Background: Post-spinal anesthesia hypotension during cesarean delivery is caused by decreased systemic vascular resistance due to the blockage of autonomic nerves, which is further worsened by aortocaval compression by the gravid uterus. The aim of this study was to assess whether peak velocities and diameters of the abdominal aorta (AA) and inferior vena cava (IVC) below the xiphoid or the right common femoral artery (RCFA) and right common femoral vein (RCFV) in the inguinal region, as measured on ultrasound, could reflect the degree of aortocaval compression and further identify parturients at risk of post-spinal hypotension.Methods: After ultrasound measurement of peak velocities and anteroposterior diameters of the AA, and IVC and peak velocities and transverse diameters of the RCFA and RCFV before anesthesia, 56 parturients undergoing elective cesarean section with spinal anesthesia were enrolled in this study. Multinomial logistic regression analysis was used to identify the risk factors for post-spinal hypotension during cesarean delivery. Receiver operating characteristic curves were used to test the abilities of the identified parameters to predict post-spinal hypotension, and the areas under the curve and the optimum cut-off values for the predictive parameters were calculated. Results: The transverse diameter of the RCFV was a risk factor for post-spinal hypotension (odds ratio = 2.022, 95% confidence interval [CI] 1.261–3.243). The area under the receiver operating characteristics curve for the prediction of post-spinal hypotension was 0.759 (0.628–0.890; P = 0.001). A transverse diameter of the RCFV longer than 12.2 mm could predict post-spinal hypotension during cesarean delivery. Conclusions: We demonstrated a higher transverse RCFV diameter was associated with hypotension and it could effectively predict parturients at risk of hypotension before anesthesia. Trial Registration: This study was registered at http://www.chictr.org.cn on 16, May, 2018. No. ChiCTR1800016163

Background: Post-spinal anesthesia hypotension during cesarean delivery is caused by decreased systemic vascular resistance due to the blockage of autonomic nerves, which is further worsened by inferior vena cava (IVC) compression by the gravid uterus. The aim of this study was to assess whether peak velocity and diameter of IVC below the xiphoid or the right common femoral vein (RCFV) in the inguinal region, as measured on ultrasound, could reflect the degree of IVC compression and further identify parturients at risk of post-spinal hypotension. Methods: After ultrasound measurement of peak velocities and anteroposterior diameters of the IVC and peak velocities and transverse diameters of the RCFV before anesthesia, 56 parturients undergoing elective cesarean section with spinal anesthesia were enrolled in this study. Hypotension was defined as having a drop of systolic arterial pressure >20% from the baseline. The primary outcome was ultrasound measurements of IVC and RCFV, and their association with post-spinal hypotension during cesarean delivery. Multinomial logistic regression analysis was used to identify the association between the measurements of ICV, RCFV and post-spinal hypotension during cesarean delivery. Receiver operating characteristic curves were used to test the abilities of the identified parameters to predict post-spinal hypotension, and the areas under the curve and the optimum cut-off values for the predictive parameters were calculated. Results: Longer transverse diameter of the RCFV was associated with the occurrence of post-spinal hypotension (odds ratio = 2.022, 95% confidence interval [CI] 1.261–3.243). The area under the receiver operating characteristics curve for the prediction of post-spinal hypotension was 0.759 (0.628–0.890; P = 0.001). A transverse diameter of the RCFV >12.2 mm could predict post-spinal hypotension during cesarean delivery. Conclusions: We demonstrated a longer transverse diameter of RCFV was associated with hypotension and it could predict parturients at major risk of hypotension before anesthesia.

Background: Post-spinal anesthesia hypotension during cesarean delivery is caused by decreased systemic vascular resistance due to the blockage of the autonomic nerves, which is further worsened by inferior vena cava (IVC) compression by the gravid uterus. This study aimed to assess whether peak velocity and diameter of the IVC below the xiphoid or right common femoral vein (RCFV) in the inguinal region, as measured on ultrasound, could reflect the degree of IVC compression and further identify parturients at risk of post-spinal hypotension.Methods: Fifty-six parturients who underwent elective cesarean section with spinal anesthesia were included in this study; peak velocities and anteroposterior diameters of the IVC and peak velocities and transverse diameters of the RCFV were measured using ultrasound before anesthesia. The primary outcome was the ultrasound measurements of IVC and RCFV acquired before spinal anesthesia and their association with post-spinal hypotension. Hypotension was defined as a drop in systolic arterial pressure by >20% from the baseline. Multinomial logistic regression analysis was used to identify the association between the measurements of IVC, RCFV, and post-spinal hypotension during cesarean delivery. Receiver operating characteristic curves were used to test the abilities of the identified parameters to predict post-spinal hypotension; the areas under the curve and optimum cut-off values for the predictive parameters were calculated.Results: A longer transverse diameter of the RCFV was associated with the occurrence of post-spinal hypotension (odds ratio = 2.022, 95% confidence interval [CI] 1.261–3.243). The area under the receiver operating characteristics curve for the prediction of post-spinal hypotension was 0.759 (95% CI 0.628–0.890, P = 0.001). A transverse diameter of >12.2 mm of the RCFV could predict post-spinal hypotension during cesarean delivery.Conclusions: A longer transverse diameter of RCFV was associated with hypotension and could predict parturients at a major risk of hypotension before anesthesia.