Ketamine for Depression in the ED.

Ketamine, a dissociative anesthetic agent, is the world's most widely used general anesthetic.  It is the battlefield anesthetic agent of most modern militaries, and is the drug of choice for surgery in remote areas by bush surgeons, and organizations such as Doctors without borders.  It is also, as most of us know, increasingly the drug of choice for procedural sedation for adult patients, as well as it's more traditional role in paediatrics, and across an ever widening range of indications.  It is also, surprisingly, turning out to be an excellent agent for acute, or even chronic depression, particularly acute suicidal depression, which so often presents to our EDs.
The principal barriers to its use in ED are the possibility of excessive salivation, the possibility of laryngospasm, and the so called emergent reaction.  The hyper salivation used to be treated in an anticipatory fashion using atropine or glycopyrrolate, however, this side effect is now considered so rare, that most clinicians who use the drug frequently, will only give these meds if the hyper salivation actually occurs.
Laryngospasm is also exceedingly rare, occurs more often with high doses, - above what we use for depression, - and can usually be managed by bagging.
None the less, both these reactions need to be borne in mind when using the drug, and information concerning them should be a part of informed consent.
Many ER docs and anesthetists are concerned about managing the emergent reactions which can occur.  The most likely patient to develop an emergent reaction is a young woman between the  ages of 17 and 23 who dreams in colour.
The best way to manage an emergent reaction is to discuss its possibility prior to administering the drug, informing the patent that when emerging from the effects of the drug, things may seem a little unusual for 5 - 15 minutes, and emphasize that this is an effect of the medication, that it can be odd sometimes, but that it will assuredly pass, and we can give something to the patient if it is troubling.  The usual medication used is 1 - 2 Mg of Midazolam I.V..
There are many protocols for using Ketamine for depression.  The dosage is usually .35 Mg/Kg I.V..  Some workers put it in a mini bag and infuse it over 15 minutes.  Others give it by I.V. push.
The protocol I have used most frequently is .35 Mg/Kg. I.V. push.  I always stay with the patient for the first five minutes or so, and sometime longer.  I also put my phone under their pillow and play some relaxing music, - what Ali once called "Spa Music."  The type music itself is not particularly important, except that it should never contain English words, and should be calming rather than excitatory.
I prepare the patient for the experience by telling them that the psychological material which surfaces can be a bit dreamy like, that occasionally it can be weird or even frightening, and that two things are important to understand.  Firstly that these images and sensations are the because they have taken the drug, and that they will pass, and secondly, that they should not try to interpret or talk about the experiences in any way during the experience itself.  Instead, they should simply breathe through whatever is happening, and we can discuss it at the end of the experience.  I try to emphasize this aspect of the experience if they become distressed or agitated - which can sometimes happen, - during the experience.  It is important to note that often on emergence, at least partial amnesia has occurred.
At NGH ER I have given Ketamine to approximately 15 people in the course of the time I have been using it for this indication.  13 have had excellent short term results, and two have had very unusually successful log term results.  One of these was a man who was acutely suicidal, partly as a result of drinking a dozen beers and some wine per day for several years, as a result of a PTSD he experienced after an assault.  When I saw him again for anther indication nine months later, his depression had lifted and he was down to one glass of wine at supper.
One of the two failures was a woman who I misdiagnosed.  Her actual reason for being in the ED was drug seeking for her Benzos which had run out prematurely, which I did not recognize until she said, "that was interesting, but I am not any better.  Now can I have a prescription for my Ativan."    The second was a woman in an acute situational crisis.  She did not have any bad effects from the Ketamine, even though her experience was among the weirdest of the patients I have treated in this fashion, but neither did she get any relief.  She was hospitalized at BGH later that day, and has ultimately done well.
Ketamine can also be used in large doses for sedation for the wilder patients who come in wishing to re decorate Exam 2.  Doses of up to 200 Mg. I.M. have been used for this indication, quite safely, instead of the usual Haldol/Ativan combo.  It is however important to understand that at these dosages, - as opposed to .35 Mg/Kg., you are doing procedural sedation, and all the safety requirements associated with this need to be in place.
I think Ketamine as a  treatment for acute suicidal depression is worth while considering.  It is no different than using Ketamine for procedural sedation, or for post intubation sedation and pain management.  There is no need to be scared of the medication, and there is an emerging corpus of literature to support your decision.  There is also a race on in the pharmaceutical industry to develop analogues of Ketamine that have the same effects, but are devoid of the dissociative effects.  You may follow the link below to take a look at some of these.

http://www.npr.org/sections/health-shots/2015/05/28/409800015/ketamine-depression-treatments-inspired-by-club-drug-move-ahead-in-tests?utm_source=facebook.com&utm_medium=social&utm_campaign=npr&utm_term=nprnews&utm_content=20150528