Saturday, May 30, 2015

Preaching To The Choir

There are some scientific papers out there that are so original and groundbreaking that they change the paradigm of science and medicine as we know it. Think about Watson and Crick's discovery of DNA or Marshall and Warren's description of H. pylori. These are truly revolutionary research that changed the course of medicine and well deserving of their Nobel prizes. This paper presented at the recent Digestive Disease Week, the preeminent GI conference in the country, isn't one of them however.

Presented at DDW by Dr. Otto Lin from the Virginia Mason Medical Center in Seattle, the study compared the effectiveness of the Sedasys system of propofol infusion with moderate sedation that GI docs normally administer. The Sedasys patients were first given 50-100 mcg of fentanyl followed by propofol infusion from the machine. The control group of patients received only midazolam and fentanyl. A total of 1,466 patients participated in the study. Of those, 1,013 underwent a colonoscopy, 285 had EGD's, and the rest had both.

So how did the robots do? According to Dr. Lin, the patients and physicians very much preferred propofol over the simple cocktail of Versed and fentanyl. Patients went to sleep faster, woke up quicker, and had better retention of facts after the procedure. Patients reported less pain during the procedure and less grogginess afterwards. However their overall satisfaction between the two modalities was not statistically different. Nine patients reportedly suffered laryngospasm that required mask ventilation to break. There were also cases of agitation and discomfort attributed to "monitoring" issues. Dr. Lin's team was so confident about Sedasys that they even started using the machine for off label uses such as complex colon polypectomies and endoscopic ultrasounds. However they didn't have enough numbers of those complicated cases to make any recommendations.

The researchers and GI docs present at the meeting hailed this paper as strong proof that propofol given by a machine is as safe and effective as one administered by an anesthesiologist. Naturally the GI audience in attendance would only see the results that were trumpeted by their GI colleagues instead of noticing the obvious and serious flaws in the study.

First of all, the study authors compared the use of propofol against a standard cocktail of Versed and fentanyl. That is hardly original work. There have been numerous papers detailing the superiority of propofol sedation against a combination of benzos and narcotics in GI procedures. It is well known that patients wake up faster, feel less confused afterwards, have superior amnesia of the procedure, and are able to leave the recovery room faster. So none of this paper's results are surprising. What they should have used as a control was propofol when given by an anesthesiologist to see if those criteria are any different when matched up against Sedasys. With this fundamental flaw in the study, the paper is essentially meaningless.

Then there is the question of the nine cases of laryngospasm among their patients. Nine episodes of laryngospasm seems excessive to me. The numbers sound even worse when one considers that the laryngospasms probably occurred within the 285 patients who underwent EGD's, not the 1,013 cases of colonoscopies. So nine patients with airway obstruction severe enough to recover positive mask ventilation is a very high rate of this complication.

I also wonder who provided the mask ventilation to break the laryngospasm. Was it the gastroenterologist? Would he have just dropped his scope in the middle of the case to run to the head of the bed to slap the mask on the patient? Was it the GI nurse who probably hadn't masked a patient since her last ACLS course a couple of years earlier? Or did they have to emergently scream for help from the nearest anesthesia provider to rescue their patient before they died on the procedure room table? My guess is that it was the latter since the GI knows that no anesthesiologist would willingly turn away from a patient whom they have never met or discussed the risks and complications of receiving propofol but is willing to help their fellow human being from dying of a needless complication of incompetent sedation.

So yeah the GI docs love the results of this "study" on the effectiveness of Sedasys. It tells them exactly what they wanted to hear. But with an estimated seven million EGD's performed in the U.S. each year, that translates to nearly 25,000 cases of laryngospasm and airway emergencies that require active intervention to keep the patient from dying if Sedasys is used for all of them. Those alarming numbers about Sedasys should be what concerns gastroenterologists and federal health regulators, not how much money they think they are saving from cutting out the anesthesiologists.

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