Beyond the Spontaneous Breathing Trial: Echocardiographic and Integrated Ultrasound Assessment During Weaning from...

Weaning failure from mechanical ventilation affects 10-20% of critically ill patients. Cardiovascular dysfunction-particularly diastolic dysfunction with elevated left atrial pressure (LAP)-underlies up to 50-60% of failed spontaneous breathing trials (SBTs) and frequently remains undetected without targeted echocardiographic assessment. This narrative review synthesises current evidence on the echocardiographic evaluation of weaning failure, with emphasis on LAP estimation, right ventricular (RV) dysfunction, and the integration of lung and diaphragm ultrasound.

A structured literature search of PubMed/MEDLINE and EMBASE was performed for publications from January 2000 to April 2026, supplemented by hand-searching of reference lists and current society guidelines. This article is reported as a narrative review; no formal systematic review protocol was registered. A qualitative synthesis emphasising pathophysiological mechanisms, echocardiographic phenotypes, and clinical applicability was performed.

Positive pressure ventilation with PEEP provides active LV afterload reduction; extubation abruptly removes this unloading and may precipitate acute filling pressure elevation in vulnerable patients. Multiparametric echocardiographic LAP assessment-integrating the E/e' ratio, deceleration time, and pulmonary vein flow-supports pre-extubation risk stratification. The dynamic PEEP reduction test, although not yet standardised or multicentre-validated, may identify patients with load-dependent cardiac decompensation before extubation. RV dysfunction is present in 20-50% of ventilated patients and worsens weaning outcomes through ventricular interdependence. Complementary lung ultrasound B-line quantification and diaphragm thickening fraction assessment together support a phenotype-specific diagnostic approach.

A structured multimodal ultrasound framework integrating echocardiography, lung ultrasound, and diaphragm ultrasound may support identification and targeted treatment of the dominant mechanism of weaning failure before extubation. Prospective multicentre validation of the integrated protocol as a whole remains a priority research need.