Impact of Intraoperative Fluctuations of Cardiac Output on Cerebrovascular Autoregulation: An Integrative Secondary Analysis of Individual-level Data

Background: Intraoperative impairment of cerebral autoregulation (CA) has been associated with perioperative neurocognitive disorders. We investigated whether intraoperative fluctuations in cardiac index are associated with changes in CA. Methods: We conducted an integrative explorative secondary analysis of individual-level data from 2 prospective observational studies including patients scheduled for radical prostatectomy. We assessed cardiac index by pulse contour analysis and CA as the cerebral oxygenation index (COx) based on near-infrared spectroscopy. We analyzed (1) the cross-correlation between cardiac index and COx, (2) the correlation between the time-weighted average (TWA) of the cardiac index below 2.5 L min(-1) m(-2), and the TWA of COx above 0.3, and (3) the difference in areas between the cardiac index curve and the COx curve among various subgroups. Results: The final analysis included 155 patients. The median cardiac index was 3.16 [IQR: 2.65, 3.72] L min(-1) m(-2). Median COx was 0.23 [IQR: 0.12, 0.34]. (1) The median cross-correlation between cardiac index and COx was 0.230 [IQR: 0.186, 0.287]. (2) The correlation (Spearman rho) between TWA of cardiac index below 2.5 L min(-1) m(-2) and TWA of COx above 0.3 was 0.095 (P=0.239). (3) Areas between the cardiac index curve and the COx curve did not differ significantly among subgroups (<65 vs. >= 65 y, P=0.903; 0 vs. >= 1 cardiovascular risk factors, P=0.518; arterial hypertension vs. none, P=0.822; open vs. robot-assisted radical prostatectomy, P=0.699). Conclusions: We found no meaningful association between intraoperative fluctuations in cardiac index and CA. However, it is possible that a potential association was masked by the influence of anesthesia on CA.