Immediate placement of a thoracostomy tube is indicated if negative pressure cannot be achieved with needle thoracocentesis, if large amounts of blood are aspirated, or if repeated thoracocenteses are required to maintain negative pleural pressure.

- A general rule of thumb for thoracostomy tube sizes is the chest tube should be the largest size that comfortably fits in the intercostal space. For most MWDs, use fenestrated tubes that are 24-36 Fr. Figure 30 shows the correct anatomic orientation for chest tubes placed in dogs. Table 9 describes techniques for chest tube placement in MWDs.
- Tube thoracostomy is a painful procedure. In emergent or critically ill patients, local analgesia may not be necessary. Consider local anesthesia, intercostal nerve blocks, and intrapleural analgesia in all other patients (See CPG 16).
- Remove chest tubes when air or fluid accumulation is less than 2-4 mL/kg body weight per day.
- The chest tube will ideally lie in the pleural space, generally oriented cranioventrally to maximize removal of air and fluid. It is best to pre-measure the tube visually before placement to ensure proper depth of insertion. Be certain the last fenestration of the tube will be within the chest cavity.
- Patients with chest tubes in place MUST be monitored continuously!
- Some form of removal of air or fluid must be used. This can be continuous suction or intermittent aspiration by personnel.

Figure 30. Anatomic Orientation for Chest Tube Placement.

Figure 30 shows correct placement of a chest tube on the lateral aspect of the chest in a dog, with the tube penetrating the skin at the 9th to 11th intercostal space (ICS), tunneling cranioventrally to penetrate the chest wall at the 7th to 8th ICS, directed toward the olecranon of the elbow. Photo courtesy of Dr. Tim Hackett.