Excess fluid can build up in the body cavities of your cat that may require intervention by your veterinarian to drain. The most common types of fluid buildup in cats that require surgical intervention to drain are pleural effusion, which is buildup of fluid in the pleural sac surrounding the lungs, and peritoneal effusion (ascites), which is fluid buildup in the abdominal cavity of your cat. Fluid accumulation can occur gradually over a period of time (chronic) or quickly over a short period of time (acute/critical).

Fluid buildup in body cavities may occur for a variety of reasons including cancer, infection, heart failure, and chemical imbalances. Often, treatment of the underlying condition will resolve the condition and fluid will absorb back into your cat's tissues, however, if fluid build up is too excessive to be reabsorbed in a timely manner, if life threatening symptoms are being caused by the accumulated fluid, or if treatment of the underlying condition is not adequate to address the production of excessive fluid, your veterinarian may need to act to drain the fluid. Excess fluid in the pleural sac may put pressure on the lungs resulting in breathing problems and excess fluid in the abdominal cavity can put pressure on vital organs, affecting functioning. When this occurs, veterinarian intervention is critical to a positive outcome. Surgical procedure to aspirate (remove) the excess fluid is required immediately.

If symptoms of organ failure or respiratory failure accompany pleural or peritoneal effusion, treatment of the underlying condition may not be adequate to address the excess pressure being put on your pet's internal organs and draining the fluid by surgical intervention will be required.

If your cat is experiencing respiratory distress, oxygen therapy will be provided. Pulse, blood pressure, and temperature will be monitored during the procedure.

If pleural effusion is present, a thoracentesis will be performed. Your cat will need to be immobilized during the procedure. This may be accomplished through sedation and having assistants immobilize the cat or anesthesia may be administered if required. 

The area will be shaved and prepared aseptically. A local anesthetic will be administered at the site where the puncture to allow drainage is to occur. 

Ultrasound may be used to locate fluid build up and guide the procedure. Your veterinarian will insert a long needle into the fluid filled sac and draw fluid out with a syringe. If a chest drain is being inserted to be used for ongoing drainage, general anesthetic will be used, a puncture made with a scalpel, a catheter inserted into the incision and guided into the pleural sac, excess fluid aspirated, and a valve attached to the drain that can be used for ongoing drainage of fluid in the pleural sac.

For ascites, a paracentesis procedure is performed to drain excess abdominal fluid. The procedure is similar to that for a thoracentesis, your cat will be immobilized, possibly with sedation and anesthesia, the abdominal area where the puncture is to be performed will be shaved and cleaned, and local anesthetic applied. Ultrasound may be used to locate excess fluid, a needle used to drain fluid or, a surgical incision, followed by a catheter insertion, and excess fluid drained. If a catheter is being used it will be left in place and a valve attached for ongoing drainage.

Surgical drainage of fluid addresses the fluid build up short-term by removing the fluid and relieving pressure on surrounding organs. The long-term effectiveness of surgical drainage of excess fluid depends on the success in addressing the underlying cause. If the underlying cause cannot be successfully treated, fluid accumulation may recur.

If the underlying cause can be treated, your cat’s recovery after removal of excess fluid should be relatively complication-free. The most common cause of excessive fluid buildup, chylothorax, has a good prognosis provided ongoing management under the care of a veterinarian is provided. 

If a catheter was inserted for ongoing drainage, this will need to be monitored and removed by your veterinarian. Long term, periodic treatment to drain fluid build-up may be required and a special diet low in sodium and fat may be required to mitigate future fluid accumulation.

The cost of treating fluid accumulation surgically depends on additional considerations and treatment taken to address the underlying condition. Fluid drainage can be an expensive procedure depending on the requirements for the procedure. For example, anesthetic requirements, ultrasound guidance during the procedure, and ongoing hospitalization and veterinary follow up if a drain is left in for a period of time to drain fluid will affect the overall cost of treatment. Depending on the cost of living in your area, the cost of this procedure can range from $500 to $1,500.00.

Surgical drainage of fluid build is associated with several risks including pneumothorax, hemorrhage, and hypotension (drop in blood pressure). Other, less serious, complications include dry tap (when no fluid is aspirated), bruising, and cough. Using ultrasound to guide the procedure, sedation, and oxygen therapy can minimize these risks. As surgical removal of fluid is usually an emergency procedure performed to relieve pressure on lungs or internal organs, the risks of not performing the procedure for your cat are greater than the risk of complications from the procedure.

Pet owners should careful monitoring their cat and seek early treatment to address any medical conditions before fluid buildup in the pleural or abdominal cavity occurs. This will help prevent the need for surgical intervention to remove fluid by your veterinarian.

Depending on your cat’s condition, a diet low in fat and/or in salt may help reduce the risk of fluid accumulation.

Routine check-ups and monitoring of existing medical conditions by your veterinarian will decrease the risk of a medical condition progressing to the point where fluid accumulation becomes excessive, requiring surgical intervention.