SurgiVet Heimlich One-Way Valve. A one way valve to be used in conjunction with a chest tube or pneumothorax set for the relief of pneumothorax in animals usually over 10kg. Air can only flow in one direction through the valve. As the animal breathes in, the air in the pleural cavity is forced out of the chest tube and through the Heimlich valve. The pneumothorax will therefore resolve itself. It is strongly recommended not to use this device if fluid is present in the chest because the duck bills in the valve will stick together. The HV100 Heimlich Valve comes complete with the valve and connecting tube ready to connect to a variety of chest tubes used to treat pneumothorax. Sterile. HV100.