Evacuation of pleural effusion (PE) represents a disputable therapy in mechanically ventilated patients. Patients on mechanical ventilation indicated by the physician to pleural fluid evacuation will be monitored throughout the procedure by electrical impedance tomography (EIT) and concurrently end-expiratory lung volume (EELV) will be measured in order to describe impact of PE evacuation on aeration and ventilation of the lungs.

Critically ill patients treated in intensive care units have a disorder of distribution and volume of body fluids due to principal illness and some therapeutic interventions. One of its manifestations is pleural effusion (PE) formation.

Patients on mechanical ventilation indicated by treating physician to pleural fluid evacuation will be monitored throughout the procedure by electrical impedance tomography (EIT) and concurrently end-expiratory lung volume (EELV) will be measured. The purpose of the study is to better understand impact of PE evacuation on aeration and ventilation of the lungs.

Inclusion Criteria:

• mechanical ventilation, presence of pleural effusion, decision of the treating physician to drain it

Exclusion Criteria:

• impossibility to apply EIT belt or to find suitable save point for drainage when the EIT belt is attached
• standard EIT exclusion criteria according to the device manufacturer