Chest pressure after colonoscopy is just gas

Dear Dr. Roach: I have a question about a recent colonoscopy procedure I had. The procedure was the second I've had, the first being when I was 50 (I'm now 60). I woke up this time with a lot of chest pressure, and felt like I was having heart pains. I had a heart attack in 2008, so I know the symptoms. My chest felt "solid."

The nurse said it was just air and that it would release after a while. She said I should go home and lie down. I was uncomfortable with her answer, but after about four hours and a lot of "releasing," the discomfort subsided.

I understand that the procedure requires air to be used for the examination, but I don't remember having that discomfort when I had the procedure the first time. Should the doctor have done something to release the air after the procedure? -- M.H.

Answer: During a colonoscopy, the bowel is filled with gas, usually air, so the lining can be examined for polyps or other abnormalities. In a colonoscopy, up to 17 liters of air is pumped in (this is about as much as in a 1-foot balloon). All of that air can cause discomfort, and this is a major reason why most people receive sedation for a colonoscopy. When the scope is withdrawn, the physician will try to remove the air, but, as you have found, that process is imperfect. The air needs to be expelled (I could use a rude term here) by the patient.

Many experts recommend using carbon dioxide instead of air. CO2 is easily absorbed by the gut and exhaled by the lungs. Several studies have shown that patients using CO2 instead of air experience less discomfort, but most endoscopists have not started using it. It is not particularly expensive, but it does require extra equipment. I hope more adopt the use of CO2.

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