Volatile Organic Compounds Analysis by GC-MS for Diagnostic of Hospitalised Patients With Respiratory Infections Using Exhaled Breath

Condition(s) studied

Investigational drug(s) / intervention(s)

Volatile Organic compounds (VOC) analysis in Exhaled breath using GC-MS: The collection and analysis of exhaled air for VOC detection is a non-invasive, painless procedure carried out offline. It can be summarised as follows: 1. Collection of 0.5-1 litre of exhaled air in a single-use Tedlar® bag 2. Transfer the exhaled air sample to a thermodesorption tube. The thermodesorption tube will be sent to the laboratory responsible for the analysis within 1-5 days of collection. 3. The breath sample will be analysed in the laboratory using thermal desorption-GC/MS. 4. Processing of the raw data to determine the chemical composition of VOCs and identify the compounds present in the exhaled air sample. 5. Statistical analysis of all generated data will be performed to identify interesting VOC profiles.

Study summary

Emerging respiratory diseases represent a global threat. Viruses such as influenza and coronaviruses have been the main drivers of pandemics over the past century. More broadly, the impact of these respiratory infections is not limited to pandemic risks. Indeed, some of them also trigger seasonal epidemics with a significant medical and economic burden. Consequently, it is essential to strengthen global surveillance, and diagnostic capacities for the pathogens responsible for respiratory infections.

The diagnosis of respiratory infections is even more important in cases of severe infection, as it helps guide and adapt patient management according to the responsible pathogen.

A promising and well-recognized approach is the analysis of exhaled breath, which contains a complex mixture of volatile organic compounds (VOCs), also known as the "volatilome." The volatilome is influenced by the patient's metabolism, immune system, and microbiome, and can be disrupted by the presence of a pathogen.

A parallel clinical study, VORTEX-1, aims to establish the performance of breath analysis for the diagnosis of respiratory infections in the context of the general population, or patient triage in emergency wards. This study targets patients with non-severe respiratory infections, mostly caused by viral pathogens.

Thanks to a specific technique, the VORTEX-1 study will make it possible to test a direct on-site sampling and analysis process, painless and with real-time chemical detection.

This methodology, highly suited to triage situations, remains difficult to apply in the case of respiratory infections requiring hospitalization. Indeed, hospitalized patients are usually admitted to different units depending on their clinical status, risk factors, or bed availability. This diversity of settings makes it impossible to implement a process that depends on an instrument which cannot be available or moved in real time across all units. To address this challenge, the investigators will use an alternative method.

In the VORTEX-2 trial, samples of exhaled gases will be collected directly at the patient's bedside using a single-use device for breath collection. The samples will then be transferred to a laboratory for analysis. This approach is more suitable for severe respiratory infections.

To be as comprehensive as possible in the study of the volatilome in the context of respiratory infections, it is important to include hospitalized patients and to develop a system that can also be implemented in routine clinical practice.

The link between the two studies (VORTEX-1 and VORTEX-2) will be established through a "control" group, consisting of healthy subjects (without respiratory infections or severe/chronic diseases), whose breath will be collected using both approaches.

Eligibility

Primary outcome measure(s)

• Description of the breath composition based on the area under each peak of exhaled air according to three levels of classification — day one
  Levels of classification : * Patients with bacterial or viral respiratory infection vs. no respiratory infection (healthy subjects = control group) * Patients with viral vs. bacterial respiratory infection vs. undetermined respiratory infection vs. healthy subjects * Patients with respiratory infection due to Legionella spp vs another bacterium vs SARS-CoV-2 vs influenza vs another virus vs undetermined respiratory infection vs healthy subjects

Trial sites (7)

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