吸入100%氧气对吸烟者和非吸烟者视网膜及视神经乳头毛细血管血流的影响。
Effect of breathing 100% oxygen on retinal and optic nerve head capillary blood flow in smokers and non-smokers.
作者信息
Langhans M, Michelson G, Groh M J
机构信息
Ophthalmology and Eye Hospital, University Erlangen-Nürnberg, Germany.
出版信息
Br J Ophthalmol. 1997 May;81(5):365-9. doi: 10.1136/bjo.81.5.365.
AIM
The effect of breathing 100% oxygen on retinal and optic nerve head capillary blood flow in smokers and non-smokers was investigated using scanning laser Doppler flowmetry (SLDF) as a new non-invasive method to visualise and quantify ocular blood flow.
METHOD
10 eyes of 10 young healthy non-smoking volunteers (mean age 26 (SD 3) years) and nine eyes of nine young healthy smoking volunteers (mean age 26 (4) years) were investigated. All participants were asked not to smoke or consume caffeine containing drinks for at least 4 hours before the measurements. Blood flow measurements were performed before and after 100% oxygen was applied to the subjects through a mask over a period of 5 minutes (6 litres per minute). Juxtapapillary retinal and optic nerve head blood flow were determined in arbitrary units using SLDF representing a combination of laser Doppler flowmetry and a scanning laser system allowing visualisation and quantification of the retinal and optic nerve head blood flow. Blood flow was determined in an area of 100 microns x 100 microns. The level of carboxyhaemoglobin was determined in all subjects. A Wilcoxon matched pairs signed ranks test (non-parametric) was used for statistical evaluation.
RESULTS
In the non-smoking group, retinal 'flow' was reduced by 33% (p = 0.005), optic nerve head 'flow' by 37% (p = 0.005). In the smoking group retinal flow was reduced by 10% (p = 0.01), optic nerve head flow by 13% (p < 0.008). The difference in reactivity to oxygen breathing between smokers and non-smokers was highly significant (p < 0.00001). Increased carboxyhaemoglobin levels were not found in either of the groups. A significant reduction of the mean arterial blood pressure of 6% (5%) (p < 0.02) was observed in the non-smoking group after administration of oxygen.
CONCLUSION
These results indicate that hyperoxia leads to a decrease in capillary blood flow of the retina and optic nerve head secondary to vasoconstriction, and that smokers do not respond to oxygen breathing as non-smokers do. The findings might be based on factors such as long term effects of nicotine on the sympathetic and parasympathetic nervous system.
目的
采用扫描激光多普勒血流仪（SLDF）这一新型非侵入性方法来可视化和量化眼部血流，研究吸入100%氧气对吸烟者和非吸烟者视网膜及视神经乳头毛细血管血流的影响。
方法
对10名年轻健康的非吸烟志愿者（平均年龄26（标准差3）岁）的10只眼睛和9名年轻健康的吸烟志愿者（平均年龄26（4）岁）的9只眼睛进行了研究。所有参与者在测量前至少4小时被要求不得吸烟或饮用含咖啡因的饮料。在通过面罩向受试者施加100%氧气5分钟（每分钟6升）之前和之后进行血流测量。使用SLDF以任意单位确定视乳头旁视网膜和视神经乳头血流，SLDF是激光多普勒血流仪和扫描激光系统的组合，可实现视网膜和视神经乳头血流的可视化和量化。在100微米×100微米的区域内测定血流。测定所有受试者的碳氧血红蛋白水平。采用Wilcoxon配对符号秩检验（非参数检验）进行统计学评估。
结果
在非吸烟组中，视网膜“血流”减少了33%（p = 0.005），视神经乳头“血流”减少了37%（p = 0.005）。在吸烟组中，视网膜血流减少了10%（p = 0.01），视神经乳头血流减少了13%（p < 0.008）。吸烟者和非吸烟者对吸氧反应性的差异非常显著（p < 0.00001）。两组均未发现碳氧血红蛋白水平升高。在非吸烟组吸氧后观察到平均动脉血压显著降低6%（5%）（p < 0.02）。
结论
这些结果表明，高氧导致视网膜和视神经乳头毛细血管血流因血管收缩而减少，且吸烟者对吸氧的反应与非吸烟者不同。这些发现可能基于尼古丁对交感和副交感神经系统的长期影响等因素。
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