Radio Freethinker

Vancouver's Number 1 Skeptical Podcast and Radio Show

Deep Sedation: Not for Everyone

Posted by Jenna Capyk on November 21, 2011

We don’t often include personal stories on the blogs, but in this particular post I’m giving a short description of some a surgery I recently underwent. I had all four of my wisdom teeth removed in an ostensibly routine procedure. As it turns out, what transpired was not entirely routine. I would therefore like to tell you a story about the Little Maxillofacial Surgeon that could, alternate title: A Tale of Anesthesia?

Some things in my surgery went well, or at least went as planned. For example. I went in to the appointment with four more teeth than I left with. Well, strictly speaking they gave me the rather gory extracted teeth in a paper cup, but I definitely had four fewer teeth in my mouth. I also left with a pocket full of rather delightful drugs and returned to a house full of cold jello and luke-warm soup. What didn’t go so swimmingly was the anesthesia. Picture this, you’re lying on a table hooked up to a machine monitoring your vitals and a doctor sticks a needle in your arm, says you’re about to drift off “just like you’ve had too many margaritas” and then starts working away. But wait, there’s pain, and you’re awake, and you’re being held down by the shoulders as your legs shake and you cry and yell and squirm on the table. They call for more drugs, but to no avail. They strap on the laughing gas but alas, there is no laughter to be had. Four teeth later you’re sitting in a recovery room, bleeding, crying, and rather traumatized. It happened to me, but the question is, could it happen to you?

As it turns out there isn’t actually much in the literature about failed anaesthesia during dental surgery. Given the how these procedures are, I found this rather surprising. I was, however, able to find one study that looked at the incidence of failed “deep sedation” and correlations with various conditions on the part of the patient. I was a little shocked to find that my experience actually would have been deemed as successful deep sedation, under this study, notwithstanding the fact that the sedation was not nearly as deep as I would have liked. The reason for this is that they defined “failure” as the inability to complete the surgery due either to patient combativeness or unsafe vital signs during the procedure. So perhaps if I had been lucid enough to kick my surgeon in the groin I would have a couple more teeth and a true story of “failed deep sedation.”

What is deep sedation then? Deep sedation and general anesthesia are both defined by depressed consciousness or unconsciousness including partial loss of protective reflexes like the ability to keep an airway open, to respond purposefully to physical stimuli or oral commands, and the ability to swat away sharp objects entering your oral cavity. Such sedation is accomplished through intravenous administration of a variety of different drugs or combinations of drugs.

From my research, it looks like about 1 % to 2 % of all patients experience failure of such anesthesia, although the study looking specifically at maxillofacial procedures like mine only counted those where they were unable to finish the procedure. Criteria for failed anesthesia in other fields varies, and so a direct comparison is pretty difficult.

The conclusions from the maxillofacial study were within this 1-2% failure range, and two main factors were suggested to be paramount in determining how a patient was likely to respond to deep sedation. The first is, unsurprisingly, pain. Local anesthesia (your run-of-the-mill freezing) is required along with the deep sedation to make sure that you don’t painfully startle the patient into wakefulness. The authors of this study assert: “painful stimuli in an already suffering and frightened patient are enough to arouse them during deep sedation.” As someone who was recently similarly aroused: duh. The point here, though, is that the doctor is not able to count on the patient’s lack of consciousness as adequate pain control and very effective local freezing actually helps the effectiveness of the more general doping.

The second factor that was perceived to be even more important than local pain control was the mental state of the patient. Anxiety was brought up again and again as one factor that can make deep sedation less effective. This is complicated by the fact that most patients choose the deep sedation option specifically because they are already anxious and are seeking to relieve said anxiety. You can see the circular logic here. The study authors urge offices to try to create a soothing environment, but comically concede that this can be rather difficult in the presence of noise from a dental drill. It turns out that anxiety is such an issue in dentistry and dental surgery that there is actually a Corah Dental Anxiety Scale. This is a questionnaire designed to assess the patient’s attitude toward different dental-related scenarios. I can only assume that this ranges from post-op jello eating to awaking screaming mid-molar-drilling. The bottom line is that anxiety is a major contributing factor in the success of dental procedures in general, however there is almost no literature on the correlation between prior anxiety and procedural outcome.

Things that did not turn out to be much of a factor in anesthesia effectiveness were length of procedure and pre-existing medical conditions. There are some exceptions with cardiovascular conditions as deep sedation causes different responses in these physiological systems. The authors also noted that experience of the surgeon could have something to do with it. Again, duh. Although there are some speculation about GABA-A receptors and alcohol abuse being contributing physiological factors, it is unsupported by the evidence at this time.

For myself, I can say that I’m glad I had a technically “successful deep sedation” experience, wish I had had a subjectively “successful deep sedation” experience, and hope to be back on steak and raw vegetables soon. In the mean time, remain calm, and always bring your anesthesiologist cookies.

One Response to “Deep Sedation: Not for Everyone”

  1. robertschrantz said

    Thanks for sharing the story…Really Deep Sedation: Not for Everyone..

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s