I don't know if anyone here can answer this or have any idea what happened to me when going under anaesthetic last week. I should first say that I have COPD from many years of smoking. I've had a very difficult time giving it away. I also should have mentioned what happened to me to the anaesthetist after I had come out of the operation but I was not feeling great with the after effects of being put to sleep. When the anaesthetist gave me the muscle relaxant in the operating room I suddenly found it very difficult to breathe. There was about 5-10 seconds of time between being given the muscle relaxant and then the anaesthetic, but during the small amount of time I was shocked at how hard it was to breathe. So, is this what is the riskiest part of being anaesthetized - the muscle relaxant? And what causes a cardiac arrest during an operation? Anyone else experience the breathing difficulty with the muscle relaxant? I have had two general anaesthetics but I was a lot younger, in my 20's then and didn't notice any breathing problems back then.