Page 74 - JSOM Spring 2018

Racemic ketamine was administered by PJs on missions on short flight time that there was not enough time to administer
which PJs were performing rotary wing (i.e., HH-60) tacti- a second dose.
cal evacuation. Each patient had some sort of ground medical
response before PJs picked up the patient. The details of who The most common route of ketamine administration was IM
(i.e., what level of provider) treated the patient on the ground (n = 10 patients), and the most common dose given was 50mg,
were not recorded. though it is noteworthy that two patients received only one
25mg dose IM and still had significant enough reduction of
After any mission during which ketamine was administered, the their pain documented that they did not require additional
PJs were asked to complete a simple survey form indicating the analgesia.
patient’s injuries, mechanism of injury, pain level, need for ad-
ministration of ketamine, dosing of ketamine, route of admin- None of the patients experienced adverse reactions. The dos-
istration, and any changes in status during the course of their ing, route, pain levels before and after ketamine, and details of
flight, including adverse reactions or the need to administer an- ketamine administration are listed in Table 1.
other dose. After each mission, the flight surgeon debriefed the
PJs for confirmation of indications, outcomes, or unexpected Discussion
results before entering deidentified data into a tracker.
Analgesia for battlefield injuries has traditionally been accom-
Clinical Guidelines plished with opioid medications such as morphine since the
The standard analgesic dosage recommended was 25mg in- time of the US Civil War until very recently in the Operation
travenously (IV) or intraosseously (IO) over 1 minute with Iraqi Freedom/OEF campaigns. In World War I, dressing sta-
repeated doses of 20mg every 15–30 minutes as needed or un- tions outside of the immediate battlefield used morphine as the
til nystagmus occurred, or 50mg intramuscularly (IM) every primary method of pain control. At that time, these dressing
15–30 minutes or until nystagmus occurred. stations were considered the frontline of medicine; fortunately,
our current Combat Medics provide analgesic treatment at the
Contraindications for use of this medication included hyper- location of the active combat engagement. Since the inception
sensitivity and acute ocular globe injury. Medics were in- of morphine in 1804, it has been the standard for treatment
structed on the ketamine adverse-effect profile, including of pain. However, it is common knowledge that morphine
hypertension, laryngospasm, respiratory depression, emer- and other opioids have significant drawbacks and adverse ef-
gence reaction, and hypersalivation. Of note, study findings fects that complicate their use, especially in trauma patients.
12
suggest that increased intraocular pressure may be as low as Known adverse effects include addiction, nausea and vomit-
1.6mmHg, which is likely of little to no consequence, and has ing, hypotension, and decreased respiratory drive; the latter
subsequently felt to be not clinically relevant. Head injuries two can be detrimental in an acutely injured patient. In the
13
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were previously considered a contraindication for ketamine; current battle space, traumatic brain injury (TBI) has been a
however, this contraindication was associated with very high major injury and the potential for opioids to cause respira-
doses of ketamine. Results of several recent studies, compris- tory depression with subsequent hypoxia/anoxia can worsen
ing more than 900 critically ill patients, caused researchers to TBI symptoms and outcome. This is not a new phenomenon;
conclude ketamine did not adversely affect cerebral perfusion anoxic brain injury from morphine toxicity was well docu-
pressure, neurologic outcome, or mortality. 14,15 mented in World War II. 17

It was not until 1960, when fentanyl citrate was incorporated
Results
in clinical practice, that there was an alternative to morphine
A total of 12 patients received ketamine for analgesia during without the potential hypotensive effects. Forty years later, the
the course of this deployment. Eight had been involved in im- fentanyl citrate trans-buccal lozenge was created. However,
provised explosive device explosions, five sustained gunshot only 25% of the lozenge is absorbed directly; 75% is swal-
wounds, and one sustained a nonbattle related injury. Pain lowed and undergoes first-pass hepatic metabolism. Studies
relief was determined by the treating PJ on the basis of their from Camp Bastion in 2010 showed frequent delay of anal-
clinical evaluation and patient interaction after administration gesic onset with the trans-buccal fentanyl route. In addition,
18
of each dose of pain medication. Two patients were excluded the risk of adverse effects such as decreased respiratory drive
from the study because of incomplete data collection or short and hypotension prevent fentanyl from being an ideal analge-
time from administration of ketamine to landing, and uncer- sic for many patients in tactical locations where medical per-
tainty about the clinical response. sonnel are few and evacuation times are unreliable.

Of the 10 patients included in this report who required pain Concurrently with the efforts the Pararescue community, the
control with ketamine, seven had received an opioid medica- MERTs, who were colocated at Camp Bastion, began report-
tion before PJ evaluation. No patients required redosing of ing the effectiveness of ketamine for prehospital analgesia.
ketamine for pain control. Pain was scored as mild, moderate, From that time, the Pararescue community began to exam-
or severe on the basis of the PJs’ judgement. This included ine the role of ketamine as a primary method for analgesia
clinical appearance of patients who did not speak English. on the battlefield and for TACEVAC. It was not long after
that ketamine became the drug of choice for providers on the
Eight of the 10 patients experienced a significant decrease in battlefield. 19
pain, with initial pain being reduced to mild or none. One of
the 10 patients did not have a postketamine pain assessment In 2011, USAF PJs began carrying ketamine for analgesic use
documented. Another was assessed to be in severe pain after and for sedation, including RSI. After its inception in the Para-
the initial ketamine 50mg IM dose (patient 2) but had such a rescue community, anecdotal stories began to emerge that,

70 | JSOM Volume 18, Edition 1/Spring 2018