Thoracentesis

Thoracocentesis is a procedure performed to remove air or fluid from around the lungs where it shouldn’t normally be.

• Your cat is given a sedation or short anaesthetic to keep it still. This is not a painful procedure; however, a needle is inserted into the chest, where there are many structures, so keeping your cat still is very important.
• In addition, cats with fluid or air around their lungs can be highly stressed and anxious due to their breathing difficulties, so sedation helps them relax and keep calm, reducing the effort they need to breathe.
• Once your cat is sedated, we typically clip the fur from the chest and use an ultrasound to identify the major area of fluid buildup (or radiography for air).
• We clean the area and apply a local anaesthetic cream and sometimes an injection of local anaesthetic.
• We then guide a needle into the fluid pocket using the ultrasound and remove as much fluid (or air) as possible.

Yes, often, although it depends on how quickly the fluid has built up and how much there is. Commonly, a cat will feel better immediately after the fluid has been drained, and its breathing effort improves dramatically.

• The most common reasons are heart disease, cancer and infections, although there are other less common reasons.
• Investigating why the fluid has occurred is very important and typically requires an ultrasound of the heart (echocardiogram) to screen for heart disease and analysis of the fluid for cancer cells or other infectious agents such as bacteria.

Generally, this is because of trauma or underlying airway disease such as asthma, cancer or a foreign body.

Yes, but unfortunately, this is one of those procedures where the risk of the procedure is far outweighed by the life-saving benefit of removing the air or fluid. The risk is that the needle can cut the lung, causing further air leakage, or cut a blood vessel, causing a haemorrhage. In the rare event that this occurs, the complications are typically mild and self-limiting, and the complications are less with the patient sedated or under anaesthesia.

In humans, this procedure is done with a local anaesthetic. In cats, we have them under sedation or anaesthesia to keep them still, not because of the pain of the procedure. The needle size itself is the same size you would have a vaccination with, so there shouldn’t be any pain after the procedure is completed.

It depends on your cat’s condition and how unwell it is. Some cats with chronic heart disease can go home the same day. Other sicker cats may need to stay in the hospital for longer while we investigate what is making them unwell and start treatments such as antibiotics or chemotherapy.

• Sometimes, it depends on the underlying cause. For example, cats with heart disease or cancer can build up fluid on multiple occasions and feel much better after it is drained. For some cats (e.g., those with terminal cancer), we may even discuss placing a special port that enables easy drainage of the fluid to keep them comfortable.
• If we think your cat has a disease where fluid recurrence is likely, we will teach you how to check its breathing rate at home when it is resting. You can also find a link to these instructions here.