A simple breath sampling method in intubated and mechanically ventilated critically ill patients

Area of Science:

• Pulmonary Medicine and Critical Care
• Analytical Chemistry
• Biomarker Discovery

Background:

• Volatile organic compounds (VOCs) in breath are potential biomarkers for pulmonary conditions.
• Analyzing VOCs in ventilated patients is challenging due to the breathing circuit.

Purpose of the Study:

• To develop and validate a novel breath sampling method for VOC analysis in ventilated patients.
• To assess the feasibility of using exhaled VOCs as biomarkers in critical care settings.

Main Methods:

• Breath sampling from the ventilatory circuit using inexpensive disposable materials.
• Gas-chromatography and mass-spectrometry (GC-MS) for VOC identification and quantification.
• In vitro (artificial lung) and in vivo (ventilated patients) experiments at varying ventilation parameters.

Main Results:

• Identified 64 ventilator-associated VOCs, with concentrations inversely correlated to minute volume in vitro.
• Detected 44 of these VOCs in vivo, unaffected by minute volume but influenced by positive end-expiratory pressure.
• Demonstrated high reproducibility of the sampling method (median intra-class correlation: 0.95).

Conclusions:

• A novel, simple, and reproducible breath sampling method for VOCs in ventilated patients was successfully developed and validated.
• This method facilitates large-scale breath analysis, potentially aiding in the diagnosis and monitoring of pulmonary infections and inflammation.