A simplified echocardiographic formula to estimate cardiac index in the intensive care unit. (1st February 2023)

• Record Type: Journal Article
• Authors: Gaspardone, Carlo; Romagnolo, Davide; Baldetti, Luca; Fasolino, Alessandro; Peveri, Beatrice; Calvo, Francesco; Gramegna, Mario; Pazzanese, Vittorio; Sacchi, Stefania; Beneduce, Alessandro; Falasconi, Giulio; Fiore, Giorgio; Rampa, Lorenzo; Ajello, Silvia; Scandroglio, Anna Mara
• Is Part Of: International journal of cardiology. Volume 372(2023)
• Page Start: 76
• Page End: 79
• Publication Date: 2023-02-01
• Subjects: Cardiac index -- Intensive care unit -- Echocardiography -- Left ventricular outflow tract -- Pulmonary artery catheterization -- Simplified formula; Cardiology -- Periodicals; Electronic journals; 616.12
• DOI: 10.1016/j.ijcard.2022.12.010
• Languages: English
• ISSNs: 0167-5273

Abstract

Abstract: Background and aim: Measurement of cardiac index (CI) is crucial in the hemodynamic assessment of critically ill patients in the intensive care unit (ICU). The most reliable trans-thoracic echocardiography (TTE) technique for CI estimation is the left ventricular outflow tract (LVOT) Doppler method that requires, among other parameters, the LVOT cross-sectional area (CSA) measurement. However, inherent and practical disadvantages, mostly related to the ICU setting, hamper LVOT-CSA assessment. In this study, we aimed to validate a simplified formula, leveraging on LVOT-velocity time integral (VTI) and heart rate (HR) only, for non-invasive estimation of CI in ICU patients. Methods and results: We prospectively enrolled 50 consecutive patients admitted to our ICU requiring pulmonary artery catheterization (PAC) over a one-year period. For each patient we measured the CI by PAC (CIPAC ) and TTE. The latter was obtained both with the "traditional formula" (traditional CITTE ), requiring LVOT-CSA assessment, and our new "simplified formula" (simplified CITTE ). The correlation between the simplified CITTE and CIPAC was strong ( r = 0.81) and resulted significantly greater than the traditional CITTE and CIPAC correlation ( r = 0.70; p < 0.05 for Pearson r coefficients comparison). Both TTE-based CI showed an acceptable agreement (+0.19 ± 0.48 L/min/m 2 for simplified CITTE and − 0.18 ± 0.58 L/min/m 2 for traditional CITTE ) with the reference CIPAC . Conclusion: In this study, we validated a practical approach, leveraging on TTE LVOT-VTI and HR only, for non-invasive estimation of CI in ICU patients. Highlights: Cardiac index is a crucial hemodynamic measure in intensive care unit patients. Doppler trans-thoracic echocardiography traditional method can estimate cardiac index. Practical disadvantages hamper cardiac index assessment by the traditional method. A new simplified echocardiography method can estimate cardiac index. The simplified method outperformed the traditional one in intensive care unit patients.