Collection of Fluid in the Lungs (Not Due to Heart Disease) in Dogs

When the exchange between carbon dioxide and oxygen is disturbed, a non-cardiogenic pulmonary edema can occur. Intense neurologic stimulation (caused by a trauma), or an illness such as sepsis (bacterial infection of the blood) can cause the buildup of lung water or fluid. NCPE is often an acute event that can quickly escalate to a life threatening situation. If your pet experiences an event that results in a shock to the central nervous system, or if he has been ill and is suddenly showing respiratory distress, take him to the emergency clinic as soon as possible. With prompt treatment, a dog who is experiencing  a mild or moderate collection of fluid in the lungs has a good prognosis for recovery. However, if it is found to be a severe case, the result will be a guarded prognosis.

Fluid accumulation in the lungs of dogs is described as cardiogenic (in relation to the heart) and non-cardiogenic (not due to heart problems). When a dog has fluid buildup unrelated to heart disease, it usually means there has been a trigger to the event, such as electric cord bite injury, or that there is a possibility of an underlying systemic illness. The medical definition is non-cardiogenic pulmonary edema (NCPE).

A dog who is experiencing non-cardiogenic collection of fluid in the lungs may have accompanying signs that are related to the cause for the event (such as burns on the mouth resulting from electric cord bite injury or cuts and bruises due to trauma). The usual signs directly related to NCPE should indicate that you must take your pet to the veterinarian without delay.

• Rapid breathing (tachypnea)
• Difficulty breathing (dyspnea)
• Gasping
• Coughing
• Weakness
• Collapse

You may also hear a crackling sound (which is coming from the lungs) as your pet breathes. It should be noted that symptoms of NCPE can appear within minutes to hours of an injury or trauma.

The collection of fluid in the lungs when not related to heart disease is documented more often in canines of a young age. This is specifically because they are more likely to experience an event like electric shock or upper airway obstruction. This can be simply explained due to the fact that puppies have a very curious nature and often explore the world with their mouths, which can accidentally get them into trouble and result in injury or illness.

• Seizure
• Any trauma that causes a shock to the central nervous system
• Neoplasia (abnormal growth of tissue)
• Electrical shock (such as from biting on an electric cord)
• Near drowning
• Brain trauma
• Acute respiratory distress syndrome (ARDS)
• Systemic inflammatory response syndrome (SIRS) caused by problems like pancreatitis, heatstroke, gastrointestinal disease, and aspiration pneumonia
• Toxin ingestion or inhalation
• Upper airway obstruction
• Sepsis (infection)

If you are aware that your pet has suffered an acute injury or accidental electrical shock for example, the diagnosis of fluid accumulation resulting in edema may be more easily reached due to immediate findings that point to the problem. Any information that you can provide will assist the veterinary team as they stabilize your pet and try to ascertain why he is in respiratory distress. Recent illnesses and medical history, travel history or behavioral changes are all pieces of the puzzle that you should relay to your veterinarian. In any case, an animal in distress will always be stabilized before determining the extent of the problem.

Standard tests that your veterinarian will order will be complete blood count, serum chemistry profile, and urinalysis. It is quite likely that a blood coagulation test will be included in the diagnostic process. An echocardiogram, to exclude conditions like left-sided heart failure, may be ordered as well as a test called the pulmonary capillary wedge pressure (PWP) which is done under anesthesia.

If possible, your veterinarian may collect edema fluid for analysis (the protein level with NCPE is usually very high) but this will only be done if your dog has coughed up fluid (otherwise the test can be performed on intubated pets only). Thoracic radiographs prove to be extremely valuable as they will clearly show pulmonary edema; in fact, the x-rays are one of the most telling tests for NCPE diagnosis.

The main treatment for pets who are suffering from accumulation of fluid in the lungs is resting with oxygen support. Improvement in patients with NCPE can be quite notable when oxygen is provided. Sometimes a ventilator will be necessary. While resting with supportive oxygen, your pet will be carefully monitored. His respiratory rate, blood pressure, and heart rate are important indicators as to whether his situation is stabilizing. 

In cases where there is dehydration, your pet may be given intravenous fluids, however, great care will be taken to ensure the edema does not worsen. If necessary, and dependent on the underlying cause of the collection of fluid, your veterinarian may choose to administer anti-seizure medication, pain relief, and sedatives (if your dog is stressed). The body temperature and oxygen saturation of the blood will be checked often as well. Any underlying factors contributing to the NCPE will be addressed as your dog’s condition improves.

How well your pet responds to the treatment will depend on the underlying cause. His condition upon arrival at the clinic will be a determining factor, too. Many pets with a moderate case of collection of fluid in the lungs can go home after a day or two in the hospital. Rest and a stress-free environment at home will be important. Your veterinarian will advise you on required follow-up. It should be noted that pets who suffer a severe episode of NCPE may not recover.