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Background: We investigated the coagulation system in patients during extracorporeal membrane oxygenation (ECMO) initiated for respiratory failure and the influence of the ECMO circuit on coagulation tests; we compared different coagulation tests for monitoring unfractionated heparin (UH) therapy; we investigated whether or not coagulation parameters were predictive of bleeding during ECMO., Methods: Pilot study on twelve consecutive adult patients admitted at our general ICU for acute respiratory failure and placed on ECMO from November 2011 to October 2012. Coagulation tests were performed before ECMO start and daily, including day of circuit change and day of circuit removal. UH was monitored with activated partial thromboplastin time (APTT) ratio, at a therapeutic range of 1.5-2.0., Results: We observed no effect of ECMO circuit on coagulation parameters measured pre- and postlung, but platelet count decreased significantly over time (-82x10(3)/mmc, 95%CI 40-123). APTT showed a correlation with antifactor Xa activity, whereas other global coagulation tests such as activated clotting time, thromboelastography and endogenous thrombin potential did not. Major bleeding occurred in three patients but no difference in any coagulation parameter was observed between them and those who did not bleed., Conclusions: This pilot study shows that ECMO initiated for respiratory support in adults does not change coagulation parameters. Over time a statistically significant reduction of platelet count was observed, possibly due to consumption within the circuit, consumption microangiopathy or the underlying patients' diseases. Although APTT was appropriate to monitor UH, major bleedings occurred and a lower therapeutic range may be advisable.

Ventilator-associated pneumonia (VAP), which develops in patients receiving mechanical ventilation, is the most common nosocomial infection in patients with acute respiratory failure. The major mechanism of lower respiratory tract colonization is aspiration of bacteria-colonized secretions from the oropharynx into the lower airways. The hydrostatic pressure of the secretions that collect in the subglottic space, which is the area above the endotracheal tube (ETT) cuff, or aerosolization of bacteria from the secretions collected within the respiratory tubing may facilitate the leakage into the lower airways. Ideally, the elimination of the mechanisms responsible for aspiration would decrease the incidence of VAP. Several preventive measures have been tested in clinical trials with little success.Here we present the results of our efforts to develop novel approaches for the prevention of VAP. Specifically, we found that keeping ventilated patients in a lateral position, which eliminates gravitational forces, is feasible and possibly advantageous. Additionally, several novel medical devices have been recently developed to prevent bacterial biofilm formation from the ETT and breathing tubing. These devices include coated ETTs, mucus shavers and mucus slurpers. Prevention of ETT bacterial colonization showed decreased bacterial colonization of the respiratory circuit and of the lower respiratory tract in laboratory studies and clinical trials. Future large studies should be designed to test the hypothesis that VAP can be prevented with these novel strategies. While there is a current focus on the use of respiratory devices to prevent biofilm formation and microaspiration, it is important to remember that lower respiratory tract colonization is multifactorial. Prevention of VAP cannot be achieved solely by eliminating bacterial biofilm on respiratory devices, and more comprehensive care of the intubated patient needs to be implemented.

Despite early diagnosis and appropriate antibiotic therapy, ventilator-associated pneumonia (VAP) remains the leading cause of death from hospital-acquired infection in ventilator-dependent patients. Strategies to prevent bacterial colonization of the trachea and lungs are the key to decrease mortality, hospital length of stay, and cost. It is well established that the VAP can result from entry of infected oropharyngeal/gastric secretions into the lower airways. Aspiration may occur during 1) intubation, 2) mechanical ventilation through leakage around the tracheal tube cuff, 3) suctioning of the tracheal tube when bacteria can detach from the biofilm within the tube, or 4) areosolization of bacterial biofilm during mechanical ventilation through the tracheal tube or the ventilator circuit biofilm. From experimental studies in sheep, we drew 3 relevant conclusions: 1) The tracheal tube and neck should be oriented horizontal/below horizontal to prevent aspiration of colonized secretions and subsequent bacterial colonization of the lower respiratory tract. 2) Continuous aspiration of subglottic secretions (CASS) can lower bacterial colonization of the respiratory tract, but at the price of severe tracheal mucosal damage at the level of the suction port. 3) Coating the interior of the tracheal tube with bactericidal agents can prevent bacterial colonization of the tube surface and of the entire respiratory circuit, during 24 hours of mechanical ventilation.