Preoperative assessment of inferior vena cava collapsibility index by ultrasound is not a reliable predictor of post-spinal anesthesia hypotension

Role of Internal Jugular Vein Collapsibility Index in Predicting Post-spinal Hypotension in Pregnant Women Undergoing Cesarean Section: A Prospective Observational Study

Introduction Post-spinal hypotension (PSH) frequently occurs in women undergoing cesarean section. In recent studies, Ultrasound-guided measurements of the internal jugular vein (IJV) have been reported to predict fluid responsiveness. We planned to evaluate the correlation between the internal jugular vein collapsibility index (IJVCI) and PSH in cesarean section patients. Methods Ninety-one parturients who underwent elective lower segment cesarean section with a singleton pregnancy were recruited. Preoperatively, patients were placed in a supine position with a 15-degree left lateral tilt. Maximum (at the end of expiration) and minimum (at the end of inspiration) IJV diameters (mm) and IJVCI were assessed using M-mode imaging during spontaneous and deep breathing. Spinal anaesthesia was performed at the L3-4 or L4-5 level. Systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, respiratory rate, and SpO2 were recorded from baseline till the delivery of the baby. Results Among 91 patients, 40 (45.5%) patients had at least one episode of hypotension. Demographic variables and baseline vitals were comparable between the hypotensive and normotensive groups (p>0.05). In spontaneous and deep breathing, IJV diameter at the end-expiration (IJVdmax), end-inspiration (IJVdmin), and IJVCI amongst both hypotensive and non-hypotensive pregnant women were statistically similar. Receiver Operating Characteristic (ROC) curve analysis showed that during spontaneous breathing, using a cut-off point of 29.5%, IJVCI had a sensitivity and specificity of 70% and 23%, respectively, for predicting PSH; whereas during deep breathing, IJVCI had a sensitivity and specificity of 77% and 27%, respectively, for predicting the same using a cut-off value of 37.5%. Conclusion We conclude that internal jugular vein parameters such as maximum diameter, minimum diameter, and IJVCI during spontaneous and deep breathing cannot be used as reliable predictors of post-spinal hypotension in pregnant patients undergoing elective cesarean section.

The use of preoperative inferior vena cava ultrasound to predict anaesthesia-induced hypotension: a systematic review

Preoperative ultrasound assessment of inferior vena cava (IVC) diameter and the collapsi-bility index might identify patients with intravascular volume depletion. The purpose of this review was to gather the existing evidence to find out whether preoperative IVC ultrasound (IVCUS) derived parameters can reliably predict hypotension after spinal or general anaesthesia. PubMed was searched to identify research articles that addressed the role of IVC ultrasound in predicting hypotension after spinal and general anaesthesia in adult patients. We included 4 randomized control trials and 17 observational studies in our final review. Among these, 15 studies involved spinal anaesthesia and 6 studies involved general anaesthesia. Heterogeneity with respect to the patient populations under evaluation, definitions used for hypotension after anaesthesia, IVCUS assessment methods, and cut-off values for IVCUS-derived parameters to predict hypotension precluded pooled meta-analysis. The maximum and minimum reported sensitivity of the IVC collapsibility index (IVCCI) for predicting post-spinal hypotension was 84.6% and 58.8% respectively, while the maximum and minimum specificities were 93.1% and 23.5% respectively. For the prediction of hypotension after general anaesthesia induction, the reported ranges of sensitivity and specificity of IVCCI were 86.67% to 45.5% and 94.29% to 77.27%, respectively. Current literature on the predictive role of IVCUS for hypotension after anaesthesia is heterogeneous both in methodology and in results. Standardization of the definition of hypotension under anaesthesia, method of IVCUS assessment, and the cut-offs for IVC diameter and the collapsibility index for prediction of hypotension after anaesthesia are necessary for drawing clinically relevant conclusions.

Can Ultrasound-Guided Femoral Vein Measurements Predict Spinal Anesthesia-Induced Hypotension in Non-Obstetric Surgery? A Prospective Observational Study

Background and objectives: To investigate whether ultrasound (US)-guided femoral vein (FV) and inferior vena cava (IVC) measurements obtained before spinal anesthesia (SA) can be utilized to predict SA-induced hypotension (SAIH) and to identify risk factors associated with SAIH in patients undergoing non-obstetric surgery under SA. Methods: This was a prospective observational study conducted between November 2021 and April 2022. The study included 95 patients over the age of 18 with an American Society of Anesthesiologists (ASA) physical status score of 1 or 2. The maximum and minimum diameters of FV and IVC were measured under US guidance before SA initiation, and the collapsibility index values of FV and IVC were calculated. Patients with and without SAIH were compared. Results: SAIH was observed in 12 patients (12.6%). Patients with and without SAIH were similar in terms of age [58 (IQR: 19-70) vs. 48 (IQR: 21-71; p = 0.081) and sex (males comprised 63.9% of the SAIH and 75.0% of the non-SAIH groups) (p = 0.533). According to univariate analysis, no significant relationship was found between SAIH and any of the FV or IVC measurements. Multiple logistic regression analysis revealed that having an ASA class of 2 was the only independent risk factor for SAIH development (p = 0.014), after adjusting for age, sex, and all other relevant parameters. Conclusions: There is not enough evidence to accept the feasibility of utilizing US-guided FV or IVC measurements to screen for SAIH development in patients undergoing non-obstetric surgery under SA. For this, multicenter studies with more participants are needed.