Relevance of chest sonography in the diagnosis of acute respiratory failure: Comparison with current diagnostic tools in intensive care units

ObjectivesThis study compares chest ultrasonography to current diagnostic tools for diagnosing the etiology of acute respiratory failure (ARF) in the ICU.MethodsThe final etiology of ARF was diagnosed in 100 patients (excluding non-respiratory causes and multiple diagnoses) using conventional diagnostic tools (excluding ultrasound). They were pneumonia (49%), chronic obstructive pulmonary disease (COPD) (16%), acute respiratory distress syndrome (ARDS) (10%), pulmonary embolism (PE) (5%), empyema (5%), bronchial asthma (BA) (5%), pneumothorax (5%), idiopathic pulmonary fibrosis (IPF) (3%) and lung contusions (2%). Thoracic ultrasound was done on admission and the obtained profiles were compared to underling etiologies obtained by conventional methods. Characteristic ultrasound profiles that produced specificities >90% were considered diagnostic.ResultsThe main diagnostic profiles were: AB profile (asymmetric anterior interstitial syndrome) and C profile (anterior consolidation) indicated pneumonia. The B profile (diffuse anterior interstitial syndrome with lung sliding) indicated ARDS or IPF. Also the B + PLAPS profile (anterior interstitial syndrome with posterior and/or lateral alveolar and/or pleural syndrome) indicated ARDS. The A profile (normal) indicated COPD or bronchial asthma (21%). The A profile (normal) plus DVT indicated pulmonary embolism (5%). The lung point and loss of lung sliding (A′ profile) indicated pneumothorax (5%). Considering CT chest as the radiological gold standard, chest ultrasound produced 90% sensitivity and 100% specificity.ConclusionsLung ultrasound provided an immediate diagnosis of the underlying etiology of acute respiratory failure in most cases; it can therefore be added to the armamentarium of ICU where urgent decisions are needed for rapid diagnosis and management of patients with ARF.