Abdulrahman 2015.

Study characteristics
Patient Sampling	Location: Doha, Qatar Period of data collection: July 2011 to January 2013 Sampling technique: consecutive sampling
Patient characteristics and setting	Sample size: 610 lung fields (305 patients) Median age: 34 years old Male gender: 98% Blunt trauma: 100% Penetrating trauma: 0% Inclusion criteria: adult ED patients with blunt chest trauma needing resuscitation and CT chest as per ATLS guidelines Exclusion criteria: chest tube prior to CT chest, penetrating trauma, incomplete/inaccurate data
Index tests	CUS Operator: trauma surgeons Probe: 10 MHz linear probe Positivity definition: absence of pleural glistening (lung slide) or comet‐tail artefacts CXR in supine position interpreted by trauma radiologist.
Target condition and reference standard(s)	Reference standard: CT of the chest interpreted by trauma radiologist or rush of air or bubbling in chest drain after tube thoracostomy Target condition: traumatic pneumothorax
Flow and timing	Time to CUS: unclear Time to CXR: unclear Patients lost to follow‐up or excluded: 12 patients excluded for duplicate entries and incomplete data
Comparative
Notes	Unclear if the same trauma radiologist interpreted both the CXR and CT.
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	Yes
Did the study avoid inappropriate exclusions?	Yes
Could the selection of patients have introduced bias?		Low risk
Are there concerns that the included patients and setting do not match the review question?			Low concern
DOMAIN 2: Index Test (CUS)
Were index test results interpreted without knowledge of the results of CT or TT?	Yes
Were index test results interpreted without knowledge of the results of the other index test?	Yes
Did the authors prespecify the criteria for a positive CUS finding?	Yes
Could the conduct or interpretation of the index test have introduced bias?		Low risk
Are there concerns that the index test, its conduct, or interpretation differ from the review question?			Low concern
DOMAIN 2: Index Test (CXR)
Were index test results interpreted without knowledge of the results of CT or TT?	Unclear
Were index test results interpreted without knowledge of the results of the other index test?	Yes
Did the authors prespecify the criteria for a positive CUS finding?
Could the conduct or interpretation of the index test have introduced bias?		Unclear risk
Are there concerns that the index test, its conduct, or interpretation differ from the review question?			Low concern
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Yes
Were the reference standard results interpreted without knowledge of the results of CUS?	Yes
Were the reference standard results interpreted without knowledge of the results of CXR?	Unclear
Could the reference standard, its conduct, or its interpretation have introduced bias?		Unclear risk
Are there concerns that the target condition as defined by the reference standard does not match the question?			Low concern
DOMAIN 4: Flow and Timing
Did all patients receive the same reference standard?	Yes
Were all patients included in the analysis?	No
Was there an appropriate interval between CUS, CXR, and CT/TT?	Unclear
Could the patient flow have introduced bias?		High risk