The association between preoperative baroreflex sensitivity and post-induction hypotension in elderly patients: a prospective cohort study

Backgrounds: Post-induction hypotension (PIH) is prevalent in elderly patients and associated with postoperative mortality and severe complications. Cardiovascular autonomic nerves are a critical part of blood pressure homeostasis and are believed to be closely related to intraoperative blood pressure fluctuations. Perioperative baroreflex sensitivity (BRS) measurement can help evaluate patients’ autonomic function. This study aims to determine the association between decreased baroreflex function in elderly patients and PIH. Methods: The study prospectively enrolled patients over 65 years old undergoing elective non-cardiac surgery under general anesthesia. In addition to routine baseline assessments, blood pressure was monitored using continuous non-invasive arterial pressure (CNAP) devices, and BRS and baroreflex effectiveness index (BEI) were calculated from blood pressure records. The primary outcome of the study was PIH, with secondary outcomes including early intraoperative hypotension and postoperative complications. Results: PIH occurred in 57.5% (n = 96) of the cohort. PIH patients had significantly lower BRS + (6.97 ± 3.50 vs 11.85 ± 6.39, p<0.001), BRS- (7.46 ± 5.21 vs 11.21 ± 6.33, p<0.001), BEI + (21.4 ± 13.9% vs 26.7 ± 15.1%, p = 0.032), and BEI- (21.0 ± 13.2% vs 30.4 ± 17.6%, p<0.001) compared to non-PIH patients. In multivariate analysis, both BRS + and BRS- were correlated with PIH (coefficients 0.820 and 0.878, respectively; both p<0.001). The AUC for predicting PIH using BRS + was 0.747. A significant interaction between BRS + and anesthetic agents was found (p for interaction = 0.022) in subgroup analysis. Conclusions: The occurrence of PIH in elderly patients is associated with a decline in baroreflex sensitivity. Measurement of BRS using CNAP devices can effectively evaluate perioperative autonomic nervous function.