Myfriend 27 years and will have a torn acl surgury tomorrow. they told him not to smoke 4days prior surgey, but he did today!how will this effect him?

Not good: Smoking causes problems with healing due to blood vessel constriction. I have seen wounds fail to heal at all because of smoking while instructed not to. He should discuss this with his surgeon before going into surgery.

Slow Healing: Bottom Line; If he doesn't quit his healing will suffer.

Healing: Cigarettes cause vasoconstriction meaning blood flow decreases to areas that need healing. I suggest quitting altogether, not just before surgery. Best of luck!

Should be OK: It is HARD to quit smoking! He should keep trying. His DR may be able to help.

Probably it will: not effect him because he is young and assuming that does not have any lung disease. He needs to call Anesthesia and inform them about his smoking.