Can a simple gas stop pneumonia after heart surgery?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Cardiac surgery with CPB at current hospitalization. 2. Age \> 18 years. 3. Signed informed consent. 4. The presence of at least one risk factor for the development of postoperative NP (CPB time ≥ 96 minutes and/or mechanical ventilation ≥ 14 hours and/or atrial fibrillation before surgery). Exclusion Criteria: 1. Emergency surgery. 2. Acute coronary syndrome 30 days before surgery. 3. Surgery for active infective endocarditis requiring antibiotic therapy. 4. Diagnosed infectious process of another localization (surgical site infection (SSI), acute and chronic urinary tract infection (active), catheter-related bloodstream infection, peritonitis, etc.). 5. Taking antibacterial drugs for 14 days preceding surgery. 6. Other complications of the postoperative period (pneumothorax requiring pleural drainage, perioperative myocardial infarction accompanied by pulmonary edema, shock of any etiology during the current hospitalization). 7. Potentially dialysis-dependent stage 2 and higher acute kidney injury (according to KDIGO) in the early postoperative period (the criteria for potentially dialysis-dependent acute kidney injury will include patients with stage 2 acute kidney injury and: oliguria against the background of normo-hypervolemia and resistance to loop diuretics and/or oliguria against the background of conducting infusion therapy due to hypovolemia and resistance to loop diuretics). 8. Continued mechanical ventilation. 9. Delirium. 10. Presence of tracheostomy. 11. Patient's participation in another clinical trial at the time of screening or within the previous 3 months. 12. Concomitant pulmonary disease with the need for respiratory support before surgery. 13. History of malignancy or other irreversible diseases/conditions with a 6-month mortality rate \>50%. 14. Presence of HIV infection.