Cerebral autoregulation in the hyperacute phase after experimental subarachnoid haemorrhage using an endovascular perforation model

Brain Communications, vol. 8, pp. fcag356

Abstract

Abstract Impaired cerebral blood flow contributes to delayed neurological deficits after subarachnoid haemorrhage, but cerebral autoregulation, which regulates cerebral blood flow to the brain in the hyperacute phase is poorly defined. We characterized early pressure- and flow-based reactivity in a rat subarachnoid haemorrhage perforation model. This is a retrospective analysis of older data acquired to investigate a different hypothesis. Male Sprague–Dawley rats underwent endovascular perforation subarachnoid haemorrhage. Arterial blood pressure, intracranial pressure and bilateral laser Doppler flow were continuously recorded. Pressure reactivity (PRx*) and flow reactivity (LDx*) were calculated as 5-min moving Pearson correlations between arterial and intracranial pressure and arterial pressure and laser Doppler flowmetry, respectively. Exposure above impairment thresholds (PRx* > 0.3; LDx* > 0.5) was compared pre-subarachnoid haemorrahge (−30–0 min) versus post-subarachnoid haemorrhage (15–60 min) and related to haemorrhage severity. Group-mean PRx* and LDx* remained below impairment thresholds. Nevertheless, time with PRx* > 0.3 increased after subarachnoid haemorrhage (median 0.0% versus 1.9%, P < 0.001) and correlated with intracranial pressure elevation (r = 0.527, P < 0.001). LDx* showed no significant pre–post change in either hemisphere. PRx* and LDx* correlated weakly (r = 0.089, P < 0.001) with frequent discordance. Cerebral autoregulation is largely preserved within 60 min after subarachnoid haemorrhage, with transient pressure–reactivity impairment in a subset linked to intracranial pressure peaks. Pressure- and flow-based indices provide non-interchangeable information.

Authors 6

1. Michael Veldeman corresponding Aachen Department of Neurosurgery

   RWTH Aachen University · Universitätsklinikum Aachen · University of Cambridge

   Affiliation as printed

   Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge , Hills Rd, Cambridge CB2 0QQ.  

   Department of Neurosurgery, Rheinisch-Westfälische Technische Hochschule, Aachen University Hospital , 52074 Aachen ,

2. Erta Beqiri

   University of Cambridge

   Affiliation as printed

   Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge , Hills Rd, Cambridge CB2 0QQ.  

3. Marek Czosnyka

   University of Cambridge

   Affiliation as printed

   Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge , Hills Rd, Cambridge CB2 0QQ.  

4. Mark Coburn

   University Hospital Bonn

   Affiliation as printed

   Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn , 53127 Bonn ,

5. Anke Höllig Aachen Department of Neurosurgery

   RWTH Aachen University · Universitätsklinikum Aachen

   Affiliation as printed

   Department of Neurosurgery, Rheinisch-Westfälische Technische Hochschule, Aachen University Hospital , 52074 Aachen ,

6. Peter Smielewski

   University of Cambridge

   Affiliation as printed

   Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge , Hills Rd, Cambridge CB2 0QQ.