Page 87 - JSOM Fall 2020

TABLE 8 Potential Adverse Reactions From Ketamine
Number of Casualties with
Casualties Potential Reaction Reaction Notes*
34 7 (20.58%) • Vivid hallucinations for ~40 minutes with retrograde amnesia
• Mild emergence reaction or “party zone” dose discomfort. Patient complained that he felt like he
was in the movie “Interstellar” and was not comfortable with that. After discharge the patient stated
“it wasn’t that bad”.
• Patient was only treated at POI for 10 minutes but at the 6–10 minute mark his speech became
unintelligible and pain response was not proportionate to injuries. Patient continued to complain
throughout transfer and was sedated in the hospital setting 45 minutes post injury. Patient continued
to yell in pain but responses were unintelligible. Patient now has no recollection of procedures post
impact until he awoke 12 hours post hospital sedation.
• Patient continued to laugh uncontrollably for about 50 minutes but stated he was not in pain.
Patient initially reached nystagmus and started to “freak out” due to hallucinations. After
midazolam was administered, patient remained calm and continued to hallucinate with
uncontrollable laughter.
• Patient had anterograde amnesia and was not in pain throughout the duration of his ketamine
experience. Patient started to hallucinate and became very talkative.
• Patient went through a mild hallucination for about 2 min until medication took complete effect
• Possible hypertonia adverse event
*Deidentified documentation from casualties’ records submitted by providers.

place for training exercises as well: train as you fight. The med- administered without an anxiolytic there is an associated 10–
ical officer needs to oversee the training for implementation of 30% risk of emergence phenomenon. 13,14 Furthermore, one
ketamine use and supervise its use in the training environment. double blind, randomized control trial specifically examining
This supervision may be direct (i.e., at the scene), or indirect the adverse effects of ketamine found that nearly 45% of par-
through the use of patient reports, phone/radio consultation, ticipants developed this side effect. A recent systematic re-
14
or after-action reviews. If the medical officer is unfamiliar with view found adverse events often not recorded. Anecdotally,
15
the use of ketamine, then they should obtain training in its use within the SOF community, during combat, ketamine adverse
prior to adding it to their pain management protocol. events include hallucinations, nausea and vomiting, even at-
tempts at self-extubation.
The concern that many medical directors have with ketamine
use, is based on ketamine’s potential adverse events, despite the The agents most frequently administered to mitigate ketamine
improved therapeutic ratio relative to morphine. This study induced emergence phenomenon are benzodiazepines, specifi-
was undertaken by select SOF organizations that routinely cally midazolam. A study of 60 perioperative patients received
used ketamine for medical coverage of training accidents. Our ketamine alone (1–3mg/kg) IV or a combination of ketamine
experience confirms the safety and efficacy of ketamine for with midazolam (1–2.5mg) IV. In the 1-hour period post-
16
traumatic pain in the prehospital setting. There were no signif- operation, ketamine infusion (n = 30) and ketamine with mid-
icant adverse events. The adverse event most concerning in the azolam (n = 30) had various results of adverse events associ-
previously discussed patients was a single occurrence of emer- ated with emergence phenomena. Adverse events for ketamine
gence phenomenon, also referred to as emergence reaction, alone included vomiting (n = 7), delirium (n = 3), nystagmus
emergence delirium, recovery reaction or recovery agitation. (n = 3), and salivation (n = 1). There were no adverse events
This patient initially received a 50mg IM of ketamine for anal- reported in the ketamine with midazolam group. In the sec-
gesia prior to rotary wing evacuation, and experienced a mild ond hour, adverse events in the ketamine alone group included
episode of emergence phenomenon while being loaded into the vomiting (n = 10), delirium (n = 6), nystagmus (n = 8), halluci-
aircraft. Once IV access was established, an additional 100mg nation (n = 8), and salivation (n = 4). Again, there were no ad-
of ketamine and 2.5mg of midazolam were administered, both verse events reported in the ketamine with midazolam group.
given IV. The patient reported disturbing hallucinations until
the IV dose took effect. While this particular episode did not Sener et al. evaluated 182 patients who received either IV ket-
17
cause any further complications, it is important to discuss the amine with midazolam or without midazolam. The dosage
issue of emergence phenomenon and how it can be mitigated. parameters in this study were 1.5mg/kg IV or 4mg/kg IM, with
We have chosen to give midazolam for emergence reactions or without 0.03mg/kg midazolam. The results demonstrated
and not prophylactically, since these are trauma patients, in for recovery agitation in IV ketamine alone in 10 (22%), IV
whom we wish to avoid potential exacerbation of hypotension ketamine with midazolam in 3 (7%), IM ketamine alone 3
or respiratory depression. (28%), and IM ketamine with midazolam 4 (9%). These data
suggested that the use of midazolam in combination with ei-
Emergence phenomenon can be defined as a self-limiting dis- ther IM or IV ketamine can reduce the incidence of recovery
sociative state of aggressive delirium seen in the early stages of agitation in adult ED patients. There appeared to be no differ-
post anesthesia recovery. The prevalence of emergence phe- ence in the incidence of any adverse events with either route
12
nomenon can be increased by a high level of pre-anesthesia (IM versus IV) of ketamine administration.
anxiety caused by pain , which is obviously and frequently
13
associated with traumatic patients. While the perfect chemical IV doses of midazolam as low as 0.02mg/kg have shown to
compound for analgesia and procedural sedation in the emer- completely eliminate the occurrence of emergence phenome-
gency setting does not exist, ketamine is valued by providers non when administered prior to ketamine induction of 1mg/kg
in austere tactical environments due to its negligible effects IV. 12,16 These doses are identical to the dual agent proce-
on the cardiovascular and respiratory systems. However, when dural analgesia protocol found in the U.S. Special Operations

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