Reliability of the mean flow index (Mx) for assessing cerebral autoregulation in healthy volunteers

Abstract

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Diagnostic and prognostic performance of Mxa and transfer function analysis-based dynamic cerebral autoregulation metrics

“…33,34 Mxa, which is closely related to Mx but based on ABP rather than CPP, is in principle readily measurable, but as shown in this and previous studies, the approaches to data pre-processing and calculation of Mx and Mxa vary between studies and may affect the results. 6,17,18,35 The repeatability and reproducibility of Mxa between measurement periods and approaches range from poor to moderate; 17,18,29,36–38 one study showing excellent reliability 8 used overlapping periods, which for mathematical reasons should yield an optimal reliability. However, the data pre-processing before calculation of Mxa directly affected the results, i.e.…”

“…[18][19][20][21][22][23] Data pre-processing Recordings were extracted from LabChart (ADInstruments, Sidney, Australia) into a tabdelimited file in the original resolution of 1,000 Hz and were visually inspected for artefacts; periods with artefacts were deleted, ensuring that such periods always started and ended in a nadir. Subsequently, recordings were divided into blocks and epochs using four pre-processing approaches that have been previously reported in the literature 6,17,18 here designated 3-60-F, 6-240-F, 10-300-F, and 10-300-60. For these designations, the first number refers to the duration of each block in seconds, the second number is the duration of each epoch in seconds, and the third number is the duration of the overlaps in seconds, with F indicating an approach where overlaps were not used.…”

“…[13][14][15][16] The prognostic performance was investigated by comparing clinical outcomes for patients with sepsis and TBI. Since there is no consensus on the approach of pre-processing for Mxa, the diagnostic and prognostic performance was investigated using four pre-processing approaches that have previously been reported in the literature 6,17,18 while TFA was assessed in accordance with current recommendations. 13…”

Cerebral Autoregulation Indices Are Not Interchangeable in Patients With Sepsis

“…Fifth, we did not specifically assess the relationship of ARI or Mxa with the occurrence of brain complications, brain imaging, or mortality, and these analyses were beyond the scope of this investigation. Finally, Mxa could be highly dependent on the analytic approach (i.e., blocks, correlation periods, and overlaps of FV and BP), with a moderate repeatability ( 34 ); a recognized “gold standard” approach has not been identified yet.…”

Neuropsychiatric outcome in attempted hanging

“…Hanging also leads to ischemia, due to occlusion of blood flow and is significant in causing cerebralnecrosis. [ 2 3 ] Furthermore, there is a selective vulnerability in different brain regions to undergo hypoxic–ischemic injuries such as hippocampus, striatum, thalamus, globus pallidus, and third layer of cerebral cortex. [ 1 ] Survivors of cerebral anoxia due to suicidal hanging may present with diverse neurological deficits and psychiatric symptoms or syndromes such as acute and chronic amnestic syndromes, dementia, Korsakoff's syndrome, and even hysteria.…”