Tag Archives: Free Air

Free Air…

April 21, 2013


An elderly patient presented with abdominal pain for a week.  The patient had peritoneal signs on exam and thus xray imaging was pursued (see discussion below):

Free air

Image 1

Free air 2

Image 2

Free Air 1

Image 3

This is an acute abdominal series showing free intraperitoneal air in the right upper quadrant.  Notice that it cannot be determined if the patient has free air on the supine view (Image 1).  This is because the air is layering to the anterior portion of the peritoneal cavity.  In order to reveal air in the peritoneum, one must layer it to one of the sides (Image 2 – patient is laying on their left side and the air flows to the right upper quadrant) or upright (Image 3 – patient is upright and the air layers under the diaphragm, in this case the right side). 

I like the acute abdominal series to look for free air in the setting of a highly concerning exam.  You can also just do an upright chest xray.  They are quick and if free air is found it will likely be a study that will change the patient’s course; surgery will in most cases take the patient to the operating room with just an xray for exploratory laparotomy.  In our case, however, surgery was tied up for a bit and this allowed an extra 1/2 hour ED stay, I pursued non-contrast CT to further identify what was going on:

Free Air CT 1

Image 4

Free Air CT 2

Image 5

This CT shows findings highly concerning for a perforated duodenal ulcer.  In Image 4 you can see the air just above the liver edge anteriorly along with free intraperitoneal fluid layering on the side of the liver and spleen.  She also has an aortic aneurysm.  Image 5 shows an area of free air and stranding near the distal duodenum.  Laparotomy revealed a perforated duodenal ulcer, the aortic aneurysm was incidental. 

Author:  Russell Jones, MD

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