Ketamine for Analgesia
Last week’s Morsel discussed patellar dislocations and mentioned the use of nitrous oxide to assist with the reduction. Many of you had great feedback on other pain management options (thank you!). Obviously, the management of pain is one of our primary objectives and the science and art of it does not lend itself to a simple, single option. Fortunately, we have many options that can be appropriately tailored to our patients.
Recently, a colleague and friend, Dr. James Homme, delivered a brilliant presentation on Ketamine for Analgesia at the ACEP/AAP Advanced Pediatric Emergency Medicine Assembly and proclaimed “To know ketamine, is to love ketamine.”
We have covered Ketamine’s use for Delayed Sequence Intubation and for the treatment of Hypercyanotic Spells and the team at Don’tForgetTheBubbles.com just covered it’s use for Conscious / Procedural Sedation. Now, let’s explore the next frontier for Ketamine usage: Analgesia!
The Problem with Brief Painful Procedures…
- Many of the procedures that we need to perform in the Emergency Department do not require a prolonged time.
- Incision and drainage, uncomplicated joint reductions, wound cleansing / debridement, uncomplicated laceration repair are all great examples of procedures that often do not require more than a few minutes of actual procedure time.
- The problem with these procedures is that they are still painful and scarey.
- This creates a difficult to solve risk : benefit ratio equation.
- Risk of full conscious / procedural sedation
- Risk of suboptimal pain and anxiety control
- Risk of physical restraint
- Unfortunately, the equation is often solved in a manner that inadequately controls the child’s discomfort in favor of being expedient.
There is No Perfect Rx, But Ketamine is Close…
- The World Health Organization has characterized Ketamine as a “core medication for basic healthcare systems.”
- While those of us in Ivory Towers can debate, it is recommended for systems with far fewer resources.
- The US Defense Health Board called Ketamine “a new alternative to conventional battlefield analgesia” in 2012.
- Ketamine is ideal for pain management in an austere environment.
- Safe and effective.
- Rapid onset.
- No respiratory depression.
- Requires little (if any) monitoring.
- Our EDs are like luxury hotels compared to the austere regions it is being used in.
- Referred to morphine as “the slipping gold standard.”
- Ketamine is ideal for pain management in an austere environment.
- The world’s literature (see references) notes Ketamine is effective at reducing pain quickly (usually by 5 minutes).
Dosage Matters
- The first publication showing Ketamine as being effective as an analgesic was in 1971.
- Ketamine used at subdissociative doses worked better than merperidine for reducing pain response.
- Since then we have become very comfortable with it as a medication for conscious / procedural sedation.
- It’s association with PCP has likely affected its usage as an analgesic, however.
Analgesic Dosages: 0.1 – 0.3 mg/kg IV; 0.5 – 1 mg/kg IM
Partial Dissociation: 0.4 – 0.8 mg/kg IV
Dissociation Dosages: 1 – 2 mg/kg IV; 2 – 4 mg/kg IM
Barriers to Ketamine’s Use
- Institutional labeling
- If your hospital has labeled it as a medication to be used for sedation purposes, you will likely met resistance to giving it for analgesia without filling out 1,000 pages of conscious sedation paperwork.
- Perhaps you can use the references below to change that.
- Certainly we use other medications for various applications (opioids, benzodiazepines, etc).
- If your hospital has labeled it as a medication to be used for sedation purposes, you will likely met resistance to giving it for analgesia without filling out 1,000 pages of conscious sedation paperwork.
- Myths about head injury
- Fear of Emergence Reaction
- This is actually a rare event for the group that receives subdissociative doses of Ketamine.
Potential Therapeutic Groups
- The awake patient who needs a brief painful procedure (5-10 min).
- The patient with chronic pain on opioids presenting with intractable pain (ex, Sickle Cell Pain Crisis).
- The patient in whom pain is associated with emotional distress.
- Ketamine not only controls pain, but it also makes people seem to be indifferent to it.
- Ketamine is also being looked at for treatment of depression.
So, while you might not be using Ketamine for Analgesia during your next shift for that I+D, maybe in the very near future you will be.
Can you clarify the peds dosing for ketamine for pain (IV, IM and IN)?
Annie,
Below is some basic guidelines… but, obviously, individual dosages may and will vary. This is what Dr. Jim Homme (a strong advocate in the appropriate utilization of Ketamine and intranasal medications) recommends.
Ketamine Analgesia
IV – 0.1-0.3 mg/kg over 1-2 minutes (usually start at 0.3 but will max at 15-20 mg depending on severity of pain).
Alternative is to dilute IV dose of 0.3 mg/kg in 50 ml NaCl and give over 15 minutes (less side effects of dizziness and feelings of “unreality”
IM – 0.5-1.0 mg/kg (use 50mg/ml or 100 mg/ml concentration)
IN – 1 – 1.5 mg/kg divided between nares (use 50mg/ml or 100 mg/ml concentration). Max 1 ml per nostril. Use atomizer.
Infusion dosing – 0.2-0.3 mg/kg/hr drip – titration up or down as needed.
Repeat doses of IV/IN after 10-15 minutes if needed.
Repeat IM dose after 20-30 minutes if needed.
This is some really good information about ketamine. It is good to know that it would be smart to know that ketamine can be used for more than just sedation. That is a created thing to know when you are dealing with a lot of pain.
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I,ve had excellent professional experiences with Ketamine! Just two questions.
1. When considering ketamine’s use in the ER, how many fasting hours do you consider safe enough?
2. Any relevant side effects we should be prepared for? I have never seen any bronchorrea.
Thank you for your comment!
Ketamine does have many excellent benefits and a great safety profile. It is, however, important, to always anticipate side effects. Bronchorrhea can occur, but I do not typically administer medicines empirically to counteract this possibility. Other commonly considered issues to ponder: laryngospasm, respiratory depression, emesis.
As for “fasting” times… there is NO evidence that a specific amount of fasting time is beneficially for procedural sedation in the Emergency Department. BUT… you should always follow your hospital’s protocols.
Thank you,
sean
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Dear Sean,
Here are a couple of articles regarding intranasal ketamine for analgesia
http://www.ncbi.nlm.nih.gov/pubmed/23560967
http://www.ncbi.nlm.nih.gov/pubmed/24712757
The authors have just finished a study on intranasal fentanyl vs intranasal ketamine… Looking forward to hearing about the findings.
Kind regards,
Simon
Thank you!
Very useful indeed!