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Three Part Question

In [victims of a mass casualties incident] is [the addition of prehospital focused abdominal ultrasound to triage better than usual triage alone] at [reducing time to necessary surgery and reducing overall mortality]?

Clinical Scenario

A bomb explodes in a busy downtown building. When emergency medical care arrives there are 70 casualties on the ground and 50 standing or sitting. The prehospital team knows the START triage system and classifies seven patients as black, 12 as red and 51 as yellow or delayed. The 12 casualties classified as red are transported to the hospital with all the vehicles that were available. You wonder whether using focused abdominal ultrasound would help in further prioritising the transportation of the remainder patients.

Search Strategy

No BestBETs or relevant critical appraisals were found on this topic at http://www.bestbets.org. No ongoing trials on this topic were registered at http://www.clinicaltrials.gov.

Medline 1950 to present, Embase 1980 to present using NHS Evidence 24/04/2013. Multifile searching:

((((exp EMERGENCY MEDICAL SERVICES/) OR (prehospital.ti,ab) OR ((pre ADJ hospital).ti,ab) OR (pre-hospital.ti,ab)) AND (((exp ULTRASONOGRAPHY/) OR (ultrasound.ti,ab) OR (ultrasongraph*.ti,ab) OR (echograph*.ti,ab)) AND ((exp WOUNDS AND INJURIES/) OR (exp MULTIPLE TRAUMA/) OR (polytrauma.ti,ab) OR ((multiple ADJ trauma).ti,ab) OR (trauma.ti,ab)))) AND ((exp MASS CASUALTY INCIDENTS/) OR ((mass AND casualt*).ti,ab) OR (exp TERRORISM/) OR (exp DISASTERS/) OR (terrorism.ti,ab) OR (disaster*.ti,ab) OR ((multiple AND victim*).ti,ab))). Limit to English Language 35 unique articles.

The Cochrane Library Issue 3 2013: (MeSH descriptor: [Ultrasonography] explode all trees AND (MeSH descriptor: [Emergency Medical Services] explode all trees OR prehospital:ti,ab,kw (Word variations have been searched))). Thirty-nine records none relevant.

Search Outcome

Five articles addressing the subject were found with the search strategy. One is a letter without pertinent data, one proposes an ultrasound protocol in case of mass casualty without showing original data. The three other studies are shown in the table

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Dan Deng et al 2010 China	Mass casualty incident: Wenchuan earthquake, China Patients received at a hospital 90 km away from epicentre 587 out of a total of 1386 ultrasounds were performed outside the hospital in the early stage (<72 h)	Retrospective review	Detection of intra-abdominal injuries	23 Hemoperitoneum	Retrospective, one hospital Unclear who performed the ultrasound No result shown for early phase only No indeterminate scan Ultrasound performed on only 376% of patients No data on stable versus unstable patients No data on time to definitive treatment
			Detection of pleural effusion	45 Pleural effusion
			Detection of other injuries	1 femoral artery
			Time spent for ultrasound	Range : 2-4 min
Sarkisian et al 1991 Armenia	Mass casualty incident: 1988 Armenian earthquake Triage area organised in the hospital main lobby Ultrasound done by radiologist. 400 of 750 patients admitted during the first 72 h had ultrasound performed	Retrospective review	Positive ultrasound	96 positive ultrasound : ( 51 trauma related (35% of abdominal fluid), 45 non trauma related; 304 negative ultrasound	Retrospective review of one hospital No FAST protocol Ultrasound done by radiologist No information on outcome of patients with negative ultrasound CT done in only three of the 400 patients who had ultrasound No data on stable versus unstable patient No data on time to definitive treatment or patient outcome
			Time spent for ultrasound	Average 4 minutes (range : 1-10min)
Sztajnkrycer et al 2006 USA	Modified START triage applied retrospectively to trauma patient in a level 1 trauma centre. Excluding <16 years old, penetrating trauma, isolated burns, fall from standing resulting in isolated injury FAST ultrasound available on 359 patients Ultrasound performed by a supervised senior surgery or emergency medicine resident	Retrospective cross-sectional study	Positive scan in subgroup classified as yellow Surgery rate	20 of 286 Positive and 15 were inconclusive. Six patients with positive FAST underwent surgery	41% of Patients in the database transferred from another hospital Not in a mass casualty setting Modified START triage applied retrospectively No patient classified as green False positive and false negative rates not shown for yellow subgroup

Comment(s)

Although Sarkisian et al1 and Dan et al3 present interesting data on the actual use of ultrasound in the setting of mass casualties, it is not clear from the data whether there was any benefit to patient outcome. Further ultrasound was not performed on scene, but in a premedical area near the hospital. In a model based on patients who had attended a level 1 trauma centre, Sztajnkrycer et al2 showed that some patients who would have been classified as yellow using START had a positive FAST. This study was not done in a mass casualty setting and thus the result cannot be easily extrapolated to a mass casualty incident.

Clinical Bottom Line

The feasibility of prehospital ultrasound in mass casualty incidents has been demonstrated, but there is, as yet, no clear evidence of benefit as part of a triage protocol.

References

1. Dan D, Mingsong L, Jie T, et al. Ultrasonographic Applications after Mass Casualty Incident Caused by Wenchuan Earthquake. J Trauma 2010;68:1417–20.
2. Sarkisian AE, Khondkarian RA, Amirbekian NM, et al. Sonographic Screening of Mass Casualties for Abdominal and Renal Injuries Following the 1988 Armenian Earthquake. J Trauma 1991;31:247–50.
3. Sztajnkrycer MD, Baez AA, Luke A. Fast Ultrasound as an Adjunct to Triage Using the Start Mass Casualty Triage System: A Preliminary Descriptive System. Prehosp Emerg Care 2006;10:96–102.