Authors: Volkan Arslan, Attending
Editor: Betül Gülalp, Prof.
Date: 20 April 2017

Is pneumoperitoneum the terra ignota in ultrasonography?

Andrzej Smereczyński, Katarzyna Kolaczyk. J Ultrason. 2015 Jun; 15(61);189-195.

Authors of this paper has emphasized that pneumoperitoneum is the most common finding of intestinal perforation has to be recognized and treated as quickly as possible.

Within the writing they gave regards to ultrasonography for its benefits and reminded us with the diagnosis methods of free gas on ultrosonography (US) even without fluid. ‘’Nowadays we don’t require any kinds of fluid to recognize free gas intraabdominally’’ is mentioned by authors. ‘’Even small amounts of 1 ml gas can be detected with US’’. Some authors believe that ultrasonography is superior to the conventional radiological methods on the basis of researchs.

In this article, authors has pointed in addition of the evaluation of free gas to the E-FAST protocol in abdomen.

For scanning, a 3,5-5 MHz convex probe is the most commonly used one, however a 7,5 MHz linear probe is superior for small gas bubbles. Imaging is assessed on the patient with supine, left lateral decubitis and right lateral decubitis position.

The commonly imaging is obtained in the patient on along right lower intercostal region and subsequent spaces while lieing on left side. Subxiphoid toracoabdominal border adjacent to the left lobe of the liver is the scanned area in supine patients. 

Authors also state that free gas in abdomen accumulates under the diaphragma describing as ‘’ Toracoabdominal Border’’.  The US performer has to have a grasp of the anatomic structures in this region to detect the free gas findings.

Authors say that expected view is a reverberation artefact and it’s range differs with the amount of gas found in abdomen. Little bubbles could be seen directly as focal thickening of the parietal peritoneum. Width of the reverberations is compatible with the amount of accumulated free air. Moreover, when large amounts of air is present US performer can see reverberation as much as seen in thorax US.

The authors state and offer ‘’The changing of the patient position to supine from lateral decubitis is useful to detect and confirm the free gas in abdomen’’. Also, with this technique you can differentiate abscess, cyst or Chilaiditi syndrome (transposition of colon between liver and diafragma).

Comments:  As emergency physicians, we perform US with various indications to answer the emergency questions and diagnose in life-threaten diseases and conditions against time. With this technique described in this article we would be able to define pneumoperitoneum as well as a part of the daily practice. US provides the visualization of free gas even in little amounts without any radiation and time-sink. 

By this way, plane graphies or computerized tomography will be less used for pneumoperitoneum. Skillfull US performers even will define the exact perforation site.

However, this article only defines the tecnique but dosn't give any information about the efficacy or safety of this technique. With further investigations of comparing US with other radiological tests via sensitiviy, spesifity, positive and negative predictive values will be discussed. The US technique will became more convincing to detect pneumoperitoneum within widened and updated indications for Point Of Care Ultrasound in Emergency Medicine.

Thanks To Dear Smereczyński and et al

Yours sincerely


*Edited by B.Gulalp; Errors in English are belongs to her:)


Best Regards To All Emergency Medicine In The World!

Hope to be gether


To contact;






Volkan Arslan, Attending

Ematus Secretary.

Betül Gülalp, Prof.

EMATUS web coordinator. Anyone...Behind the passion and heart...


Mehmet Ali Aslaner | 20 April 2017 20:27

Dear Scott, thank you for your valuable suggestion and comment. We are trying to do better.
Best regards.

All comments are always open and valuable in this website; Criticism develops the process; Follow us!

Jeff Scott | 20 April 2017 16:15

Great post / column

I would recommend having a native english speaker
edit the post prior to release.


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Authors: Mehmet Ali Aslaner, Asst. Prof. · 24 January 2018