Ventilator-Associated Pneumonia. Mucus Slurper. Mucuciliary Transport.

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Projects 1. The respective role of tracheal orientation and enteral feeding, in Ventilator Associated Pneumonia. Subject: 13 pigs Results: pigs with the tracheal orientation 30 degrees above the horizontal (a model of the semi-recumbent position, considered best current clinical practice), developed pneumonia. Instead, pigs kept in the Trendelenburg position did not develop pneumonia, despite two major risk factors for Ventilator Associated Pneumonia (mechanical ventilation for up to one week, and enteral feeding). 2. Possibility of safe mechanical ventilation in Trendelenburg position with a deflated cuff. Subject: 4 pigs Results: pigs ventilated up to one week with a deflated cuff did not develop pneumonia or lung colonization despite the presence of a deflate cuff since secretions were gravitationally drained. 3. In-vivo evaluation of double-layer Latex tracheal tube cuff. Subject: 9 pigs (5 with new cuff and 4 acting as controls) Results: the leak-proof cuff appeared to be safe with no evidence of tracheal lesions. The cuff appeared not damaged after 72 hours of mechanical ventilation. Lung colonization in the semi-recumbent position was reduced compared to controls. 4. Carbon-dioxide removal via bicarbonate ultrafiltration. Subject: 7 sheep Results: we removed carbon dioxide effectively in the form of bicarbonates, using a commercial Hemofilter (Baxter HA-2000); with replacement solution devoid of bicarbonate, keeping the strong ion difference, and the pH constant. The process appeared to be safe. 5. In-vivo testing of the new Lycra prototype cuff (ongoing). Subject: 3 pigs Results: we tested the new Lycra cuff in-vivo. We had no leakage (as assessed with methylene blue), and no evidence of tracheal damage. 6. Study of lung-perfusion in a model of primary-ARDS. Comparison of CT-scan and MRI as a tool to image ARDS and estimate degree of lung recruitment (ongoing). Subject: 4 pigs Pigs ventilated in the semi-recumbent position developed pneumonia and respiratory failure. Such respiratory failure meets all criteria for ARDS. We studied lung perfusion with microsphere injection, and its response to PEEP increase and body rotation (two maneuvers commonly employed in ICU to improve patient oxygenation). Pigs were imaged both with CT scan and MRI at 3 different PEEP levels, and when turned (from prone to supine).