Page 59 - JSOM Spring 2024

Additionally, the imperfect pairing of the beveled needle tip for discontinuing and resuming blood collection may prove
within the hub of the assembled RL catheter introduces a dis- fruitful in scenarios such as unanticipated enemy engagement,
continuity that permits localized turbulent flow and stasis of response to indirect fire, the need to relocate quickly, or the
blood that has not yet reached the anticoagulant solution in need to collect a second unit of blood from the same donor.
the collection bag. Therefore, clotting around this connection
may occur, further reducing the RL flow rate. While we did Third, donor considerations are important. The flexible plastic
not directly assess coagulation in the connection, the potential catheter of the RL confers less donor discomfort than the SS,
impact of the RL design on clotting and blood flow remains an where the long metallic needle must remain in the vein of the
open area for future research. However, it is important to note donor for the duration of collection. Also, unlike the SS, the
that the proportion of collection bags with incomplete fill was occlusive dressing securing the RL fosters cleanliness in what
essentially identical for SS (20%) and RL (19%). may be an otherwise unsanitary environment.

Clinical and Tactical Implications In sum, the time benefit of the SS technique may foster im-
Forward-deployed medical responders should be well-trained in proved survivability when time is paramount, while the flexible
utilizing FWB to preserve the life of the traumatically wounded utility of the RL technique may prove beneficial under some
when CS-LTOWB is not available. Unlike CS-LTOWB, the use circumstances. Accordingly, the present findings have informed
of FWB in WBB scenarios requires the additional step of ac- Valkyrie training program instruction on blood collection.
quiring blood from a donor. The present study demonstrates Medical responders should appreciate the advantages and dis-
that forward-deployed medical responders should also be well- advantages of each technique to make sound decisions based on
trained in both SS and RL, appreciate the advantages and lim- immediate situational dynamics when acquiring donor blood.
itations of each technique, and choose appropriately.
Limitations
Time is usually the most important consideration in WBB This study was limited to students enrolled in the Valkyrie
scenarios, as the awaiting casualty pays for excess time spent Emergency Whole Blood Transfusion Training course. The
during the blood collection process with worsening acute trau- majority of the participants reported no previous experience
matic coagulopathy and increasing risk of mortality. The total collecting whole blood. Medical responders with more expe-
time averaged about 3.5 minutes faster using SS than using rience in whole blood collection may confer different results.
RL. Extrapolating from the estimation that mortality may in- Further, because the present process improvement study was
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crease as much as 5% per minute following injury translates carefully designed to avoid interfering with the natural flow of
to a 17.5% (3.5 × 5% = 17.5%) increased mortality risk if the Valkyrie training program, it was not feasible to control for
RL is chosen over SS. Further, blood product administration potentially confounding variables, such as morphological dif-
within 36 minutes of injury can lead to improvements in pa- ferences in role-players. Deconditioned individuals may pose a
tient mortality rates. The 3.5-minute difference favoring SS challenge to even experienced phlebotomists, and some donors
2
over RL in the present study represents roughly 10% of the in this study might be widely considered a “tough stick.” It
36-minute window. Therefore, SS should be the clear choice is reasonable to believe that an emergency donor panel com-
when speed is the imperative consideration. posed entirely of fit warfighters with prominent venous mor-
phology may yield higher first-attempt IV success rates and
However, time is often not the only consideration when choos- faster IV access times. Variations in cardiac output and venous
ing between SS and RL. Notably, in this study, RL was pre- pressure may affect fill time, and we did not account for phys-
ferred over SS by most study participants, even though they iologic variations between donors.
rated SS as faster. Further, study participants were more than
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twice as likely to indicate they would eagerly use RL than SS in This study was limited to the use of 16-gauge RL catheters.
a combat zone and roughly half as likely to reluctantly use RL While the smaller 18-gauge RL catheter is also common, we can
than SS in a combat zone. The reasons for these preferences are infer from Equation 1 that an 18-gauge RL catheter is neces-
multifold, with important clinical and tactical implications. sarily slower than a 16-gauge RL catheter. Quantitative assess-
ment of differences in blood collection bag fill times between
First, while RL had a somewhat lower first-attempt success 16-gauge and 18-gauge RL catheters remains an important area
rate than SS, a missed venipuncture attempt with RL is easily for investigation. Additionally, during venipuncture practice ses-
repeated because IV catheters are relatively inexpensive, gener- sions on training days 1 and 2, the students practiced with the
ally plentiful in deployed environments, and multiple catheters 16-gauge catheters used in RL, not the bare needles used in SS,
can be used if an initial attempt fails. In contrast, a failed veni- which could be a potential source of bias in our formal testing.
puncture attempt with SS leads to an uncomfortable decision However, the first-attempt success rate was somewhat higher
point: the practitioner must either re-attempt venipuncture for SS than RL, and students indicated that SS was faster than
with the same SS needle or use an entirely new collection bag, RL. Further, responses of students who preferred RL focused on
as the SS needle and bag are integrated and functionally insep- security, reliability, and utility, not on IV access, so it is unlikely
arable. Choosing to reuse the SS device may result in failure that the practice protocol unduly biased study findings.
because lodged skin plugs or clotted blood may obstruct blood
flow. In addition, reusing the SS device increases the risk of bac- In the present study, time to venipuncture included all the time
terial contamination. However, using a new SS device is time- that elapsed from the end of the casualty report reading un-
consuming, expensive in the training environment, and logisti- til venipuncture was successfully achieved. We did not parse-
cally challenging in far-forward operations with limited supply. out components of preparation time or time spent on failed
attempts. We could have assembled SS and RL components
Second, RL permits a “quick disconnect” that can be reestab- out-of-package for the students prior to each trial. But to fos-
lished without the need to regain IV access. This flexibility ter realism, we chose to not control for this variable for two

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