Change in the Phase III Slope of the Volumetric Capnography by Prone Positioning in Acute Respiratory Distress Syndrome

Assessment of the Effects of Prone Positioning Among ARDS Patients on Ventilation Homogenization by the Phase Iii Slope of the Volumetric Capnography

This study evaluates the effects of prone positioning on homogenization of ventilation.

After initiation of mechanical ventilation and assessing the eligibility of the patient, informed consent will be taken from the closest kin. If eligible, following steps will be performed which are part of standard ARDS patient care.

1. Low-flow Pressure Volume curve and assessment of airway opening pressure
2. Calculation of recruitment to inflation ratio
3. Optimizing Positive End-Expiratory Pressure

Afterwards, phase III slope of the patient will be recorded at four timepoints:

Supine 1 (immediately before turning to prone position) Prone 1 (immediately after prone position) Prone 2 (at the end of the 16-24 hour prone cycle) Supine 2 (immediately after turning to supine position)

Inclusion Criteria:

• ARDS criteria met
• intubated and mechanically ventilated as a result of respiratory failure
• PaO2/FiO2 <200

Exclusion Criteria:

• age older than 18
• Chronic pulmonary disease, pneumothoraces, intraabdominal hypertension (> 12 mmHg), pregnancy, not expected to survive >24 hours, hemodynamic instability