Vince needs to see a vet immediately!!
Vince needs to be put on antibiotics such as baytril + azithromycin (10 mg/Ib), may need a dex injection, may need Lasix, may need a bronchodilator, may need to be put on oxygen
A very tiny piece of dark chocolate (not milk chocolate) may help to keep his airway open until you can get to a vet
It may also be too late and Vince may need to be humanely put to sleep by a good vet to prevent further suffering - you will need to be his advocate because most vets do not know how to do it properly
Therefore you will need to ask questions and make sure it is done properly …. and stay with Vince if at all possible ……….
Vince will need to be given the gas/oxygen mix used for surgery, once deeply unconscious the vet will test for eye and toe reflexes (gently pinch the toes), once unconscious to at least a surgical level Vince will be injected, Vince will need to be kept unconscious with the gas/oxygen mix until dead …. he will stop breathing and awhile later his heart will stop beating …. his brain will continue to be alive for several minutes …… the vet will check for a heart beat several minutes after the vet was unable to detect a heart beat, to make sure his heart has stopped.
I always take my rat's bodies home so their friends know what happened to them, and later have them cremated.
A conscious rat must never be injected into the heart - this is so cruel that it is illegal in some places
I am very sorry that this is happening to Vince