View Full Version : Anesthesia Awareness, Please help
09-24-2006, 12:09 AM
I am a SICU RN currently taking my last class in a BSN completion program. It is my dream to pursue nurse anesthesia. I try to turn every project I am required to do in my program to anesthesia. I am writing a paper on Cyber support available to professsionals and patients regarding anesthesia awareness. I did purchase the book Silelnced Screams. I am wondering if anyone can share any situations they have or have learned from related to anesthesia recall.
Are you aware of any discussion groups for patients to share their experiences? I have great respect for the posters on this site and respectfully ask for your help. How do you go about interviewing patients to see if they have recall? Have you had a patient say they remembered everything, but could not back it up?
I thank you and appreciate any help or advice you can provide.
09-24-2006, 06:22 AM
This is an area difficult of study. The reasons for this include the fact that the actual incidence of awareness under anesthesia remains unknown. Previous reliable estimates placed the incidence at around 1:250,000 anesthetics. Aspect Medical routinely claims it is more frequent than 1:20,000. Even with the higher frequency, that would translate to 50/million anesthetics.
Such an incidence would require a study population in the multiple millions to generate enough statistical power to come to a believable conclusion. Obviously, if the true incidence is less frequent, even bigger samples would be required for adequate statistical power.
The other great issue is defining what me mean by "recall". The sense of hearing is the last faculty to be lost with onset of anesthesia and the first to be regained. Patients can hear things, without knowing where in the operative process they find themselves. I have had patients who insist they had recall go on to describe having the dressing applied. Coming up with an objective definition is a problem.
In my personal belief (as opposed to being a fact), the increase in the incidence of reported awareness that has developed since the 90's, and which parallels the decline in the use of nitrous oxide, is causally related to that decline. The rise of the myth of amnesia being attainable by 0.5 MAC of an inhalation agent contributes mightily to this, in my opinion as a pharmacologist.
I call it a myth because as a pharmacologist by education and an applied pharmacologist by profession, I have never seen evidence, clinical or research, to support the assertion. I know from clinical experience that 70% nitrous, if combined with a reasonable dose of narcotics reliably produces amnesia. 70% nitrous would NOT be half MAC, it would be more like 0.7 MAC. Patients receiving 50% nitrous DO NOT HAVE AMNESIA. Ergo, I am unpersuaded that 0.5 MAC of something else will do what 0.5 MAC of this will not.
So, good luck with your study project. Just because it is difficult doesn't mean you can't make a meaningful contribution. Just don't accept unsupported claims as fact. Regards, Lou
09-24-2006, 09:44 AM
Hey ccrn & all the best in your pursuit of our profession.
Generally... when I see my pts post-op, I will be very forth coming in asking them if they remember anything, or I may ask what the last thing they recall was. If they say yes, I ask questions to elaborate on their memories.
We had an instance within our group recently where a pt claimed she had recall. The anesthesia providers involved interviewed her. She was offered psychological counseling, but she declined. Numerous calls & followups were done. She later (a few months after the fact) decided that the incident was most likely a vivid 'dream' and did not think that she had recall afterall. My point being that we openly addressed it & offered her as much assistance as she needed to resolve any issues.
I have heard of other situations in the which the pt could state verbatim the conversations that were occuring. Pretty safe to say that pt had recall.
To expand a bit on what Lou was talking about, b/c I'm not sure if you have been informed yet of the anesthesia lingo... MAC stands for minimum alveolar concentration. It applies to the anesthetic gases that we use (volatile & inorganic). Every agent has a MAC value which is represented as a %. So... for example, Sevoflurane has a MAC of around 2% (depends on what reference you read). One MAC is the value at which 50% of pts will not move in response to a stimulus (such as surgical incision). To keep 95% of pts from moving with stimulus, the literature states that roughly 1.3MAC is ideal. This explanation is very simplified as many factors can affect a pt's anesthetic requirements. When Lou referred to 0.5 and 0.7 MAC, this is what he means.
Here is a reference list of MAC values as published in Clinical Anesthesiology by Morgan, Mikhail & Murray. As I had stated before, these values vary a bit depending on what source you read.
Nitrous oxide 105%
Hope this is helpful. All the best!
09-24-2006, 10:03 AM
Click HERE (http://www.nurse-anesthesia.org/showthread.php?t=162)for a post about it.
I think there is always going to be a percentage increase in the phenom. due to sensationalism. The more people hear about this (and the more lawsuits and settlements occur), the reports will increase.
I do not want to lessen the terror that Anesthesia awareness must be for those who endure it however, I wonder how much of it is a bad dream under anesthesia, a pt looking for a paycheck or a true awareness. Its hard to say. How can you measure such a thing?
09-24-2006, 11:58 AM
Lou, Chris, and Mike,
Thank you for your responses. They are all very helpful.This is the best and most professional website for CRNA's, SRNA's, and those very serious about entering this awesome profession. Thank you for your understanding and helping me in my research. I am just at the beginning of my project. It seems like this subject is going to be even more sensationalized with the movie Awake coming out. I don't think the general public understands what this really is. I am interested in it because I hope to someday be a CRNA and want to do everything in my power to prevent it and dispell myths. I am more concerned with the patient that is paralyzed and can feel everything. This is truly a tradgedy. I know there are some cases of it,but this seems like it would be extremely rare.
Are there any other CRNA's out there with advice or situations to share? This is very beneficial to talk about. I recently went to a seminar where a CRNA that was in active duty in Iraq spoke about this. In many situations he did have quite a bit of recall and some sensations but that was related to patients being major trauma and in middle of CPR when he got them. I understand this is a whole different story when you are saving a life and you have zero BP. Interestingly, this guy was a very strong proponent of the BIS monitor. I really don't want to go there, I am quite skeptical about this monitor and I am not even a SRNA yet.
Thank again for your help. Other CRNA's please share your experiences.
09-24-2006, 02:09 PM
One thing to add... most common times for recall (according to literature) - trauma, OB & during cardiac rewarming.
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