Although this evening was quite quiet at Kingsnorth Vets, I one particularly interesting case.
In the kennels, preparing to go home was a black Labrador. The previous week she had been spayed but been brought back in after she had suddenly become lethargic and was struggling to breath. The vets found that she had a muffled heartbeat so performed an echocardiogram. Using this, they diagnosed her with pericardial effusion.
Pericardial effusion is a condition where excess fluid builds up in the pericardium. The vet explained to me that the pericardium is a smooth membrane which surrounds the heart. Although its function is not known for certain, it is generally acknowledged that it has a lubricating purpose, ensuring that the contractions of the heart are not hindered by the lungs. However, if fluid (either blood or lymph) leaks into the pericardium, it can compress the heart making contractions difficult. In dogs, the right atrium is the first to be affected so appears squashed on the echo. The fluid often comes from a bleeding tumour on the heart so the prognosis for this poor dog wasn’t great.
Luckily there were no signs of a tumour on the echo, but nevertheless, they immediately withdrew as much of the fluid as possible to alleviate the pressure on the heart. Very often this will solve the problem, at least in the short term. However, now she had developed arrhythmia – her heart was beating irregularly. The vet had never come across this as a result of pericardial effusion but was more concerned that it had caused tachycardia – her heart rate had accelerated rapidly. She had been placed on two intravenous drips, both giving her doses of medication to reduce her heart rate. The nurse showed me that one of catheters had been placed in the left celaphic vein – the front leg normally used for IV, whilst the other had been placed in left saphenous vein – the back leg. This was because the original drip had been unsuccessfully placed in the right celaphic vein, bruising it.
The saphenous vein is not normally used for intravenous injections because it’s quite wobbly. So although it is easy to find and raise, it can be hard to steadily put a needle in. However, on some occasions it might it be the best option. If a dog is agitated or aggressive, the saphenous vein is useful as it is further away from the dog’s teeth. It can also be useful because there is more to hold onto, so the leg can be held steady for quick needle insertion in a restless animal. One of the vets mentioned that he found it easier to take blood from this vein on puppies whose celaphic veins were just too small, whilst someone else said that they had previously used it for euthanasia, giving the dog more space around it head so it remained calm, or so that its owners could be nearer. Another consideration is that bandaging is harder around the hock than the around the wrist, but a bandage is more likely to stay in place.
The Labrador was going to go home for the evening, with the decision made that she was in a stable condition and would be more comfortable at home. The nurse removed the drips, but left the catheters in place under bandages in case the dog was rushed in that night. The owners were sent home with medication to reduce the heart rate, and an appointment was made for tomorrow. If all was well the catheters would be removed and a course of action would be decided.
The final question left hanging, was whether this pericardial effusion could have anything to do with anaesthetic the dog had been under last week for her spay. This made me recognise how everything interlinks and no piece of information can be discarded when evaluating a case. This is just one of the things which makes veterinary medicine such a challenging career. It’s a good thing that I like challenges!