In the April 2011 issue of the Annals of Emergency Medicine, the American College of Emergency Physicians published a clinical policy focusing on critical issues in the emergency department evaluation of adult patients presenting with acute blunt abdominal trauma. This is a revision of a clinical policy on acute blunt abdominal trauma that was published in 2004.

This clinical policy can also be found on ACEP’s Web site (www.acep.org) and will be abstracted on the National Guideline Clearinghouse Web site (www.guidelines.gov).

This clinical policy takes an evidence-based approach to answering four frequently encountered questions related to emergency department decision making. Recommendations (Level A, B, or C) for patient management are provided based on the strength of evidence using the Clinical Policies Committee’s well-established methodology.

Level A recommendations represent patient management principles that reflect a high degree of clinical certainty. Level B recommendations represent patient management principles that reflect moderate clinical certainty. Level C recommendations represent other patient management strategies based on Class III studies or, in the absence of any adequate published literature, based on consensus of the members of the Clinical Policies Committee.

During development, expert review comments were received from physicians in the fields of emergency medicine, surgery, and radiology, and from members of the American College of Surgeons Committee on Trauma, the Society for Academic Emergency Medicine, ACEP’s Emergency Medical Services Committee, ACEP’s Emergency Ultrasound Section, ACEP’s Quality and Performance Committee, and ACEP’s Trauma and Injury Prevention Section. Their responses were used to further refine and enhance this policy; however, their responses did not imply endorsement of this clinical policy.

The management of blunt trauma has always presented a diagnostic challenge. The range of injuries that can occur, along with the dire consequences of missing a serious injury, has led to an increased use of diagnostic modalities such as CT scanning and ultrasound. Nowhere is this more apparent than with blunt abdominal trauma. Abdominal injuries will often have delayed presentation even when life-threatening organ damage is present. Specifically, bleeding from splenic and liver lacerations initially may be contained within the organ capsule. As bleeding progresses, the capsule can rupture and lead to rapid exsanguination.

The identification of life-threatening injuries is of utmost importance. New-generation CT scanners can readily identify even small injuries to solid organs. However, in recent years there has been increased focus on the long-term effects of the radiation exposure from CT scans. With this in mind, it is important to accurately identify those patients who would benefit from further diagnostic imaging and those who can be safely observed.

In a hemodynamically unstable patient with blunt abdominal trauma, is bedside ultrasound the diagnostic modality of choice?

• Level A recommendations: None specified.
• Level B recommendations: In hemodynamically unstable patients (systolic blood pressure less than or equal to 90 mm Hg) with blunt abdominal trauma, bedside ultrasound, when available, should be the initial diagnostic modality performed to identify the need for emergent laparotomy.
• Level C recommendations: None specified.

Comments: In a hemodynamically unstable patient with blunt abdominal trauma, identification of free fluid in the abdomen directly affects management. Abdominal free fluid is an indication for emergent laparotomy. Bedside ultrasound performed by a credentialed operator has been shown to have high sensitivity and specificity for identifying abdominal free fluid and has no known side effects. However, it is not useful for identification of a source of bleeding or for the evaluation of hollow viscera.

Does oral contrast improve the diagnostic performance of CT in blunt abdominal trauma?

• Level A recommendations: None specified.
• Level B recommendations: Oral contrast is not required in the diagnostic imaging for evaluation of blunt abdominal trauma (all of the studies reviewed included the use of IV contrast).
• Level C recommendations: For patients with a negative CT result with IV contrast only, in whom there is high suspicion of bowel injury, further evaluation or close follow-up is indicated.

Comments: CT scan with IV contrast has mostly replaced diagnostic peritoneal lavage as the criterion standard for identification of intra-abdominal injuries in stable blunt abdominal trauma patients. Despite some local practices to use oral contrast for patients with blunt abdominal trauma, data supporting its use are limited. In addition, the use of oral contrast may necessitate delayed imaging to allow it to transit the bowel.

In a clinically stable patient with isolated blunt abdominal trauma, is it safe to discharge the patient after a negative abdominal CT scan result?

• Level A recommendations: None specified.
• Level B recommendations: Clinically stable patients with isolated blunt abdominal trauma can be safely discharged after a negative result for abdominal CT with IV contrast.
• Level C recommendations: Further observation, close follow-up, and/or imaging may be warranted in select patients based on clinical judgment.

Comments: With increasing ED wait times and hospital crowding, the question of ED observation time has become increasingly pertinent. The risk of delayed presentation of intra-abdominal injury with normal CT scans with IV contrast has been shown to be small. With further advances in CT scanning technology, including the widespread use of 64-slice scanners, the sensitivity of CT for identification of intra-abdominal injury is expected to increase.

In patients with isolated blunt abdominal trauma, are there clinical predictors that allow the clinician to identify patients at low risk for adverse outcome who do not need an abdominal CT?

• Level A recommendations: None specified.
• Level B recommendations: None specified.
• Level C recommendations: Patients with isolated abdominal trauma for whom occult abdominal injury is being considered may not need abdominal CT scanning if the following are absent: abdominal tenderness, hypotension, altered mental status, costal margin tenderness, abnormal chest radiograph, hematocrit under 30%, and hematuria.

Comments: CT has become the criterion standard imaging study in high-risk patients with blunt abdominal injuries. However, there has been increased concern regarding long-term effects of radiation, especially in younger patients. Use of specific patient characteristics as defined by a clinical decision rule or variables shown to be independently associated with poor outcome may help guide imaging.

Ways to identify patients who do not require diagnostic imaging have not been adequately studied and should be a focus of further research.

This clinical policy is not intended to be generalized to multitrauma patients. The treating physician’s clinical judgment regarding the patient’s risk for serious injury should take precedence over any clinical decision rules.

Dr. Chenoweth is a resident physician in the Department of Emergency Medicine at the University of California, Davis Medical Center in Sacramento. Dr. Diercks is a Professor of Emergency Medicine at the University of California, Davis Medical Center, and is a member of ACEP’s Clinical Policies Committee.