ABSTRACT
Patients suffering from acute respiratory failure are frequently treated with positive pressure ventilation in interdisciplinary intensive care units (ICUs). Due to the severity of their illness and the effect of sedative medications that may be necessary during the course of mechanical ventilation, these critically ill patients are often unable to communicate with their caregivers. Moreover, the lungs of critically ill patients may suffer further damage due to the potentially detrimental effects 192of ventilator-induced lung injury (VILI, [ 981 ] and sometimes patient self-inflicted lung injury (P-SILI, [ 156 ]). Therefore, precise monitoring is essential for early detection of changes in the patient's condition as well as for individual adaptation of care. Conventional monitoring of ventilation in non-ventilated ICU patients comprises continuous monitoring of oxygen saturation with pulse oximetry and monitoring of respiratory rate by thoracic impedance measurements through electrocardiography (ECG) electrodes. In mechanically ventilated patients, the above-mentioned conventional monitoring parameters are commonly complemented by monitoring of airway pressure, tidal volume and expired carbon dioxide. These parameters provide important information about the effectiveness and invasiveness of ventilation on a global scale.
