Late-breaking abstract: Exhalation of specific volatile compounds under changing ventilation in mechanically ventilated patients

Disturbances in ventilation and occurrence of atelectasis are frequent problems in mechanical ventilation. Global parameters of gas exchange detected by blood gas analysis cannot differentiate causes sufficiently. This study was intended to identify ventilation dependent concentration changes of volatile compounds in the breath. In 10 mechanically ventilated patients having undergone cardiac surgery standard monitoring was extended by electrical impedance tomography (EIT) visualizing dynamic changes in ventilation distribution in defined areas of the lung. Exhaled breath was analyzed in real-time by means of proton-transfer-reaction-time-of flight-mass spectrometry (PTR-TOF-MS). All patients underwent a defined pulmonary recruitement maneuver. On the basis of EIT-data we divided patients into two groups – responders (> 50%) and nonresponders ( Specific endogenous and exogenous VOCs in the breath mirror changes of ventilation. The combination of ventilation imaging by means of EIT and real time breath analysis can be used to identify markers of ventilatory disorders. These markers could be employed for non-invasive control of therapeutic ventilation strategies.