In this proposal, the investigators wish to investigate, identify and validate potential biomarkers in collected exhaled breath condensates (EBC) from patients with sepsis.

In this proposed project, we will focus on the identification of potential biomarkers in EBC with ability to predict development of multi-organ failure. Currently, no tools could be used to evaluate the effect of mitochondrial dysfunction in sepsis. All the human studies discussing mitochondrial dysfunction in sepsis use tissue biopsies as study materials. Repeated tissue biopsy is invasive and not applicable. EBC could be collected non-invasively and conveniently. A study has demonstrated the use of metabolomic technologies in mitochondrial diseases. We believe that the metabolomic biomarkers of EBC could be used to demonstrate mitochondrial dysfunction in lungs and respiratory tracts of septic patients. Such metabolomic biomarkers may also reflect similar on-going mitochondrial dysfunction in other organ systems, and could potentially become a novel diagnostic tool and a therapeutic target in future sepsis therapy.

Inclusion Criteria:

• above 20 years old
• admitted to ICU with the diagnosis of sepsis and treated with mechanical ventilation via an endotracheal tube

Exclusion Criteria:

• pregnant
• active malignancy
• in an immunosuppressed status such as HIV disease, neutropenia, being treated with immunosuppressive agents
• expected to have an unavoidable very short life expectancy after admission, i.e., < 3 days

Patients who are admitted to ICU with the diagnosis of sepsis and treated with mechanical ventilation via an endotracheal tube.