ICU survivors are at an increased risk of hospital and ICU readmission. Among the complications of ICU stay, diaphragmatic dysfunction is common, with a prevalence of 60 to 80%, and is associated with increased mortality and prolonged hospital stays. Furthermore, several studies have reported that the observation of impaired respiratory muscle function upon ICU discharge is associated with a poor long-term prognosis. However, the incidence and prognostic impact of persistent diaphragmatic dysfunction at ICU discharge have never been evaluated. The measurement of dyspnea, a composite evaluation of respiratory muscle function, has not been assessed for predicting prognosis upon ICU discharge.

The hypothesis of the project is that the presence of ICU-acquired diaphragmatic dysfunction at ICU discharge is associated with a poorer prognosis within 90 days.

Diaphragmatic function of patients will be assessed by ultrasound within 24 hours following the weaning from ventilatory support and on the day the patient is deemed eligible for ICU discharge.

ICU discharge will be defined a priori using a checklist. Diaphragmatic activity will be assessed by bedside diaphragmatic ultrasound. Patients will be positioned in a semi-sitting position (trunk inclination between 30 and 45°) to allow for better visualization of the right hemidiaphragm. The diaphragmatic assessment will include the measurement of inspiratory and expiratory thickness to calculate the diaphragmatic thickening fraction (intercostal approach) and the measurement of diaphragmatic excursion (subcostal approach) during the respiratory cycle. These measurements will be taken at rest. Diaphragmatic dysfunction will be defined by a thickening fraction strictly less than 20% and/or a diaphragmatic excursion strictly less than 1 cm at rest.

Dyspnea will be assessed using a visual analog scale (VAS) ranging from 0 (no dyspnea) to 10 (maximum dyspnea). It will be evaluated within 24 hours following the weaning from ventilatory support and on the day the patient is deemed eligible for ICU discharge.

Inclusion Criteria:

1. Age ≥ 18 years
2. Invasive or non-invasive respiratory support (ventilation, high-flow oxygen therapy, whatever the reason) for at least 48 hours.
3. Weaning from respiratory support (invasive or not) within the last 24 hours.
4. Patient (or trusted person/relative) informed and not opposed to the study.

Exclusion Criteria:

1. Known pre-existing diaphragmatic dysfunction (phrenic lesion, neuromuscular disease, etc.)
2. Patients with tracheostomy
3. Non-communicating patients
4. Patients deprived of liberty by court or administrative order, or under legal protection (guardianship, curators).

The eligible population will be that of adult patients who have been in intensive care and have received invasive mechanical ventilation for at least 48 hours or non-invasive ventilation or humidified high-flow oxygen therapy for at least 48 hours, with a PaO2/FiO2 ratio < 200 before ventilatory support was introduced.

The procedures carried out with the French data privacy authority (CNIL, Commission nationale de l'informatique et des libertés) do not provide for the transmission of the database, nor do the information and consent documents signed by the patients. Consultation by the editorial board or interested researchers of individual participant data that underlie the results reported in the article after deidentification may nevertheless be considered, subject to prior determination of the terms and conditions of such consultation and in respect for compliance with the applicable regulations.

Beginning 3 months and ending 3 years following article publication. Requests out of these time frame can also be submitted to the sponsor

Researchers who provide a methodologically sound proposal.