Product Reference Guide - Controlsoft

Evidence Review

Using Clinical Pathways to Aid in the Diagnosisof Necrotizing Soft Tissue Infections Synthesisof Evidence

Lynn Schuster, RN, DNP, ACNP-BC, Diane E. Nunez, RN, DNP, ANP-BC

ABSTRACTBackground: Necrotizing soft tissue infections (NSTIs) are rare, rapidly spreading infections that

occur in the soft tissue compartments. The mortality rate is high and has been found to decrease ifpatients are treated early and aggressively with surgical debridement and broad-spectrum antibiotics.Unfortunately these infections present similarly to other types of skin and soft tissue infections (SSTIs)making diagnosis difficult.

Aims: This paper reviews the evidence surrounding the early diagnosis of NSTIs. This was usedto develop a clinical practice guideline (CPG) for implementation in the emergency department (ED)setting to assist the provider in distinguishing NSTIs from SSTIs to potentially decrease the time frompresentation to diagnosis.

Methods: A review of the literature was performed. Studies were identified and critiqued by tworeviewers independently for clinical relevance, study design, and statistical analysis.

Results: Signs and symptoms, or “hard signs,” associated with NSTIs include: pain out of proportionto the exam, rapidly spreading infection, presence of bullae, skin ecchymosis or sloughing, gas in thetissues, skin anesthesia, edema extending beyond the erythema, and symptoms of sepsis. Unfortunatelyonly 43% of the patients with an NSTI will present with these signs. Studies have found an associationbetween laboratory values and NSTIs with the most commonly associated findings being leukocytosis,azotemia, and hyponatremia. Using these complimentary clinical and laboratory values, the LaboratoryRisk Indicator for NECrotizing fasciitis (LRINEC) score is an emerging tool that providers can use todetermine the risk of an NSTI. A clinical pathway was developed and implemented in the ED for allpatients presenting with an SSTI to assist providers in confirming or negating the presence of an NSTI.

Implication for Practice: Educating ED providers about the signs, symptoms, and laboratory findingsassociated with NSTIs will lead to earlier diagnosis and treatment and decreased morbidity and mortality.

KEYWORDS necrotizing fasciitis, soft tissue infection, diagnosis, clinical practice guideline

BACKGROUND AND SIGNIFICANCE

Necrotizing soft tissue infections (NSTIs) are serious,rapidly spreading, infections of the skin, subcuta-

neous tissues, and muscle. Although the incidence ofNSTIs is low, only 3.5 cases per 100,000 people (Endorfet al. 2009), there is significant morbidity and mortality as-sociated with this condition. In a review of the literature,

Lynn Schuster, Director, Acute Care Nurse Practitioner Hospitalists, Banner Gateway Medical Center, Gilbert, AZ; Diane E. Nunez, Clinical Associate Professor, Arizona StateUniversity, College of Nursing & Health Innovation, Phoenix, AZ

Address correspondence to Dr. Diane E. Nunez, Arizona State University, College of Nursing & Health Innovation, 500 N. 3rd Street, Phoenix, AZ 85004; [email protected]

Accepted 19 March 2011Copyright ©2011 Sigma Theta Tau Internationaldoi: 10.1111/j.1741-6787.2011.00235.x

Endorf et al. (2009) reported a 24–40% mortality rate. Ifthe patients survive the infection they are often left withextensive soft tissue disfigurement or loss of extremities.

Necrotizing infections are difficult to diagnose as theyoften present similarly to other common skin and soft tis-sue infections (SSTIs) with symptoms of pain, erythema,warmth, and swelling. May and colleagues (2009) revealed

88 Second Quarter 2012 �Worldviews on Evidence-Based Nursing

Clinical Pathways to Aid in the Diagnosis of Infections

that 50% of patients with NSTIs are misdiagnosed on ad-mission. Some signs and symptoms that should alert thehealthcare provider to an NSTI are the presence of bul-lae, skin ecchymosis or sloughing, gas in the tissues, skinanesthesia, pain out of proportion to the exam, edema thatextends beyond the skin erythema, rapidly spreading infec-tion, and symptoms of sepsis such as hypotension, tachy-cardia and organ failure (Stevens et al. 2005). These areoften referred to as “hard signs” of an NSTI. Early recog-nition of these infections is essential, as they will spreadto the deep tissues creating fluid pockets that do not allowthe body’s healing cells to reach the tissues in need. Al-though soft tissue infections are more commonly seen inthe emergency room setting, with an incidence of 24.8 per1,000 person years compared with 0.04 per 1,000 per-son years for necrotizing infections (Ellis Simonsenet al. 2006), it is imperative that the healthcare provideris able to differentiate between necrotizing and nonnecro-tizing infections as delayed treatment increases mortality(May et al. 2009). Patients with necrotizing infections re-quire broad-spectrum antibiotics and immediate surgeryfor aggressive debridement of the necrotic tissue (Mayet al. 2009).

The Institute of Medicine has recommended the use ofevidence-based clinical pathways to reduce errors (Kohn2000). Wright and colleagues (2008) studied the im-plementation of evidence-based clinical pathways in theemergency room setting to decrease provider error. Pa-tients were given a higher quality of care after the im-plementation of clinical guidelines with patients receivingtreatments more rapidly, had decreased time spent in theemergency room, and had decreased readmission rates(Wright et al. 2008).

At a Southwestern tertiary care medical center in theUnited States; 90% of patients that presented to the emer-gency room were erroneously diagnosed with a soft tis-sue infection, when they were later determined to have anecrotizing infection (L. Schuster, personal communica-tions, August 21, 2010). There is often a knowledge deficitamong staff members when these patients present to thehospital about the warning signs that should trigger thedifferential diagnosis of a necrotizing infection. By imple-menting clinical practice guidelines (CPGs) to assist withthe triage of patients presenting to the emergency roomwith a soft tissue infection to rule out a necrotizing in-fection, it is anticipated that the time from presentationto diagnosis and treatment will decrease. This inquiry hasled to the clinically relevant question: in adult patientspresenting with an SSTI, how does the use of an evidence-based CPG for screening patients for NSTIs compare withnot using a clinical guideline in affect to the time to thediagnosis of a necrotizing infection?

SEARCH METHODS

To address the question of the impact of clinical guide-lines on early diagnosis of NSTI, an extensive review ofthe literature was performed. The search included reviewsof CINAHL, Medline/Ovid, MD Consult, Cochrane, Na-tional Guideline Clearinghouse, and Pub Med. The searchterms that were used included: “NSTIs,” “fasciitis,” “softtissue infections,” “diagnosis,” “early diagnosis,” “clinicalpathways,” “clinical guidelines,” and “Laboratory Risk In-dicator for NECrotizing Fasciitis (LRINEC) score.” Thefollowing limits were placed: English and adults. Initiallythe dates were limited from 2005 to present, however thedates were expanded to 1900 until present to ensure cap-ture of landmark studies prior to those dates. The searchfindings using these keywords resulted in numerous re-sults, up to 69,000. Therefore the results were further de-fined by applying controlled vocabulary, Boolean/phrasesearch mode, MeSH terms, and implode and explode. Inaddition to the search of the databases, the bibliographiesof the search results were scanned for additional studies.

Inclusion criteria for the studies included adult popu-lation, diagnosis of NSTIs, and use of diagnostic criteriafor NSTIs. Exclusion criteria included studies that solelyaddressed treatment of NSTIs.

The keywords search method for CINAHL yielded 1,038results. This was narrowed down to 13 relevant articles,with two of four clinical trials being relevant to this project;four clinical guidelines were retained for reference. A re-view was performed of the reference lists from the perti-nent articles and one further relevant article was obtained.A Medline/OVID keyword search yielded 37,674 results.The results were narrowed by using the focus feature with“diagnosis” for the subheading, refining the list to 237 re-sults. These results were focused by searching for “NSTI”and “diagnosis,” yielding three clinical trials, two of whichwere used in this study. A keyword search of MD Con-sult yielded 230 results. When “diagnosis” was added to“NSTI,” 18 results were obtained, four of which were per-tinent to this project.

The Cochrane reviews and libraries were searched us-ing the keyword SSTI AND diagnosis which yielded 15 re-sults. However, after reviewing the abstracts of these papersnone of them met the inclusion criteria for this study. TheNational Guideline Clearinghouse was searched using theprevious keywords; six results were obtained with one per-tinent guideline meeting inclusion criteria. To concludethe search, PUBMED was explored using the keywordsnecrotic soft tissue infection with 773 results. NSTIs anddiagnosis narrowed it down to 40 results. In review ofthe studies, many had already been captured by previ-ous database searches, however one new clinical trial was

Worldviews on Evidence-Based Nursing �Second Quarter 2012 89


obtained. In total, 11 clinical trials, 9 review articles, and5 clinical guidelines were used for this evidence-based re-view through the exhaustive search of six databases. Tworeviewers, the chief of surgery and an associate professorat Arizona State University, reviewed the studies. Theirlevels of agreement about clinical relevance, study design,and statistical analysis were congruent.

CRITICAL APPRAISAL AND SYNTHESIS OFEVIDENCE

Overall, the chosen studies were of good quality, notingconfidence intervals (CI), standard deviations (SD), levelof significance (p), mean values (M), odds ratio (OR), sen-sitivities (Se), and specificities (Sp). Eight out of nine ofthe studies (evaluation table, Table 1) reviewed for thispaper were retrospective studies that showed level II ev-idence, the remaining study was prospective and showedlevel II evidence. Unfortunately, the majority of the studieson this subject matter are retrospective as it is unethicalto withhold diagnostic measures for these patients as theywould suffer from severe morbidity and mortality if theydo not have an adequate workup to rule out or confirm thediagnosis. This limits the potential validity of these studiesas bias can be introduced during the chart review process.The nine studies that were reviewed displayed a moderatedegree of homogeneity in regards to sample demographics(Table 2). The majority of the patients were males, in theirmid-40s to early 50s. The largest risk factors for necrotiz-ing infections in most of the studies were intravenous druguse (IVDA), diabetes, and liver disease (Table 3).

There was a moderate degree of sample heterogeneity inregards to the statistical measurements used, with the Stu-dent t-test being used most frequently in three of the ninestudies. Each of the studies had a relatively small samplesize, ranging from 21 to 359 subjects, likely representingthe rare nature of this disease; this could limit the validityof the findings. Another limiting factor is there are incon-sistent definitions for NSTIs throughout the studies. Thegold standard for diagnosing NSTIs is a tissue biopsy, how-ever some of the studies allowed surgeon opinion, whichcould limit the validity of the findings. Finally, there wassome heterogeneity among the independent and depen-dent variables that were studied; however, each study ex-cept for one (Frazee et al. 2008) found that a sodium (Na)level <135 mEq/L was associated with necrotizing infec-tions. Each study also found an association between ele-vated white blood cell (WBC) count and NSTIs; however,the definitions of an elevated WBC count were inconsis-tent throughout the studies. Three studies looked at thevalue of using the LRINEC scoring system as a promising

objective score that can be used to diagnose or rule out anNSTI.

CONCLUSIONS ABOUT EVIDENCE

The synthesis of study findings support early diagnostictesting to include complete blood count (CBC), compre-hensive metabolic panel (CMP), blood and wound cul-tures, C-reactive protein (CRP), and creatinine kinase oneach patient that presents to the emergency department(ED) with a soft tissue infection (CPG, Figure 1). If thereare hard signs of a necrotizing infection present (bul-lae, necrosis, pain out of proportion to the exam, rapidlyspreading infection, gas, skin anesthesia, sepsis) promptconsultation with surgical services should be initiated. Ifthe patient does not have hard signs, a LRINEC score can becalculated (Figure 1, LRINEC Score), and for scores ≥6,surgery consult should promptly occur to initiate rapidintervention. For scores <6 but with clinical concern, di-agnostic imaging such as an X-Ray, CT scan, or MRI isindicated depending on the location of the infection.

Among all studies reviewed, WBC >15.4 mm3 andNa < 135 mEq/L are the strongest predictors to early di-agnosis of necrotizing infections. Both of these values areincorporated in the LRINEC score. The LRINIC score is anemerging objective scoring system to aid in the predictionand early diagnosis of NSTIs, however it should be usedin conjunction with clinical judgment, as there is limitedstudy data to date.

DISCUSSION

The purpose of this review was to evaluate the efficacyof objective laboratory data and clinical measures to pro-mote early diagnosis of NSTIs. Using these measures inthe development of a CPG in the emergency room settingwill guide practitioners’ initial diagnostic workup whilesuggesting issues requiring attention for the translation ofthe intervention’s effectiveness in patients presenting withinitial SSTIs.

Interventions using early obtained laboratory diagnos-tics of CBC, CMP, blood and wound cultures, CRP, andcreatinine kinase showed improvements in clinical diag-nosis and referral for treatment interventions. In patientswith hard signs of an NSTI (bullae, necrosis, pain outof proportion to the exam, rapidly spreading infection,gas, skin anesthesia, sepsis) with positive data of elevatedWBC count and low sodium demonstrated a predictive cor-relate of clinical diagnosis of necrotizing infection. Thiseffect implies reduced morbidity and mortality in NSTIsas compared to usual care when measured across dimen-sions of health outcomes. If the health issue guiding the


Clinical Pathways to Aid in the Diagnosis of InfectionsTA

BLE

1Ev

alua

tion

tabl

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CON

CEPT

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ty

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TAB

LE1

(Con

tinue

d)M

AJO

RD

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ION

CON

CEPT

UA

LD

ESIG

N/

SAM

PLE/

VARI

AB

LES

MEA

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MEN

TD

ATA

FOR

USE

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TATI

ON

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MEW

ORK

MET

HO

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TTIN

GST

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IED

OF

DA

TAA

NA

LYSI

SFI

ND

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SPR

ACT

ICE

Hsia

oet

al.(

2008

)Phy

siol

ogic

Retro

spec

tive

Purp

ose=

Toid

entif

yth

epo

sitiv

ean

dne

gativ

epr

edic

tors

ofM

inpt

sw

ithN

STI

N=

128

A=

61+/

–12

.9M

a=

67%

DM59

%Ci

rrho

sis

=11

%IV

DA=

4%Ca

ncer

=7%

ESRD

=4%

LO=

UE/L

E88

%,T

r4%

Setti

ng=

ACin

Taiw

anI=

ERad

mit,

d/c

dxof

NST

IEx

=N

otad

mitt

edth

roug

hER

,No

C&S,

A<

18,r

eadm

itted

forN

STI

with

in30

days

IV1=

SBP<

90IV

2=

Vibr

ioIV

3=

Aero

mon

asIV

4=

Mal

igna

ncy

IV5=

Band

s>0%

IV6=

Corr

ectD

xDV

=M

ofN

STIp

ts

Data

colle

ctio

nsh

eet

Sim

ple

and

mul

tivar

iate

logi

stic

regr

essi

onan

alys

is

OR(9

5%CI

)+p

valu

eIV

1=

6.62

(1.5

2–28

.77)

IV2=

7.03

(1.2

1–41

.03)

IV3=

10.2

2(1.

34–7

7.96

)IV

4=

46.5

4(5.

76–3

76.0

3)IV

5=

5.61

(1.4

8–21

.3)

IV6=

38%

Leve

l2St

reng

ths:

Blin

ded

data

extra

ctor

Wea

knes

ses:

Retro

spec

tive,

high

erin

cide

nce

ofvi

brio

,Aer

omon

asan

dci

rrho

sis

than

othe

rstu

dies

,not

allp

tsha

dtis

sue

confi

rmat

ion

ofN

STI.

No

IVDA

case

sCo

nclu

sion

:Aer

omon

asor

Vibr

ioin

fect

ion,

canc

er,h

ypot

ensi

onor

band

s>

10ha

vein

crea

sed

M.

Clin

ical

sign

ifica

nce:

Pts

with

abov

efin

ding

sw

illne

edag

gres

sive

treat

men

tas

Mis

high

er

Suet

al.(

2008

)Ph

ysio

logi

cRe

trosp

ectiv

e,ob

serv

atio

nalc

ohor

tst

udy

Purp

ose=

Tode

term

ine

the

rela

tions

hip

b/tt

heLR

INEC

scor

ean

dM

,LO

S,an

dne

edfo

rsu

rger

y

N=

209

pts

with

NST

I,di

vide

din

totw

ogr

oups

∗Gro

up1

LRIN

ECsc

ore

<6

n=1

09∗G

roup

2LR

INEC

≥6n

=10

0M

a=70

%A

=56

.8-1

5DM

=56

%Ci

r=28

%ES

RD=

22%

No

cm=

25%

Setti

ng:T

e,AC

,and

1Co

m,A

CTa

iwan

I=Ad

ultp

tsad

mitt

edth

roug

hth

eER

with

ad/

cdx

ofN

STI

EX=

<18

year

sol

d,tx

from

othe

rin

stitu

tions

,unc

erta

inLR

INEC

scor

e.On

ly1s

tadm

itus

edfo

rpts

with

mul

tiple

adm

issi

ons

forN

STI

IV1=

LRIN

ECSc

ore

DV1=

MDV

2=

Amp

DV3=

SU

LRIN

ECsc

ore

Man

n-W

hitn

eyU-

test

and

aSt

uden

tt-te

stw

ere

used

toco

mpa

reth

est

atis

tical

lysi

gnifi

cant

diffe

renc

esbe

twee

nth

etw

ogr

oups

.

Grou

p1:

DV1=

11%

DV2=

17.4

%DV

3=

30+/

–51.

8h

Grou

p2

:DV

1=

21%

DV2=

36%

DV3=

27.4

+/–5

1.8

hOv

eral

lDV1

=15

..8%

Over

allD

V2=

26.3

%AU

CDV

2=

0.75

1(0

.700

–0.8

02)

AUC

DV1=

0.60

7(0

.547

–0.6

66)Le

vel2

Stre

ngth

s:si

mila

rfind

ings

ofot

her

stud

ies

Wea

knes

ses:

retro

spec

tive,

med

ical

reco

rds

may

bein

com

plet

eor

inac

cura

tely

inte

rpre

ted,

nota

llca

ses

ofN

STIc

onfir

med

bytis

sue

path

olog

yCo

nclu

sion

:Pts

with

aLR

INEC

scor

e≥6

have

incr

ease

dM

and

Amp

Clin

ical

sign

ifica

nce:

Pt’s

with

aLR

INEC

scor

e≥6

will

need

surg

ery

cons

ultf

orfu

rther

eval

uatio

n

Wal

leta

l.(2

000)

Phys

iolo

gic

Retro

spec

tive

stud

yPu

rpos

e=to

iden

tify

obje

ctiv

eda

taon

adm

issi

onto

help

diffe

rent

iate

NST

Ifro

mSS

TI

N=

42pt

s,N

STIn

=21

Non

-NST

In=

21M

a=

81%

A=

39DM

=14

%IV

DA=

67%

HIV

=10

%LO

=UE

43%

,LE

43%

,BU

5%Se

tting

=U

NST

I=N

ecro

ticfa

scia

onOR

and

path

findi

ngs

Non

-NST

I=Ce

llulit

isor

absc

ess

w/o

necr

osis

onpa

thor

OR,r

esol

ved

with

abx

only

IV1=

WBC

>14

IV2=

BUN

>15

IV3=

Na<

135

DV1=

NST

IDV

2=

M

Data

colle

ctio

nsh

eet

MV

and

UVan

alys

is,

Stud

ent’s

t-te

st,

chi-s

quar

ete

stor

Fish

er’s

exac

ttes

t.

IV1:

Se=

81%

,Sp

=76

%,P

PV77

%,N

PV=

80%

IV2:

Se=

70%

,Sp

=88

%,

PPV

=88

%,N

PV=

71%

IV3:

Se=

75%

,Sp

=10

0%,

PPV

=10

0%,N

PV=

77%

DV2=

0if

WBC

<20

DV2=

46%

ifW

BC>

20DV

2=

100%

ifW

BC>

30

Leve

l2St

reng

ths:

mat

ched

com

paris

ongr

oup

Wea

knes

ses:

retro

spec

tive,

smal

lsa

mpl

esi

zeCo

nclu

sion

:ele

vate

dW

BCan

dBU

Nan

dde

crea

sed

Na

can

help

dist

ingu

ish

NST

Ifro

mSS

TI,e

leva

ted

WBC

isth

ebe

stob

ject

ive

pred

icto

rofM

.Tra

nsfe

rfro

man

othe

rfac

ility

incr

ease

dM

Clin

ical

sign

ifica

nce:

Susp

icio

nfo

rNST

Iw

illbe

rais

edw

hen

apt

pres

ents

with

anel

evat

edW

BCan

dBU

Nan

dlo

wN

a.W

illpr

ovid

eag

gres

sive

treat

men

tif

WBC

>20

(Con

tinue

d)



TAB

LE1

(Con

tinue

d)M

AJO

RD

ECIS

ION

CON

CEPT

UA

LD

ESIG

N/

SAM

PLE/

VARI

AB

LES

MEA

SURE

MEN

TD

ATA

FOR

USE

INCI

TATI

ON

FRA

MEW

ORK

MET

HO

DSE

TTIN

GST

UD

IED

OF

DA

TAA

NA

LYSI

SFI

ND

ING

SPR

ACT

ICE

Wal

leta

l.(2

000)

Phys

iolo

gic

Retro

spec

tive

Purp

ose=

tode

term

ine

Ifa

mod

elof

WBC

>15

.4or

Na<

135

onad

mit

can

pred

ictN

STIw

hen

hard

sign

sar

eno

tpr

esen

t

NST

In=

31SS

TIn

=32

8M

a=

77%

A=

45DM

=19

%He

patit

is=

19%

IVDA

=71

%LO

=UE

48%

,LE

32%

,BU

6%Se

tting

=U

Com

paris

onw

ithot

hers

tudy

byW

all.

I=Co

nsec

utiv

epa

tient

sw

ithd/

cdx

ofN

STIo

rSST

IN

STI=

Nec

rotic

fasc

iaor

mus

cle

inOR

.SS

TI=

No

necr

otic

fasc

iaor

mus

cle

inOR

orre

solv

edw

ithab

x

IV1=

Mod

el(p

ositi

veif

WBC

>15

.4or

NA<

135)

DV1=

NST

IDV

2=

SSTI

Data

colle

ctio

nsh

eet

Clas

sific

atio

nan

dre

gres

sion

tree

anal

ysis

(CAR

T),

stud

entt

-test

,di

scre

teva

riabl

esw

ere

anal

yzed

usin

gth

ech

i-squ

are

orFi

sher

exac

ttes

t

IV1: Se

=90

%(9

5%CI

,74–

98%

)Sp

=76

%(9

5%CI

,71–

80%

)PP

V26

%(9

5%CI

18–3

5%)

NPV

99%

(95%

CI97

–100

%)

LEVE

L2

Stre

ngth

s:Si

mila

rto

othe

rstu

dies

.In

clud

edal

lpts

with

SSTI

even

ifN

STI

nots

uspe

cted

.W

eakn

ess:

Retro

spec

tive

stud

y,sm

all

stud

ypo

pula

tion,

char

trev

iew

may

besu

bjec

tive.

Conc

lusi

on:P

tsw

/oha

rdsi

gns

ofN

STI

and

ane

gativ

em

odel

are

unlik

ely

toha

veN

STI;

61%

with

outh

ard

sign

s.W

BCm

ore

pred

ictiv

eth

anN

aCl

inic

alSi

gnifi

canc

e:Su

spic

ion

rais

edfo

rNST

IifW

BC>

15.4

and

Na<

135

Won

get

al.(

2004

)Phy

siol

ogic

Retro

spec

tive

Purp

ose=

deve

lop

asc

orin

gsy

stem

for

dist

ingu

ishi

ngN

STI

from

SSTI

Deve

lopm

enta

lcoh

ortn

=31

4N

STIn

=89

SSTI

n=

225

Valid

atio

nco

hort

n=1

40N

STIn

=14

5SS

TIn

=30

9A

=56

(27–

84)

Ma

=60

%DM

=71

%PV

D=

23%

No

Cm=

14%

Setti

ng=

2AC

,Te

inSi

ngap

ore

INST

I=gr

ayis

hne

crot

icfa

scia

,lac

kof

resi

stan

ceto

blun

tdis

sect

ion,

lack

ofbl

eedi

ng,,

and

foul

-sm

ellin

g“d

ishw

ater

”pu

s.IS

STI=

Clin

ical

impr

essi

on,

abx

>48

h,ab

sces

sEX

=LO

S<48

hor

only

poab

x

IV1=

WBC

IV2=

Na

IV3=

HgB

IV4=

CRP

IV5=

CrIV

6=

BGDV

1=

NST

IDV

2=

SSTI

LRIN

ECsc

ore

Hosm

er-L

emes

how

good

ness

offit

test

used

tova

lidat

eth

eLR

INEC

LRIN

EC:P

PV=

92%

,NPV

=96

%IV

1=

20.7

2+/

–8.

9IV

2=

129.

3+/

–4.

9IV

3=

12.1

+/–

2.49

IV4=

254.

3+/

–84

.1IV

5=

1.56

+/–

1.17

IV6=

281+/

–16

2

Leve

l2St

reng

ths:

Find

ings

sim

ilart

oot

her

stud

ies.

Wea

knes

s:Re

trosp

ectiv

e,sm

alls

ampl

esi

ze,s

ubje

ctiv

ech

artr

evie

wCo

nclu

sion

:LR

INEC

scor

e≥6

isst

rong

lysu

spic

ion

forN

STI.

If≥8

ther

eis

ahi

ghpr

edic

tive

valu

efo

rNST

I.Cl

inic

alsi

gnifi

canc

e:Pt

’sw

itha

LRIN

ECsc

ore

≥6ne

eda

surg

ery

cons

ult

(Con

tinue

d)



TAB

LE1

(Con

tinue

d)M

AJO

RD

ECIS

ION

CON

CEPT

UA

LD

ESIG

N/

SAM

PLE/

VARI

AB

LES

MEA

SURE

MEN

TD

ATA

FOR

USE

INCI

TATI

ON

FRA

MEW

ORK

MET

HO

DSE

TTIN

GST

UD

IED

OF

DA

TAA

NA

LYSI

SFI

ND

ING

SPR

ACT

ICE

Yagh

oubi

anet

al.(

2007

)Ph

ysio

logi

cRe

trosp

ectiv

ePu

rpos

e=to

dete

rmin

eth

epr

edic

tors

ofM

for

NST

I

N=

124

Grou

p1

(pts

that

died

)n=

21A

=48

(42–

54)

Ma

=66

%DM

=24

%IV

DA=

67%

Canc

er=

14%

Live

rdis

ease

=7%

HIV

=0

Txfro

man

othe

rH=

35%

Grou

p2

(sur

vivo

rs)n

=10

3A

=43

(36–

53)

Ma

=68

%DM

=40

%IV

DA=

26%

Canc

er=

2%Li

verd

isea

se=

10%

HIV

=6%

Txfro

man

othe

rH=

13%

LO=

LE52

%Se

tting

=Un

iver

sity

Med

ical

Cent

erI=

D/C

dxof

NST

Icon

firm

edw

ithOR

&pa

thre

ports

IV1=

La>

54.1

IV2=

Na<

135

IV3=

WBC

>15

.4IV

4=

SCIV

5=

SUIV

6=

Hard

sign

sIV

7=

Amp

IV8=

MDV

=M

orta

lity

Exce

ldat

aco

llect

ion

shee

ttra

nsla

ted

into

ana

tive

SAS

Clas

sific

atio

nan

dre

gres

sion

tree

anal

ysis

(CAR

T).

Wilc

oxon

rank

sum

test

and

Xsq

uare

dor

Fish

erex

actt

est

IV1=

32%

MIV

2=

19%

MIV

3=

62%

IV4

=3.

5h

IV5

=8.

5h

IV6

=44

%IV

7=

15%

IV8

=17

%La

<54

.1+

Na

<13

5=

19%

MLA

<54

.1+

NA>

135=

0%M

Se=

100%

(0.8

4–1.

00)

Sp=

28%

(0.1

9–0.

37)

PPV

=23

%(0

.14–

0.32

)N

PV=

100%

(0.8

8–1.

00)

Leve

l2St

reng

ths:

Find

ings

sim

ilart

oot

her

stud

ies

Wea

knes

s:Re

trosp

ectiv

e,sm

all

sam

ple

size

,sub

ject

ive

char

trev

iew

Conc

lusi

on:C

ance

r,IV

DA,t

xfro

man

othe

rhos

pita

l,ab

dom

enLO

,hy

pote

nsio

n,La

>54

.1an

dN

a<

135

onad

mit

incr

ease

MCl

inic

alsi

gnifi

canc

e:Ag

gres

sive

treat

men

tsho

uld

bepr

ovid

edif

abov

efa

ctor

sar

epr

esen

tas

mor

talit

yis

incr

ease

d.If

Na

>13

5an

dLa

<54

.1,m

orta

lity

is0

and

treat

men

tcan

beco

nser

vativ

e

Not

e.A

=ag

e(m

ean)

;abx

=an

tibio

tics;

AC=

acad

emic

;Am

p=

ampu

tatio

n;AU

C=

area

unde

rthe

curv

e;BG

=bl

ood

gluc

ose;

BSA

=bo

dysu

rface

area

;b/t

=be

twee

n;BU

=Bu

ttock

;C=

Coun

ty;C

ir=

cirr

hosi

s;Cm

=co

mor

bidi

ties;

Com

=co

mm

unity

;Cr=

seru

mcr

eatin

ine;

CRF

=ch

roni

cre

nalf

ailu

re;C

RP=

Cre

activ

epr

otei

n;C&

S=

cultu

rere

sults

;D=

dura

tion

ofsy

mpt

oms;

d/c

=di

scha

rge;

DM=

diab

etes

mel

litus

;DV

=de

pend

entv

aria

ble;

Dx=

diag

nosi

s;ER

=em

erge

ncy

room

;ESR

D=

end

stag

ere

nald

isea

se;E

X=

excl

usio

n;F=

fem

ale;

h=

hour

;H=

hosp

ital;

HgB

=he

mog

lobi

n;Hx

=m

edic

alhi

stor

y;I=

incl

usio

n;IV

=in

depe

nden

tvar

iabl

e;IV

DA=

intra

veno

usdr

ugab

use;

La=

seru

mla

ctat

e;LE

=lo

wer

extre

mity

LO=

loca

tion;

LOS

=le

ngth

ofst

ay;

LRIN

EC=

labo

rato

ryris

kin

dica

torf

orne

crot

izing

fasc

iitis

scor

e;M

=m

orta

lity;

Ma

=m

ale;

MV

=m

ultiv

aria

te;N

a=

seru

mso

dium

;NPV

=ne

gativ

epr

edic

tive

valu

e;N

STI=

necr

otizi

ngso

fttis

sue

infe

ctio

n;Or

=od

dsra

tio;O

R=

oper

atin

gro

om;P

ath

=pa

thol

ogy;

PE=

phys

ical

Exam

;po

=or

al;P

PV=

posi

tive

pred

ictiv

eva

lue;

Pts

=pa

tient

s;SB

P=

syst

olic

bloo

dpr

essu

re;S

C=

surg

ery

cons

ult;

Se=

sens

itivi

ty;S

p=

spec

ifici

ty;S

STI=

skin

and

soft

tissu

ein

fect

ion;

SU=

time

from

pres

enta

tion

tosu

rger

y;Sx

=sy

mpt

oms;

T=

tem

pera

ture

;Te

=te

rtiar

y;Tr

=tru

nk;T

x=

trans

ferr

ed;U

=ur

ban;

UE=

uppe

rext

rem

ity;U

V=

univ

aria

te;V

S=

vita

lsig

ns;W

BC=

whi

tebl

ood

cell;

w/o

=w

ithou

t.



TABLE 2Synthesis table

CHAN FRAZEE HOLLAND HSIAO SU WALL WALL #2 WONG YAGHOUBIAN

Year 2008 2008 2009 2008 2008 2000 2000 2004 2007Retrospective X X X X X X X XProspective XNumber of subjects 21 122 28 128 209 42 359 314 124DemographicsMean age 42 44 61 57 39 45 56% Males 90 64 80 67 70 81 77 60 69% IV drug user 29 80 4 67 71 31% Diabetic 52 22 59 56 14 19 71 38% renal dz 5 4 22% liver dz 5 11 28 19 19%HIV 4 10% Cancer 7PVD 23No co morbidities 19 25 14Findings% Mortality 16 19 21 21 17% Amputation 4 17 26 15Time to SE 3.5 hTime to OR 8.4 h 60.4 h 28.7 +/– 51.7 h 8.5 h% Diagnosed correctly on admission 59 38 67SettingAcademic X X X X XTertiary X X X X XCommunity X X XUnited States X X X X XTaiwan X XSingapore XAustralia XIndependent variablesLRINEC X X XCRP X X XWBC >15 X X X X X X X X XBands > 10% XNa < 135 X X X X X X X XLactic acid> XCr X X X X XBUN X XSBP < 100 X X X X XSQ gas X X X X XTemp >38◦C X X X XHR >100 X X XRR>20 XPain X X XHard signs X X XAdmit to nonsurgical service XDependent variablesMortality X X X XDx of NSTI X X X XDx of SSTI XAmputation XNonsevere NSTI XSevere NSTI XNote. Cr = creatinine; CRP = C reactive protein; DV = dependent variable; Dz = renal disease; ER = emergency room; IVDA = intravenous; LRINEC = laboratoryrisk indicator for necrotizing fasciitis score; Na = serum sodium; NSTI = necrotizing soft tissue infection; OR = operating room; PVD = peripheral vasculardisease; SE = surgical evaluation; Temp = temperature.



TABLE 3Laboratory risk indicator for necrotizing fasciitis (LRINEC) score

C REACTIVE PROTEIN

< 150 0 points≥ 150 4 points

White cell count< 15 0 points15–25 1 point> 25 2 points

Hemoglobin>13.5 0 points11–13.5 1 point< 11 2 points

Sodium≥135 0 points<135 2 points

Creatinine≤ 1.59 0 points> 1.59 2 points

Glucose≤ 180 0 points> 180 1 point

intervention (e.g., objective laboratory data with clinicaljudgment to diagnose NSTIs) was clearly delineated, theintervention would readily be described as effective in aparticular setting, for a particular population. From the re-ports reviewed, the diagnostic interventions as applied tothe development of a CPG for diagnosis of NSTIs appearsto be effective using a variety of patient cohorts, and is ef-fective in some settings, but not others, and is effective inoutcomes such as early diagnosis, morbidity, and mortalityoutcomes.

While this evidenced-based review of the clinical out-comes of interventions using the LRINEC scoring systemshow emerging support for the use of this intervention, theissues of applicability and generalizability remain a discus-sion point. Clinicians may perceive available evidence doesnot apply to their settings due to disparate participant char-acteristics or insufficient contextual information offered inreports to ascertain applicability. These issues present aschallenges associated with changing clinician behavior andwill impact clinical interventions for improved patient careoutcomes (Litaker et al. 2006). This application in healthcare has tended to be mechanistic, with undesirable vari-ation in health service delivery and should be consideredwhen designing and implementing any CPG. Standardiz-ing care using CPGs without identifying desirable variationor unique adaptations that take advantage of system op-portunities and strengths misses an important prospect to

implementing interventions in complex adaptive systems(Berwick 2003).

LIMITATIONS

While this review primarily focused on efficacy of the in-terventions, the discussion is not complete without a briefnotice of the translation of the intervention to acutely illpatients in the ED setting. And for this notice, the interven-tions reviewed need to be considered for their treatmentevaluation and in the case of LRINEC, the preliminary na-ture of the data. Applied to clinical practice change, inter-vention theory provides a systematic approach to interven-tion development, implementation, and evaluation, anddirects us in moving from outcomes focused approachesto those examining the central processes underlying inter-vention effects (Sidani & Sechrest 1999). When interven-tions are examined in light of explanations of the prob-lem amenable to treatment, critical inputs of the interven-tion, mediating processes, and expected outcomes of theintervention further an understanding of what interven-tions work, for whom, and under what conditions therebystrengthening causal inferences (Sidani & Sechrest 1999;Berwick 2003).

THEORETICAL APPLICATION

The problem in each of the reviewed interventions wasdefined as the “outcome” that is, reduced morbidity andmortality associated with this condition. More theoreti-cally appropriate would be a problem defined as “insuf-ficient means for rapid and accurate diagnosis” and theconceptual issue around a paucity of objective measures toguide clinical practice. This approach would clearly guideclinicians to include objective measures, diagnostics, andhard signs as measures of intervention applicability. Themajority of studies reviewed applied Physiologic Theoryas the conceptual framework guiding interventions. Thistheory provides an explanatory mediator of the degree ofbiologic response and potential for morbidity and mortal-ity in NSTIs.

These moderating variables influence the differential ef-fects of interventions across populations and settings andwill further strengthen our understanding of the evidenceavailable in development of CPGs to inform practice andimprove patient outcomes. Additional effort is needed todetermine the relevance of objective measures such as theLRINEC scoring system and its predictability in groupswith diverse cultural and socioeconomic backgrounds. Thefindings from this review suggest that evidence-based dis-ease management needs to focus on common underly-ing physiologic and prognostic constructs that will foster



NECROTIZING INFECTIONS

Pt presents to theemergency room with

signs of skin or soft tissueinfection (SSTI)

ER INITIATES WORKUP,CONSIDER FOLLOWING LABS:CBC, CMP, BLOOD AND WOUNDCULTURES, MAG,ESR, CRP, CK,

UA, LACTIC ACID

MEETADMISSIONCRITERIA?

ALOC, Sepsis, Rapidlyspreading lesion,

immunosuppression,failure of outpatienttreatment, co-morbidities,

noncompliance

Signs of a necrotizinginfection?

ORLRINEC >6?

Discharge homewith outpatienttreatment

STAT SURGICALCONSULT andANTIBIOTICS

(Vanco +Clinda +Zosyn). Consult IDand pharmacy for

Vancomanagement

YES

NO

YES

NO

LRINEC SCORE

CRP: < 150 0CRP > 150 4

WBC < 15 0WBC 15-25 1WBC >25 2

Hgb >13.5 0Hgb 11-13.5 1Hgb <11 2

Na> 135 0Na< 135 2

Cr < 1.59 0

Cr >1.59 2

Glucose <180 0Glucose >180 1

Bullae, skin ecchymosisor sloughing, presenceof gas in the tissues,skin anesthesia, painout of proportion to theexam, edema that

extends beyond the skinerythema, rapidlyspreading infection,

FollowHospital

Standard ofCare forFurtherTreatment

Figure 1. Clinical practice guideline.

improved diagnosis, early communication and referral, andprompt treatment to reduce morbidity and mortality in thepresence of NSTIs.

Bennet and Bennet (2004) discuss a theoretical frame-work underpinning system complexity. Advances in tech-nology are one factor contributing to the world becominga more complex organism. Complexity theory representsthe interconnectedness and the sharing of knowledge thatoccurs within systems. Though there are many benefits to

ease in sharing information, it has also led to an increasein uncertainty and rapid growth and in order to surviveand be competitive in the current environment, individu-als and organizations must learn to adapt to these changesby staying abreast of the latest technologies while findingways to keep track of the information that is at their fin-gertips. The Intelligent Complex Adaptive System model(ICAS) has been developed as a possible way to accomplishchange and was used as the theoretical framework guiding



the application of a clinical pathway for NSTI diagnosis ina large healthcare system (Bennet & Bennet 2004).

The foundation for the ICAS model revolves aroundeight fundamental characteristics: Permeable Boundaries,Selectivity, Flow, Optimum Complexity, Knowledge Cen-tricity, Multidimensionality, Shared Purpose, and Organi-zational Intelligence. The development of these strategiesstrengthens the organization and gives it tools to cope withthe challenges of living in a rapidly changing environment(Bennet & Bennet 2004).

Permeable Boundaries allow a system to be interactivewith the external environment so that they can be awareof external needs and respond appropriately. Selectivityis the process of filtering out endless information to seekout information that is pertinent to the system. Flow rep-resents the internal movement of people and knowledgewithin the system and across boundaries in response todemands. Optimum Complexity is the necessity to cre-ate a diverse internal system so that external complexitycan be challenged. Knowledge Centricity is the dynamicsharing of knowledge within an organization so that col-laboration can occur among the various parts of a systemto develop solutions to problems. Multidimensionality isthe importance of developing a broad base of knowledgethat extends beyond the boundaries of ones’ specific job re-quirements. Shared Purpose provides a shared vision anddirection among members of the system, and Organiza-tional Intelligence is the process of using the knowledgegenerated by the system to follow through with the ob-jectives and goals of the organization (Bennet & Bennet2004).

Drawing on the principles from the ICAS model, devel-opment of a CPG for NSTIs, information is shared withthe knowledge workers (healthcare providers) regardingNSTIs and the evidence-based recommendations to guidediagnosis and treatment. The workers will not be forced tocomply with these standards; however, it is anticipated thatcompliance with recommendations are achieved throughimplementation of the ICAS model constructs. Each iden-tified stakeholder plays a vital role in practice change andfluid interdependence and communication will drive anypractice change success. Frequent evaluation of systemprocesses enhance performance and projected outcomesthroughout all stages of CPG development and implemen-tation.

While conceptual models and theoretical frameworkswere not clearly stated in the majority of the reviewedinterventions, what was clear is how theoretical mediat-ing variables contributed to outcome changes in terms ofaccurate diagnoses and guides for clinician judgment. Lim-itations to the efficacy of objective measures designed toevaluate the presence of predictors of NSTIs may be re-

lated to a simplistic “black box” approach that focuses ondetermining whether an intervention worked or did notwork, without consideration of the systems’ internal work-ings (Sidani & Sechrest 1999). A more effective emphasismight be on the interpretation of the causal connection be-tween the intervention (objective data plus clinician judg-ment) and the intended outcome. Understanding the bio-logic and physiologic mechanisms underlying the NSTIs,without consideration of contextual variables and clinicaljudgment, may lead to overestimation of the condition andimplementation of intervention protocols.

MEDIATING PROCESSES

This review demonstrated that contextual variables such asage, setting, location of infection, socioeconomic factors,and marital status were not specified as influencing out-comes and related interventions. What is unclear is that ifthese variables had additive or a singularly influential ef-fect on early diagnosis or outcome of disease. Missing fromthis review is information that assesses the confoundingdiversity that exists between initial case presentation, pop-ulation characteristics, factors related to clinical decisionmaking and its effect on time to diagnosis.

Examination of interventions for early diagnosis andprompt treatment of NSTIs requires attention to the pop-ulation experiencing the problem of interest, or clarify-ing for whom and under what conditions an interventionmight be most effective. In the ED setting, moderatorsare the context and characteristics of patients presentingfor care and are important considerations in the designand evaluation of intervention effectiveness and general-izability of any CPG. Salient moderators of interventioneffect were clearly addressed in the majority of studiesto explain intervention effects. The overall low incidence,general predominance of men, and lack of significant eth-nic representation in the reviewed studies would requireconsideration of gender and ethnicity in any interventionimplementation. Understanding the participant character-istics and biologic or sociologic interactions such as age,gender, ethnicity, and socioeconomic status, in additionto infection location, comorbid diagnoses, and time to di-agnosis will aid in the application and generalizability ofa CPG in the early diagnosis and prompt treatment ofNSTIs.

CONCLUSIONS

Specific interventions described in this review can be trans-lated to the development and implementation of a CPG asa process of evidence-based practice in acute care settings,specifically the ED where patients are most likely to first



present for care. Successful engagement of diagnostic andpathway protocols for relevant changes within complex or-ganizational systems can be initiated through applicationof clinical evidence, shared vision, organizational mission,and incorporation of individual values, while ensuring re-sources are strategically utilized. A complex healthcare sys-tem culture requires focus on translating diagnostic andcare improvements for acutely ill patients presenting withelusive and clinically challenging disease, while consid-ering the interdependent variables of complex adaptivesystems found in health care today. The evidence-basedpractice process is an integral part of translational researchusing champions of change to develop new pathways ofcare through individual mentorship and system-wide ed-ucation. These processes mediate the rapid engagement ofnew research, change clinician practice, and ultimately re-duce morbidity and mortality of patients presenting withSSTIs, preventing development of these early signs into lifethreatening NSTI.

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