Sunday, December 31, 2017

How To Safely Place a Chest Tube in Dogs and Cats

Indications

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 1: The end of a red rubber catheter is grasped within a Carmalt clamp
from: 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
Insert the tip of the tube into the skin incision and advance it through the tissue tunnel to the level of the 8th intercostal space.(Fig 2)
Fig. 2: The red rubber tube and Carmalt clamp are advanced from the 10th to the 8th intercostal space
Firmly grasp the tube and insert through the chest wall with a forceful but controlled effort. (Fig. 3)
Fig. 3: Cross sectional view of Carmalt clamp and chest tube entering the pleural cavity through the  intercostal space.
from: 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
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)
Fig. 4: Sequence of steps(A-D) for inserting an Argyle thoracic drain tube with inner trocar into the chest cavity.
from: Crisp MS, Buffington CA. Critical Care Techniques. In: Saunders Manual of Small Animal Practice. 2nd edition, Birchard and Sherding, eds., Elsevier, St. Louis, 2000, pg. 21.
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.
Use large suture or wire to secure the stopcock and adapter to the tube and place a purse string and finger trap pattern suture to secure the tube to the skin (Fig. 6).   
Fig. 6: Secure the thoracic drain tube to the skin with a purse string /finger trap suture combination.
A “C” clamp can also be placed on the tube for added safety in case the stopcock should become dislodged.  Apply antibiotic ointment to the tube entry site in the skin and protect the tube on the patient with a bandage.

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.
Patients with thoracic drain tubes require 24 hour monitoring. If the tube becomes damaged or the stopcock is dislodged, immediate pneumothorax will occur and could be life threatening. Change the chest bandage as needed and check the tube location to be sure it is not pulling out and that the stopcock and Christmas tree adapter are tight and not leaking. Place an Elizabethan collar on the animal if necessary.

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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