Page 32 - JSOM Spring 2025

5 participants completed their rucks after blood donation, and FIGURE 1 (A) A participant donates blood in the field immediately
8 completed it without donation. All participants performed prior to performing a ruck march. (B) A participant performs a
the opposite condition on the second day. Following the ruck, ruck march following blood donation (BD) while wearing portable
metabolic measurement equipment to evaluate respiratory rate and
each participant received their blood back via autotransfusion, minute ventilation. Photo taken at 2,945m elevation.
allowing first-day donors to complete their euvolemic control
ruck the following day. (A)

To reduce participant bias, we originally blindfolded partic-
ipants to hide their BD status, with all participants receiv-
ing a venipuncture needle stick followed by either donation
or none. However, BD participants easily sensed the loss of
blood, most reported as a perceptible cooling of their arm,
and donors often had to be physically manipulated to enhance
blood transfusion due to the cold outdoor temperatures, either
through standing or hand clenches, which also compromised
the blinding process. We ultimately determined that all partic-
ipants easily perceived their donation status despite blindfold-
ing and discontinued the blinding process.
Military Fresh Whole Blood Transfusion Training
The FWBT training occurred in a remote mountainous region Photos courtesy of NHRC.
at an elevation of 2,800m. The training was intended to pro-
vide FWBT field instruction and practice in the presence of
cold and hypoxia (Figure 1) to prepare participants for blood
transfusion in austere environments. Per course objectives,
participants also conducted ruck marches following donation (B)
to simulate physical demands commonly associated with the
operational requirements of donors and give the medical pro-
viders a firsthand understanding of the effects of blood dona-
tion. The ruck march route was 3.2km long and consisted of
a 1.6-km ascent with a 250-m elevation gain (2,800–3,050m)
followed by a return descent of 1.6km to baseline elevation
(Figure 2).

Each day, participants performed intravenous cannulation and
blood collection under the instruction of the supervising med-
ical officer. The Combat Medical Fresh Whole Blood Trans-
fusion Set (NSN 6515-01-657-4750, Harrisburg, NC) was
used for FWBT and contained all materials necessary for both
donation and autotransfusion. The amount of blood collected
from each participant during BD was approximately 450mL
as determined by two instructors using field volume measure-
ment techniques described in the Joint Trauma System Clinical FIGURE 2 Elevation and distance profile of the ruck march
3
Practice Guideline for Whole Blood donation, namely bag cir- depicting checkpoints (Start, CP1, CP2, CP3, Finish).
cumference as measured using a 10-inch 550 cord and filling
of the blood bag to the fill line.

Following BD or without donation, participants individually
performed the 3.2-km out-and-back ruck march with loaded
rucksacks (24.2 [SD 2.1] kg) on a snow-covered route. Upon
completion of the march, participants returned to the training
area, and donors had their blood intravenously autotransfused
to complete the FWBT training. Participants only performed
one march each day (BD or control march), and the opposite
was performed on the second day. The weather was variable,
with heavy snow and cold air temperature (−4°C) on the first
day and sunny with mild air temperature (10°C) on the second.
responses and perceptual ratings during each march. Note that
Experimental Protocol the order of counterbalancing is indicated as the BD-control or
The experimental protocol was executed concurrently with the control-BD groups.
FWBT training exercise. The protocol included a) counterbal-
ancing of ruck marches to ensure all participants performed Four hours prior to beginning blood donation, participants in-
one march under each condition (BD and control) and b) gested a core temperature (T ) sensor (VitalSense; Philips Res-
c
measurement of time to complete the march and physiological pironics, Bend, OR) and had a skin temperature sensor affixed
30 | JSOM Volume 25, Edition 1 / Spring 2025