The purpose of this study is to evaluate different peptide biomarkers, variations in the microbiome and patterns in the bacterial transcriptome as prognostic or diagnostic biomarkers of VAP.

Inclusion Criteria:

• Admission to an intensive care unit
• Intubation within last 24 hours
• Anticipated mechanical ventilation of at least 48 hours

Exclusion Criteria:

• FiO2 above 70% or PEEP above 15
• Severe coagulopathy (spontaneous PK(INR) >1.8 or thrombocytes <50). Prophylaxis treatment dose of LMWH or factor Xa inhibitors/NOAC is not an exclusion criteria. If higher doses of these substances are administered, the responsible clinician should be consulted before sample collection.
• Ongoing infection of the lungs at admission to the ICU.
• Severely elevated or instable intracranial pressure.

General intensive care unit population.

Individual participant data that underlie the results reported in published articles will be shared with investigators after deidentification upon request.

IPD will be available from 6 months to 5 years after publication.

Approval of the relevant ethical board is necessary for access