Impact of Transthoracic Echocardiography on 28-Day Mortality in Acute Respiratory Failure: A Retrospective Analysis by MIMIC-III

Background: Acute respiratory failure (ARF) is a common and severe condition in the intensive care unit (ICU) with a poor prognosis. Transthoracic echocardiography (TTE), a noninvasive and reproducible imaging modality, offers unique advantages for assessing cardiac function and hemodynamic status. However, its impact on outcomes in ARF patients remains unclear. Methods: In this retrospective study using the MIMIC-III database, 3,697 adult patients with ARF were analyzed. Patients were stratified into a TTE group (n = 1,996) and a non-TTE group (n = 1,701) based on whether TTE was performed. To reduce baseline imbalances, we employed propensity score matching (PSM), multivariable logistic regression, inverse probability of treatment weighting (IPTW), and doubly robust estimation to evaluate the association between TTE use and 28-day mortality, as well as secondary outcomes such as duration of mechanical ventilation, vasopressor use, and fluid management. Sensitivity analyses were also conducted. Results: Prior to matching, the TTE group exhibited significantly higher Simplified Acute Physiology Score (SAPS) and Sequential Organ Failure Assessment (SOFA) scores, as well as higher proportions of patients receiving mechanical ventilation and vasopressors, indicating more severe illness compared to the non-TTE group. After PSM, the groups were well-balanced in terms of age, gender, service unit, and key interventions (standardized mean differences < 0.2). Across all statistical models, TTE use was consistently associated with a significant reduction in 28-day mortality (e.g., OR = 0.67, 95% CI: 0.55–0.81, p < 0.001 in the PSM analysis; OR = 0.56, 95% CI: 0.39–0.79, p < 0.001 in the multivariable logistic regression). Sensitivity analyses confirmed these findings. Conclusion: The use of TTE in ARF patients appears to be independently associated with a significant reduction in 28-day mortality, potentially by enabling more precise and timely therapeutic interventions through comprehensive hemodynamic assessment. Future prospective, multicenter studies are warranted to validate these findings and further explore the role of TTE in optimizing clinical management and resource allocation in this high-risk population.