Artikel
Arteriovenous differences and transcranial doppler sonography in the monitoring of cerebral vasospasm after aneurysmal subarachnoid hemorrhage
Arteriovenöse Differenzen und transkranielle Dopplersonographie beim Monitoring des zerebralen Vasospasmus nach aneurysmatischer Subarachnoidalblutung
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Autoren
Veröffentlicht: | 4. Mai 2005 |
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Gliederung
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Objective
After subarachnoid hemorrhage (SAH) the detection of hemodynamically significant vasospasm is frequently difficult especially in comatose patients. Most clinicians use transcranial Doppler sonography (TCD) to detect increasing mean blood flow velocities of the basal arteries as marker of cerebral vasospasm without accounting for the effects of sedation and variations in blood pressure or PaCO2. This study was conducted to test the hypothesis that the arteriovenos difference for oxygen (avDO2) is equally usefull for the evaluation of vasospasm than TCD.
Methods
A total of 15 SAH patients (m:f = 1:1.1, age 54.5±12.2 years, median Hunt & Hess 4) were prospectively enrolled. All patients were sedated with standardized continuous doses of midazolam and fentanyl. TCD studies and avDO2 were conducted at the same time or in close proximity. The blood flow velocity of the middle cerebral artery was recorded. A cranial CT was conducted if the avDO2 increased by at least 0.8 Vol%.
Results
Overall 54 measurements were recorded in 15 patients between Day 1 and 13 after SAH. Between Day 3 and 10 a total of 16 studies showed a mean increase in avDO2 by 1.23±1 vol% while TCD velocities remained either unchanged, increased or decreased. In all cases where CT studies were prompted vasospasm related hypodensities were seen.
Conclusions
TCD velocities alone are a poor parameter to follow the severity of vasospasm. In contrast, the daily avDO2 seemed to be more robust for the monitoring. However, additional metabolic information is warranted.