Thoracic drain tubes are indicated for animals with disorders of the thoracic cavity that cause accumulation of air or fluid in the pleural space. Some examples are: pneumothorax due to trauma or spontaneous causes such as emphysematous bullae, or pleural effusion due to infection (pyothorax) or neoplasia. If repeated drainage of the thorax is anticipated for palliative care of the patient, a thoracic drain is more effective and less painful for the patient than repeated thoracocentesis with a needle or catheter. A properly performed thoracic drain tube placement is a safe and effective means of managing patients with acute or chronic pleural disorders.
Technique
Equipment
Basic surgical pack
Red rubber catheters (8 – 20 Fr),
or Argyle catheters with trocar (same sizes)
3-way stopcocks
Christmas tree adapters
Syringes (12 – 60mls)
Bandage materials
Antibiotic ointment
Suture material (2-0 or 3-0 monofilament non-absorbable)
Place the animal under general anesthesia and prepare the lateral thorax for aseptic surgery. Make a small (2-3 cm) skin incision at the 10th intercostal space.
Incise through the subcutaneous tissue and the lattisimus dorsi muscle. Use a Carmalt or Pean forcep to create a tunnel underneath the lattisimus dorsi muscle from the skin incision to the 8th intercostal space. Grasp the tip of a red rubber catheter with a Carmalt forcep or use an Argyle trocar catheter. (Fig. 1)
Fig. 2: The red rubber tube and Carmalt clamp are advanced from the 10th to the 8th intercostal space |
Once the tube has penetrated the chest wall, advance it into the pleural space. If using the Argyle tube, slide the trocar out of the tube and then slide the tube inside the pleural cavity.(Fig. 4)
If using a red rubber catheter and forceps, after entering the chest open the forceps, slide the catheter into the pleural cavity, then remove the forceps from the incision. Promptly place a clamp on the tube after entering the chest to prevent pneumonthorax.
Place a 3-way stopcock on the end of the tube(Fig. 5); a Christmas tree adapter may be necessary to fit the stopcock to the flared end of the tube.
Fig. 5: Stopcock secured to the end of the chest tube with wire; heavy suture can also be used. |
Fig. 6: Secure the thoracic drain tube to the skin with a purse string /finger trap suture combination. |
Postoperative Care
Obtain radiographs of the thorax to ensure correct placement of the tube.(Fig. 7)
Fig. 7: Lateral thoracic radiograph of a cat with a thoracic drain tube in place. |
Evacuation of air and/or fluid can be performed either manually or with a continuous suction device which, when connected to a source of negative pressure, allows for drainage of the thoracic cavity. In most animals intermittent manual drainage of the chest cavity is sufficient to keep the animal’s respiratory status stable.
In some cases a sudden increase in the amount of air being pulled from the drain tube can be due to a leak in the tube or its apparatus. Test the integrity of the tube by clamping the tube close to the patient and try applying negative pressure to the stopcock with a syringe. If air is easily withdrawn, a leak is present. Check all connections for tightness and check the tube for cracks or holes allowing air to leak into the system.
In addition to other routine supportive care measures, analgesic therapy with a NSAID or opioid such as Tramadol is indicated due to the painful nature of the indwelling tube in the pleural space. The pleura is one of the most sensitive tissues in the body and the tube acts as a foreign body rubbing on the pleural membranes.
Thoracic drain tubes can be left in the patient for several days or even a few weeks at a time depending on the need for continued drainage. Since dogs do not have a complete mediastinum, a unilateral tube is usually adequate for drainage of both sides of the pleural cavity. However in some cases, such as chronic pyothorax or chylothorax, fibrinous adhesions in the cavity can make the fluid loculated, decreasing the function of the tube. Bilateral tubes may then be necessary.
Remove the chest tube when the amount of fluid or air is minimal. The chest tube acts as a foreign body in the pleural space and can create 1-2 mls/kg/24 hours of fluid. After removal of the tube apply antiobiotic ointment to the skin incision and keep the incision covered with a bandage for another 1-2 days.
The following is a video produced by my colleague Dr. Ron Bright demonstrating chest tube placement on a cadaver dog using an Argyle thoracic drain tube with trocar.
References
Bateman SW, et.al. Emergency and Critical Care Techniques and Nutrition. In: Saunders Manual of Small Animal Practice. 3rd edition, Birchard and Sherding, eds., Elsevier, St. Louis, 2006. Pg. 29
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