title: Not so FAST.
abstract: BACKGROUND
  Focused assessment with sonography for trauma (FAST) as a screening tool in the evaluation of blunt abdominal trauma will lead to underdiagnosis of abdominal injuries and may have an impact on treatment and outcome in trauma patients.
  
  
  METHODS
  From October 2001 to June 2002, a protocol for evaluating hemodynamically stable trauma patients with suspected blunt abdominal injury (BAI) admitted to our institution was implemented using FAST examination as a screening tool for BAI and computed tomographic (CT) scanning of the abdomen and pelvis as a confirmatory test. At the completion of the secondary survey, patients underwent a four-view FAST examination (Sonosite, Bothell, WA) followed within 1 hour by an abdominal/pelvic CT scan. The FAST examination was considered positive if it demonstrated evidence of free intra-abdominal fluid. Clinical, laboratory, and imaging results were recorded at admission, and FAST examination results were compared with CT scan findings, noting the discordance.
  
  
  RESULTS
  Patients with suspicion for BAI were evaluated according to protocol (n = 372). Thirteen cases were excluded for inadequate FAST examinations, leaving 359 patients for analysis. There were 313 true-negative FAST examinations, 16 true-positives, 22 false-negatives, and 8 false-positives. Using CT scanning as the confirmatory test for hemoperitoneum, FAST examination had a sensitivity of 42%, a specificity of 98%, a positive predictive value of 67%, a negative predictive value of 93%, and an accuracy of 92%; chi analysis showed significant discordance between FAST examination and CT scan (5.85%, < 0.001). Six patients with false-negative FAST examinations required laparotomy for intra-abdominal injuries; 16 patients required admission for nonoperative management of injury. Of the 313 true-negative FAST examinations, 19 patients were noted to have intra-abdominal injuries without hemoperitoneum and 11 patients were noted to have retroperitoneal injuries.
  
  
  CONCLUSIONS
  Use of FAST examination as a screening tool for BAI in the hemodynamically stable trauma patient results in underdiagnosis of intra-abdominal injury. This may have an impact on treatment and outcome in trauma patients. Hemodynamically stable patients with suspected BAI should undergo routine CT scanning.
authors.affiliation: Division of Trauma/Surgical Critical Care, Lehigh Valley Hospital, Cedar Crest & I-78, P.O. Box 689, Allentown, PA 18105-1556, USA.
authors.forename: M Todd
authors.initials: MT
authors.lastname: Miller
authors.forename: Michael D
authors.initials: MD
authors.lastname: Pasquale
authors.forename: William J
authors.initials: WJ
authors.lastname: Bromberg
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Wasser
authors.forename: John
authors.initials: J
authors.lastname: Cox
mesh_terms: D000007:Abdominal Injuries / Q000150:complications / Q000000981:diagnostic imaging*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003951:Diagnostic Errors; D005188:False Negative Reactions; D005189:False Positive Reactions; D006465:Hemoperitoneum / Q000209:etiology; D006801:Humans; D008403:Mass Screening / Q000379:methods* / Q000592:standards; D008875:Middle Aged; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods / Q000592:standards; D014193:Trauma Centers; D014218:Triage / Q000145:classification; D014463:Ultrasonography / Q000379:methods / Q000592:standards; D014949:Wounds, Nonpenetrating / Q000150:complications / Q000000981:diagnostic imaging*