Pulse contour analysis versus transthoracic echocardiography in assessment of cardiac output in patients with low cardiac output syndrome post cardiac surgery

Abstract

Low cardiac output syndrome (LCOS) is a critical postoperative complication following cardiac surgery, leading to increased morbidity and mortality. This study aimed to evaluate the reliability of pulse contour analysis (PCA) using the Flotrac EV1000 system compared with transthoracic echocardiography (TTE) for Cardiac output (CO) measurement in LCOS patients. A single-center, prospective observational study was conducted on 50 patients with LCOS post-cardiac surgery. CO was measured using both TTE and PCA. Hemodynamic, clinical, and biochemical parameters were recorded, and correlations between CO measurements and clinical variables were assessed. The study population had a mean age of 52.2 ± 11.3 years, with 68% males and 60% classified as obese. Both PCA and TTE confirmed low cardiac output (PCA: 2.42 ± 0.56 L/min; TTE: 2.48 ± 0.58 L/min) with a very strong correlation between the two methods (r = 0.97, p < 0.001). Cardiac output positively correlated with body size, blood pressure, urine output, and central venous oxygen saturation, while negative correlations were noted with urea, creatinine, and lactate levels. These findings highlight the association between hemodynamic compromise and renal dysfunction in LCOS. Pulse contour analysis provides a reliable, continuous alternative to transthoracic echocardiography for cardiac output monitoring in LCOS patients post-cardiac surgery. Its real-time capability enhances clinical decision-making and supports timely interventions in the ICU setting.