Kirkpatrick 2004.

Study characteristics
Patient Sampling	Location: Vancouver, BC, Canada Period of data collection: July 2000 to October 2002 Sampling technique: unclear sampling technique
Patient characteristics and setting	Sample size: 266 lung fields (134 patients) Mean age: 37 years old Male gender: 74% Blunt trauma: 92% Penetrating trauma: 8% Inclusion criteria: adult trauma ED patients who did not require immediate invasive interventions (TT or needle decompression) Exclusion criteria: chest tube already in situ, gross subcutaneous emphysema that obscured acoustic window
Index tests	CUS Operator: trauma surgeons Probe: 10 to 5 MHz linear probe Positivity definition: absence of lung sliding or absence of comet‐tail artefacts CXR in supine position; unclear who interpreted CXR.
Target condition and reference standard(s)	Reference standard: CT of the chest; unclear who interpreted the CT Target condition: traumatic pneumothorax
Flow and timing	Time to CUS: unclear Time to CXR: unclear Patients lost‐to‐follow‐up or excluded: 411 lung fields from 225 patients were enrolled. Only 266 lung fields from 134 patients who received CUS, CXR, and CT were included in the secondary analysis.
Comparative
Notes	Only the data from the secondary analysis of patients that received CUS, CXR, and CT were included.
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	Unclear
Did the study avoid inappropriate exclusions?	Yes
Could the selection of patients have introduced bias?		Unclear 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?	Unclear
Did the authors prespecify the criteria for a positive CUS finding?	Yes
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 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?	Unclear
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?	Unclear
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?			Unclear
DOMAIN 4: Flow and Timing
Did all patients receive the same reference standard?	No
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