应用过度换气指数评价脑血管反应性  

Application of hyperventilation index for assessing cerebrovascular reactivity

作　　者：马欣[1] 华扬[2] 凌晨[2] 

机构地区：[1]首都医科大学宣武医院神经内科,北京100053 [2]首都医科大学宣武医院超声诊断科,北京100053

出　　处：《中国脑血管病杂志》2007年第11期505-508,共4页Chinese Journal of Cerebrovascular Diseases

摘　　要：目的探讨在过度换气试验中,应用过度换气指数（HVI）评价脑血管反应性（CVR）的可行性。方法选择37名健康体检者,采用自身配对设计,应用TCD监测屏气试验及过度换气试验前、后的双侧MCA平均血流速度。计算屏气时间及过度换气时间均为10^-30s时的屏气指数（BHI）、过度换气流速下降率（HVR）;建立包含时间因素的过度换气指数（HVI）计算公式,HVI=（静息状态平均血流速度-过度换气后平均血流速度）×100/（静息状态平均血流速度×过度换气秒数）。以BHI为标准,评价以HVI反映CVR的可行性。结果①过度换气时间30s以内,MCA血流速度变化随时间延长呈线性降低,30s后进入平台期。②HVI为1.48±0.24,BHI为1.47±0.27,两者差异无统计学意义（P=0.84）,且呈正相关（r=0.72,P=0.00）,回归方程为Y（BHI）=0.000＋0.984X（HVI）。HVR为（30.3±5.5）%,与HVI具有相关性（r=0.536,P=0.00）,但与BHI无相关性（r=0.07,P=0.34）。结论过度换气及屏气时间为10^-30s时,运用HVI及BHI作为评价CVR的指标具有相同的临床意义。　Objective To investigate the application of hyperventilation index （HVI） for assessing the feasibility of cerebrovascular reactivity （CVR） in the hyperventilation test.Methods Thirty-seven healthy persons were selected by using a self-paired design. Before and after breath-holding test and hyperventilation test, the mean flow velocity of bilateral middle cerebral artery （MCA） were monitored by TCD. When breath-holding time and hyperventilation time were 10-30 seconds, breath-holding index （BHI） and hyperventilation ratio of reduction in velocity（HVR） were calculated. The calculation formula of HVI was established as HVI=（[rest mean flow velocity-mean flow velocity after ventilation]/rest mean flow velocity） ×100/ventilation time. By using BHI as a standard to assess the feasibility of HVI for reflection of CVR.Results The duration of hyperventilation was within 30 seconds. The chages of MCA blood-flow velocity was reduced linearly with the prolonged time, and they entered to a plateau phase after 30 seconds. The HVI was 1.48±0.24 and the BHI was 1.47±0.27, These was no statistical significance difference（P=0.84） but had a positive correlation between them（r=0.72,P=0.00）. The regression equation was Y（BHI）=0.000＋0.984X（HVI）. The HVR was 30.3±5.5%, it had a correlation with HVI （r=0.536, P=0.00）, but had no correlation with BHI （r=0.07, P=0.34）.Conclusion The hyperventilation time and breath-holding time are 10-30 s. The use of HVI and BHI as indicators for assessing CVR has the same clinical significance.

关 键 词：大脑中动脉 血流速度 屏气试验 过度换气试验 脑血管反应性 

分 类 号：R445.1[医药卫生—影像医学与核医学]