Observation of hemodynamic parameters using a non-invasive cardiac output monitor system to identify predictive indicators for post-spinal anesthesia hypotension in parturients undergoing cesarean section

The administration of high-level spinal anesthesia for cesarean section may lead to significant hemodynamic changes. Bioreactance-based non-invasive cardiac output monitoring (NICOM™) provides an accurate monitoring system for parturients under spinal anesthesia. The present study hypothesized that baseline hemodynamic parameters obtained via the NICOM™ system could serve as predictive indicators for post-spinal anesthesia hypotension. Therefore, 80 full-term parturients with singleton pregnancies who underwent scheduled cesarean section were enrolled and allocated to either a supine position group or a 15˚ left tilt group. All parturients received standard pre-hydration with 750 ml of 0.9% saline. Baseline cardiac output index (CI), total peripheral resistance index (TPRI) and stroke volume (SV) were recorded using the NICOM™ system. Subsequently, spinal anesthesia with 2.4 ml of 0.5% hyperbaric bupivacaine, 10 µg of fentanyl and 0.2 mg of morphine was administered. Receiver operating characteristic (ROC) curves and multivariate logistic regression were used to analyze the data. A total of 40 parturients (51.9%) developed hypotension. The areas under the ROC curves were 0.666, 0.594 and 0.622 for the CI, TPRI and SV, respectively. The optimal cut-off value of the CI in predicting hypotension was 3.68 l/min/m2 (ROC, sensitivity=85.0%, specificity=48.6%). Furthermore, CI was considered as an independent factor for post-spinal anesthesia hypotension. In conclusion, the baseline CI obtained via the bioreactance-based NICOM™ system may serve as a predictor of post-spinal anesthesia hypotension in parturients regardless of patient position.