Transcranial Doppler Pulsatility Index: What it is and What it Isn't
Transcranial Doppler Pulsatility Index: What it is and What it Isn't
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DOI：
10.1007/s12028-012-9672-6
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发表时间：
2012-08-01
影响因子：
3.5
通讯作者：
Czosnyka, Marek
中科院分区：
文献类型：
--
作者：
de Riva, Nicolas;Budohoski, Karol P.;Czosnyka, Marek
经颅多普勒（TCD）搏动指数（PI）传统上被解释为远端脑血管阻力（CVR）的描述符。我们试图评估PI和CVR在CVR增加（轻度低碳酸血症）和降低（颅内压-ICP的平台波）的情况下的关系。分析了头部外伤患者接受动脉血压（ABP）、ICP、脑灌注压（CPP）监测和TCD评估脑血流速度（FV）的记录。比较基线与ICP平台波（n = 20例）或短期（30-60 min）低碳酸血症（n = 31例）之间的Gosling搏动指数（PI）。此外，还对“频谱”PI（用FV的基波计算）进行了建模研究，得到了PI与脑血管阻抗平衡关系的理论公式，在平台波期间，PI显著增加（p < 0.001），而CVR降低（p < 0.001）。低碳酸血症时PI和CVR增加（P < 0.001）。模型公式解释了Gosling PI的65%以上的变异性和“频谱”PI的90%以上的变异性（分别为R = 0.81和R = 0.95）。TCD搏动指数可以容易和快速地评估，但通常被误解为CVR的描述符。数学模型呈现PI与多个血液动力学变量之间的复杂关系。
Transcranial Doppler (TCD) pulsatility index (PI) has traditionally been interpreted as a descriptor of distal cerebrovascular resistance (CVR). We sought to evaluate the relationship between PI and CVR in situations, where CVR increases (mild hypocapnia) and decreases (plateau waves of intracranial pressure-ICP).Recordings from patients with head-injury undergoing monitoring of arterial blood pressure (ABP), ICP, cerebral perfusion pressure (CPP), and TCD assessed cerebral blood flow velocities (FV) were analyzed. The Gosling pulsatility index (PI) was compared between baseline and ICP plateau waves (n = 20 patients) or short term (30-60 min) hypocapnia (n = 31). In addition, a modeling study was conducted with the "spectral" PI (calculated using fundamental harmonic of FV) resulting in a theoretical formula expressing the dependence of PI on balance of cerebrovascular impedances.PI increased significantly (p < 0.001) while CVR decreased (p < 0.001) during plateau waves. During hypocapnia PI and CVR increased (p < 0.001). The modeling formula explained more than 65% of the variability of Gosling PI and 90% of the variability of the "spectral" PI (R = 0.81 and R = 0.95, respectively).TCD pulsatility index can be easily and quickly assessed but is usually misinterpreted as a descriptor of CVR. The mathematical model presents a complex relationship between PI and multiple haemodynamic variables.