Diagnosis of Acute Respiratory disTress Syndrome by exhaled breath (DARTS)

Patients with acute respiratory distress syndrome (ARDS) have protein filled fluid in their lungs. This results in problems with getting the oxygen to enter the blood. Around 2 in 5 patients with ARDs die during the first 90 days resulting in 10.000 deaths in the Netherlands per year. Recognition of patients with ARDS is difficult because the tests that are available are not good enough. Using a breath test that allows for diagnosis at the bedside, we could improve patient care. 

In a previous project we identified a molecule (octane) in the exhaled breath of patients with ARDS. It was present in around 2 times higher concentrations than in patients without the condition. In this project we aimed to develop a bedside test for this marker and validate that it can be used to diagnose ARDS correctly. In order to be useful in the clinic, the breath test had to provide a result within 60 minutes and had to detect octane at the right concentration as it constitutes just 1 in a billion molecules in the breath. 

First, we developed a novel method for measuring octane in breath of patients on the intensive care unit. Using microtechnology we could reduce the size of the instrument from 2x1 meter to 50x50cm and the cost from 500.000 euro to 15.000 euro per device. Next, we measured octane in the breath of more than 500 patients on multiple occasions resulting in more than 1000 breath samples analyzed. The new breath test was just as accurate as the old test in detecting octane. 

Next, patients were split into patients with and without ARDS, based on the judgement of three independent experts. However, the levels of octane in breath of patients with and without ARDS we not different enough to use it as a diagnostic test. We therefore conclude that breath biomarkers can be measured at the bedside within 60 minutes after sample collection using newly developed technology, but that the octane concentration in exhaled breath is not predictive of ARDS development and therefore has no place in clinical practice.