, C;Fisher, J
本研究的目的是同时量化一组临床正常受试者在异速高氧刺激下视网膜小动脉直径和血流速度的大小和反应特征。样本包括10名受试者（平均年龄25岁，范围21-40岁）。受试者最初呼吸空气5-10分钟，然后呼吸0- 2 20分钟，然后通过顺序再呼吸循环（Hi-Ox; Viasys）进行最后10分钟的空气呼吸，以维持异呼吸障碍。用佳能激光血流仪（CLBF-100）同时测量视网膜小动脉直径和血流速度。计算了直径和速度的响应幅度、响应时间和滞后时间。在高氧刺激下，视网膜直径从对照值111.6 μ m （SD 13.1）减少到99.8 μ m (SD 10.6; P < 0.001) μ m，并在高氧解除后恢复。同时，视网膜血流速度和流量分别从对照组的32.2 (SD 6.4) mm/s和9.4 (SD 2.5) mu l/min下降到20.7 (SD 3.4) mm/s和5.1 (SD 1.3) mu l/min（速度和流量均P < 0.001），并在停止高氧后恢复。各参数的响应时间和响应滞后在效果与恢复、直径与速度之间无显著差异。我们的结论是，视网膜小动脉血管对高氧刺激的反应是迅速的，最大的血管收缩效应最多在4分钟内发生。虽然直径对等速高氧刺激的响应有先于速度的趋势，但直径和速度对等速高氧刺激的响应特征无显著差异。
The aim of this study was to simultaneously quantify the magnitude and response characteristics of retinal arteriolar diameter and blood velocity induced by an isocapnic hyperoxic provocation in a group of clinically normal subjects. The sample comprised 10 subjects ( mean age, 25 yr; range, 21-40 yr). Subjects initially breathed air for 5-10 min, then breathed O-2 for 20 min, and then air for a final 10-min period via a sequential rebreathing circuit (Hi-Ox; Viasys) to maintain isocapnia. Retinal arteriolar diameter and blood velocity measurements were simultaneously acquired with a Canon laser blood flowmeter (CLBF-100). The response magnitude, time, and lag of diameter and velocity were calculated. In response to hyperoxic provocation, retinal diameter was reduced from control values of 111.6 (SD 13.1) to 99.8 (SD 10.6; P < 0.001) mu m and recovered after withdrawal of hyperoxia. Retinal blood velocity and flow concomitantly declined from control values of 32.2 (SD 6.4) mm/s and 9.4 (SD 2.5) mu l/min to 20.7 (SD 3.4) mm/s and 5.1 (SD 1.3) mu l/min, respectively (P < 0.001 for both velocity and flow), and recovered after withdrawal of hyperoxia. The response times and response lags were not significantly different for each parameter between effect and recovery or between diameter and velocity. We conclude that arteriolar retinal vascular reactivity to hyperoxic provocation is rapid with a maximal vasoconstrictive effect occurring within a maximum of 4 min. Although there was a trend for diameter to respond before velocity to the isocapnic hyperoxic provocation, the response characteristics were not significantly different between diameter and velocity.