Page 108 - Journal of Special Operations Medicine - Fall 2015

addressed in other studies. 1,2,4 A risk with this type of Exact management of these reactions may vary, especially
retrospective chart review is that some adverse events with consideration of each tactical environment. Simple
might not have been recorded or that there was an verbal reassurance may be sufficient to alleviate patient
overreporting of events. However, the methodology is reaction and distress, especially as they metabolized the
strong enough to believe that no serious events were drug and the effects subside. Alternately, synergistic med-
encountered or omitted. This study did not reference ications such as small doses of fentanyl or midazolam
how long ketamine provided analgesia. have been shown to reduce dysphoric reactions. 7

For our purposes, how does this change or support the The transient hypoxia rate was 1.5%. In the study, this
use of ketamine in the tactical environment? The patient was readily reversed with the administration of 2L oxy-
population was slightly older than would typically be gen via nasal cannula. One of the patients was hypoxic
seen in a military population. In addition, the popula- to begin with and required BiPAP to treat his COPD
tion in this study is likely to have had more comorbid exacerbation. This rate of hypoxia is quite low, and four
illness than those an SOF Medic might encounter. These of the seven patients also received opioids, which might
points indirectly support the use of LDK in our patient have contributed to this. This rate is less than that re-
population. ported with opioid-based pain protocols. Specifically,
the authors reference Chang et al, who found a 5%
8
In this study, the permitted IM subdissociated dose was hypoxia rate in patients receiving opioids alone. The
25mg. This is less than what is permitted in the TCCC direct implication of this adverse reaction to the SOF
guidelines (50mg). So it is unclear if the rates of adverse environment is the treatment of the transient hypoxia.
reactions would be increased when used in a tactical In many circumstances, oxygen will be unavailable. The
situation. It is also important to note that 93% of uses increase in the amount of oxygen delivered by 2L via
of LDK in this study were IV and at the rate of 20mg nasal prongs is quite limited, and it is possible that their
or less. This is the recommended initial dose for the IV hypoxia would have responded spontaneously. We just
administration of ketamine in the TCCC guidelines. do not know how these patients would have responded
without treatment. This should not be a contraindi-
Ketamine was used for a wide variety of indications in cation to the use of LDK in the tactical environment.
this study (a full list is listed in the original study Table The medic must be aware of the possibility and remain
1). These indications included abdominal pain (33%), vigilant in their care and observation of the casualty. In
musculoskeletal pain (12%), back pain (12%), skin and response to transient hypoxia, a Tactical Medic might
soft tissue (12%), and other (23%). Greater detail on have the following interventions at his disposal: stimu-
the indications is not provided in the article, so it is diffi- lation, airway positioning, bag-valve mask, mouth to
cult to draw a comparison to the type of painful injuries mask respirations, or naloxone administration (if opi-
that might be seen in a tactical environment. oids were also used). Portable pulse oximetry might be a
useful monitoring adjunct when administering analgesia
The strength of this report are the adverse reaction to patients in a tactical environment.
rates. The presence of a 1% emesis rate is acceptable
for the management of combat casualties. In addition, The last difference with the applicability of this article to
all protected their own airway. The authors of this study the tactical environment is the actual dose of ketamine.
3
also report that this is typically far less than experienced In the TCCC guidelines, ketamine is listed as an option
with opioid use. for moderate to severe pain. The dose in this recommen-
dation is either ketamine 50mg IM or IN (intranasal) or
The dysphoric reaction of 3.5% is also less than has been ketamine 20mg slow IV or intraosseously. It also per-
reported with higher doses of ketamine. The authors ac- mits repeat does every 20 or 30 minutes depending on
knowledge three prospective studies showing dysphoria the route of administration. The IV dose is in keeping
rates of 16% to 26% with higher doses. That most with the study methodology. The intranasal dose was not
4–6
of these patients settled with reassurance is also impor- studied; therefore, it is difficult to extrapolate how side
tant. The fact that three patients needed lorazepam is effects might relate. The IM dose exceeds that permitted
not particularly worrisome. It may cause some clinicians in the study, so it is possible that the side effect rate could
to make sure this medication is included in their team’s exceed or differ from what was experienced in the study.
clinical scope of practice. A greater issue is the environ-
ment in which a Tactical Medic is treating casualties, it
is likely to be very different than a busy urban ED. This Summary
environment might be far more stimulating, austere,
and/or stressful. The effect of reassurance may be less This is an important article that demonstrates the use
effective in this environment. Further combat experience of subdissociative doses of ketamine for the treatment
with the medication is required to know the exact impli- of pain in an urban ED. The study does not evaluate
cation and frequency of this adverse reaction in combat the effect of the medication on analgesia, but the ad-
casualties. verse event in 530 patients was 6%. The majority of

96 Journal of Special Operations Medicine Volume 15, Edition 3/Fall 2015