What is the management approach for a patient presenting with a seatbelt sign?

Management of Patients with Seatbelt Sign

The presence of a seatbelt sign should prompt a CT scan and maintain a high index of suspicion for bowel injury, even if the patient appears stable initially. 1, 2

Initial Assessment and Imaging

• The seatbelt sign (abdominal wall ecchymosis corresponding to the site of the seatbelt) increases the risk of intra-abdominal injuries by approximately 8-fold compared to belted patients without this sign 3
• Management of blunt abdominal trauma patients with seatbelt sign should follow a structured approach: primary survey, E-FAST, physical examination, secondary survey, blood chemistry, vital signs, followed by contrast-enhanced abdominal CT 1, 2
• CT scan should be performed even if abdominal ultrasound (FAST) does not reveal signs of injury, as FAST requires at least 400-620 mL of fluid to be detected and has limited sensitivity for bowel injuries 2, 4

Diagnostic Findings on CT

• Highly specific CT findings for bowel injury include:

  • Bowel wall hematoma (100% specificity)
  • Oral contrast extravasation (100% specificity)
  • Free intraperitoneal air without pneumothorax (99% specificity)
  • Bowel wall discontinuity (99% specificity) 2

• Highly sensitive but less specific CT findings include:

  • Free peritoneal fluid without solid organ injury (66% sensitivity, 85% specificity)
  • Bowel wall thickening (35% sensitivity, 95% specificity)
  • Mesenteric stranding (34% sensitivity, 92% specificity) 2

Hospital Admission and Observation

• Patients with high-risk mechanisms (including seatbelt sign) and non-specific CT findings should be admitted for observation with serial clinical examinations 1
• Approximately 20% of bowel injuries may be missed on initial CT, making observation critical even with negative initial imaging 2, 5
• In patients not clinically evaluable, diagnosis of hollow viscus injuries relies on injury pattern, vital signs, inflammatory markers trends and follow-up CT 1

Serial Monitoring

• Perform serial clinical examinations (as frequently as every 8 hours) by consistent specialists or consultants 1
• Monitor vital signs and obtain serial inflammatory markers (every 24 hours) 1
• Clinical signs of intestinal injuries might not be obvious on presentation and may develop 24 hours to several days after the injury 5
• Persistently elevated or rising levels of inflammatory markers may indicate evolving bowel injury 1

Indications for Repeat Imaging

• Patients with equivocal signs on initial CT scan should be re-imaged after 6 hours 1
• Consider repeat CT in patients who demonstrate evolving clinical signs suspicious for bowel injury 1
• Although highly sensitive, serum procalcitonin and CRP are not necessarily specific and should be used as supportive biomarkers rather than definitive diagnostic tools 1

Surgical Intervention

• The presence of highly specific CT findings such as extraluminal air, extraluminal oral contrast, or bowel wall defects warrants prompt surgical exploration 1
• In patients who are clinically suspected of having bowel injuries and are deteriorating clinically, if imaging is equivocal, a diagnostic laparotomy should be performed 1
• Delay in diagnosis of bowel injury is linked to increased morbidity and mortality 1

Common Pitfalls

• Relying solely on initial CT findings when clinical suspicion is high (approximately 20% of bowel injuries may be missed on initial CT) 2, 5
• Discharging patients with seatbelt sign without adequate observation period, even if initial imaging is negative 5
• Failing to recognize that signs of peritonitis may develop gradually over 24-72 hours after injury 5
• Over-reliance on inflammatory markers without clinical correlation, which may lead to either missed injuries or unnecessary laparotomies 1