Colonoscopy anesthesia: 7 things to know

If you’ve never had a colonoscopy before, you might have some questions about anesthesia. 

Is there more than one option, for instance? If so, how does each work, why might doctors pick one over the other, and what side effects can you expect to experience afterward?

For answers, we consulted anesthesiologist Katherine Hagan, M.D.

How many different types of anesthesia are used for colonoscopies?

Generally speaking, there are three types of anesthesia used for colonoscopies:

• Moderate or “conscious” sedation: This is the oldest method and the one many people are more familiar with. It combines a sedative from the benzodiazepine family, such as midazolam, with a synthetic opioid painkiller such as fentanyl. These are delivered through an IV and may be administered by a trained gastroenterologist or an anesthesiologist.
  
• Monitored anesthesia care (MAC) or deep sedation: This method typically involves propofol. It, too, is delivered through an IV but will be administered by the anesthesia team. It does not normally require a breathing tube.
• General anesthesia: This is the same type of anesthesia people have when they’re undergoing major surgery, so it is administered by an anesthesiologist. It also requires breathing assistance, because it can suppress normal respiration. Once a patient has a breathing tube in place, they are kept unconscious through a combination of IV drugs and/or gasses delivered through the breathing tube.

Which kind of anesthesia is used the most frequently for colonoscopies?

We shifted to MAC for colonoscopies here at MD Anderson a few years ago. While we use general anesthesia in some cases, most of our patients get monitored anesthesia care now for colonoscopies.

That means going to sleep in one room and then waking up in the recovery area, in terms of what you might remember about it.  Routine colonoscopies are normally done only once every 10 years, so it’s not something you’ll have to repeat any time soon, in most cases.

How do patients benefit from deep sedation for a colonoscopy?

It takes more time to properly sedate someone using moderate sedation. And deep sedation with propofol allows a patient to go all the way to sleep, as opposed to just being somewhat asleep, where they still might have some awareness of the procedure. Patients are very unlikely to have any conscious memories of a colonoscopy with propofol.

The drugs used during moderate sedation may also leave patients with a groggy or hungover feeling afterward, and there’s a higher chance of them experiencing nausea or vomiting. That is less likely with propofol.

Finally, delirium is more common among elderly patients receiving medications used for moderate sedation. And those side effects can linger for much longer than with propofol, which wears off more quickly.

How common is general anesthesia for colonoscopies? 

We might use general anesthesia if we discover that someone still has food in their stomach or if we know they’re going to have a very long procedure, such as an upper endoscopy that goes all the way down to the bile ducts, or a colonoscopy during which a large polyp will be removed. That’s because there’s an increased risk of aspiration, or breathing in something other than air into the lungs. And that can cause an infection.

But the more sedated you are, the more likely it is that you might need some type of intervention to help you breathe. If you receive deep sedation with propofol, there is always the possibility that you will require a breathing tube if you aren’t breathing well enough on your own. In that situation, you would also receive a general anesthetic. Still, in this situation, intubation is not our plan — it’s our backup plan. We rarely need to use a breathing tube during monitored anesthesia care. It doesn’t happen very often.

Do these drugs have any other side effects?

Sometimes propofol produces an uncomfortable burning or warm sensation in the vein, but it goes away quickly.

Propofol also wears off pretty quickly, so it won’t take long for you to feel normal after you wake up.

Can patients ever drive themselves home from a colonoscopy?

No. Afterward, patients must stay in a recovery area for between 30 to 45 minutes. Then, a friend or family member can take you home. No ride services are allowed. Your driver needs to be a trusted person who’s familiar to you.

Anything else patients need to know about anesthesia during a colonoscopy?

All of our endoscopic procedures are done under the “care team model.” That means you’ll be monitored constantly by either an anesthesiologist or a certified registered nurse anesthetist (CRNA) the whole time you’re under anesthesia.

Anesthesiologists typically cover more than one patient in multiple rooms, but a CRNA will be assigned to take care of you for the entirety of the procedure. And either the anesthesiologist or the CRNA will be in the room with you at any given time.

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