Page 84 - JSOM Spring 2024

onset (<1 min) with doses of 6–8 puffs typically lasting up to pain score and maximal emergency department (ED) pain
30 minutes. This drug is currently only available in Australia, score to determine the improvement after the intervention. 34–37
Canada, and Europe, many of the partner forces in the Global
War on Terrorism. It was previously available in the U.S. but Results
removed from the market after reports of renal and liver tox-
22
icity with repeated dosing. Therefore, use of >3 hours is gen- From 2007 to 2023, there were 48,301 encounters in our
27
erally not recommended. While methoxyflurane does have original data set, of which 22 had documentation of at least
abuse-prevention features, misuse and toxicity are still possi- one methoxyflurane administration. The median age of these
28
ble. The U.S. Food and Drug Administration (FDA) has re- patients was 23 (range 21–31) years, and all were men. Most
cently released the hold on the drug, allowing clinical trials to patients belonged to partner forces (50%), followed by U.S.
be potentially conducted for investigational drug application Military (27%). Most (64%) were battle injuries. Explosives
purposes (NCT05137184). This study describes the prehos- were the most common mechanism of injury (46%), followed
29
pital use of methoxyflurane within the Department of Defense by firearms (23%). The median injury severity score (ISS) was
Trauma Registry (DODTR). 5 (IQR 1–17), with the extremities as the most frequent ana-
tomic location of serious injury (27%). Twenty-three percent
of casualties (5) had a tourniquet applied. All survived to hos-
Methods
pital discharge (Table 1). One-half of the casualties received
Data Acquisition concomitant pain medications (Table 2). Two pain scores were
The U.S. Army Institute of Surgical Research Regulatory Com- available for only three casualties, with a median pain score
pliance Office reviewed protocol H-23-004x and determined change of –3 on a scale of 10.
our study met exempt category #4 criteria, and thus institu-
tional review board approval was not required. We requested TABLE 1 Description of Methoxyflurane Recipients (N=22)
and received HIPAA waiver M-11013. We requested all en- No (%) of
counters within the DODTR that had at least one intervention Characteristics recipients*
or assessment available within the first 72 hours following Demographics
injury. Data were transferred to the study team under the De- Age, median (range) 23 (21–31)
fense Health Agency data sharing agreement 23-2977.
Men 22 (100)
DODTR Description Patient category
The DODTR, formerly the Joint Theater Trauma Registry U.S. Military 6 (27)
(JTTR), is the data repository for DoD trauma-related inju- Coalition military 1 (5)
ries. 30,31 The DODTR includes documentation regarding de- Partner force 11 (50)
mographics, injury-producing incidents, diagnoses, treatments, Humanitarian 3 (14)
and outcomes of injuries sustained by U.S./non-U.S. Military Classification of injury
and U.S./non-U.S. civilian personnel in wartime and peacetime Battle 14 (64)
(including humanitarian) from the point of injury to final dis-
position. Short-term outcome data are available for non-U.S. Non-battle 8 (36)
casualties. Mechanism of injury
Explosive 10 (46)
The DODTR comprises all patients admitted to a role 3 (fixed- Fall 3 (14)
facility), forward resuscitative surgical detachment (FRSD, leg- Firearm 5 (23)
acy Forward Surgical Team), or role 2+. All patients have an Motor vehicle 1 (5)
injury diagnosis using the International Classification of Disease Other 3 (14)
9th Edition (ICD-9) between 800 and 959.9, near-drowning/ Composite ISS, median (IQR) 5 (1–17)
drowning with associated injury (ICD-9 994.1), or inhalational Serious injuries by body region
injury (ICD-9 987.9) and trauma occurring within 72 hours
from presentation. The registry defines the prehospital setting Head/neck 1 (5)
as any location prior to reaching an FRSD, or field hospital Face 0 (0)
(legacy combat support hospital). This includes role 1 (point of Thorax 2 (9)
injury, casualty collection point, battalion aid station) and role Abdomen 2 (9)
2 without surgical capabilities (temporary limited-capability Extremities 6 (27)
forward-positioned hospital inside combat zone). Skin 1 (5)
Outcome
Analysis Survival to discharge 22 (100)
We performed all statistical analyses using Microsoft Excel
(version 365, Redmond, WA, https://www.microsoft.com/) and *Unless otherwise indicated.
IQR = interquartile range; ISS = injury severity score.
JMP Statistical Discovery (SAS version 17, Cary, NC https://
www.jmp.com/). We present continuous variables as means Discussion
and 95% CIs. Non-parametric continuous variables and ordi-
nal variables are presented as medians and interquartile ranges In this report, we describe the use of methoxyflurane in the
(IQRs). Nominal variables are presented as percentages and deployed combat setting to 22 casualties, including 6 U.S.
numbers. We defined serious injury to a body region as an Military personnel. Half of the casualties received other pain
abbreviated injury scale (AIS) ≥3. 32,33 Given the limitations in medications, suggesting that the methoxyflurane was likely
prehospital documentation, we used the maximum prehospital sufficient for pain control during the prehospital continuum

82 | JSOM Volume 23, Edition 1 / Spring 2024