title: Focused abdominal sonography for trauma in the emergency department for blunt abdominal trauma.
abstract: BACKGROUND
  Blunt abdominal trauma (BAT) is a diagnostic challenge to the emergency physician (EP). The introduction of bedside ultrasound provides another diagnostic tool for the EP to detect intra-abdominal injuries.
  
  
  OBJECTIVE
  To evaluate the performance of EP in a local emergency department in Hong Kong to perform the 'focused abdominal sonography for trauma' (FAST) in BAT patients.
  
  
  METHODS
  This was a retrospective cohort study including all the trauma team cases in a 36-month period in the emergency department of a public hospital in Hong Kong. The results of FAST scans were analyzed and compared with CT scans when the FAST was positive or followed by a period of clinical observation when the FAST was negative. Descriptive statistics and sensitivity, specificity, and predictive values were calculated.
  
  
  RESULTS
  There was a total of 273 cases, and FAST scans were performed in 242 cases. The sensitivity and specificity were 86% and 99%, respectively. The negative predictive value was 0.98, while the positive predictive value was 0.94. The overall accuracy was 97%.
  
  
  CONCLUSIONS
  The performance of the EP in using FAST scans in BAT patients was encouraging. The high specificity (99%), positive predictive value (0.98), and likelihood ratio for positive tests (86) make it a good 'rule in' tool for BAT patients. The high negative predictive value also makes the FAST scan a useful screening tool. However, ultrasound examination is operator dependent, and FAST scan has its own limitations. For negative FAST scan cases, we recommend a period of monitoring, serial FAST scans, or further investigations, such as CT scan or peritoneal lavage.
authors.affiliation: Accident and Emergency Department, Tuen Mun Hospital, Hong Kong, cltsui333@netvigator.com
authors.forename: Chi Leung
authors.initials: CL
authors.lastname: Tsui
authors.forename: Hin Tat
authors.initials: HT
authors.lastname: Fung
authors.forename: Kin Lai
authors.initials: KL
authors.lastname: Chung
authors.forename: Chak Wah
authors.initials: CW
authors.lastname: Kam