I knew someone who had to get some test done on their intestines and they had to get injections of some medicine called something like "Lovenix" that was supposed to thin the blood. Why would you thin the blood when their might be cutting which could cause bleeding?

good question. the blood thinners should be stopped a few days before surgery and resumed right after, to keep the patient from developing a blood clot. i was the unlucky one, i developed a blood clot after surgery, because i wasn't put on a blood thinner.i got a clot in both lungs and i almost died. the doctor will probably stop the thinners before surgery, because if he doesn't, the patient might bleed to death.

depending on the situation, blood thinners may be used during surgery. At low doses, they don't substantially increase the risk of bleeding but may reduce the chance of developing blood clots. Some surgeons use them nearly on every patient who will undergo major surgery; others choose to use them selectively, in people who may have increased risk of developing clots. That includes obese people, people with history of prior clots, certain surgeries such as pelvic surgeries, very lenthy surgeries, etc. As with most decisions regarding surgery, it is a balancing of risk. It is not true, as stated in the above answer, that blood thinners must be stopped during the surgery. It's a matter of dose, and indications