Propofol in GI Endoscopy: a Large Clinical Experience

How We Discovered this Fork in the Road:

In the opening months of an ambulatory surgery center, the medical director, an anesthesiologist, was frequently available for propofol administration for endoscopic tests.  Knowing a second physician in the room means extra cost, we limited this approach to patients who would be difficult to sedate: (1) patients on methadone; (2) patients on daily narcotics; (3) patients taking multiple anxiolytics; (4) patients who appear terrified; (5) patients with a history of very painful endoscopic experiences (usually elsewhere); (6) some psychiatric patients; patients with a history of post-traumatic stress disorder; and (8) patients with a history of violence in the medical setting. 

We saw multiple advantages, with the main three being: (1) totally painless procedures; (2) rapid recovery; and (3) smooth titration.   We saw great potential.   We then addressed the issues in training nurses - the length and style of training and the fail-safes necessary.

Training:
In October 1998, the nurses began administering Diprivan for endoscopic sedation.  One anesthesiologist took the responsibility for overseeing their retraining.  The attitude was that we would be very selective in choosing ULENAs (upper and lower endoscopy nurse assistants), that they would have abundant recovery room experience and ample endoscopic experience, and they would be ACLS-certified.

The nurses observed Diprivan induction in the OR, watched a video of conscious sedation guidelines, and passed an exam of the pharmacokinetics and properties of the drug.

The final steps were the nurses observing an anesthesiologist sedating patients in the endoscopy suite, and then vice-versa.  The sponsoring anesthesiologist was one with 17 months experience with endoscopic sedation (some anesthesiologists sedate to deeper levels than necessary).  Overall, the extra training took the nurses two weeks.

Dosing:
We take into account the size, age, preprocedure anxiety levels, and psychotropic drug use in determining the opening dose of between 20 and 40 mg.  We've used Diprivan only.  By seeing the patient's response, the nurse administers enough propofol so that the patient's eyes begin to close over roughly 60 - 120 seconds.  The physician checks tongue tone then posterior pharyngeal sensitivity, or for colonoscopy, the digital exam then sigmoid sensitivity.  According to nociceptive body language, small incremental doses ranging from 5 to 30 mg are given at intervals.  The most common increment is 10 mg.  If there is uncertainty, it is always good to give a small increment and then wait 20 - 30 seconds to see what the result is.  As a rule, for any given level of body language disturbance, the amount needed varies with how much it took to get started.  The nurse palpates each exhalation.  Robust breathing is a sine qua non of considering another aliquot.

Monitoring:
The ULENA palpates every breath (through gloves and gown to fulfill safety requirements).  A pulse oximeter/blood pressure monitor is used. Supplemental nasal oxygen is used as well as a running IV.  The nurse is very attentive to the possibility of excess secretions and vomitus.  The nurse stays with the patient until the patient is alert enough to decide which kind of fruit juice he or she wants, ideally within two to four minutes after the termination of the procedure.

Patient Selection:
Outside of our protocol, we have performed nurse-administered propofol to ASA-4 patients in the hospital setting.  Titration is basically the same.  These patients tend to need less.  The basic tenet is that you can always give more, if needed, but the only reversal agent for propofol is time itself.

Our 4500 consecutive patients as of February 16, 2001 at the ambulatory surgery center have largely been ASA-1 to ASA-2, with roughly 10% being class 3.  Largely class selection has been a mixture of prudence with this new sedation technique and also that the surgery center attracts healthier patients. 

The last hospital patient who was not on a ventilator that had nurse-administered propofol for ERCP was a large 75-year-old ex-Marine who had four types of lung disease, two types of heart disease, autonomic neuropathy, sepsis, ileus, ruptured gallbladder, acute renal failure, and other problems.  We gave 20 mg to start and 30 mg all together.  His test was successful, quick, painless, and he spoke normally within ten seconds of removing the scope.

Many times we need anesthesiologists and we should consider their help according to the patient's individual needs and risks, regardless of ASA class.  Achalasia, upper GI bleeding, gastric obstruction, foreign objects, head and neck cancer, and surgically-altered anatomy may pose special challenges.

Results:
We have five gastroenterologists, with a small contribution from an outside surgeon, who have achieved over 7800 consecutive patients with no complications related to sedation, no mortality of any cause, and a perfect record of painless exams with total amnesia.  Our original three nurses have been joined by three others.  It is rare that patients cannot be discharged within 20 minutes.

Seventy-six percent of our patients feel they would be able to return to full work or leisure activity within two hours.  Most of out physicians in active practice have returned to work within two hours if they choose to do so.  Some surgery center employees have gone back to computer work witching 30 minutes.

Patient satisfaction has been very high and had enhanced the reputation of gastroenterology in our community.  Especially it seems colonoscopy has gained tremendously in patient acceptance.  Patients almost always remember the results the physician tells them before discharge, saving the patient the anxiety of not knowing and the physician many phone calls or unnecessary follow-up visits.  Frequently, and intense charismatic experience seems to occur in this setting.

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