Targeting optimal blood pressure monitoring: what’s next?

The article “Optimal blood pressure during cardiopulmonary bypass defined by cerebral autoregulation” by Hori et al. (1) comes from a reputable group with extensive experience on intraoperative brain monitoring during cardiac surgery using continuous measurement of arterial pressure, cerebral blood velocity [transcranial Doppler (TCD)] and brain oxygenation [near-infrared spectroscopy (NIRS)] (2-7). Using the mean velocity index (Mx), a cerebral autoregulation index correlating mean arterial blood pressure (MAP) and TCD-derived middle cerebral artery (MCA) mean blood velocity, the authors sought to define the lower and upper limits of cerebral autoregulation (LLA and ULA, respectively) in 614 cardiac surgery patients undergoing cardiopulmonary bypass (CPB). They further tried to identify an “optimal-MAP” in this patient population, defining it as a MAP at which cerebral autoregulation was most performant (lowest Mx value). This current study is an extension of their previous work, incorporating patients from 3 specific cohorts