Mechanical ventilation is an important treatment modality for intensive care unit (ICU) patients, but it also brings a series of problems such as ventilator-associated pneumonia, ventilator-induced lung injury, and atelectasis. Continuous High-Frequency Oscillation (CHFO )is often considered to have a protective effect on the lungs. CHFO provides effective gas exchange at supraphysiological frequencies while minimizing pressure fluctuations, producing tidal volumes smaller than dead space and adjusting around a continuously expanding pressure to optimize end-expiratory lung volume (EELV) by achieving and maintaining lung recruitment. However, the physiological effects and safety of CHFO in critically ill patients on mechanical ventilation lack relevant research. The objective of this research is to assess the feasibility, safety, and efficacy of CHFO in a population of mechanically ventilated critically ill patients.

This is an interventional study evaluating the beneficial impact of CHFO of patients with mechanical ventilation on pathophysiological parameters.

This therapeutic study aims to treat patients using CHFO machine (MetaNeb system). The study consists of comparing pulmonary pathophysiological parameters before and after the treatment of CHFO in patients with invasive mechanical ventilation.

The primary outcome is the difference between the end-expiratory lung volume (EELV) and chest electrical impedance tomography (EIT) measured at the end of CHFO (10 min) and the basal value measured at the beginning of the protocol.

The minimum number of subjects to enroll in this study is 30 patients with invasive mechanical ventilation. Intermediate analyses are planned every 5 patients in order to reevaluate the needed number of patients.

The basal value at the beginning of the protocol, collection of ventilatory parameters on the ventilator, collection of arterial blood gas analyses and measurement of heart rate, and blood pressure. In the middle of treatment, collection of arterial blood gas analyses and measurement of heart rate, and blood pressure. At the end of the treatment, collection of ventilatory parameters on the ventilator, collection of arterial blood gas analyses and measurement of heart rate, and blood pressure.

Inclusion Criteria:

• Patients older than 18 and younger than 90 years;
• Admitted to the ICU after October 15, 2024, who are intubated and expected to be unable to be extubated within 48 hours due to ARDS, or have atelectasis, or have VAP.
• Signed informed consent for MetaNeb treatment.

Exclusion Criteria:

• Refusal to participate in the proposed study.
• Age < 20 years;
• Pregnancy;
• Significant hemodynamic instability defined as an increase of more than 20% in catecholamine doses in the last hour, despite optimization of blood volume, for a target mean blood pressure between 65 and 75 mmHg.
• Participation in another trial within 30 days prior to meeting eligibility criteria;
• Severe chronic respiratory disease requiring long-term oxygen therapy or home mechanical ventilation;
• Pneumothorax;
• Expected duration of mechanical ventilation < 48 hours
• Decision to refuse life-sustaining treatment.

Analysis of data will be conducted by a statistician not involved in interventions at bedside