Boris suffered from Hypertrophic Cardiomyopathy (HCM) which caused Chronic Heart Failure (CHF). He had a blood test last August that confirmed the condition. He initially presented with slightly laboured breathing and had slowed up which was due to a small amount of fluid outside his lungs (pleural effusion). Within a few months the x rays showed fluid within his lungs (pulmonary Edema)
I resisted having fluid drained due to the dangers of the procedure, dangers of sedating and stress of vet visits (although Boris was calm enough to allow x rays without sedation) and relied on meds; mainly frusemide in varying doses depending on how difficult his breathing was. The tabs come in 20mg which I split into 1/2 and 1/4. From googling, it looks like they also come in 40mg. I kept a detailed record of dosage and can see that it ranged from 20mg to 27mg per day but on one occasion I gave 35mg responding to "coughing, uncomfortable and head hanging". He was much better after a big wee. I recall the vet referring to his prescription bible and showing me exactly what it said about dosage to help me understand better. He was so helpful throughout. Had a number of telephone consultations to cut down the vet visits.
Boris was also on Hypercard and Aspirin (he wouldn't tolerate my suggestion of Clopidogrel as too bitter tasting) . Meds were given 3 times a day at 8 hourly intervals and I spent virtually every waking minute for 4 months worrying that he may get a blood clot and be in pain. It was awful but he seemed well quite a bit of the time; just slower and slept a good deal. Had to keep him separated from the others too overnight to ensure he didn't get over excited.
I kept a record of his weight and breathing rate, videoing him and then replaying it to count and recount to ensure I had got it right as often I would be panicking about increasing the frusemide but vet was clear that stress and sedation were dangerous for my beautiful boy. He never got as far as open mouth breathing (which is extreme emergency requiring immediate oxygen therapy) but his nostrils flared on one occasion which required oxygen therapy overnight and he did develop an occasional cough. The cough is less common in cats than dogs.
The evening we found him was following a vet visit in the morning. He had been off his food for a few days and x ray showed little fluid so we thought likely potassium too low and vet gave him a tiny dose. He perked up hugely during the day and we went out for just over an hour early evening. It was such a shock. He looked peaceful and I can only hope it was quick.
I so understand what you are going through
It was such a lonely horrible time; hoping for a miracle whilst researching latest developments when my head was clear enough. I send both you and Moses by very best wishes
