Short-term deceleration capacity of heart rate predicts post-induction hypotension in patients with low ASA status: a prospective observational study

Background: Autonomic dysfunction is a risk factor for hypotension after anesthesia induction. Deceleration capacity of heart rate (DC) is a new method to evaluate autonomic function. This prospective observational study was designed to evaluate whether the deceleration capacity of heart rate measured by a 5-minute preoperative Electrocardiogram (ECG) can reliably predict post-induction hypotension (PIH). Methods: Patients aged 18 to 65 undergoing elective surgery with lower ASA status I or II were included in this study. DC, root mean square density (RMSSD) and low frequency/high frequency ratio (LF/HF) were calculated from 5-minute segments of ECG measured in the quiet state before surgery. PIH was defined as mean arterial pressure (MAP) <65mmHg or a decrease of >30% for at least 1 minute from induction of anesthesia to 10 minutes after tracheal intubation. Patients were divided into PIH and non-PIH groups according to whether they developed PIH or not. Results: A total of 141 patients were enrolled in this study, of whom 63 (44.7%) presented with PIH. The RMSSD ( p = 0.036) and DC ( p < 0.001) of the PIH group were smaller, and the LF/HF was higher ( p = 0.039). After adjusting for confounding factors (Model 2), DC was identified as an independent predictor of PIH (Odds Ratio: 0.377). The receiver operating characteristic (ROC) analysis showed that DC had a good diagnostic value as a predictor (AUC: 0.777; 95%CI: 0.705-0.909; p < 0.001). Conclusions: These results suggest that DC measured in 5 minutes is a reliable predictor of PIH in individuals of ASA I-II status undergoing elective surgery. Trial registration: Chinese Clinical Trial Registry, identifier: ChiCTR2400094595, Date: 25/12/2024.