Page 71 - Journal of Special Operations Medicine - Spring 2016

was injured. Although they were not always accurate, rose to a mean of 87mmHg. This can be interpreted as
the agreement between point of injury and the medical providing evidence that a patient’s vital signs regress to-
treatment facility was statistically almost perfect. The ward the resuscitation and transfusion trigger.
5
lack of 100% agreement in the number of patients and
mechanism of injury likely results from the “fog of war” This project has a few limitations that should be con-
and is an unavoidable issue. However, no comparable sidered. First, no survival data were collected and the
studies exist in the civilian literature to determine if this ultimate clinical significance of the accuracy of NATO
is true. The high degree of agreement in bodily injuries 9-line and MIST reports cannot be ascertained from this
is surprising when compared with that reported in civil- project. Second, information about the transport time,
ian literature. Civilian prehospital personnel generally treatments given at the point of injury, or treatments
have 70% to 80% sensitivity in identifying the injured given while en route were not collected. These may have
region, whereas military personnel had a greater than affected the patient’s condition on arrival to the Role
16
90% sensitivity. This may be reflective of the injury pat- II facility and could confound the results. Third, data
terns encountered in this particular patient population, sets were frequently missing. Although MIST reports
as there was predominance of head and extremity in- are standardized, they are not required to be submitted
juries and there is improved sensitivity with these two with a casualty evacuation request and not infrequently
regions when the injury severity is greater. 16-18 were missing one or more variables. Whether there was
a selection bias in the patients who had a MIST report
The individual pulse, MAP, and respiratory rate for each is unknown; however, they did appear to be provided
casualty demonstrated no correlation between the point proportionally to the triage category. Finally, this is an
of injury and on arrival at the Role II facility. This is not observational study that only covered a small area of
entirely surprising, as the average time between injury Afghanistan. Conclusions based upon triage accuracy
and arrival at the Role II facility during Operation En- make an assumption that the same criteria were being
during Freedom has been in excess of 50 minutes and used by all medics at the point of injury. Although all
19
other studies have also shown considerable variability in medics should have been familiar with the standards de-
individual vital signs during prolong prehospital trans- scribed in FM 4-02.2, it is unknown if they were being
ports. 20-22 Several factors could potential influence the followed.
change in vital signs over time, including ongoing bleed-
ing, tourniquet application, effects of resuscitation, per- Conclusion
formance of medical procedures, physiologic effects of
travel, and medication administration. This observational Triage at the point of injury has a substantial correla-
study did not collect information regarding any of these tion with the medical needs of the patient on arrival to a
variables and we cannot conclusively state which vari- Role II surgical facility. The undertriage rate is low and
ables may have contributed to the change in vital signs. near the civilian standard of 5%. With the exception
of vital signs, the NATO 9-line and MIST reports have
Although this study cannot conclude why vital signs a statistically high correlation with what eventually ar-
were different between the point of injury and the Role rives at the Role II facility. Although some variation in
II facility, it was observed that they regress toward trig- vital signs were observed, there was a general trend over
gers for resuscitation. That is to suggest, for the hemody- time toward approaching the threshold for damage con-
namically unstable patient, under a policy of permissive trol resuscitation.
hypotension, vital signs would not necessarily return to
normal with resuscitation, but rather to around the trig- Disclaimers
gers for resuscitation (i.e., a pulse of around 110 bpm
and a systolic blood pressure of around 90mmHg). Fig- The views expressed herein are those of the authors and
ures 2B and 3B provide evidence that this is occurring. do not reflect the official policy of the Department of the
The Clinical Practice Guideline for damage control re- Army, Department of Defense, or the US Government.
suscitation recommends permissive hypotension in the
prehospital environment (in the absence of a central Disclosures
nervous system injury) and qualifies this as a MAP of
around 90mmHg. Further, a systolic blood pressure The authors have indicated they have no financial rela-
23
of less than 100mmHg or pulse greater than 105 bpm tionships relevant to this article to disclose.
have both been associated with increased odds of need-
ing massive transfusion. During transport, the pulse
24
and MAP gravitate toward these triggers. In fact, pa- References
tients with a MAP above 90mmHg dropped to a mean 1. Department of the Army. Medical evacuation: ATP 4-02.2.
of 93mmHg and those with a pressure below 90mmHg Washington, DC; August 2014.

Triage Accuracy and Reliability During OEF 55