Exploring the predictive value of carotid Doppler ultrasound and clinical features for spinal anesthesia-induced hypotension: a prospective observational study

BACKGROUND: The induction of spinal anesthesia is often followed by hypotension, which has been associated with post-operative end-organ damage. A timely prediction of spinal anesthesia-induced hypotension (SAIH) paired with appropriate interventions may reduce the risk of adverse outcomes. This study investigated the value of carotid Doppler ultrasound measurements and clinical variables, both individually and combined, to predict SAIH.

METHODS: Adult patients who were scheduled for elective surgery under spinal anesthesia were included. Carotid ultrasound imaging and baseline vital sign measurements were performed pre-operatively, well in advance of the induction of spinal anesthesia. The occurrence of hypotension was observed for ten minutes after the induction of spinal anesthesia. Logistic regression models studied linear relationships within the derived set of ultrasound and clinical features, and support vector machine models evaluated nonlinear relationships.

RESULTS: A total of 40 patients were included, and 45% of them developed SAIH. The logistic regression models performed better than the support vector machine models. The best-performing logistic regression model combined carotid ultrasound and clinical features and had a sensitivity of 75 [73-81]%, specificity of 75 [71-81]%, AUROC of 0.81 [0.75-0.95], positive predictive value of 75 [65-81]%, negative predictive value of 75 [71-88]% and F1 score of 0.75 [0.71-0.76]. The key features that were shown to predict SAIH were baseline mean arterial pressure, fasting time, ASA class, and weight.

CONCLUSIONS: Combining carotid Doppler ultrasound measurements and clinical variables can predict the occurrence of SAIH.

TRIAL REGISTRATION: The study was retrospectively registered at clinicaltrials.gov (NCT06711289) on 2 December 2024.