Page 26 - JSOM Fall 2020

TABLE 2 Passive and Active External Rewarming Options for Field and Evacuation Platforms
Rewarming Level of
Prehospital Reference Effectiveness Evidence a Comments
Sleeping bag Giesbrecht et al. 62 √ B Insufficient alone to prevent heat loss; works better
with vapor barrier wrap with a when patient is
shivering
Impermeable outer Grissom et al. 63 √√ B Traditional passive rewarming approach in austere
layer with sleeping medicine courses. Works well with shivering patient
bag insulation with mild hypothermia to retain heat production and
(burrito wrap) prevent body heat loss; active external heating source
not required
Wool blanket Allen et al. 61 NE C Prospective randomized study. No human volunteers.
A single WB was least effective to prevent heat loss in
fluid-bag torso simulation.
Space blanket Allen et al. 61 NE to √ C Prospective randomized study. No human volunteers;
SB was placed over the simulation torso and tucked in
and was not as effective to prevent heat loss but better
than the wool blanket.
Human remains Allen et al. 61 √ C Prospective randomized study. No human volunteers.
pouch The HRP did not maintain torso bladder temperature
Passive better than the wool blanket.
Rewarming Heat-reflective shell Allen et al. 61 √√√ C Prospective randomized study. No human volunteers.
Methods New shell version was used as a passive bag. There was
no statistical difference between the HRS and BB in
heat loss between first- and second-generation HPMKs.
Hot Pocket Allen et al. 61 √√√ C Prospective randomized study. No human volunteers.
(HRP, wool The use of the HP system was very effective and one of
blanket, and space two best passive methods of heat-loss prevention that
blanket) performed the same as two of the three active heating
methods tested at 120 min.
Blizzard Blanket Allen et al. 61 √√√ C Prospective randomized study. No human volunteers.
The use of the BB alone was one of two best passive
methods of heat-loss prevention that performed the
same as two of the three active heating methods tested
at 120 min.
Vapor barrier + Thomassen et al. 64 √√√ A Strong evidence in favor of vapor barrier wrapped
hypothermia wrap Henriksson et al. 65 around human volunteers who were then placed inside
Henriksson et al. 66 hypothermia “burrito wrap” system. These three
studies are the evidence for the recommendations
on how to assemble an improvised a hypothermia
enclosure system 78
Small chemical Co-author NE C Small chemical heat packs used for hands are
packs Consensus insufficient to provide heat transfer to core or to
prevent further heat loss. Better options available.
Warm IV/IO fluids/ Lehavi et al. 56 NE A Do not infuse fluids cooler than 100°F (38°C). Fluids
blood products Haverkamp et al. 57 alone not effective for core temperature rewarming. Use
fluids adjunctively with HPMK during MEDEVAC.
Body-to-body skin Giesbrecht et al. √ B Suppresses shivering in victim with skin-to-skin contact;
62
contact Hultzer et al. 68 no more effective than shivering for mild accidental
hypothermia; lack of evidence for any benefit in
nonshivering hypothermic patient; loss of manpower
Hot water bottles Co-author √ C Impractical. Insufficient to transfer heat to effect core
Consensus temperature. Many bottles are needed; hot water
replacement every 20 min
Active
Rewarming Walking Giesbrecht et al. 67 √√ B Use to generate heat production in cold-stressed (>35°C
Methods [95°F]) victims with shivering intact; well protected
from cold, wet, and wind; and with observer; use with
caution—may cause afterdrop, 0.91°C core temperature
decrease lasting nearly 30 min
Ready-Heat Allen et al. 61 √√ C Prospective randomized study. Whole-body heat
Blanket blanket – 8h at 104°F (40°C); wrap torso and avoid
direct placement on skin; use vapor barrier as outside
layer
HeatPac Giesbrecht et al. 67 √√√ B Effective to deliver heat and maintain thermal balance;
Kulkarni et al. costly; long-term experience in Scandinavian militaries
69
and in research studies; resource dependent; uses
charcoal as a consumable; potential carbon monoxide
risk in low-ventilation space; use outdoors only. Newer
options available
(continues)

24 | JSOM Volume 20, Edition 3 / Fall 2020