OS2-6-1

LIFE2012 2012 年 11 月 2 日－4 日 愛知 (名古屋大学)

人体損傷の重症度クライテリアとその許容レベル
Criteria of Human Injury Severity and Its Acceptable Levels○ 松浦弘幸（長寿研）中野正博（純真学園大）玉川雅彰（九工大）行正徹（産医大）山中真（純真学園大）根本哲也（長寿研）久保田怜（長寿研）石川耕介（長寿研）
松崎照美（長寿研）神谷直樹（長寿研）近藤理恵（長寿研）久保田正美（JARI）
Hiroyuki MATSUURA, National Center for Geriatrics and Gerontology
Masahiro NAKANO, Jyunshin Gakuen University
Masaaki TAMAGAWA, Kyushu Institute of Technology
Toru YUKIMASA, University of Occupational and Environmental Health
Masami KUBOTA, Japan Automobile Research Institute
Abstract: We have been studying and searching the comprehensive risk adjustors for human injuries in the case of falling,
descent and glitch of intelligent machines, utilizing dummies (Hyb-III) in JARI. Finally we adopted the clinical indicator
TRISS, which is composed of three types of risk adjustor - anatomic, physiological, and comorbid. And they can beeasily combined so that information from all three sources is used to predict outcome. Notice that we can reach the level
acceptable, TRISS > 0.980 if NISS <4 and RTS > 7.8404. Because this score of TRISS is almost as large as maxTRIS =0.9843 in the case of three largest AIS = (0,0,0). Thus, our purpose of research should be focused on the decision of eachmaxAIS score being less than or equal 1. The level acceptable will be both maxAIS =1 or maxAIS = 0, and so we shallperform experiments to decide these maxAIS values utilizing physical parameters.

1. Introduction

Japan Automobile Research Institute (JARI). And we havebeen attempting to estimate the physical quantities as impact,pressure, acceleration, duration of the impact and an effect ofprotectors when we had fallings and a descents from various
situations, for examples, from high place, bicycle, invalid chair,mobile robots, and so on. According to our experiments wefound that our injuries and trauma were almost divided into two
major factors, which were physical factor and bio-medical
factors [1]. The physical factors are mainly governed by our
external and physical situations as our body height, weight,
height of standing positions and so on. And we found thatthose physical factors mainly addressed to anatomical injuries
and anatomic scores. The most advised trauma-specific coding
lexicon is the Abbreviated Injury Scale (AIS) which was first
conceived as system to define the type and severity of injuries.
Thus, the physical factors have relations with AIS, and we canestimate the anatomical injury severity using only those external
physical factors, and we made up calculating programs
depending on only those physical factors in order to estimating
AIS, HIC (head injury criteria) and mortality rates [1-3]. On
the other hand, it is difficult and complicated to calculate thebio-medical factors, because those are the individualphysiologic status and our comobidities, i.e., liver cirrhosis,
COPD, heart illness and so on. It is considered that the three
types of risk adjustment, anatomic, physiological and comorbid,
can be easily combined so that information from all threesources is used to predict outcomes.
In this paper, we would like to mention concepts of eachcriteria and risks, which we apply for our interesting problemsof risk managements. Using those combined risk adjustment,
we intend to search a level acceptable and permutable for ourhuman injuries. And one of the most important and difficult−1−

tasks is to translate the physical data obtained through ourdummy experiments into the clinical status or biomedical
severities.

2. Trauma Severity

From medical standpoints, trauma severity is defined simply as
the quantification of the risk of an outcome following trauma.
It is generally thought that an amalgam combines elements ofclinical acumen and statistical theory to provide a single metricused to describe aspects of patient condition after sometraumatic incident. Generally speaking, the outcome of trauma
severity is used for the prediction of survival, ICU length ofstay, and performance of procedure. However, the severity
scores are not typically used for clinical decision-making in theacute setting. And those scores are used for field triage,referrals, outcomes prediction and quality improvements. In
general, we have three types of risk adjustments (scores), which
are a Anatomic injury Score, Physiologic Derangement Scores,and Comordity Scores
Anatomic injury score are the most developed types of risk
adjustment following trauma, and the majority of scoringalgorithms are designed to predict mortality.
At first, it is necessary to categorize both injuries and clinicaldata before making severity scores, and we enable to transcribe
clinical records of traumatic incidents into codes that areunderstood individual injuries.
Among a lot of injury cords,
the Abbreviated Injury Scale (AIS) is especially said the mostadvanced trauma-specific coding lexicon which was first
constructed as system to define the type and severity of injuries
arising from automobile accidents [4]. The AIS codes, which
are classified by injury of region, type of anatomic structure,
specific structure and level, consisted of a six-digit number.
We are ordinarily a lot of interest of AIS severity, which arefollowing the decimal having the range from 1 to 6. Thedecimal from 1 to 6 describes numerically the severity of theinjury. The AIS severity of 1 is a superficial injury while a 6
is thought to be unsurvivable (Tab.1). The AIS severity (from1 to 6) is the simplest form of a score. The maximum AIS(maxAIS), which is the largest AIS value among a set ofinjuries within a damaged human body. In clinical meaning,the maxAIS is highly associated with mortality but ignoresinformation provided from other injuries.
TABLE 1. AIS Components, Definition of 1-6
AIS
ORDINALMOTARITY
SEVERITYDESCRIPTION(range %)0.0
Minor injury
10.1 – 0.4
Moderate injury
2
0.8 – 2.1
Serious injury
3
7.9 – 10.6
Sever injury
4
53.1 – 58.4
Critical injury
5
Virtually unsurvival
6injury
In 1974, Baker et al. proposed the method of a multi-injury
score, what is called, Injury Severity Score (ISS)[5]. The ISS
divides the body into six regions ―head or neck, face,abdominal, chest, extremities, and external. The largest AIS
value in each of the three most severely injured regions issubset, and then we should take the sum of the squares of these
AIS values in order to make up ISS. The ISS enable to predictwell mortality of injured human, however, ISS has a lot ofdefects. For example, the ISS only considered one injury ineach of the body regions and thus ignores important injury
information.
Osler et al. formulated the New Injury Severity Score (NISS) toimprove some of the ISS defects. Especially, they attemptedto introduce effects of multiple occurrences of serious injuries
within a body region[6]. The NISS is the sum of the square ofthe three most sever AIS values, regardless of body region.
Those improvements bring us a slight prediction advantage.
Thus, we should adopt the NISS severity score instead of ISS,
and NISS enable to calculate with using the sum of the squareof the three most sever AIS values, and NISS is given as thefollowing relation (Eq.(1) ):Using Tab. 1 and Tab. 2, the three largest AIS values―1stmaxAIS, 2ndmaxAIS, 3rd maxAIS－ are chosen, and then NISS
2 following definition: 2scoreby )theNISScan=be(1determined
st max AIS+ (2nd max AIS )(1)
2+ (3notice,rd max) of table1 does not mean theWe shouldthe AIS
mortality
effects of multiple occurrences of serious injuries within a body
region, multi-injury score, but it is related to the single injury
score. An estimation of our acceptable AIS level, given
injuries by falling and descent and wound from robots, enables
to practice with those tables (Tab1, Tab2). It is desirable thatthe AIS level is taken less than AIS 1 because of no mortality(0%) within a single injury (Tab.1). The Eq.(1) suggests thelevel acceptable of multi-injury of human body, and thenmaximum NISS (maxNISS) is decided by the three maxAIS
scores. The Eq.1 gives a relation,
NISS = (1) 2 + (1) 2 + (1) 2 ≤ 3(2)
and maxNISS = 3.

Instead of using single AIS score, we canconsider in NISS describing multi-injuryof our body (Fig1, [7]). The Fig.1 showsa relation between NISS and survival rate P(s). The injuries
are divided into
two trauma. One is Bunt type, another is Penetrating type.
The point A means100% level survival position which NISS
score has vales less than 4 in spite of our age (whether morethan 55 years old or not). Thus, we can decide the acceptablelevel by using NISS. The Fig.1 teaches us a following relation,survival rate P(s):P ( NISS ) ⇒ P ( s < 4) ≅ 1.0 ).
(2)
So, We obtain maxNISS less or equal 3. Considering both
relations Eq.(1) and Eq.(2), we notice they are same values.
So max NISS of the level acceptable has following
combinations of maxAIS.
The possible max NISS,P-maxNISS (maxNISS socre) = (1st max AIS, 2nd max AIS, 3rdmaxAIS):
P-maxNISS (3) = (1,1,1), (2) = (1,1,0), (1) = (1,0,0), (0) =(0,0,0) < (4) = (2,0,0)(4)
The above combinations include all of cases of possible level
acceptable within survival rate 1.0.
（to be continue in Life 2012 conference）
Conclusion
We have been studying and searching the comprehensive risk
adjustors for human injuries in the case of falling, descent andglitch of intelligent machines, utilizing dummies (HybIII) inJARI. Finally we adopted the clinical indicator TRISS, whichis composed of three types of risk adjustor - anatomic,
physiological, and comorbid. And they can be easily
combined so that information from all three sources is used topredict outcome. Notice that we can reach the level acceptable,
TRISS > 0.980 if NISS <4 and RTS > 7.8404. Because thisscore of TRISS (0.980←(1,1,1)) is almost as large as maxTRIS= 0.9843 in the case of three largest AIS = (0,0,0). Thus, ourpurpose of research should be focused on the decision of eachmaxAIS score being less than or equal 1. The level acceptable
will be both maxAIS =1 or maxAIS = 0, and so we shallperform experiments to decide these maxAIS values utilizing
physical parameters, pressure, impact, force and so on.
Acknowledgment.
This work is partially supported by New Energy and Industrial
Technology Development Organization (NEDO).
[1]Matsuura H, Nakano M, Tamagawa M, Nemoto T, Kubota
R, Kubota M., Mechanical Injury of Human Bodies, ICIC
Express Letters, An International Jurnal of Research andSurveys, ICIC International, vol. 6, No.6, pp1629-1634,
2011[2] Kenneth D. Boffard(ed.), Manual of Definitive SurgicalTrauma Care, Iatsic (International Association for Trauma
Surgery and Intensive Care), HODDER ARNOLD, London
UK, 2010.
[3] Partrick DK, J. Wayne M, and Turner MO ( David F,Kenneth LM, and Ernest M., ed.,), Trauma, McGrawHill,
U.S.A. 2008.

−2−