Page 26 - Journal of Special Operations Medicine - Spring 2014

lesions or aqueductal stenosis. More recent studies One impediment to optimal use of ketamine on the bat-
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have not noted the same effect in patients without these tlefield is that drug manufacturers are constrained from
conditions. 39–42 Filanovsky noted that, based on its phar- marketing an IM auto-injector by Food and Drug Ad-
macological properties, ketamine appears to be “the ministration regulations. Since analgesia is an off-label
perfect agent for the induction of head-injured patients use of ketamine, companies are not allowed to commer-
for intubation.” 39 cialize the medication for this use and marketing of a ket-
amine auto-injector is therefore prohibited. This forces
Although the DHB memo on ketamine noted the po- combat medical personnel on the battlefield to spend ad-
tential for increased intraocular pressure with ketamine ditional time preparing the medication for injection and
use, two recent studies have reported that ketamine use introduces the potential for medication errors.
was not associated with clinically significant elevations
in intraocular pressure. 43,44 There is good evidence that Ketamine may also be delivered via the intranasal
ketamine does not cause dose-related adverse events route. 15,48 A pilot project in which 50mg of ketamine
within the range of clinically administered doses. 38,45 is drawn up in syringes with atomizers for intranasal
Black and McManus note that “ketamine has also been use in the field by medics has been implemented by the
utilized successfully as a prehospital analgesic in the Third Infantry Division in Regional Command (South)
combat setting. Ketamine in subanesthetic doses is an al- in Afghanistan (LTC David Cole, division surgeon, and
most ideal analgesic because of its profound pain relief, CPT Paul Stringer, division pharmacist, personal com-
its potentiation of opioids, its role in preventing opioid munication, 2013).
hyperalgesia, and its large margin of safety.” 46

IV ketamine, when combined with IV morphine, was Selecting the Optimal Agent
found to be safe and effective for adult trauma patients. for Battlefield Analgesia
Adding ketamine produced a reduction of 2.4 points in The simplified triple-option approach to battlefield an-
the verbal numeric rating pain scale compared with IV algesia has three primary goals:
morphine alone. Intranasal ketamine produced a sig-
47
nificant reduction in pain intensity compared to placebo • To preserve the fighting force
(p < .0001). Pain relief occurred within 10 minutes of • To achieve rapid and maximal relief of pain from
ketamine administration and lasted for up to 60 min- combat wounds
utes. Of note, there were no patients in the ketamine • To minimize the likelihood of adverse effects on the
group who required rescue pain medications, while 7 of casualty from the analgesic medication used
20 (35%) patients in the placebo group did. Ketamine
administered intranasally was well tolerated with no se- There are currently four options for battlefield analge-
rious adverse events reported. 48 sia recommended by the CoTCCC: meloxicam/Tylenol
(PO), morphine (IV), fentanyl (OTFC), and ketamine
In a 2011 survey of combat medical personnel con- (IM, IV, or IN).
ducted by the Naval Medical Lessons Learned Center,
ketamine’s rating of 4.67 (of a possible 5) as a battle- Alonso-Serra and colleagues stated that, “There is insuf-
field analgesic agent was the highest given to any of the ficient published evidence to decide which is the best
prehospital analgesic options; IV morphine was second agent for prehospital analgesia. The medical director
with 4.48, OTFC third with 4.42, and IM morphine of each EMS system must evaluate different alterna-
last at 4.13. Guldner and colleagues stated that, “Ket- tives available on the market and decide which agent or
22
amine is a unique agent that can be administered either agents are most suitable for the system’s local needs and
intravenously or intramuscularly to produce predict- capabilities.” To restate this observation for battlefield
20
able and profound analgesia, with an exceptional safety analgesia, the optimal analgesic choice for a particular
profile.” Ketamine has been suggested as a useful field casualty depends on the nature of the casualty’s injuries,
49
agent for challenging situations such as disasters. Ket- his or her level of pain and physiologic condition, as
20
amine has been the single most popular agent for use well as the tactical circumstances.
in painful emergency department procedures in children
for nearly two decades. Ketamine may also be useful Beecher noted that many combat casualties do not have
38
as an adjunct to reduce the amount of opioid required severe pain. These casualties may therefore be able to
52
to provide effective analgesia. The review by Jennings remain engaged as combatants, helping their unit achieve
50
et al in 2011 found ketamine to be a safe and effective or maintain tactical superiority and accomplish its mis-
option for prehospital analgesia. Ketamine was noted sion. In this setting, one seeks whatever analgesia can be
to be as effective or more effective for this purpose than obtained without administering an agent that may pro-
opioids alone. 51 duce an altered sensorium, as both opioids and ketamine

18 Journal of Special Operations Medicine Volume 14, Edition 1/Spring 2014