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A VALIDATION STUDY OF 5 TRIAGE SYSTEMS

USING DATA FROM THE 2005 GRANITEVILLE,SOUTH CAROLINA, CHLORINE SPILL

Authors: Joan M. Culley, PhD, MPH, RN, CWOCN, Erik Svendsen, PhD, Jean Craig, PhD, andAbbas Tavakoli, DrPH, Columbia, SC, New Orleans, LA, Charleston, SC

Introduction: Lack of outcomes-based research results in un-certainty about the effectiveness of any of the current triagesystems in determining priority of care during actual chemicaldisasters. The purpose of this study was to determine whetherthe level of injury severity extrapolated from 5 triage systemscorrelated with actual injury severity outcomes of victimsexposed to a chlorine disaster.

Methods: Using secondary data analysis, data for 631 victimswere merged, de-identified, and analyzed. Using logic modelsfrom the triage systems, the actual injury severity wascompared with the extrapolated injury severity classifications.

Results: Analysis showed weak to modest correlationsbetween the extrapolated injury severity triage outcomeclassifications and the actual injury severity outcomes(Spearman correlation range 0.38 to 0.71, P b .0001). There

lley is Associate Professor, College of Nursing, University of Southlumbia, SC.

n is Associate Professor, Department of Global Environmental Healthool of Public Health and Tropical Medicine, Tulane University,s, LA.

is Systems Architect and Database Warehouse, Office ofInformatics Systems/Health Sciences South Carolina, Medicalf South Carolina, Charleston, SC.

oli is Clinical Assistant Professor and Director, Nursing Statisticsollege of Nursing, University of South Carolina, Columbia, SC.

was supported by the National Institutes of Health/Nationaledicine (R21LMO10833).

dence, write: Joan M. Culley, PhD, MPH, RN, CWOCN, CollegeUniversity of South Carolina, Columbia, SC 29208; E-mail:u.

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$36.00

2014 Emergency Nurses Association. Published by Elsevier Inc.served.

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was slight to fair agreement between the extrapolated injuryseverity triage outcome classifications and the actual injuryseverity outcomes (weighted j = - 0.23 to 0.42).

Discussion: The extrapolated injury severity triage outcomecategories from the 5 triage systems did not agree with the actualinjury severity categories. Oxygen saturation measured by pulseoximetry provides early indications and is very predictive ofoutcome severity in incidents involving irritant chemicalexposures such as chlorine, and should be a part of a masscasualty protocol for any irritant chemical incident. Additionalresearch is needed to identify the most sensitive clinicalmeasures for triaging victims of toxic inhalation disasters.

Key words: Triage; Mass casualty incident; Chemical incidents;Validation study

Effective response to mass-casualty incidents, whichencompass a broad spectrum of threats and hazards,represents one of the greatest challenges to our

nation’s emergency response infrastructure.1 Natural,unintended (technological), or deliberate catastrophicevents (all-hazards events) will necessitate the effectiveand timely management of mass casualties.2,3 Chemicalincidents involving irritant chemicals such as chlorine posea significant threat to life and require rapid assessment. Inthe aftermath of a disaster such as a large chemical spill, firstresponders have only seconds to evaluate the condition of avictim before moving to the next victim. Casualtiesgenerated by such disasters can overwhelm health carecapabilities, jeopardizing the lives of victims and health careproviders alike.1 To mitigate the “surge” of casualties into ahealth care facility after a mass-casualty event, hospitals andemergency responders use triage to assess patients andprioritize care with the goal of saving as many lives aspossible. However, the proposed national guideline forexisting mass-casualty triage does not take fully intoaccount all-hazards events4 that include chemical incidentsrequiring decontamination and toxidrome (a group ofsymptoms or a specific syndrome associated with exposureto a specific poison or agent5,6) assessment.

This study evaluated 5 frequently used triage systems:(1) Simple Triage and Rapid Treatment (START)7;

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TABLE 1Five triage systems used for triage simulation studies based on abstracted hospital record data for 2005 Graniteville,South Carolina, chlorine spill

Triage system Description

START7 (field triage system) Uses ability to walk, respirations, circulation, and mental status forindividuals aged ≥8 y

JumpSTART Pediatric Triage Algorithm8

(field triage system)Uses same assessments as START but is designed for individualsaged b8 y and includes a more comprehensive neurologic assessment

SALT9 (field triage system) Uses ability to walk, respirations, pulse, mental status, available resources,and injuries to assess individuals aged ≥8 y

CBRN6 (field triage system) Uses ability to walk and respirations and is the only system that additionallyassesses contamination and toxidrome a symptoms related to chemical,biological, radiologic, or nuclear incidents to assess individuals aged N8 y

ESI10 (emergency department—based system) Uses patient acuity, pulse, respiration, SpO2, and number of resourcesneeded for all ages

BRN, Chemical/Biological/Radiologic/Nuclear Mass Casualty Triage System; ESI, Emergency Severity Index; SALT, Sort, Assess, Lifesaving Interventions, Treatment/Transport; START, Simple Triaged Rapid Treatment; SpO2, arterial oxygen saturation measured by pulse oximetry.a Toxidrome refers to a group of symptoms or a specific syndrome associated with exposure to a specific poison or agent.5,6

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Can

(2) JumpSTART8; (3) Sort, Assess, Lifesaving Interventions,Treatment/Transport (SALT)9; (4) Chemical/Biological/Radiologic/Nuclear Mass Casualty Triage System (CBRN)6;and (5) Emergency Severity Index (ESI).10 Table 1 describeseach of these systems.

Mass-casualty research is not suitable for randomized,controlled, experimental exposure studies. Therefore cur-rent mass-casualty research designs and evaluation strategiesusually are anecdotal, and many of the data reported havelittle external validity.11–14 The ability to collect accurate,timely, and valid data at the time of an incident is difficult.Because data are often missing or biased, it is impossible totest the utility of a specific model. There is no gold standardfor measuring the efficacy of triage.1,15 Strategies are neededto study the accuracy and efficacy16,17 of initial triage fromactual mass-casualty datasets.

Lack of outcomes-based research results in uncertaintyabout the efficacy of any of the triage systems on patientoutcomes.18 This research builds on the work of Lerner et al,4

Kirk and Deaton,19 Jenkins et al,17 Wenck et al,20 and VanSickle et al16 in identifying the most relevant and appropriatedata needed for initial triage of mass casualties using an all-hazards approach. For this study, initial triage assessmentsmade by first responders, ED personnel, and primary careproviders were used so that a priority code for treatment and/ortransport could be determined.

On January 6, 2005, a freight train carrying tanker carsof liquid chlorine was inadvertently switched onto anindustrial spur in the center of Graniteville, South Carolina,where it crashed into a parked locomotive. The trainderailed and heavily damaged chlorine tankers ruptured,

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immediately releasing approximately 60 tons of chlo-rine.5,21 Within minutes, the dense chlorine gas infiltratedthe surrounding town with a population of over 7,000persons. Nine people died, 71 were hospitalized, 840 weretreated as outpatients, and 220 had immediate healthproblems including skin, eye, nose, and throat injuries.16,21

The South Carolina Department of Health and Environ-mental Control (SC DHEC) and epidemiologists from theCenters for Disease Control and Prevention (CDC) collecteddata at the scene during the first few weeks after the incident.

The purpose of this research was to identify andvalidate triage systems appropriate for use in chemical eventsusing the Graniteville data. The research questions were asfollows: Do 5 currently used triage systems correlate withthe level of care needed after a chemical mass-casualty event,such as a chlorine spill? What, if any, additional informationwould improve accurate triage classifications duringchemical incidents?

Methods

DESIGN

This report presents the results of a secondary data analysisused to study the efficacy of 5 triage systems, using datafrom a real chemical mass-casualty event. The Division ofAcute Disease Epidemiology and the regional and countyoffices of the SC DHEC and the CDC collaborated todesign and conduct public health interventions22,23 andsurveillance20 to better clinically characterize the chlorine-exposed victims. Abstracted ED and medical record data

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collected by the SC DHEC and the CDC were linked withthe other public health datasets of the chlorine disastervictims within the South Carolina Office of Research andStatistics. These data provided the research dataset used inthis study.

Because none of the databases included data regardingactual triage categories assigned during the chlorineincident, a statistical logic model was created for each triagesystem to generate “extrapolated” injury severity triageoutcome classifications (triage category) for each triagesystem. Logic for each of the 5 triage decision trees oralgorithms was coded in Statistical Analysis System (SAS)software, version 9.2 (SAS Institute, Cary, NC),24 to createa statistical logic model for each triage system.

Wenck et al20 used 9 injury severity categories to classifypatients who received medical care after the 2005 chlorineexposure: (1) deceased, (2) hospitalized for 3 or more nightswith ventilator and/or intensive care unit support, (3) hospi-talized for 3 or more nights, (4) hospitalized for 1 to 2 nights,(5) multiple ED visits during acute period, (6) ED visit withsubstantial respiratory symptoms, (7) ED visit with mildsymptoms, (8) EDpresentation because of exposure only, and(9) non-emergent medical office visit. These actual injuryseverity categories were used to retrospectively identifypatients who actually needed treatment immediately andthose who did not. For analysis, categories 1 through 4 wereclassified as having a severe medical outcome and assigned an“immediate” extrapolated injury severity status for triage;categories 5 through 7 were classified as having a less severemedical outcome and assigned a “delayed” extrapolated injuryseverity status for triage; and categories 8 and 9 were assigneda “minimal” extrapolated injury severity status for triage. Forthe purpose of assessing accuracy of the 5 triage systems, the 9actual injury severity category measures, as determined byWenck et al, were considered the standard with which theextrapolated injury severity triage outcome categories fromthe 5 triage systems were compared.

SAMPLE

Data were abstracted by public health officials from 155 EDrecords of patients who were either admitted to the hospitalor seen more than once in the emergency department of thelocal medical center.16 The public health authority madethe decision as to which patient records were abstractedbased on the assumption that patients who were treatedmultiple times in the emergency department would havebeen hospitalized in a non-surge scenario. In addition tothese 155 patients, another 257 patients whose medicalrecords had not been abstracted yet were included in thesample because other linked public health datasets, which

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included data from these same patients, had sufficient datadetailing their initial clinical presentation.

Collected data on the victims were entered into 6datasets.16,20,23,25 After these linked data were deidentifiedand data use agreements were approved by all parties, the datawere provided to the research team by the South CarolinaOffice of Research and Statistics for use in this study. The studywas approved by the Institutional Review Boards of theUniversity of South Carolina and the SC DHEC beforeinitiation. Every member of the research team reviewed thedeidentified datasets for accuracy; duplicate records wereeliminated. The datasets were then merged to generate aresearch dataset to create codes for the 5 triage systems. Thesedata were used to determine whether the triage categories fromthe 5 triage systems correlated with patient outcomes and toexplore what additional information would improve predic-tions of accurate triage classifications during chemical incidents.

MEASURES

Actual patient outcome data were used to determine whetherextrapolated triage scores from the 5 triage systems correlatedand/or agreed with the actual patient injury severity developedbyWenck et al.20 Triage categories were extrapolated based onthe statistical logic model created for each triage system.

EXTRAPOLATED INJURY SEVERITY TRIAGEOUTCOME CATEGORY

The biophysical response to acute chlorine exposure is uniformand very characteristic despite route of exposure and individualsusceptibility. This permits the analysis of linkages betweeninjury severity and triage systems for an acute chlorinedisaster.26,27 Select variables that characterize severity of injuryoutcome after a chlorine exposure were used in the developmentof a statistical logicmodel to study the effectiveness of the 5 triagesystems in extrapolating injury severity category outcomes.Variables (triage data elements) included physiological measure-ments, toxidrome signs/symptoms, resources, arterial oxygensaturation (SpO2), and injury severity categories. Triage systemsthat are often studied typically assess physiological parametersand resource constraints to determine their accuracy inidentifying patients with critical injury. However, few studieshave shown strong agreement among triage systems using actualpatient outcomes.18

Each triage system data element was operationalized toselect or extrapolate the correct value from the clinical dataavailable. For example, the clinical records did not have adata entry field for “does not obey commands,” which is akey component of the START/JumpSTART triage assess-ment. Therefore it was determined that the patient did obey

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TABLE 2Frequency and percent of victims’ actual injury severity outcomes as categorized using extrapolated injury severitytriage outcomes for 2005 Graniteville, South Carolina, chlorine spill

Actual injury severity outcome a [n (%)] Extrapolated injury severity triage outcome category [n (%)]

START/JumpSTART:

all ages

ESI:

all ages

CBRN:

adults

SALT:

adults

631 (100)Deceased: 8 (1.27) Black (deceased):

8 (1.27)Level 0 (dead):8 (1.27)

T4:8 (1.27)

White (dead) or black(expectant): 8 (1.27)

Hospitalized ≥3 nights with intensive careunit/ventilator, hospitalized ≥3 nights, orhospitalized 1-2 nights: 72 (11.41)

Red (immediate):38 (6.02)

Levels 1 and 2:131 (20.76)

T1 b:87 (13.79)

Red (immediate):78 (12.36)

Emergency department, multiple visits;emergency department with substantialrespiratory symptoms; or emergencydepartment with mild symptoms: 257 (40.73)

Yellow (delayed):0 (0)

Levels 3 and 4:459 (72.74)

T2:30 (4.75)

Yellow (delayed):1 (0.16)

Emergency department without symptoms orphysician office visit: 75 (11.89)

Green (minor):546 (86.53)

Level 5: 0 (0) T3:506 (80.19)

Green (minimal/normal):544 (86.21)

Missing data: 219 (34.7) Not classified:39 (6.18)

Not classified:33 (5.23)

Not classified:0 (0)

Not classified:0 (0)

CBRN, Chemical/Biological/Radiologic/Nuclear Mass Casualty Triage System; ESI, Emergency Severity Index; SALT, Sort, Assess, Lifesaving Interventions, Treatment/Transport; START, Simple Triageand Rapid Treatment; SpO2, arterial oxygen saturation.

a Outcomes categories were collapsed into 4 categories for analysis: deceased (8 declared dead at scene and not triaged and 1 taken to emergency department and died at hospital); intensive care unit/hospitalization of any length of stay; emergency department with substantial or mild symptoms; and emergency department without symptoms for exposure or non-emergency medical office visit.

b All values are significant (P b .001) except for the CBRN T1 value.

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commands if all other data elements that required obedience(eg, able to give a medical history) were completed. Many datameasures required for completion of the triage systems werereadily available, such as respiratory rate or blood pressure atpresentation. Such data elements were culled from the clinicaldata and used in the triage system analysis. Because this studyfocused on triage efficacy, the initial clinical presentation datawere exclusively used to assess triage efficacy and the later clinicaldata, collected during the remainder of the hospitalization ortreatment within the emergency department, were simplyused contextually or to determine the actual severity of injury.5

This methodology was described by Culley and colleagues.5

Pulse oximetry was previously found useful in assessing thehealth of surge patients.16 However, because of the surge ofpatients to the emergency department at the time of the chlorineincident, thismedical resourcewas not completed for all patients.5

DATA ANALYSIS

Descriptive statistics were used to describe selected variablessuch as demographic data and patient outcomes (actual andextrapolated). The research database was analyzed usingmeasures of central tendency for descriptive variables andpatient outcomes. Spearman correlation was used to compare

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actual injury severity (from the study of Wenck et al20) withthe extrapolated injury severity triage outcome classificationsand SpO2. We calculated κ statistics to examine the level ofagreement between extrapolated injury severity triageoutcome classifications and actual injury severity.

Results

The final merged dataset consisted of 631 abstractedrecords. The actual outcome sample size, and therefore thenumber of rows with populated columns for each triagemodel, varied from 110 to 412 depending on the dataavailable from the records. The SC DHEC datasets includeinformation on patients hospitalized in 9 hospitals (n = 71),patients examined during the first few days after theaccident (N = 631), or patients who died (n = 9). The dataincluded patients ranging in age from 4 months to 85 years;male patients comprised 58.9%. Regarding race, 59.9% ofpatients were classified as white, 35.2% as black, and 2.5%as Hispanic, with race categorized as “other” for 2.4%.

Spearman correlations between the extrapolated injuryseverity triage outcome classifications and the actual injuryseverity outcomes ranged from 0.38 to 0.64 (P b .0001).

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TABLE 3SpO2 correlated with actual injury severity categories and ESI triage system extrapolated injury severity triageoutcome categories for 2005 Graniteville, South Carolina, chlorine spill

Actual injury severity category a Actual SpO2 (n = 110) [n (%)] ESI category ESI extrapolated injury severity

triage outcome category with

SpO2 (n = 112) [n (%)]

45%-89% 90%-91% ≥92% 45%-89% 90%-91% ≥92%

Deceased 1 (0.91) 0 (0) 0 (0) Level 0: dead a a a

Hospitalized ≥3 nights with intensive careunit/ventilator; hospitalized ≥3 nights;or hospitalized 1-2 nights

24 (21.82) 7 (6.36) 36 (32.73) Levels 1 and2: red

27 (24.11) 8 (7.14) 40 (35.41)

Emergency department, multiple visits;emergency department with substantialrespiratory symptoms; or emergencydepartment with mild symptoms

2 (1.82) 1 (0.91) 39 (35.45) Levels 3 and4: yellow

0 (0) 0 (0) 37 (33.04)

Emergency department without symptomsor physician office visit

0 (0) 0 (0) 0 (0) Level 5: green 0 (0) 0 (0) 0 (0)

ESI, Emergency Severity Index; SpO2, arterial oxygen saturation.a Outcomes categories were collapsed into 4 categories for analysis: deceased (8 declared dead at scene and not triaged and 1 taken to emergency department and died at hospital); intensive care unit/

hospitalization of any length of stay; emergency department with substantial or mild symptoms; and emergency department without symptoms for exposure or non-emergency medical office visit.

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The Spearman correlations between actual injury severityand the triage systems were as follows: CBRN, r = 0.64;SALT, r = 0.44; START, r = 0.55; ESI, r = 0.59; and EDSpO2, r = 0.38. The Spearman correlation between ED SpO2

and CBRN was r = 0.52; SALT, r = 0.60; START, r = 0.60;and ESI, r = 0.71. There was slight to fair agreement betweenthe extrapolated injury severity triage outcome classificationsand the actual injury severity outcomes. The simple κstatistics for ESI, CBRN, START/JumpSTART, and SALTwere 0.36 (95% confidence interval [CI], 0.28 to 0.43), 0.15(95% CI, 0.09 to 0.20), 0.14 (95% CI, 0.11 to 0.18),and 0.13 (95% CI, 0.09 to 0.16), respectively, and theweighted κ statistics were 0.42 (95% CI, 0.34 to 0.49), 0.30(95% CI, 0.24 to 0.36), 0.25 (95% CI, 0.19 to 0.31), and0.23 (95% CI, 0.17 to 0.29), respectively.

Table 2 summarizes the results of the extrapolatedinjury severity outcome categories compared with the actualinjury severity outcomes. The data showed an overestima-tion of victims classified as levels l and 2 using the ESI triagesystem and an underestimation of victims classified as red(immediate) by the START/JumpSTART system. Victimsclassified as T1 using the CBRN system showed similartriage misclassifications. Victims classified as yellow(delayed) were either over- or under-triaged or not classifiedby the START/JumpSTART and SALT systems. All of thetriage systems except the ESI dramatically overestimated thegreen (minor), level 5, or T3 category by 68% to 75%. Allof the victims in this study were seen in the emergency

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department of the local hospital. The ESI, designed for EDtriage, determines “how many different resources areneeded” as a variable to differentiate among triagecategories. All victims in this study used at least 1 resource(intravenous line, radiographs, oxygen, and so on) whenseen in the emergency department. Level 5 in the ESIsystem specifies that no resources are needed; therefore noneof the victims were classified as level 5 or green by thissystem. This accounts for the large number of victimsclassified as level 3 or 4, indicating that at least 1 resourcewas needed.

ARTERIAL OXYGEN SATURATION

The results of this study indicated that 23.6% of the victimsassessed (n = 27) had SpO2 lower than 90%, 7.3% (n = 8)had SpO2 of 90% to 91%, and 68.2% (n = 75) had SpO2 of92% or greater (Table 3). Analyses of the SpO2 values forESI compared with the actual injury severity outcomesindicated similar values for all triage categories.

Discussion

The Graniteville chlorine disaster presented an idealopportunity to test the accuracy of common triage systems.Anecdotal information strongly suggests that triage was usedin the 9 hospitals that received patients from theGraniteville chlorine disaster.28,29 However, no data on

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the actual triage approaches were available within any of thedatabases used. Ambulance run data were not available inthe datasets used for this analysis primarily because mostpatients self-transported.20 Therefore this study does notuse any data that specified a triage category or make anyinferences on the efficacy of the actual triage provided to theGraniteville chlorine spill disaster victims.

The hospitals rapidly ascertained the limitations of theavailable triage systems and used other approaches, such asSpO2 and their clinical judgment, to triage patients.19,28,29

Data from the poison control center clinical toxicologist’sconsultations suggest that a methodology was rapidlydeveloped and used in the hospitals based on a toxicsyndrome.19,29 Given the lack of data on the actual triageapproaches used in the Graniteville disaster, this studyextrapolated how Graniteville disaster patients might havebeen triaged had the clinicians exclusively used each of the 5aforementioned triage systems. Inferences are based only onthe extrapolated injury severity triage outcome categoriesand their correlation and agreement with the actual injuryseverity scores within the Graniteville disaster population.

Many chemicals such as chlorine and phosgene have alatency period from exposure to onset of symptoms thatmay result in the rapid deterioration of a patient’s conditionafter initial triage.6,30 Victims of chlorine exposure mayhave difficulty breathing or shortness of breath immediatelyif high concentrations of chlorine gas are inhaled, or signsand symptoms may be delayed if concentrations are low.16

Children may be more vulnerable to the effects of chlorine.31

A review of the literature indicates that none of the triagesystems examined has been evaluated for sensitivity andspecificity under conditions that include chemicals and theirdelayed effects and a variety of criteria and parameters,including physiological “cutoff” values32–34; this wassupported by data from our study.

The triage systems studied showed only modest efficacyin establishing priorities for the treatment of victimsexposed to chlorine. The ESI, the only triage systemstudied that uses SpO2 as a physiological measure,performed better than the other triage systems (r = 0.71).The CBRN system specifically addresses toxidrome symp-toms related to chemicals such as chlorine. Incorrectlyperformed triage can underestimate the need of criticallyinjured patients for immediate care, resulting in preventabledeaths or deformities (under-triage), or overestimate theextent of minor injuries, resulting in death or disability ofpatients with more severe injuries (over-triage).1 Analysis ofdata from the CBRN system showed that 80% of thevictims studied were classified as having an extrapolatedinjury severity triage outcome category of T3 (minor), orwere under-triaged, compared with only 12% classified as

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minor from the actual injury severity category. Theextrapolated injury severity triage outcome category wasT1 (immediate) for 14% (over-triaged) and T2 for 5%(under-triaged) compared with actual injury severitycategories of T1 for 11% and T2 for 41%.

Sensitivity measures how likely a test detects thepresence of a characteristic in someone with the character-istic. A value of 1 indicates a perfect sensitivity and a value of0 indicates no sensitivity. The results showed goodsensitivity for ESI with outcome (0.86) and very poorsensitivity for CBRN (0.03), START/JumpSTART (0),and SALT (0.03) with outcome. The specificity of eachtriage system with outcome was 0.44, 0.64, 0.75, and 0.88for ESI, CBRN, START/JumpSTART, and SALT,respectively. The positive predictive value was 0.27 forESI with outcome and was close to 0 for the other triagesystems with outcome. Such accuracy could lead to criticalmisdiagnoses and faulty treatment decisions had thecurrently available triage systems been used exclusively.

Limitations

Two specific issues influenced the outcomes of this study.First, during chemical incidents, the time from exposure totriage assessment is a critical determinant of an accuratetriage classification. During the disaster examined, victimswere admitted to the emergency department over a timeframe of more than 8 hours. Chemicals such as chlorine andphosgene have a latency period. Because the data abstractedincluded only the initial SpO2 measurement on arrival inthe emergency department, this may have influenced theextrapolated severity outcome. Four of the triage systemsstudied are intended for field triage (START, JumpSTART,CBRN, and SALT), whereas the ESI system is used inhospital emergency departments. Although all 5 of thesesystems have similar characteristics, they are implementeddifferently in the field than in a hospital setting. Theinfluences of a latency period in sign and symptomevolution in both of these settings may be different, andthis warrants further investigation. Second, because of thesurge of large numbers of patients, many patients did notreceive an SpO2 assessment. Accuracy and completeness ofcharting also influence the statistical analysis.

Implications for Emergency Nurses

Mitchell et al35 stress the need for triage competencytraining of emergency nurses for chemical incidents. SpO2

measured by pulse oximetry, one of the best predictors of

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triage classification for inhalation chemical hazards, shouldbe incorporated into the competency training of emergencynurses. Our study illustrates the importance of SpO2 in theinitial assessment of victims of chlorine exposure whenother assessments do not prove to be reliable indicators ofthe severity of the health effects from a chemical exposure.SpO2 offers a relatively inexpensive, simple, and reliablemeans to monitor respiratory function in a wide variety ofsettings. An electronic clip-on sensing device is typicallyattached to the tip of the finger. SpO2 readings wererecorded for some of the victims seen in the emergencydepartment as a result of the 2005 chlorine leak. Publishedresearch on these data indicated that SpO2 was predictive ofacute medical outcomes.16,20 Van Sickle et al16 showed thatthe most frequently reported symptoms among the patients(ie, coughing and burning eyes) were not sufficient todistinguish mild from severe injury and that SpO2 providedearly indications of injury outcome severity as assessed bythe duration of hospitalization and need for intensive caresupport. The study by Van Sickle et al further showed thatpatients who were hypoxic on room air (SpO2 b90%) werehospitalized 3 times as long as those who were not hypoxic(P b .001) and that SpO2 provided early indications ofoutcome severity. SpO2 is a very easy and quick approach tounderstanding the physiological functioning and latencyeffects of victims of chemical disasters and should be thefirst-priority assessment used in emergency departments.

Conclusions

This study is unique in that the dataset included children insufficient numbers for analysis. The most important findingwas that SpO2 was very predictive of actual injury severity ina respiratory irritant chemical event and should be a part of amass-casualty protocol for any chemical spill. The extrap-olated injury severity triage outcome categories from the 5triage systems studied did not agree with the actual injuryseverity categories.

SpO2 provides early indications of outcome severity inincidents involving exposures to irritant chemicals such aschlorine. Additional research is needed to identify andvalidate the most sensitive clinical measures for triagingvictims of toxic inhalation disasters. Research is needed to(1) explore the effect of SpO2 as an assessment variable fortriage involving exposures to irritant chemicals such aschlorine and (2) explore additional information in an all-hazards mass-casualty triage system that could sufficientlyimprove accurate triage classifications for initial treatmentinvolving a chemical incident.36

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Acknowledgment

The research team acknowledges Dr David Van Sickle and his team fromthe CDC and the SC DHEC for their efforts in abstracting and entering theepidemiologic surveillance data that were used for this research. Theresearch team thanks Chris Finney from the South Carolina Office ofResearch and Statistics for providing the merged data in a deidentifiedformat for this study and Ben Card for providing the technology resourcesto protect the data, as well as teleconferencing support. The research teamalso thanks Beth Herron, Dr Jane Richter, and Dr JoAnne Herman for theirhelp and support in the preparation of this article.

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