Brain lesion size and phase shift as an index of cerebral autoregulation in XXXX with severe head injury.

@entity1 @entity131 @entity772 @entity9623 @entity13147 @entity130
BACKGROUND: Whether the phase relationship (phase shift) between cerebral blood flow velocity as assessed by transcranial Doppler ultrasound and blood pressure at 0.1 Hz can be used to assess cerebral autoregulation (CA) in @entity1 with severe @entity131 ( @entity131 ). METHODS: In 33 healthy volunteers (mean age, SD; 37+/-17 years, range 17-65) middle cerebral artery (MCA) blood velocity (V) was recorded simultaneously with finger blood pressure (BP) over a period of 10 minutes under normocapnic and hypocapnic conditions to generate normative data. In 27 @entity1 with severe @entity131 (Glasgow @entity772 scale score < or =8) serial close in time investigations of cranial computed tomography (CT) scanning and phase shift assessment were performed on days 1, 3, 5, and 8 after @entity130 . Phase shift in the MCA was compared to brain parenchyma lesion size in the @entity9623 territory on CT scanning. Lesion size was classified into 0, normal; 1, presence of a small lesion (diameter <3 cm); 2, presence of a large lesion (>3 cm). FINDINGS: Compared to normocapnia, @entity13147 significantly increased phase shift at 0.1 Hz from 78+/-28 degrees to 101+/-25 degrees (p < 0.001). In the @entity131 @entity1 , 115 comparisons between CT findings and CA results were possible. Phase shift detected a pathological CA in 31 instances, which were more frequent in CT lesion type 2 (19/42) than in group 0 (7/44) and group 1 (5/29). INTERPRETATION: When CA is intended to be assessed by use of phase shift, the hyperventilation setting needs its own reference values. In MCA territories containing a traumatic lesion greater than 3 cm in diameter phase shift at 0.1 Hz will detect a high frequency (44%) of a disturbed state of CA.
