A Validation/Interventional Study on Stress Index in Predicting Mechanical Stress in ARDS Patients

30% of ARDS patients ventilated according to NIH protocol presents CT scan evidence of hyperinflation. Functional analysis of pressure-time curve (Stress Index=SI) has been shown to identify this condition in experimental settings. We tested the hypothesis that the SI is an accurate predictor of mechanical stress due to overdistention in ARDS patients.

The study presents two parts : a preliminary validation study and a clinical study.

Inclusion Criteria:

• Age ≥ 18 years
• Diagnosis of ARDS based on American-European Consensus Conference criteria

Exclusion Criteria:

• >3 days since ARDS criteria were met and mechanical ventilation was started
• History of ventricular fibrillation or tachyarrhythmia, unstable angina or myocardial infarction within preceding month
• Pre-existing chronic obstructive pulmonary disease
• Major chest wall abnormalities
• Chest tube with persistent air leak
• Abdominal distension
• Body mass index >30
• Pregnancy
• Known intracranial abnormality
• Enrollment in another interventional study