Efficacy of the inferior vena cava collapsibility index in predicting anaesthesia-induced hypotension in elderly patients undergoing hip arthroplasty

The inferior vena cava collapsibility index (IVCCI) has been used to predict fluid responsiveness. This study aimed to evaluate the accuracy of the perioperative IVCCI to predict postinduction hypotension (PIH) under general anaesthesia (GA) combined with lumbar plexus sacral plexus block (LSPB) in elderly patients undergoing hip arthroplasty. A total of forty patients aged over 65 years were recruited for this prospective observational study. The diameters of the inferior vena cava (IVC), common iliac vein (CIV) and IVCCI were measured at baseline and 15 min post-LSPB. PIH was defined as a systolic blood pressure less than 90 mmHg or a ≥ 30% drop from baseline; patients were divided into hypotensive and nonhypotensive groups. The primary objective of this study was to evaluate the ability of the IVCCI to predict PIH via receiver operating characteristic (ROC) analysis. The secondary objective was to observe the change in CIV diameter. Eighteen patients (45%) developed PIH during GA. No statistically significant differences in baseline or post-LSPB IVCCI were detected between hypotensive and nonhypotensive patients (p > 0.05), whereas a significant expansion of the CIV (0.83 cm to 1.10 cm) was observed 15 min post-LSPB in all patients (p < 0.0001). According to the ROC curve analysis, the IVCCI cannot accurately predict severe PIH: the area under the ROC curve for the IVCCI was 0.54 (95% confidence interval: 0.35-0.72, P = 0.69). Thus, the IVCCI is not an effective predictor of PIH during GA combined with LSPB in elderly patients undergoing hip arthroplasty. Additionally, significant expansion of the CIV was observed 15 min after LSPB, indicating sympathetic blockade of the unilateral lower extremity.