Page 29 - JSOM Fall 2020

FIGURE 1 Specifications for four commercial and a self-assembled hypothermia enclosure wraps. 22

(A)

(B) (C) (D)

(E)

System MARSARS (A) Doctor Down (B) Wiggy’s (C) User-assembled (D) HPMK (E)
Volume (L) 62.6 39.5 37.4 28.8 6.1
Enclosure
Weight (kg) 5.4 6.4 3.6 2.3 0.8
Heat packs
Number/type 3 gel 2 gel 2 dry 3 gel 4 dry*
Weight (kg) 3.3 1.1 0.4 3.2 0.8
Tight fit around face no yes no yes yes
List price (USD) $528 $900 $335 $170 $108
*Four dry chemical heat packs inserted in one heat blanket.

Phillips et al. reported a case of an adult with moderate hypo- Q2. Is an improvised, user-assembled, heated
thermia who was rewarmed in the field using an RHB from a hypothermia wrap effective?
HPMK inside a user-assembled insulated hypothermia wrap. The six passive insulation systems studied by Allen et al.
77
61
The casualty, a 53-year-old woman, became lost and was were (1) a US Army wool blanket, (2) a space blanket, (3)
found by search-and-rescue personnel after about 24 hours the Blizzard Blanket , (4) the HRS (both the Blizzard Blan-
™
in a cool and rainy mountain environment. Initially alert and ket and HRS are part of the original HPMK), (5) a human-
oriented, she subsequently became less responsive, her initial remains pouch, and (6) “Hot Pocket” (a space blanket and a
shivering had stopped, and she had peripheral cyanosis. Wet US Army issue wool blanket used together as insulation inside
clothes were removed and she was covered with an RHB in- a human-remains pouch). The best-performing passive enclo-
side a synthetic sleeping bag, and an outer tarp was wrapped sure systems in this study were the Hot Pocket and Blizzard
to enclose the entire ensemble. After 90 minutes inside the hy- Blanket . It was noted that these two enclosure systems were
™
pothermia wrap, she was evacuated and while en route to the more effective than a wool blanket for reducing heat loss. It
emergency department, she complained of being hot, was fully is important to stress that, at room temperature, the Blizzard
alert and oriented, and was removed from the hypothermia Blanket and the Hot Pocket passive enclosure systems were
™
wrap. At the hospital, her temporal artery temperature was as effective as two of three active warming enclosure systems,
37.7°C (100°F) and vital signs were normal. To our knowl- but not the HPMK.
edge, this is the only case report in a primary hypothermia
patient, and it demonstrated the effective use of an external As a result of feedback from many civilian first responders
warming enclosure system that can rewarm a nonshivering pa- and prehospital care providers, a concise and simplified pri-
tient who was likely moderately hypothermic. mary hypothermia decision aid (the Cold Card) was specifi-
cally designed for field use. This two-sided card summarizes
78
Conclusion the current consensus regarding how to assess and manage
An active heat source within an insulated hypothermia wrap is cold-exposed patients. The principles from the Cold Card for
recommended for all cold-exposed or hypothermic trauma vic- making a hypothermia wrap are the same for managing a TIH
tims. The noninsulated HPMK is effective only for short-term casualty. The hypothermia wrap includes (1) an outer vapor
use in cold environments and should be upgraded to an insu- barrier (tarp or plastic sheet), (2) an insulated ground pad, (3)
lated system as soon as possible. Level of evidence: A (insula- a hooded sleeping bag, (4) an internal vapor barrier (plastic or
tion to decrease heat loss, active heat sources to increase heat foil sheets), and (5) a heat source applied to the torso but not
gain); Level of evidence: C (benefit from active heat sources to directly on skin (e.g., the RHB). The casualty is then wrapped
rewarm patients and to reverse hypothermia) up like a burrito. Such equipment has multiple uses in the field

Management of Hypothermia in Tactical Combat Casualty Care | 27