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

Abstract

Objectives: This study compares chest ultrasonography to current diagnostic tools for diagnosing the etiology of acute respiratory failure (ARF) in the ICU. Methods: The 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. Results: The 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. Conclusions: Lung 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.

Keywords

• Acute respiratory failure
• Chest ultrasonography
• ICU
• Diagnostic ultrasonic profiles
• Etiology
• Conventional diagnosis