Page 17 - JSOM Fall 2018

Study of Tourniquet Use in Simulated First Aid

User Judgment

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John F. Kragh Jr, MD *; Andy R. Tan ; Nicola J. Newton ;
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James K. Aden 3rd, PhD ; Michael A. Dubick, PhD 1

ABSTRACT
Background: The purpose of this study was to survey the judg­ For example, Daniel Kahneman shared one for groundbreak­
ments of tourniquet users in simulation to discern opportuni­ ing work that showed just how unreliable intuitive judgment
ties for further study. Methods: The study design constituted could be or, as the awarders put it, “for having integrated
two parts: questions posed to four tourniquet users and then insights from psychological research into economic science,
their tourniquet use was surveyed in simulated first aid, where especially concerning human judgment and decision­making
the users had to decide how to perform among five different under uncertainty.” Readers from the operational health
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cases. The questions addressed judged confidence, blood vol­ community may recall that Kahneman had worked in a psy­
umes, a reason bleeding resumes, regret of preventable death, chology unit within the Israeli military services. Kahneman
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hemorrhage assessment, need for side­by­side use of tourni­ later explained an example of judgment in commenting on
quets, shock severity, predicting reliability, and difference Michael Lewis’s bestselling book Moneyball, a story about in­
in blood losses. The mechanical performance was tested on efficient predictions made by professional scouts of the Oak­
a manikin. Case 1 had no bleeding. Case 2 had limb­wound land Athletics baseball team. The scouts judged traditionally
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bleeding that indicated tourniquet use in first aid. Case 3 was by forecasting the potential performance of ballplayers by
like case 2, except the patient was a child. Case 4 was like case including how their build and behavior looked like those of
2, except caregiving was under gunfire. Case 5 was like case stereotypically good players. Although this way of predict­
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4, but two tourniquets were to be used side by side. Each user ing is common, it is also flawed. 2,3,5 Billy Beane was the team’s
made tests of the five cases to constitute a block. Each user had general manager and had previously worked as a player and a
three blocks. Case order was randomized within blocks. The scout, but he disagreed with his scouts by choosing players by
study had 60 tests. Results: In answering questions relevant to statistics of their previous performance. Because the scouts of
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first­aid use of limb tourniquets, judgments were in line with other teams continued to make inefficient predictions by the
previous studies of judgment science, and thus were plausibly traditional way, Oakland got specific players cheaply by un­
applicable. Mechanical performance results on the manikin dertaking its new way, because other teams had undervalued
were as follows: 38 satisfactory, 10 unsatisfactory (a loose those players. With such change in judgments, Oakland soon
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tourniquet and nine incorrect tourniquet placements), and 12 improved. Eventually, many teams, sports, and organizations
not applicable (case 1 needed no mechanical intervention). For adopted similar methods, such as through extensive use of an­
cases 1 to 5, satisfactory results were: 100%, 83%, 100%, alytics, to improve judgments. 2
75%, and 58%, respectively. For blocks 1 to 3, satisfactory re­
sults were 50%, 83%, and 83%, respectively. Conclusion: For Awareness in medicine of such judgment science is increasing,
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tourniquet use in simulated first aid, the results are plausibly but so far it is infrequently derived from first­aid data. When
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applicable because user judgments were coherent with those in we discuss judgment science within the operational health com­
previous studies of judgment science. However, the opportuni­ munity, we find that little awareness of such science persists, in
ties for further studies were noted. part because few health studies deal directly with both judg­
ment and the community. In prior works, we noted how care­
Keywords: psychomotor performance; practice-based learn- giver judgments affected clinical outcomes in caregiving and
ing; choice behavior; motivation; readiness in its simulation. 11–14 As investigators, we thought that judg­
ment science may be relevant to first aid, so we took an initial
look to generate hypotheses for further study. As educators, we
Introduction thought that by studying judgments, awareness of such science
may be improved within the community. The purpose of the
Judgment guides how people make choices, and judgment sci­ present study was to compare judgments of tourniquet users in
ence has been highlighted since 2002 by several Nobel prizes. simulation to discern opportunities for additional study.

*Correspondence to 3698 Chambers Pass, Joint Base San Antonio Fort Sam Houston, TX 78234­7767; or john.f.kragh.civ@mail.mil
1 Drs Kragh and Dubick are affiliated with the US Army Institute of Surgical Research, where Dr Kragh is a researcher of bleeding control, and
Dr Dubick is a resuscitation researcher and the manager of the Damage Control Resuscitation task area. Dr Kragh is also an associate professor
in the Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD. Cadets Tan and Newton are US Military
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Academy cadets at West Point, NY, where they study mechanical engineering. Dr Aden is a statistician at the Brooke Army Medical Center, Fort
Sam Houston, TX.
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