These notes are based on observations & research relevant to Coco's particular case, which involved pleural effusions. Her condition included mitral valve insufficiency. The guidelines given are intended only to help a pet owner without other resources decide whether a pet should be taken immediately to an emergency clinic, not as a conclusive diagnostic checklist. If competent medical advice is available, it should be taken. In that case, the observable symptoms listed may be helpful to a veterinary professional in his advising the pet "owner". Some of the signs are subtle and subjective, and therefore might be missed by the average person. The assumption is that if these symptoms are seen by an untrained person past a certain stage, an emergency situation probably exists.
What causes congestion due to heart failure?
The heart functions in two ways. It pushes blood out through the arteries, and sucks it in from the veins. The greatest pressure is on the arterial side. Pressure is minimal on the venous side. The greater volume of blood builds up on the venous side, waiting to be pumped back through. (Normal state). When the heart is failing to function up to a certain level of efficiency, there is a buildup on the venous side in excess of what the heart can draw in. At some point, there may be seepage from this buildup (in the form of plasma fluids, not necessarily whole blood) out of the vascular system into organs and body tissues. This is the congestion that is referred to in congestive heart failure. Location of the congestion varies, and can be an indication of where the defect of the heart lies. One form, which Coco had, results in clear fluid leaking into the pleural space, outside the lobes of the lung, but inside the sac which contains the lung. The effect is to limit the expansion of the lungs, both by filling space and by breaking the contact with the pleura which is part of the mechanism of lung expansion.
Due to the fact that congestive fluids are often relatively "free" and unconfined, they are subject to shifting within the body. This makes some positions more comfortable than others for the pet. One sign of congestion is a reluctance to lie down on the side to sleep, or restlessness and frequent getting up when attempting to sleep in this position. Cats with pleural effusions will often sleep sitting up with their arms fully extended and head held up (Sphinx position) so that the fluids settle away from the heart and lungs. In extreme cases they may even try to sleep standing up.
Nature of Breathing, Demeanor and Responsiveness
The most obvious effect of pleural effusion is increased effort of breathing. This may not be noticed until the congestion has progressed, for two reasons. One is that cats have a natural tendency to "mask" their symptoms by self-limiting their activity so that they don't get out of breath. The other is that, like humans, cats have a certain reserve capacity to their lungs. Until the congestion limits lung expansion below this reserve there would be no functional effect unless strenuous activity was engaged in.
Early signs of excessive congestion are a lessened activity
level. (Which also could be due to any number of other medical
reasons, or hot weather, or laziness.) Overall attitude may not
change, the kitty may just choose to step up rather than jumping,
walk rather than running. It is possible that nothing is noticed
until relatively easy activity results in breathlessness. If the
kitty seems to lie around a lot, and when returning from the cat
box sits breathing quickly for a bit, and always prefers to assume
the "sphinx" position, never curled up, this bears a
Auscultation and Percussion.
Auscultation and percussion are diagnostic techniques that may be useful in detecting the presence of fluid in the body cavity. Auscultation is simply the medical term for listening, usually through a stethoscope. With practice, meaningful information can be obtained by listening with your ear held against your pet's side. The hardest part is often getting the purring to stop. Percussion is a technique in which you listen on one side, and tap on the other. The tap causes a sound wave to pass through the body and the presence of fluid may affect its resonance.
Auscultation is a skill to be learned with practice, and is to a certain extent subjective with relationship to a healthy cat. I'll try to give some general hints that I hope may be useful. I'd strongly recommend the purchase of a stethoscope. Simple models found for less than $10 are virtually useless for veterinary purposes, but servicable units may be had in the $25 range with 3 heads to cover every anticipated use. Recommended is one with a standard (pediatric) head, and a bell head).
Percussion as described in the texts involves laying the fingers of the left hand on one side of the body, and striking the middle knuckle of the middle finger with the middle finger of the right hand, while listening on the other side (with or without a stethoscope). In practical terms, none of us have three hands. I found that I was able to pick up resonance by tapping/slapping with the flat of the first knuckle of the middle finger, using the other hand to hold the stethoscope on the other side.
Pleural effusion was most generally detectable back of the lungs, i.e. toward the tail. My memory tells me that the presence of fluid between the tapping point and the listening point was evidenced by hearing a bell-like note pass across. The logic being that fluid is a better conductor of sound than air. On looking it up in my old vet manual, the opposite is indicated - resonance indicates air, lack of resonance, fluid. Either my memory, or my interpretation, is incorrect. My recommendation is to be aware of the technique, try it on your cat at all positions until you become familiar with the way he/she sounds inside. Then you will be in a position to tell if a change has occurred, which if nothing else may be meaningful to your vet.
Auscultation with a stethoscope can tell a lot about the insides of a body. It takes a lot of practice, but there are detailed descriptions in the literature that should enable anybody to get some kind of a handle on it, at least for their own purposes. As regards pleural effusion, the main usefulness that I found was that I could hear a muffled heartbeat further back (behind the lungs) when fluid was present than when it was not. Becoming accustomed to the sound of your cat's heart is a good exercise.
THE PRIMARY USE OF THE STETHOSCOPE:
While you are practicing auscultation (love that word), you will find that most of the time, you are listening to your baby purr. It will lull you almost to sleep at first, until you remind yourself that you are trying to engage in serious business. You will probably not do what the book says, however, which is to shake the kitty or display a dog. What you will do is try to escape the purr by moving the stethoscope south, away from the source. What you will find there is a delightful and ever-changing assortment of musical gurgles, squirts, and other indescribable pleasures. Eventually, maybe kitty will get bored and stop purring. Maybe not.