The preoperative ultrasonographic evaluation of the transverse diameter of the right common femoral vein for predicting post-spinal hypotension in elderly patients: a prospective observational study

Abstract

Background: In elderly regional anaesthesia, a predominantly subarachnoid block (SAB) is favoured to prevent the potential cognitive impairment associated with general anaesthesia during the postoperative period. The inferior vena cava (IVC) tributary is the right common femoral vein (RCFV), which serves as the primary continuation of the right external iliac vein. This study aimed to assess the transverse diameter of the RCFV within the inguinal region and its correlation with post-spinal hypotension (PSH) in elderly individuals.
Methods: This prospective observational study included 68 elderly individuals aged > 65 years allocated for surgical procedures under spinal anaesthesia (SA). The ultrasound (US) measurements were performed 15 minutes before anaesthesia. During endexpiration, the peak velocities and RCFV transverse diameter were assessed 1 cm before the merging of the great saphenous vein into the common femoral vein. The anteroposterior diameter and peak velocity of the IVC were assessed 2–3 cm below the IVC right atrial junction. The IVC collapsibility index (IVCCI) was measured.
Results: Hypotension occurred in 43 patients (63.24%). The RCFV transverse diameter was significantly smaller in the hypotensive patients (8.16 ± 2.36 mm) compared with the non-hypotensive patients (12.08 ± 2.14 mm; p < 0.001). The RCFV transverse diameter predicted hypotension (area under the curve [AUC] = 0.889; p < 0.001) at a ≤ 10 mm cut-off, with 83.72% sensitivity, 68% specificity, 81.8% positive predictive value, and 70.8% negative predictive value. Conclusion: Preoperative US measurement of the RCFV transverse diameter is an uncomplicated and non-invasive technique for predicting PSH in elderly individuals.