Acute abdominal series

Background

• Differs from KUB in that patient is upright vs supine on KUB

Diagnosis

1. Films
   1. Upright chest film: r/o free air
   2. Upright abd film: air-fluid levels
   3. Supine abd film: width of bowel loops most visible (estimate of amount of distention)
2. Air in colon or rectum makes complete obstruction less likely (esp if symptoms >24hr)
3. If pt does not tolerate upright position left lateral decub abd film can substitute

To differentiate large and small bowel:

1. Small bowel has lines (plica circulares) all the way through the bowel
2. Large bowel has lines (haustra) only halfway through the bowel

Bowel Diameters: 3/6/9 rule

• Small bowel - 3 cm
• Colon - 6 cm
• Cecum - 9 cm

• Abdominal x-ray has poor Sn and Sp for SBO
  • If concerned need CT

See Also

• SBO