Ketamine? What is it? What’s it used for? Where did it even come from? Ketamine is a pharmacological drug that was discovered in 1962 and created by scientist Calvin Stevens, PhD. It was first tested on humans in 1964 and then was approved by the United States in 1970. During the Vietnam War (1955-1975), it was used mainly for surgical anesthesia. After the Vietnam War, with the success of the drug, it was introduced into the World Health Organizations List of Essential Medicines.
Ketamine is considered a dissociative anesthetic drug. This drug makes the patient detach from themselves and from the environment. This drug disrupts the neurotransmitter (brain chemical) glutamate. Glutamate is involved with learning, memory, emotion, pain recognition. It can exhibit sympathomimetic activity which can lead to rapid heart rate and elevated blood pressure. The drug was originally produced as a fast acting general anesthesia but now in today’s world, the drug is being introduced for pain control, depression management, veterinary practices, EMS ambulances, psychiatric patients with excited delirium syndrome, septic shock patients, hypotension patients, and even burn patients. With so many uses for this drug, there is still a hesitation on using it in the medical field. Ketamine started becoming popular for night clubs during the 1980’s. When used at high dosages, people can feel like they are falling into what is called a “K-Hole.” This is when the patient is on the verge of becoming unconscious. Overdosing can become deadly, Narcan will not work for this drug, as this isn’t an opioid drug and at higher dosages the patient can become addicted, but at lower dosages for medical reasons that is quit rare.
For a post related to Narcan administration, check out this post:
A couple years ago, my partner and I responded to a patient in her early 20s. Patient was reported to be unresponsive by her mother. Upon arrival, we noted that patient was lying supine on the living room floor. Patient was still unresponsive, breathing 2-4 times a minute, and cyanotic. A strong carotid pulse was…
Ketamine can be given to the patient multiple ways, including intravenous, intramuscular, orally, nebulized, rectally, and sub-cutaneous. It has high lipid solubility, meaning it can rapidly cross the blood-brain barrier, providing rapid onset of action usually within 1 minute after administration. Higher dosing for combative patients in the pre-hospital field is usually around 4mg/kg IM (This can vary on your service so please use your guidelines). It provides a good analgesia while keeping the patients airway patent, ventilation rate normal, and less strain on cardiac volume. Based on these facts, ketamine has been becoming popular in the emergency rooms for pain control. In multiple blind studies, over the course of decades, Ketamine given to patients with musculoskeletal trauma, given at low-dose by subcutaneous dosages (0.1 mg/kg) vs intravenous morphine (0.1 mg/kg IV every 4 hours) demonstrated better pain relief, less sedation and less nausea and vomiting with ketamine than with morphine. In addition, none of the patients in the ketamine group required supplementary analgesia. For low dose ketamine, the dosage ranges from 5-30mg (.5-1mg/kg).
Ketamine has also many other benefits compared to your usual morphine or fentanyl for pain control. Ketamine has been on the rise for elderly patients in the pre-hospital field in a state like Arizona. With opioid drugs like morphine and fentanyl, the patient can lose their respiratory drive, go hypotensive and possibly overdose at low dosages. With NSAIDs the elderly could have worsening side effects with worsening renal failure, GI bleeding, and lack of titration for pain relieve. Ketamine started being given in a sub-dissociative dosing range (0.1-0.3 mg/kg) resulting in anti-hyperalgesia (decrease sensation to pain), anti-allodynia (pain from a non-painful stimulus) and anti-tolerance, which makes ketamine a useful analgesic for managing a variety of acute and chronic painful conditions like cancer, fractures, etc. in the elderly.
Ketamine’s effect on the respiratory center and circulatory system is quit different to the other kind of anesthetics, like Etomidate. It usually stimulates rather than depresses these systems. There have been times the patient has given ketamine and had a surgical procedure and not needed airway support. There is some confusion still with this drug though, as providers think it is a paralytic like Succinylcholine, Rocuronium, and/or Vecuronium. Ketamine is not a paralytic.
For a post on Ketamine use in asthmatic patients, check out this post.
This drug has recently become popular in the EMS field in 2016. Ketamine is an easy to dose drug that is weight based, with multiple ways to administer the drug for safety of the EMS provider and the patient, and also appropriate time of onset of the drug. It has been the “go to” drug for a lot of EMS providers in recent years, especially for the EMS providers in the state of Arizona and Ohio. The primary mechanism of action that interested the drug into the EMS field was three things, analgesia, amnesia, and hypnosis.
With the rise of drug use going on in the nation, a new syndrome is on the rise called Excited Delirium Syndrome. This syndrome is from stimulant abuse that alters with the patient’s dopamine processing in their brain to cause them to become hyperthermic, agitated, violent, and possibly even cause sudden cardiac death. There are only a few drugs that can help patients like this, one being midazolam (Versed), the other being Haloperidol, and then Ketamine. One downfall in giving patients like this Versed, which is a benzodiazepine, is the slow onset of effect given IM route. The downfall with giving Haldol, is it lowers the patient’s seizure threshold. So how is Ketamine beneficial in a patent with Excited Delirium? Ketamine works quickly giving it IM route and also IV administration if doable. Ketamine doesn’t lower the patient’s seizure threshold and is still able to provide the patient with an open and patent airway without jeopardizing the patient’s blood pressure making them hypotensive. In 2005 Hennepin County EMS had 5 Excited Delirium patients that were all 5 were given IM Ketamine. In all 5 cases, none of the patients become more violent after the administration of the drug and more importantly no adverse effects were seen by the EMS providers. In Ohio Columbus Division of Fire published an article in 2015 on them giving patients Ketamine to thirty-five patients. They stated they had a 91% success rate after the administration of Ketamine, with an average dosing being 324mg IM. In three patients Ketamine didn’t help and they had to go to Versed.
Even though Ketamine is still new to the EMS community but with it having so many advantages. It’s shocking that over the recent years it has just been introduced to the EMS field. It has been advocated as one of the safest and most versatile anesthetic drugs for the EMS field. Hopefully in the near future many more EMS providers can see the benefits of Ketamine and introduce this drug to their ambulances. With the proper training and knowledge, Ketamine can perform many benefits to the EMS providers, public, and most importantly the patients that EMS providers encounter on a regular basis.
Post Author: JD
Scopeducation Admin Insert:
Ketamine dosages vary depending on your service depending if you are prehospital or hospital. Please make sure you follow your specific guidelines. This post was for general education on the subject. We have seen in many instances of Ketamine administration in which patients have unfortunately ended up going into cardiac arrest. Rapid administration of this drug can lead to apnea/respiratory arrest, laryngospasms, and even hypersalivation. Very few medications should be “slammed” into a patient (obviously the best known medication you need to rapidly administer is Adenosine). Administer slowly, especially when giving it through an IV/IO. Patient’s may experience an emergence reaction which is when they awaken from sedation and will become agitated and hallucinate. These are best treated with a benzodiazepine of your choosing. With any sedated patients, you must constantly monitor their cardiac rhythm, SPO2, ETCO2, BP, ect. Basically the whole enchilada of vitals. You wouldn’t give a patient a bunch of Propofol and just look at them and not monitor them, so why is there confusion with Ketamine? And once the patient is sedated IMMEDIATELY PLACE YOUR MONITORING EQUIPMENT! As medical providers, we should know everything about every single medication we administer. Same goes for Ketamine. So do your research on this before administering it. No medication is ever 100% safe. But when Ketamine is used when it is needed and the patient and their vitals are monitored, there rarely will be an issue.
This site is meant to be used for educational use only. We strive to push evidence based medicine with no bias to help you obtain all the important information. You should always follow your protocols that have been set in place.
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Davis, K. (2017, October 12). Ketamine: Uses, effects, risks, and warnings. Retrieved September 15, 2020, from https://www.medicalnewstoday.com/articles/302663.php
Henderson, L. (2016, October 13). Ketamine Considerations for Prehospital Use. Retrieved September 15, 2020, from https://www.jems.com/articles/print/volume-41/issue-11/features/ketamine-considerations-for-prehospital-use.html
Roberts, J., MD. (n.d.). InFocus: Ketamine an Ideal Treatment for Excited Delirium : Emergency Medicine News. Retrieved September 15, 2020, from https://journals.lww.com/em-news/fulltext/2015/12000/infocus__ketamine_an_ideal_treatment_for_excited.18.aspx
Rosenbaum, S. B., Gupta, V., & Palacios, J. (2020, March 31). Ketamine. Retrieved September 15, 2020, from https://www.ncbi.nlm.nih.gov/books/NBK470357/
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