A major limitation of the field is the lack of a gold standard for assessment of cerebral blood flow autoregulation (CA). In the meeting of 6th July 2011, a proposal was discussed as a starting point of an international collaborative project on sharing data and analytical techniques with the objective of improving the reliability and developing multi-centre agreement on recommendations for estimates of dynamic CA.
The current literature on dynamic CA shows considerable diversity of analytical techniques, such as transfer function analysis, ARI, Mx and Px indices, neural networks, ARMA modelling, multi-modal pressure-flow, and others. Combined with the different protocols that have been used for assessment of CA (spontaneous fluctuations, thigh cuff manouevres, changes in posture, synchronised breathing, lower-body negative pressure, etc.) and the many different biological factors that can influence CA (posture, blood gases, temperature, sympathetic activity, CMRO2, pathology, etc.) this methodological diversity does not facilitate translation of CA studies to routine clinical use. Furthermore, we currently do not have sufficient evidence from comparisons of methods to support general recommendations for specific experimental protocols and analysis methods. To address this issue, the proposal would involve:
The CARNet committee will soon be inviting demonstrations of interest for participation in this project.