The OPTICC trial: a multi-institutional study of occult pneumothoraces in critical care

Abstract 

Background

The management of pneumothoraces detected on CT but not on supine chest radiographs remains controversial, especially in those undergoing positive pressure ventilation (PPV) who are at risk for complications with both observation and treatment. Previous limited study yielded confusion regarding the need for routine drainage of these occult pneumothoraces (OPTXs). We conducted a pilot study at 2 trauma centers to address the feasibility and safety of randomizing traumatized patients undergoing PPV to drainage or observation.

Methods

Stable mechanically ventilated (or en route to surgery) adults with OPTXs were identified at 2 centers (Calgary and Quebec). Patients were randomized to observation (unless drainage became clinically indicated) or to chest drainage. Episodes of respiratory distress (need for thoracostomy tube, acute/sustained increase in oxygen requirements, difficulty in achieving adequate ventilation and self-reported distress) and subsequent imaging abnormalities were recorded until discharge.

Results

From August 2006 to April 2008, 24 trauma patients were enrolled (17 Calgary and 7 Quebec), with 2 later exclusions (final CT found no OPTX). Thirteen patients (59%) were randomized to observation, 9 to drainage (41%). Four observed (31%) later had chest tubes placed nonurgently for worsening OPTXs/effusions; none with increased morbidity. Overall rates of respiratory distress (drainage: 33%, observation: 41%) and mortality (drainage: 22%, observation: 15%) were similar across groups, as were median intensive care unit (drainage: 3, observation: 4) and in-hospital days (drainage: 10, observation: 16).

Conclusions

With no important differences in morbidity, the OPTICC pilot lays the foundation for a future definitive trial comparing drainage or observation in posttraumatic OPTXs requiring PPV.

Keywords: Pneumothorax, Occult pneumothorax, Critical care, Injury, Mechanical ventilation