If I were you, I wouldn't get anything bigger than a large.....unless you plan on gaining a few pounds in the next few years and you plan on washing it a lot. This is the best deal around for straitjackets. http://www.handcuffwarehouse.com/hurestja.html
This is a very heavy jacket that will last a lifetime.
That would be a Humane Restraint Co. Jacket and, at the ~ 44 chest measurement, large would definitely be plenty big enough (maybe a bit too big); one might even squeeze into a medium.
As for washing: I tried washing mine years ago; the canvas sleeves fill with water, causing a weight imbalance in the washing machine. I had to stop it 2-3 times to dump the water out of the sleeves. Better just to air it out.
And yes, it is very heavy and sturdy. A new HR jacket is about as stiff as cardboard!