Friese 2007.

Study characteristics
Patient sampling	Retrospective study
Patient characteristics and setting	Study location: Texas, USA Study period: November 2003 to February 2005 Care setting: level I trauma centre Mass casualty: no Participants enrolled: 126 Participants included in analysis: 96: 47 men and 49 women Age: mean age 42.3 ± 22.5 years Type of injury: pelvic trauma Injury severity: not reported Haemodynamic stability: increased risk for haemorrhage Inclusion criteria: "the trauma registry was queried for all patients admitted to the trauma service through our emergency department during the study period with the diagnosis of pelvic fracture and the presence of at least one of the following risk factors for haemorrhage: age 55 years, the presence of haemorrhagic shock (systolic blood pressure 100 mm Hg), or an unstable fracture pattern. Additional inclusion criteria were the use of the FAST examination to evaluate the peritoneal space for the presence of haemoperitoneum on arrival to the emergency department and a confirmation of the presence or absence of haemoperitoneum by laparotomy or abdominopelvic computed tomography (CT) scan." Exclusion criteria: "DPL performed before confirmatory evaluation and treatment at an outside facility before arrival at our emergency department."
Index tests	Index test: FAST US protocol: all FAST examinations were performed by surgery residents (postgraduate year 3 or higher) who were required to complete the American College of Surgeons course on the use of ultrasound in the acute setting. The trauma bay protocol specifies that all FAST examinations were performed as an adjunct to the primary trauma survey, which meant that the FAST examination was completed within 5 to 10 minutes of participant arrival in the emergency department. A true‐positive FAST examination was defined as free intraperitoneal fluid detected on US and haemoperitoneum confirmed at laparotomy or abdominopelvic CT scan. A true‐negative FAST examination was defined as no free fluid noted on abdominal US and the absence of haemoperitoneum noted at laparotomy or abdominopelvic CT scan. A false‐positive FAST examination was defined as free intraperitoneal fluid detected on US and the absence of haemoperitoneum on laparotomy or abdominopelvic CT scan. A false‐negative FAST examination was defined as no free intraperitoneal fluid detected on abdominal US and haemoperitoneum found at laparotomy or abdominopelvic CT scan. Hardware used: portable 2102 HAWK ultrasound unit (B&K Medical, Willmington, MA) with a low‐frequency (3.5‐MHz) transducer and a curvilinear array Description of imaging technique: standard 4‐view FAST examination
Target condition and reference standard(s)	Target condition: free fluid and air Reference standard: CT (technical specifications not reported), laparotomy Description of technique: all operative and abdominopelvic CT scan reports were also reviewed for documentation of the presence of haemoperitoneum. CT scan and operative findings were based on the final dictated and transcribed reports placed in the permanent medical record from the attending radiologist and attending surgeon. Special information about the technique of the reference standard was not reported.
Flow and timing	Time between US and reference standard: not reported
Comparative
Notes
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
		Unclear	High
DOMAIN 2: Index Test All tests
Were the index test results interpreted without knowledge of the results of the reference standard?	Unclear
If a threshold was used, was it pre‐specified?	Yes
Was the qualification of the US operator appropriate?	Yes
Was the US hardware (i.e. generation, manufacturer, probe, etc.) up to date?	Yes
Was the US protocol (i.e. 'classic' FAST) appropriate?	Yes
Are there concerns that the definition or performance of the index test (i.e. POC US of trauma) do not match generally accepted, established, or practiced rules or recommendations?	No
		Low	Low
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 the index tests?	Unclear
Was the qualification of the doctors (i.e. radiologists, surgeons, etc.) determining the reference standard appropriate?	Yes
Was the reference imaging standard (i.e. MDCT‐rows (4 to ≥ 256 slices), contrast‐imaging, etc.) up to date?	Unclear
Are there concerns that the definition or performance of the reference tests (e.g. CT, MRI, laparatomy, thoracotomy, autopsy, etc.) do not match generally accepted, established, or practiced rules or recommendations?	Yes
		Unclear	High
DOMAIN 4: Flow and Timing
Was there an appropriate interval between index test and reference standard?	Yes
Did all patients receive the same reference standard?	No
Were all patients included in the analysis?	Yes
Did all participants receive a reference standard? (Risk of partial verification bias)	Yes
		Low