For example, the odds of developing colorectal cancer between the ages of 20 and 40 in the absence of specific risk factors are about 1 in 1,250 (0.08%).The rate of complications varies with the practitioner and institution performing the procedure, and other variables. Perforation
The most serious complication generally is gastrointestinal perforation, which is life-threatening and in most cases requires immediate major surgery for repair. Fewer than 20% of cases may be successfully managed with a conservative (non-surgical) approach.A 2003 analysis of the relative risks of sigmoidoscopy and colonoscopy brought into attention that the risk of perforation after colonoscopy is approximately double that after sigmoidoscopy (consistent with the fact that colonoscopy examines a longer section of the colon), a difference that appeared to be decreasing. Bleeding
Bleeding complications may be treated immediately during the procedure by cauterization using the instrument. Delayed bleeding may also occur at the site of polyp removal up to a week after the procedure, and a repeat procedure can then be performed to treat the bleeding site. Even more rarely, splenic rupture can occur after colonoscopy because of adhesions between the colon and the spleen. Anaesthesia
As with any procedure involving anaesthesia, other complications would include cardiopulmonary complications such as a temporary drop in blood pressure and oxygen saturation usually the result of overmedication, and are easily reversed. Anesthesia can also increase the risk of developing blood clots and lead to pulmonary embolism or deep venous thrombosis.
In order to inspect this surface thoroughly, the physician blows it up like a balloon, using air from a compressor or carbon dioxide from a gas bottle (CO2 is absorbed into the bloodstream through the mucosal lining of the colon much faster than air and then exhaled through the lungs which is associated with less post procedural pain), in order to get the creases out. The stomach, intestines, and colon have a so-called "second brain" wrapped around them, which autonomously runs the chemical factory of digestion. It uses complex hormone signals and nerve signals to communicate with the brain and the rest of the body. Normally a colons job is to digest food and regulate the intestinal flora. The harmful bacteria in rancid food, for example, creates gas. The colon has distension sensors that can tell when there is unexpected gas pushing the colon walls out—thus the "second brain" tells the person that he or she is having intestinal difficulties by way of the sensation of nausea. Doctors typically recommend either total anesthesia or a partial twilight sedative to either preclude or to lessen the patients awareness of pain or discomfort, or just the unusual sensations of the procedure. Once the colon has been inflated, the doctor inspects it with the scope as it is slowly pulled backward. If any polyps are found they are then cut out for later biopsy. Some doctors prefer to work with totally anesthetized patients inasmuch as the lack of any perceived pain or discomfort allows for a leisurely examination.