Apparently, this happened during that show according to wiki. I can believe that given the long set they did.
"Mike Portnoy collapsed after the show was over. The official statement on his FAQ reads: I collapsed due to over-exhaustion, dehydration, stress, too little food and nutrition, too many Red Bulls, etc. It took me several hours of throwing up, being wrapped in blankets and laying down before I was carried out of the venue hours after the show."