Respiratory Variation of Velocity Time Integral and Peak Velocity of Left Ventricular Outflow Tract for Predicting Hypotension After Induction of General Anesthesia in Elderly Patients

Background : Hypotension after induction of general anesthesia may lead to severe complications in elderly patients. This study investigated whether the respiratory variation of velocity time integral (ΔVTI) and peak velocity (ΔVpeak) of left ventricular outflow tract (LVOT) could predict hypotension after induction of general anesthesia in elderly patients. Methods : 120 elderly patients undergoing selective operation under general anesthesia were enrolled in this study. ΔVTI and ΔVpeak of LVOT were measured by transthoracic echocardiography before induction of general anesthesia. After induction, mean arterial pressure (MAP) was recorded every 1 min for 15 min. Hypotension was defined as a decrease of more than 30% in MAP at baseline or MAP below 65 mmHg from the start of induction. Receiver operating characteristic curves with gray zone and multivariate logistic regression analysis were used to assess the ability of ΔVTI and ΔVpeak of LVOT to predict hypotension after induction of general anesthesia. Results : Hypotension occurred in 64 (53.3%) patients after induction of general anesthesia. The area under receiver operating characteristic curves (AUC) for δVpeak of LVOT to predict hypotension after induction of general anesthesia was 0.811, and the optimal cutoff value was 13.1% with a gray zone of 9.9% to 13.8%, including 45.0% of patients. The AUC for ΔVTI of LVOT was 0.890, and the optimal cutoff value was 13.8% with a gray zone of 11.1% to 13.9%, including 25.8% of patients. After adjusting for confounders, ΔVTI (Odds ratio = 2.24) and ΔVpeak (Odds ratio = 2.09) of LVOT were two significant independent predictors of hypotension after induction of general anesthesia. Conclusions : ΔVTI of LVOT was a reliable predictor of hypotension after the induction of general anesthesia in elderly patients. ΔVpeak of LVOT should be used cautiously to predict hypotension after induction of general anesthesia due to nearly half of elderly patients in the gray zone. Trial registration : This study was registered in the Chinese Clinical Trial Registry (registration number: ChiCTR2300077117).