Clinical implications and feasibility of cerebral autoregulation-based precision blood pressure monitoring in major noncardiac surgery: A protocol for AUTOREGULATE-NONCARDIAC, a multicentre prospective cohort study and peri-operative precision medicine platform.

Background Peri-operative hypotension is strongly associated with organ injury following noncardiac surgery, however hypotension avoidance trials have not shown meaningful improvements in cardiovascular outcomes and only inconsistent improvements in renal and neurological outcomes. The true haemodynamic drivers of peri-operative organ injury are probably falls in BP below individual autoregulatory boundaries and not below population-based harm thresholds. Novel methods of personalising peri-operative blood pressure (BP) management are needed. Cerebral autoregulation (cAR)-guided precision BP monitoring is an established paradigm that uses near-infrared spectroscopy (NIRS) to noninvasively estimate the safe BP range for the brain and potentially other vital organs. We aim to assess the feasibility and clinical implications of cAR-based precision BP monitoring in major noncardiac surgery. Objectives To investigate the association of intra-operative BP excursions below the lower level of cerebral autoregulation, and other measures of disturbed cerebral autoregulatory function, with the primary and secondary outcomes, to determine the feasibility of cAR-based precision BP monitoring in noncardiac surgery. Design Multicentre, prospective cohort study. Setting 3 Swiss tertiary care centres. Patients Inclusion criteria: Adults ≥45 years of age, at cardiovascular risk, undergoing elective major noncardiac surgery with invasive BP monitoring, surgical time ≥90 min, postoperative hospital stay ≥1 night. Exclusion criteria include pregnancy, emergency or urological surgery, glomerular filtration rate <30 ml min-1, dialysis. Primary Outcome Measures Composite of peri-operative myocardial injury and/or peri-operative acute kidney injury on postoperative days 1 to 3.Secondary Outcomes Composite of major cardiovascular, renal and neurological complications up to 1 year following surgery: acute coronary syndrome, acute congestive heart failure, coronary revascularisation, stroke, new or progressive chronic kidney disease, new need for renal replacement therapy, all-cause mortality, cardiovascular mortality. Results N/A. Conclusions N/A. Trial Registration Association of Intraoperative Blood Pressure Excursions Below Cerebral Autoregulatory Boundaries With Organ Injury Following Major Noncardiac Surgery (AUTOREGULATE-NONCARDIAC), Clinicaltrials.gov NCT05336864. registered 13/04/2022.