The role of echocardiographic volume parameters in predicting post-induction hypotension in geriatric patients under general anesthesia: a retrospective study

Post-induction hypotension (PIH), a common hemodynamic disturbance during anesthesia induction, is associated with increased postoperative complications, particularly in elderly patients. While the etiology of PIH is multifactorial and prediction remains challenging, preoperative transthoracic echocardiography (TTE) offers a quantitative assessment of cardiac structure and function. However, the predictive utility of preoperative TTE parameters specifically for PIH occurrence is not well established. Therefore, this study aimed to investigate the incidence of PIH in elderly patients undergoing urological surgery and the incremental predictive value of using preoperative TTE parameters to predict PIH. This retrospective cohort study included geriatric patients aged 65 to 95 who underwent urological surgery under general anesthesia from December 2015 to July 2020. Patients were randomly assigned to training (n = 1100) and validation (n = 450) cohorts. The training cohort was further divided into non-PIH and PIH groups. Univariate and multivariate logistic regression analyses identified independent predictors of PIH, which were incorporated into a nomogram. Model performance was evaluated using receiver operating characteristic (ROC) curves, with discrimination assessed by the area under the curve (AUC). Calibration was evaluated by internal (training cohort) and external (validation cohort) validation. Demographic characteristics were comparable between the training and validation cohorts (p > 0.05). PIH occurred in the training cohort’s 37.4% (411/1100). Six independent predictors of PIH were identified. Three of them were continuous variables: decreased stroke volume (SV, OR: 0.976, 95%CI 0.965–0.986, p < 0.001), elevated pre-induction heart rate (aHR, OR: 1.016, 95% CI 1.004–1.027, p = 0.008), lower pre-induction systolic blood pressure (aSBP, OR: 0.973, 95%CI 0.966—0.980, p < 0.001); and three of them were categorical variables: operation type, operation position and anesthesia maintenance. Compared with transurethral surgery, the open surgery (OR: 2.522, 95%CI 1.065–5.970) has less PIH(p = 0.021). Compared with the supine position, the lithotomy position (OR: 0.581, 95%CI 0.408–0.827) had more PIH(p = 0.008). Compared with other maintenance anesthetics, the isoflurane group had more PIH(p = 0.032). The model demonstrated moderate discrimination, with an AUC of 0.701 (c-index 0.701) in the training cohort and 0.654 (c-index 0.669) in the validation cohort. Calibration plots showed good agreement between predicted and observed PIH probabilities in both cohorts. This study identifies stroke volume (SV), a volumetric parameter derived from preoperative transthoracic echocardiography (TTE), as a novel and independent predictor of post-induction hypotension (PIH) in geriatric populations. Alongside established hemodynamic parameters [pre-induction heart rate (aHR) and systolic blood pressure (aSBP)] and procedure-related factors (operation style, operation position, and anesthetic maintenance), SV contributes to the prediction of PIH. These findings suggest that preoperative TTE assessment, particularly SV measurement, in combination with standard clinical parameters, may hold potential clinical significance for perioperative risk stratification in this population. Further investigation is warranted to explore the role of advanced hemodynamic indices in optimizing perioperative care for older adults.