Integrated cardiopulmonary ultrasound in diagnosing acute respiratory failure in critically Ill patients

Abstract

Background
Acute respiratory failure (ARF) is a critical condition that requires prompt identification of its underlying cause to guide appropriate management. Conventional imaging techniques may be limited in critically ill patients due to logistical constraints and radiation exposure. Point-of-care ultrasound offers a practical bedside alternative.


Aim
The present study aimed to evaluate the diagnostic performance of integrated lung ultrasound and transthoracic echocardiography in determining the etiology of acute respiratory failure in patients admitted to the respiratory intensive care unit.
Transthoracic echocardiography was used to assess right ventricular dysfunction and provide supportive findings suggestive of pulmonary embolism.


Patients and methods
This prospective observational study included 50 adult patients admitted with ARF to the Respiratory Intensive Care Unit at Kafr Elsheikh University Hospital over one year. All patients underwent clinical assessment, laboratory investigations, arterial blood gas analysis, lung ultrasonography using the BLUE protocol, and transthoracic echocardiography on admission. Final diagnoses were established using a composite reference standard. Diagnostic accuracy was assessed using agreement analysis and ROC curves.


Results

The combined ultrasound approach demonstrated improved agreement with the final diagnosis compared to lung ultrasound alone (κ = 0.642 vs. 0.435,
p
 < 0.001). It also showed superior diagnostic performance (AUC = 0.955 vs. 0.792). The addition of echocardiography enhanced the identification of pulmonary embolism and differentiation between cardiogenic and non-cardiogenic causes.



Conclusion
Combined lung and cardiac ultrasound provide an effective, non-invasive bedside approach for evaluating ARF, improving diagnostic accuracy, and supporting early clinical decision-making.