title: Hemodynamic Disturbances in the Early Phase After Subarachnoid Hemorrhage: Regional Cerebral Blood Flow Studied by Bedside Xenon-enhanced CT.
abstract: BACKGROUND
  The mechanisms leading to neurological deterioration and the devastating course of delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH) are still not well understood. Bedside xenon-enhanced computerized tomography (XeCT) enables measurements of regional cerebral blood flow (rCBF) during neurosurgical intensive care. In the present study, CBF characteristics in the early phase after severe SAH were explored and related to clinical characteristics and early clinical course outcome.
  
  
  METHODS
  Patients diagnosed with SAH and requiring mechanical ventilation were prospectively enrolled in the study. Bedside XeCT was performed within day 0 to 3.
  
  
  RESULTS
  Data from 64 patients were obtained. Median global CBF was 34.9 mL/100 g/min (interquartile range [IQR], 26.7 to 41.6). There was a difference in CBF related to age with higher global CBF in the younger patients (30 to 49 y). CBF was also related to the severity of SAH with lower CBF in Fisher grade 4 compared with grade 3. rCBF disturbances and hypoperfusion were common; in 43 of the 64 patients rCBF<20 mL/100 g/min was detected in more than 10% of the region-of-interest (ROI) area and in 17 patients such low-flow area exceeded 30%. rCBF was not related to the localization of the aneurysm; there was no difference in rCBF of ipsilateral compared with contralateral vascular territories. In patients who initially were in Hunt & Hess grade I to III, median global CBF day 0 to 3 was significantly lower for patients who were in poor neurological state at discharge compared with patients in good neurological state, 25.5 mL/100 g/min (IQR, 21.3 to 28.3) versus 37.8 mL/100 g/min (IQR, 30.5 to 47.6).
  
  
  CONCLUSIONS
  CBF disturbances are common in the early phase after SAH. In many patients, CBF was heterogenic and substantial areas with low rCBF were detected. Age and CT Fisher grade were factors influencing global cortical CBF. Bedside XeCT may be a tool to identify patients at risk of deteriorating so they can receive intensified management, but this needs further exploration.
authors.affiliation: Departments of Neuroscience/Neurosurgery.|Surgical Sciences/Anesthesia and Intensive care.
authors.forename: Henrik
authors.initials: H
authors.lastname: Engquist
authors.affiliation: Departments of Neuroscience/Neurosurgery.
authors.forename: Anders
authors.initials: A
authors.lastname: Lewén
authors.affiliation: Departments of Neuroscience/Neurosurgery.
authors.forename: Tim
authors.initials: T
authors.lastname: Howells
authors.affiliation: Departments of Neuroscience/Neurosurgery.|Surgical Sciences/Radiology, Uppsala University, Uppsala, Sweden.
authors.forename: Ulf
authors.initials: U
authors.lastname: Johnson
authors.affiliation: Departments of Neuroscience/Neurosurgery.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Ronne-Engström
authors.affiliation: Departments of Neuroscience/Neurosurgery.
authors.forename: Pelle
authors.initials: P
authors.lastname: Nilsson
authors.affiliation: Departments of Neuroscience/Neurosurgery.
authors.forename: Per
authors.initials: P
authors.lastname: Enblad
authors.affiliation: Departments of Neuroscience/Neurosurgery.
authors.forename: Elham
authors.initials: E
authors.lastname: Rostami
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D002560:Cerebrovascular Circulation; D003287:Contrast Media; D005260:Female; D007839:Functional Laterality; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000209:etiology / Q000503:physiopathology; D011446:Prospective Studies; D013345:Subarachnoid Hemorrhage / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014978:Xenon
chemical_list: D003287:Contrast Media; D014978:Xenon