Artikel
Evaluation of the cerebrovascular pressure reactivity and optimal cerebral perfusion pressure in subarachnoid haemorrhage patients
Auswertung der zerebrovaskulären Druckreaktivität und des optimalen zerebralen Perfusionsdrucks bei subarachnoidalen Blutungspatienten
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Veröffentlicht: | 30. Mai 2008 |
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Objective: It has recently been suggested for head injured patients that cerebral perfusion pressure (CPP) should be maintained at a point where cerebrovascular pressure reactivity (PRx) is strongest. Our aim was to investigate whether a similar phenomenon of optimal CPP (CPPopt) can be seen in patients after subarachnoid haemorrhage (SAH) and how cerebral vasospasm modifies its parameters.
Methods: It is a retrospective analysis of simultaneous intracranial pressure (ICP), arterial blood pressure, transcranial doppler(TCD) medial cerebral artery flow velocities (FV) recordings obtained from patients suffering from SAH. Variables were recorded in 42 poor grade patients. Initial values were recorded during the first 48 hours in 25 patients. Paired analysis between baseline and vasospasm could be performed in 8 patients.
Results: PRx at CPPopt measured during the first 48 hours was significantly lower in the group of 16 patients that survived 3 months after the SAH than in 9 patients who died (-0.17±0.05 versus 0.1±0.09; p<0.01). Analysis of all data show that CPPopt increased from 78±3mmHg (mean±sem; N=29) during baseline (first 3 days) to 98±4mmHg (p<0.0001; N=17) when vasospasm was confirmed by TCD. No significant increase was observed between baseline and later recordings in a subgroup of patients that never reached the criteria of vasospasm (85±6mmHg; p=0.28; N=6). PRx values showed a trend towards an increase from -0.04±0.05 (N=29) to 0.1±0.06 (N=16; p=0.08). In patients followed for at least 8 days, CPPopt increased from 73±3mmHg during baseline to 99±4mmHg (p=0.002; N=8) when vasospasm was observed on TCD. The pressure reactivity measured at CPPopt worsened from PRx of -0.17±0.06 during the baseline period to 0.21±0.09 when vasospasm was confirmed (p=0.003; N=8).
Conclusions: The measurement of high PRx at optimal CPP during the first 48 hours after subarachnoid haemorrhage correlates with poor outcome. Both PRx recorded at optimal CPP and CPPopt increase with vasospasm but increase in CPPopt is more sensitive than increase in PRx.