Evaluation of a Medical Chest Drainage System Functional in the Micorgravity Environment

Chest trauma is a frequent occurrence in both civilian and military injuries. One of the common complications of chest trauma is the development of a collapsed lung (pneumothorax), with air and blood entering the pleural cavity (hemothorax). These conditions are treated by insertion of a tube into the space between the lung and chest wall, and attaching a thoracic drainage device with a suction source. This suction device is required to decompress a chest through a thoracostomy tube in the event of a chest injury, pneumothorax or decompression accident. Suction pressure is usually provided by a central vacuum supply in a hospital, but portable suction generators can be used during ground and aeromedical transport.  However, there is currently no medical thoracic drainage system and suction capability that can function with a thoracic chest tube drainage system in the space operational environment.

On Earth, pneumothorax and hemothorax are treated by insertion of a thoracic drainage catheter through the wall of the chest and connecting it to a series of chambers under balanced suction to evacuate the blood and air from the thoracic cavity. The classic system is a gravity-dependent three-bottle system. The first bottle collects any fluid or blood from the patient’s chest, the second prevents back flow and high negative pressure from damaging the lung of the patient, and the third is used to regulate the negative pressure applied to the system. In the late 1970s, advances in technology produced integrated systems that are in a single container. Recent advances in technology involving the dry suction valves provide suction using adjustable regulators without requiring a water column. Most commercial devices require the addition of a water seal, though some can be operated without.  A modification to the system to replace the water seal valve in the position of bottle two is the modification for this flight experiment.  The three primary test objectives for this experiment are:  validation that the device functions in the “dry” state (pneumothorax treatment); validation of 2-phase separators during microgravity; and confirmation of improvement with the evolved design.