Transthoracic Echocardiography of Inferior Vena Cava Before Spinal Anesthesia Can Predict Hypotension

Plain-language summary

Study Protocol: Outcome Measurements Primary Outcome The main outcome will be the preoperative performance of the dIVCmax/IVCCI ratio to foresee the incidence of hypotension after spinal anesthesia in a greater extent to that of the established IVCCI measurements. Secondary Outcomes To identify other echocardiographic or clinical measurements that can predict an intraoperative spinal-induced haemodynamic instability. Sample Size Calculation A pilot study of 20 patients revealed a detected area under the ROC curve (AUC) of 0,91 for dIVCmax/IVCCI and for dIVCmax 0,82 with rank correlation between the two assays being 0.87 in both positive and negative cases. Based on this result, a sample of 56 patients will achieve 80% power to detect significant difference (at a level 0.05) between dIVCmax/IVCCI and dIVCmax. Potential Benefits of the Study The results of this study will allow us to determine which clinical or US-measurement can yield better performance so as a preoperative prediction of spinal-induced hypotension can be achieved; that way these measurements can permit and guide a targeted preoperative fluid challenges prior to the implementation of spinal anesthesia Potential Side Effects of the Study Participation in this protocol will not put patients at higher risk for complications since we do not perform any intervention (either pharmacological or surgical) There will be no occupational risks to researchers or assistants. Proposed Timetable According to the exclusion criteria and taking into account the number of cases performed in our department per monthly basis, it should take us approximately 6 months to recruit 60 patients.

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