called "wet-dry" systems. Systems which use a water seal and water column regulator are called "wet" systems. Dry systems are advantageous as tip-overs of wet systems can spill and mix with blood, mandating the replacement of the system. Even newer systems are smaller and more ambulatory so the patient can be sent home for drainage if indicated. The free end of the tube is usually attached to an underwater seal, below the level of the chest. This allows the air or fluid to escape from the pleural space, and prevents anything returning to the chest. Alternatively, the tube can be attached to a flutter valve. This allows patients with pneumothorax to remain more mobile. More recently digital or electronic chest drainage systems have been introduced. An onboard motor is used as vacuum source along with an integrated suction control canister and water seal. These systems monitor the patient and will alert if the measured data are out of range. Due to the digital control of the negative pressure, the system is able to objectively quantify the presence of a pleural or system leak. Digital drainage systems allow clinicians to mobilize patients early, even for those on continuous suction, which is difficult to accomplish with the traditional water-seal system under suction. Recently published clinical data indicates, that application of such systems can also lead to a reduction in complications. Technique Thoracostomy It can be inserted in an area described as the "safe zone", which is a region bordered by the lateral border of pectoralis major, a horizontal line inferior to the axilla, the anterior border of latissimus dorsi and a horizontal line superior to the nipple. This should translate to the tube being inserted into the fifth intercostal space slightly anterior to the mid axillary line. Chest tubes are usually inserted under local anesthesia. The skin over the area of insertion is first cleansed with antiseptic solution, such as iodine, before sterile drapes are placed around the area. The local anesthetic is injected into the skin and down to the muscle, and after the area is numb a small incision is made in the skin and a passage made through the skin and muscle into the chest. The tube is placed through this passage. If necessary, patients may be given additional analgesics for the procedure. Once the tube is in place it is sutured to the skin to prevent it falling