Purpose:The emergency physicians face significant clinical uncertainty when multiple trauma patients arrive in the emergency department (ED).The priorities for assessment and treatment of polytrauma patients are established in the primary survey.Focused assessment with sonography for trauma (FAST) is very essential clinical skill during trauma resuscitation.Use of point of care ultrasound among the trauma team working in the primary survey in emergency care settings is lacking in Suez Canal University Hospitals even ultrasound machine not available in ED.This study aims to evaluate the accuracy of FAST in hemodynamically unstable polytraumatized patients and to determine its role as an indication of laparotomy.Methods:This study is a cross-sectional study included 150 polytrauma patients with a blunt mechanism admitted in Suez Canal University Hospital.Firstly primary survey by airway check,cervical spine securing with neck collar,maintenance of breathing/circulation and management of life threading conditions if present were conducted accordingly to ATLS (advanced trauma life support) guidelines.The patients were assessed in the primary survey using the FAST as a tool to determine the presence of intraabdominal collection.Results:A total of 150 patients,and FAST scans were performed in all cases.The sensitivity and specificity were 92.6％ and 100％,respectively.The negative predictive value was 92％,while the positive predictive value of FAST was 100％.The accuracy of FAST was 96％.Conclusion:FAST is an important method to detect intra-abdominal fluid in the initial assessment in hemodynamically unstable polytrauma patients with high accuracy.