Temporary hypercapnia leads to a reproducible increase of cerebral blood flow (CBF) and brain tissue oxygenation (StiO2) as shown in a previous study (Trial-Identification: NCT01799525). The aim of this study now was to measure the course of carbon dioxide partial pressure (pCO2) reactivity after prolonged hypercapnia, and to evaluate the therapeutic effect of graded hypercapnia.
Cerebral vasospasm still is the leading cause of delayed cerebral ischemia (DCI) and secondary ischemic deficits after aneurysmal subarachnoid hemorrhage (SAH). Hypercapnia leads to a reproducible increase of cerebral blood flow (CBF) and brain tissue oxygenation (StiO2) as shown in a previous study (Trial-Identification: NCT01799525). Furthermore, the increase of CBF and StiO2 sustained after normalization of ventilation and no rebound effect was found. So, a possible optimization of the hypercapnic period may lead to prolonged effects of increased CBF and StiO2. Aim of this stuy is to find the ideal duration of hypercapnia and to evaluate the therapeutic effect of graded hypercapnia. For this, intubated and mechanically ventilated patients with an aneurysmal SAH Hunt/Hess 3-5, Fisher grade 2-4 on the initial CT scan and supplied with an external ventricular drainage will be included within the first 96 hours after ictus. Between day 4 and 14 they undergo a trial intervention in which the respiratory minute volume will be reduced in order to maintain a target PaCO2 of 50 - 55 mmHg for 2 hours. Arterial blood gas analysis (ABG) and transcranial Doppler sonography (TCD) is performed in 15-minute intervals. Intracranial pressure (ICP), cerebral perfusion pressure (CPP), and cardiovascular parameters are monitored continuously, serial measurement of CBF and StiO2 under continous hypercapnia is performed. Primary endpoint of this trial is change of CBF under hypercapnia, secondary endpoints are StiO2, measures non-invasively with near-infrared spectroscopy, mean flow velocity of intracranial vessels in TCD, delayed cerebral infarction in cranial CT and Glasgow Outcome Score (GOS) after 6 months.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
12
Temporary daily hypercapnia for 2 hours between day 4 and 14 after SAH
Cerebral blood flow (CBF)
Changes of CBF (absolute, ml/100g tissue/min) under changes of arterial pCO2
Time frame: 2-4 hours, day 4-14 after SAH
Cerebral tissue oxygen saturation
Changes of tissue oxygen saturation measured by near-infrared spectroscopy (NIRS)
Time frame: 2-4 hours, day 4-14 after SAH
Glasgow Outcome Score (GOS)
Glasgow Outcome Score (GOS 1 - 5, GOS 1 = Death, GOS 5 = none or low disability) after 14 days, after discharge and 6 months
Time frame: up to 6 months
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