CTSNet Step-by-Step Series: Chest Drains
At the end of a cardiac procedure, two or three chest tubes are placed in the mediastinal space to continuously monitor postoperative blood loss and to prevent undesirable blood collection, especially in the pericardial space. Pleural tubes are sometimes used when the pleural space is entered, for example, when left or right internal mammary arteries are used as a graft. In this case, a left pleural chest tube will also be placed before closing the chest in order to drain blood, pleural fluid, or evacuate air introduced during surgery.
Risks associated with the insertion of chest tubes include: chest tube blockage; injury to the heart, great vessels, or lung (very rare); open or tension pneumothorax; infection or empyema; and reduced patient mobility and patient discomfort causing a delay in recovery.
Equipment includes chest tubes, a drainage system of connecting tubes, and a collecting system comprising either under-water sealed drains or high-vacuum systems such as redivac drains. At the completion of open cardiac procedures, chest tubes are placed through separate stab incisions, typically near the inferior aspect of the sternotomy incision. One drain is placed inferiorly in the cardiac wall, and the second drain is placed anteriorly, overlying the heart. If either pleural space is opened during the procedure, a third drain is placed into the dependent portion of the pleural space.
Once the tube is in place, it is sutured to the skin to prevent movement. A scalpel is used to create a 1 cm incision inferior to the sternotomy incision. Using a number 1-0 silk suture, both a stay stitch and a purse string suture are placed prior to insertion of the chest tube. The stay stitch is placed at the end of the incision. Ensure that a long length of suture material is left at either end to allow for the stitch to be tied onto the tube. Cut the needle off, and tie the ends together using a surgeon’s knot. The purpose of the stay stitch is to secure the chest tube to the patient and prevent it from falling out. Then, the purse string suture for the chest tube is placed using a horizontal mattress stitch. To do this, first take a bite through one end of the incision, again leaving a long length of suture material. Then, without cutting your suture, place another stitch at the opposite end of the incision, as shown in the diagram. Finally, the distal ends of the suture are tied using a simple knot. The purpose of the purse string suture is to allow for closure of the wound upon removal of the tube.
Once the stay stitch and purse string suture are created, Robert’s forceps are placed through the incision and tunneled through the subcutaneous and muscle layers. With the drain in place in the desired location, the tip of the tube is grasped with the Robert’s forceps and brought out to the skin surface. Some chest tubes may have a yellow tip on one end to aid passage to the skin. If this is the case, ensure that the wide part of the tip is aligned with the incision to minimize trauma. Finally, secure the chest drain in place by wrapping the stay stitch around the drain multiple times and firmly knotting it in place with a surgeon’s knot. At minimum, 4 - 5 throws should be used.
The chest tube is then connected to the drainage canister using additional tubing and connectors and it is connected to a suction source, typically regulated to 20 cm of water. To prevent the chest tubes from becoming blocked and causing tamponade, they can be manipulated to prevent clots. Chest tube clearance methods are used on an as-needed basis rather than routinely. These include milking the tube by twisting or squeezing to move fluid within the tube or tapping the tube with forceps to facilitate drainage of blood down the narrow section of the tube. Chest tubes should be removed when the total drainage is less than an indicated limit, for example 100 ml over 8 hours. Prolonging the duration of drainage may increase the total chest tube output without any effect on the incidence of postoperative pericardial effusions. Mediastinal tubes should always be removed off suction, because graft avulsion might theoretically occur if suction is maintained.
- Bjessmo S, Hylander S, Vedin J, Mohlkert D, Ivert T. Comparison of three different chest drainages after coronary artery bypass surgery--a randomised trial in 150 patients. Eur J Cardiothorac Surg. 2007;31(3):372-375.