Breathing problems

My 15 year old cat, Kitty was diagnosed almost 6 years ago with diabetes. We have had many ups and downs, he was on PZI for a few years and then we couldn't get it anymore, and so was put on Lantus, and was fairly well regulated, and for two years has done really well. A few days ago he started acting tired, and seemed to have trouble breathing. I checked his sugar and found that he was high in the morning, around 17 on the G test. I gave him his usual 5 units, but 12 hours later his sugar was still too low to give him a shot- around 7. I did not give him any until next morning, but by then he was having trouble breathing, his mouth open gasping. I gave him water and food by hand and then gave him his regular shot. He was not good all day, but I kept feeding him by hand throught the day and by the time for his evening shot his sugar was up, so I gave him his usual 5 units.
This morning he is breathing much better and was even able to eat a little on his own. I gave him some water and a little extra food by hand, and he is looking and breathing much better now. The question is this: His sugar this morning at 9 am was at 7 when it was time to give his shot, so I didn't give it, and waited. By 10 am it was at 9.2 and by 11 am it was 9.6. I will watch his sugar all day and give a shot when it gets higher, but I wonder, should I lower his dose to 3 units and try giving that every 12 hours. Do you think that he may have come to a point where he doesn't require so much and it is overlapping and causing this trouble. I would appreciate your opinions on what is happening here. I have put in a call to the vet, but one is out of town and the other will call later. Thank You, Lois & Kitty

 

The breathing may have nothing to do with the diabetes. In addition to URI labored breathing could be a tipoff of heart problems. Open mouth breathing is a very serious sign of illness and I suggest you get him to an emergency facility if you can't get him to your own vet.