The clearer your lungs are before surgery, the better you'll handle the anesthesia and the fewer potential complications you'll have. Both weed smoke and cigarette smoke are irritating to the lungs and contain a lot of crap. And both of them can dimiish the elasticity of your alveoli, the little air sacks in which the gas-exchange of oxygen occurs. In the hospitals in the area where I live, if they find out you've been smoking before surgery, they'll sometimes reschedule you for another day. That tends to happen a lot more when it's going to be big surgery involving intubation as they anesthetize you, and I'm guessing a cystectomy (depends on where the cyst is, though) might be simply sedation anesthesia. Take as many deep breaths as you can to clear your lungs and give them some exercise for the rest of today and don't smoke anymore. Ask your anesthesiologist when he calls you tonight if you're going to be intubated. Because if you are, you really need to try and remain smoke free afterwards, too, for 48 or more hours. Do a Google on "Smoking and anesthesia" and read what you find. This is fairly common medical knowledge (lest I be charged with giving medical advice).