Episode 65- When can we use oral ketamine for procedural sedation?
This week, we talk about how to use oral ketamine for (minor) procedural sedation in the agitated/ combative patient
“When can we use oral ketamine for procedural sedation?”:
– If you have an agitated/combative adult or pediatric patient who needs a simple procedure and refuses an IV or any IM medications. Specifically, these patients may have underlying mental or neurological disorder (like autism or Down syndrome) and explaining the need for the procedure or needle stick can be very challenging
– Published case reports and case series have described their experience with using 5-10 mg/kg oral ketamine (giving the IV solution undiluted or mixed with soda or juice to mask/disguise the taste) with uneventful procedural and recovery periods
– When given orally, ketamine has an onset of ~ 10-15 minutes, a peak effect of ~ 30 minutes, and a duration of 4-12 hours. It is only about 20-30% bioavailable, and this is why we need to give higher doses than we’re used to. Consider using ideal body weight or an adjusted body weight in obesity
– Consider giving oral midazolam (0.3-0.5 mg/kg, maximum dose of 20 mg) to help with the emergence reactions of ketamine
– The usual side effects of ketamine still apply, so treat this as procedural sedation with resuscitation equipment nearby, the attending provider in the room, and nurses doing frequent vital sign monitoring
Hello and welcome to Episode 65 of ER-Rx. This week, we’re gonna talk about ketamine. Love it or hate it, it does have its own unique set of properties, and if used correctly in the right patient and at the right dose, it can be very useful. In this episode, we’ll discuss how to give ketamine orally prior to minor procedures in patients who won’t take IM or IV medications. Specifically, this often refers to patients who have underlying mental or neurological disorders, like autism or Down syndrome.
We use ketamine for a number of reasons in the ER. It’s mostly used to control severe agitation, as an induction agent for rapid sequence intubation (RSI) or procedural sedation, or we use it at much lower doses for pain control. When used for agitation, RSI, or procedural sedation, it’s given IV at a dose of 1-2 mg/kg or IM around 4 mg/kg. When used for pain control, we give about 0.1-0.3 mg/kg IV, which ends up being around 10-30 mg for the typical patient.
But what if you find yourself in a situation where you have an agitated or combative adult or pediatric patient who needs a simple procedure, like repairing a laceration, who also refuses an IV or any IM medications? And, again, what if that patient has an underlying mental or neurological disorder where explaining the need for the procedure or needle stick can be very challenging?
This is where we can get creative. If all else fails, and we can convince the patient or the caregiver to try an oral medication, ketamine may be the right call. In an article published in 1998, the authors reported their experience with using oral ketamine mixed in Coca-Cola at a dose of 600 mg (which ended up being 5 mg/kg in one patient and about 10 mg/kg in the other), they used this for the removal of an infected toenail and for dental reconstruction and cleaning. Within 20 minutes, the patients, aged 19 and 35 years, were sedated and cooperative during the procedure and recovery was uneventful.
A second case report from the anesthesia literature from 2008 describes giving a 16-year-old, 80 kg patient 240 mg (which was about 3 mg/kg) of oral ketamine and 20 mg (or about 0.25 mg/kg) of midazolam mixed in Dr. Pepper prior to taking him to the OR. At first, the patient was extremely combative and he wouldn’t allow his parents or the medical staff to go near him. Twenty minutes after the ketamine and midazolam combination, he fell asleep and was taken to the OR, where he had an uneventful procedure and recovery period.
This method seems a lot better than the alternative of physical restraints and forced IM injections, which can be very traumatic to the patient and the caregiver. Other oral options like benzos and antipsychotics are not always successful in achieving adequate sedation and cooperation in these patients.
When given orally for sedation, ketamine has an onset of about 10-15 minutes, a peak effect of about 30 minutes, and a duration of 4-12 hours. Remember that it is only about 20-30% bioavailable, and this is why we need to give higher doses than we’re used to seeing; typically, most studies used 5-10 mg/kg when given orally. Consider using ideal body weight or an adjusted body weight in obesity, knowing you can always give more if needed to reach an adequate level of sedation. You can give the IV solution orally undiluted, but I highly recommend you give it with soda or juice to mask the bad taste of ketamine and any other meds given with it.
Keep in mind our usual side effects of ketamine still apply here, so if you have any patients that may have a difficult airway, are at risk of aspiration, or have previous adverse reactions to sedative premedication- they may not be candidates for oral ketamine. It’s also a good idea to treat this as you usually would treat any procedural sedation with resuscitation equipment nearby, the attending provider in the room, and nurses doing frequent vital sign monito ring. You can also consider giving some oral benzodiazepines, like midazolam, at a dose of 0.3-0.5 mg/kg (with a maximum dose of 20 mg) to help with the emergence symptoms of ketamine.
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