Expert: Jennifer Evans, MSN, CRNA - 1/2/2012

Question
Thanks for reading my question.  My PCP has me getting a colonoscopy due to bad family history; I was supposed to do this at age 40 and I'm now 59 so I'm a little late at getting this done...and I have avoided this test because of the sedation that is often (but not always used). If I get sedation I would like to avoid the amnesia effect if possible: I understand that the versed/fentanyl combo causes the worst amnesia, especially if higher doses have to be used.  The endo doc recommends propofol as "wonderful" but she won't give me specifics about it's amnestic effects; my layman's understanding is that ideally a patient would "sleep" thru the procedure with propofol then wake up quickly. Would one expect amnesia beyond that normally experienced while asleep?  The GI doc didn't see to know and the anesthesia service that they use wasn't very helpful.  I don't really want sedation anyway and will possibly just skip the sedation drugs if amnesia is possible.  Couldn't they just have some painkiller (they use fentanyl) in standby is the exam got too painful?  It's fast-acting and they use it in the combo anyway; I realize that painkiller only is not the "usual" way that they do  it, but for me it's shaping up as a choice between fentanyl only or nothing.  I would value your opinion. One last question: the CRNA told me that if I opted for no drugs (did not sign the sedation consent) that she would still have to be present???? Is this right?  thanks

Answer
Hello Bob,

 Midazolam (Versed) or the family of drugs called Benzodiazepines (Ativan,Xanax,Valium) cause the most prograde amnesia. Versed can make patients have entire conversations that they don't remember. It is the Versed in the Versed/Fentanyl combo causing the amnesia as Fentanyl is a narcotic for pain and in low doses does not cause unconsciousness.

Propofol is nicknamed "Milk of Amnesia" because of it's milky white color and that Anesthesia Providers are licensed to use it.  It's amnesia properties haven't been extensively studied although it is believed to cause mild amnesia because the patient falls asleep so quickly from propofol and therefore dreams quickly and does not remember.  Even low doses of propofol are potent enough to induce sleep.  People usually fall right asleep and do not talk with Propofol.  All brain wave studies have shown the positive areas light up  while asleep with Propofol demonstrating that it causes positive/pleasant, and/or romantic dreams.  You should expect amnesia like that from sleep, and during twilight anesthesia with propofol it is possible to still hear the procedure, if you are in and out of sleep.

Most people who have EGDs or Colonoscopies opt for a Propofol anesthetic because the patients sleep through the procedure while breathing on their own, and because of the nature of the study they do not want to be awake during the procedure.  A lot of practitioners like for the patient to be asleep because the inflation and turning the scope in the bowel can be uncomfortable and the exam is more awkward with an awake patient, but nonetheless it is the patient's choice.

You can use Fentanyl only if you feel you want to be awake for the procedure.  Depending on the clinical site you can use an infusion of Remifentanil, an ultra-short acting narcotic which would keep you pain free and completely awake in a low dose infusion.  Remifentanil is very expensive and most outpatient clinics do not supply it; usually just hospitals have it.

Where I work we just use straight Propofol infusions and patients do very well and go home quickly.  I understand you do not want to have amnesia, but are you willing to sleep through the procedure?  I believe  Propofol only would be your best decision as it can be awkward having a colonoscopy with 3-4 people in the room.  Sometimes for better visualization or to maneuver around a curve they need to press on your abdomen and that can be painful too.  These moments of painful stimuli will be harder for the anesthesia provider to counteract with just Fentanyl, but easier to counteract with Propofol.  If you have a good rapport with your PCP and trust the care that you have received you should feel comfortable falling asleep in their care.  

**With a family history requiring a recommended baseline @ 40 the procedure could take longer if there are polyps or patches that they need to biopsy.  It is always better to discuss the findings with your doctor when you are awake and not under the influence,  even  of Fentanyl.  Propofol Only will help you wake up quickly for debriefing as well.


As for a CRNA needing to be present: It depends on the policy of the clinic/hospital, but most places require a CRNA to be present if the procedure is booked as Anesthesia Standby or Monitored Anesthesia Care (which is what propofol would be), because in the event you need further assistance, one needs to be assigned to the room and ready to help.  If it booked as straight local, the anesthesia provider does not have to be present and nothing but local, like lidocaine, is used.  I have never seen a booking for a straight local colonoscopy and do not believe that is even an option, but you could ask.


Good luck & I Hope this was helpful to you!

-Jennifer, CRNA