Department of Neurosurgery, University of Geneva Medical Center, Geneva, Switzerland.
Neurocrit Care. 2010 Apr;12(2):225-33. doi: 10.1007/s12028-009-9300-2.
We examined a bedside technique transcerebral double-indicator dilution (TCID) for global cerebral blood flow (CBF) as well as the concept of effective cerebral perfusion pressure (CPP(eff)) during different treatment options for intracranial hypertension, and compared global CBF and CPP(eff) with simultaneously obtained conventional parameters.
Twenty-six patients developing intracranial hypertension in the course of traumatic brain injury or subarachnoid hemorrhage were prospectively analyzed using a combined assessment during elevated ventilation (n = 15) or osmotherapy (hypertonic saline or mannitol). For calculation of global CBF, injections of ice-cold indocyanine green boluses were performed and temperature and dye concentration changes were monitored in the thoracic aorta and the jugular bulb. CBF was then calculated according to the mean transit time principle. Estimation of CCP, the arterial pressure at which cerebral blood flow becomes zero, was performed by synchronized registration of corresponding values of blood flow velocity in the middle cerebral artery and arterial pressure and extrapolation to zero-flow velocity. CPP(eff) was calculated as mean arterial pressure minus critical closing pressure (CPP(eff) = MAP(c) - CCP).
Elevated ventilation causes a decrease in both ICP (P < 0.001) and CBF (P < 0.001). While CPP(conv) increased (P < 0.001), CPP(eff) decreased during this observation (P = 0.002). Administration of osmotherapeutic agents resulted in a decrease of ICP (P < 0.001) and a temporary increase of CBF (P = 0.052). CPP(conv) and CPP(eff) showed no striking difference under osmotherapy.
TCID allows repeated measurements of global CBF at the bedside. Elevated ventilation lowered and osmotherapy temporarily raised global CBF. In situations of increased vasotonus, CPP(eff) is a better indicator of blood flow changes than conventional CPP.
我们研究了一种床边经颅双指示剂稀释（TCID）技术，用于测量颅内高压患者的全脑血流（CBF）以及有效脑灌注压（CPP（eff）），并将全脑 CBF 与同时获得的常规参数进行了比较。
对 26 例创伤性脑损伤或蛛网膜下腔出血患者在颅内压升高期间进行前瞻性分析，采用升压治疗（n = 15）或渗透性治疗（高渗盐水或甘露醇）的联合评估。为了计算全脑 CBF，进行了冰冷吲哚菁绿 bolus 注射，并在胸主动脉和颈静脉球监测温度和染料浓度变化。然后根据平均传输时间原理计算 CBF。通过同步记录大脑中动脉血流速度和动脉压的相应值，并外推至零流速，来估计 CCP，即脑血流为零时的动脉压。CPP（eff）计算为平均动脉压减去临界关闭压（CPP（eff）= MAP（c）- CCP）。
升压治疗可降低 ICP（P < 0.001）和 CBF（P < 0.001）。CPP（conv）升高（P < 0.001），CPP（eff）降低（P = 0.002）。渗透性治疗导致 ICP 降低（P < 0.001）和 CBF 暂时升高（P = 0.052）。CPP（conv）和 CPP（eff）在渗透性治疗下无明显差异。
TCID 可在床边重复测量全脑 CBF。升压治疗降低全脑 CBF，渗透性治疗暂时升高全脑 CBF。在血管紧张度增加的情况下，CPP（eff）比常规 CPP 更能反映血流变化。
