Increased risk of critical CBF levels in SAH patients with actual CPP below calculated optimal CPP
(English)In: Journal of Neurosurgical Anesthesiology, ISSN 0898-4921, E-ISSN 1537-1921Article in journal (Other academic) Submitted
Background: The ability to keep an even cerebral blood flow (CBF) during variations in systemic arterial blood pressure (MAP) is termed cerebral pressure autoregulation (CPA). Pressure reactivity index (PRx) is an established measure of CPA. Using PRx optimal CPP (CPPopt) can be calculated, i.e. the level of CPP where autoregulation functions best. CPPopt has not been extensively studied in patients with subarachnoid haemorrhage, and the relation between cerebral blood flow (CBF) and CPPopt has not been examined. The objective was to assess to which extent CPPopt can be calculated in SAH patients and to investigate CPPopt in relation to CBF.
Methods: Retrospective study of prospectively collected data. CBF was measured bedside with Xenon-enhanced CT (Xe-CT). The difference between actual CPP and CPPopt was calculated (CPP∆). Correlations between CPP∆ and CBF parameters were calculated with Spearman's rank order correlation. Separate calculations were done using all patients (day 0-14 after onset) as well as in two subgroups (day 0-3 and day 4-14).
Results: 64 patients were studied. CPPopt could be calculated in adjunct to 60 % of the Xe-CT scans (78% of the patients). Actual CPP < CPPopt was associated with higher amounts of low-flow regions (CBF < 10 ml / 100g ml) both in the early phase (day 0-3, p= 0.02) and the late acute phase (day 4-14, p = 0.02)
Conclusions: Calculation of CPPopt is possible in a majority of SAH patients. Actual CPP below CPPopt is associated with low CBF.
cerebral blood flow, autoregulation, CPP, subarachnoid haemorrhage
Research subject Neurosurgery
IdentifiersURN: urn:nbn:se:uu:diva-294191OAI: oai:DiVA.org:uu-294191DiVA: diva2:972566