Carotid blood flow changes following a simulated end-inspiratory occlusion maneuver measured by ultrasound can predict hypotension after the induction of general anesthesia: an observational study.

BACKGROUND: The primary purpose of this study was to investigate the predictive value of alterations in cervical artery hemodynamic parameters induced by a simulated end-inspiratory occlusion test (sEIOT) measured by ultrasound for predicting postinduction hypotension (PIH) during general anesthesia.

METHODS: Patients undergoing gastrointestinal tumor resection under general anesthesia were selected for this study. Ultrasound has been utilized to assess hemodynamic parameters in carotid artery blood flow before induction, specifically focusing on variations in corrected flow time (ΔFTc) and peak blood flow velocity (ΔCDPV), both before and after sEIOT. Anesthesia was induced by midazolam, sufentanil, propofol, and rocuronium, and blood pressure (BP) and heart rate (HR) were recorded within the first 10 min following endotracheal intubation. PIH was defined as fall in systolic blood pressure (SBP) or mean arterial pressure (MAP) by > 30% of baseline or MAP to < 60 mm Hg.

RESULTS: The area under the receiver operating characteristic curves (AUC) for carotid artery ΔFTc was 0.88 (95%CI, 0.81 to 0.96; P < 0.001), and the optimal cutoff value was -16.57%, with a sensitivity of 91.4% and specificity of 77.60%. The gray zone for carotid artery ΔFTc was -16.34% to -15.36% and included 14% of the patients. The AUC for ΔCDPV was 0.54, with an optimal cutoff value of -1.47%. The sensitivity and specificity were calculated as 55.20% and 57.10%, respectively.

CONCLUSION: The corrected blood flow time changes in the carotid artery induced by sEIOT can predict hypotension following general anesthesia-induced hypotension, wherein ΔFTc less than 16.57% is the threshold.

TRIAL REGISTRATION: Chinese Clinical Trial Registry ( www.chictr.org.cn ; 20/06/2023; ChiCTR2300072632).