Role of chest ultrasound in diagnosis of causes of acute respiratory failure

Background
Acute respiratory failure (ARF) has an impact on both the average duration of hospital stays and the death rate during those hospitalizations. Detecting the sensitivity and specificity of chest ultrasonography (US) in identifying the underlying respiratory etiology of ARF was the aim of the study.


Patients and Methods
This prospective observational cross–sectional trial was conducted on 112 individuals, aged greater than or equal to 18 years old, with ARF, existence of a minimum of two of the following objective ARF considerations: an arterial pH less than 7.35, a pulse oximetry-measured oxygen saturation of 90% or lower while breathing room air, a PaO2/FiO2 ratio of 300 mmHg or less, a PaO2 of 60 mmHg or less, and/or a PaCO2 of greater than 45 mmHg. The cardiothoracic US was performed on all patients without knowledge of their clinical data, and without being involved in making decisions or management. The diagnosis made by pulmonary US was compared with the final diagnosis reached by the team in the ICU. The final diagnosis made by ICU team (using clinical data, chest radiography, chest computed tomography, echocardiography and computed tomography angiography) was considered the gold standard.


Results
Chest US can detect causes of ARF: pneumothorax, pulmonary edema, chronic obstructive pulmonary disease, Asthma, pulmonary embolism, and pneumonia, respectively, with 75, 100, 86.7, and 86.7% sensitivity and 100, 94.3, 88.7, 100, and 98.5% specificity.


Conclusions
The US seems to be a promising diagnostic technique that can help make early treatment decisions using repeatable physiopathologic data.