Estimating the Usefulness of Inferior Vena Cava Collapsibility Index as a Predictor for Post-Spinal Hypotension in Orthopedic Patients Undergoing Elective Surgery in a Tertiary Care Hospital.

Subarachnoid block, colloquially referred to as spinal anesthesia, is a commonly employed method of anesthesia for most of the lower limb orthopedic procedures. Patients in preoperative hypovolemic states are more prone to post-spinal anesthesia hypotension (PSAH). Most orthopedic patients present in a preoperative fluid deficit state, thus, its recognition and appropriate correction are prudent. Ultrasonographic measurement of the inferior vena cava collapsibility index (IVCCI) is a tool to detect and correct hypotension secondary to hypovolemia. We hypothesized that pre-spinal IVCCI measurement is a reliable predictor of PSAH in patients undergoing elective lower limb orthopedic procedures. Ninety-nine participants, ASA grade I and II, aged 18-60 years, undergoing elective lower limb orthopedic surgeries were enrolled. Preoperative ultrasound inferior vena cava evaluation was performed and IVCCI was calculated. Preloading was done with intravenous crystalloid and subarachnoid block was administered in lateral position. Participants were placed supine and thereafter, level of sensory block was ascertained, and noninvasive blood pressure was measured every 2.5 min for 30 min. One hundred patients were screened and one was excluded due to failure of block. Mean IVCCI was 47.33 ± 9.62%. The receiver operating characteristic curve showed IVCCI has satisfactory predictive validity for predicting hypotension with AUC of 0.829 and P < 0.001. The sensitivity and specificity of IVCCI was found to be 87.36% and 83.3% at a cut-off value of 51.67%. Preoperative ultrasound evaluation of IVCCI is a reliable predictor for PSAH at a value of 51.67%.