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

Volatile Organic Compounds Analysis for Rapid Testing Using EXhaled Breath for Respiratory Infection in Hospitalised Patients

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.

Inclusion Criteria:

• Age ≥ 18 years old
• Having signed a written informed consent
• Presenting a NEWS-2 score of 5 (>4) or one of the individual score criteria rated 3
• Hospitalized in one of the HCL (Hospices Civils de Lyon) departments participating in the study
• With clinical signs of acute respiratory infection, or with a clinical presentation of acute community-acquired pneumonia, nasopharyngitis, angina or laryngitis (except for healthy patients)

Exclusion Criteria:

• Healthy volunteers:
• Age: < 18 years
• Alcohol consumption less than 12 hours
• Person with co-morbidities such as chronic respiratory failure, type II diabetes, cancerous processes, chronic liver disease, chronic kidney disease
• Clinical signs of acute respiratory infection
• Persons who are unable to blow into exhaled-air analysis devices (in accordance with instructions for use)
• Persons under legal protection
• Pregnant women, women in labor or nursing mothers
• Persons deprived of their liberty by judicial or administrative decision
• Persons under psychiatric care
• Persons admitted to a health or social institution for purposes other than research
• Adults under legal protection (guardianship, curatorship)
• Persons not affiliated to a social security scheme or beneficiaries of a similar scheme
• Patients with respiratory symptoms
• Age: < 18 years
• Patients whose symptoms have been present for more than 7 days
• Persons unable to blow into the device for breath analysis (in accordance with the operating instructions)
• Patients suffering from cystic fibrosis
• Patients with severe chronic respiratory insufficiency requiring long-term oxygen therapy or NIV (non-invasive ventilation), excluding CPAP (Continuous Positive Airway Pressure) for sleep apnea
• Patients under legal protection
• Pregnant women, women in labor or nursing mothers
• Persons deprived of their liberty by judicial or administrative decision
• Persons under psychiatric care
• Persons admitted to a health or social institution for purposes other than research
• Adults under legal protection (guardianship, curatorship)
• Persons not affiliated to a social security scheme or beneficiaries of a similar scheme