Experimental case report: development of a pneumothorax monitored by electrical impedance tomography.

Electrical impedance tomography (EIT) is a non-invasive, radiation-free functional imaging technique, which allows continuous bedside measurement of regional lung ventilation. Pneumothorax is an uncommon but nevertheless potentially dangerous incident that may arise unexpectedly. We report an incident of an accidental tension pneumothorax during an experimental ventilation study in a pig that was continuously monitored by EIT. The early sign of the occurring pneumothorax, prior to all clinical signs, was a fast increase of end-expiratory impedance in the ventral part of the right lung indicating that non-ventilated air entered this part, followed by a disappearance of ventilation in this region. At the same time the ventilation-related impedance changes of the left lung remained almost unchanged. The pneumothorax onset was localized using a newly introduced pneumothorax dynamics map directly derived from dynamic EIT data. We conclude that non-invasive EIT may be helpful as a tool to detect the development of a pneumothorax, which could be of particular interest during invasive procedures such as insertion of a central venous catheter.