When this cat was hit by a car the force of the impact pushed the cat's abdominal contents forwards, rupturing the diaphragm. The diaphragm is a sheet of muscle that separates the abdomen from the chest. It functions as part of a bellows system to expand and deflate the lungs allowing inspiration and expiration.

Normally when the chest expands and the diaphragm contracts the lungs are pulled open causing air to be inhaled. However, when the diaphragm is torn, abdominal contents spill into the chest cavity, filling the gap between the thoracic wall and the lungs. The diaphragm can no longer function properly and when the chest expands the abdominal contents simply move forwards, stopping the lungs from inflating.

When this cat came into the practice its chest was heaving as it attempted to breathe. Its gums were pale and slightly cyanosed (blue) from lack of proper oxygenation. When we listened to the chest with a stethoscope there were very few lung sounds and the heart beat was muffled and higher up in the chest than normal.

A diagnosis of suspected diaphragmatic hernia was made and a radiograph (x-ray) was taken.

The relevant features have been marked on the duplicate radiograph underneath. You can see a line of marked difference in density called the diaphragmatic line. This is usually more noticeable in a normal cat as the chest contains fully inflated lungs and air is not very dense and so appears black on x-ray.

The abdomen is fairly dense and therefore much lighter on radiograph. Two "breaks" in the diaphragmatic line can be seen in this case with abdominal contents spilling through.
The spleen and some bowel have caused the heart to be raised up off the sternum (breast bone). A collapsed lung lobe is also visible – this looks like a fairly dense patch within the lung field. Around this collapsed lung lobe are a few small areas of normally inflated lung.

The cat was given a general anaesthetic and an endotracheal tube placed in its windpipe. The tube was connected to an oxygen supply via a re-breathing bag. This is very important in repairing diaphragmatic hernias because as soon as the abdomen is opened the lungs fully collapse. The cat must then be artificially respirated with the re-breathing bag. Gentle regular squeezing of the bag ensures that the lungs continue to inflate and deflate throughout the operation, thus delivering vital oxygen to the body.

Once inside the abdomen, the misplaced abdominal organs are retrieved from the thoracic cavity and inspected for any damage. In this image you can see that the bowels and spleen have been retrieved from the chest and the tear in the diaphragm is being sutured closed. There was a large haematoma (bruise) on the spleen caused by the original accident but it was of no risk to the cat and was left alone. The lungs are inspected for any damage and watched to see that they are inflating fully as the surgical nurse continues to “breathe” for the cat using the re-breathing bag technique. The sutures in the torn diaphragm are placed one at a time. Before the last one is pulled tight the lungs are fully inflated to force all air out of the surrounding chest cavity and the final suture is then pulled closed to seal the hole. The abdominal organs are returned to their normal position within the abdominal cavity and the incision in the abdominal wall is closed.

This cat made an uneventful recovery. Perhaps the first of its nine lives saved….