Modified Inhaled Nitric Oxide in Ventilated Patients With Acute Respiratory Failure

Pneumonia is the main cause of ICU admission in patients with acute respiratory failure (ARF). Severe pneumonia is a serious lung infection caused by bacteria, fungi, viruses, and other pathogens. It often leads to respiratory failure requiring mechanical ventilation. It is also accompanied by septic shock or multiple organ dysfunction, and patients need intensive care. The average mortality rate is 30%-40%. Therefore, there is an urgent need to find treatments that improve outcomes in patients with severe pneumonia. Inhaled nitric oxide (iNO) can selectively dilate pulmonary vessels in well-ventilated lung areas. This reduces pulmonary artery pressure, improves the ventilation/perfusion ratio, and increases oxygenation. At 80 ppm, iNO can effectively reduce mean pulmonary artery pressure and pulmonary vascular resistance. It also reduces oxidative stress and has anti-inflammatory effects. Short-term inhalation is safe. The level of positive end-expiratory pressure (PEEP) affects the effect of NO. Setting PEEP according to airway opening pressure (AOP) can deliver iNO efficiently to target areas. Based on this, the study team designed this randomized controlled trial to investigate whether a modified iNO regimen, PEEP set according to AOP combined with 80 ppm NO, improves outcomes in patients with acute respiratory failure receiving mechanical ventilation.

Inclusion Criteria: 1. Age ≥ 18 years. 2. Acute respiratory failure (PaO₂/FiO₂ ratio \< 300 mmHg). 3. Endotracheal intubation due to pneumonia. 4. Duration of mechanical ventilation ≤ 72 h. Exclusion Criteria: 1. Expected duration of mechanical ventilation \< 48 h. 2. Severe chronic respiratory disease requiring long-term home oxygen therapy or noninvasive ventilation. 3. Severe other organs dysfunction with a low expected survival (7 days) or palliative care. 4. History of pulmonary malignancy, pneumonectomy, or lung transplantation. 5. Patients who received iNO or ECMO prior to enrollment. 6. Pregnancy or lactation. 7. Refusal to sign the informed consent.