Accuracy of Ultrasonography for the Diagnosis of Pneumoperitoneum in the Emergency Department
Accuracy of Ultrasonography for the Diagnosis of Pneumoperitoneum in the Emergency Department
Pneumoperitoneum could be due to life threatening conditions and its quickly diagnosis is
 important in the emergency department (ED). Signs and symptoms are non-specific and
 radiography has low accuracy in the acute setting. Computed tomography (CT) is considered the
 gold standard, however it is not a cost-effective option in the vast population of patients
 with abdominal pain. Ultrasonography is able to detect as little as 2 ml of free air, however
 diagnostic accuracy of ultrasonography remains unclear. This study evaluates the accuracy of
 ultrasonography for the diagnosis of pneumoperitoneum, the most accurate abdominal scan and
 the most accurate echographic sign for the detection of free air.

 Methods Consecutive patients presenting to ED for acute abdominal pain and with a diagnosis
 of pneumoperitoneum at CT or at surgery (study group) and a similar number of patients
 without a diagnosis of pneumoperitoneum (control group) undergo abdominal ultrasonography in
 a standardized protocol that include 10 scans for each patient registered on a video of 5
 seconds. The videos are randomly reviewed by 4 sonographers and by 2 physicians with no
 experience in ultrasonography blind to final diagnosis and to all clinical data with the aim
 of detecting for each scan pneumoperitoneum. Accuracy of ultrasonography for the diagnosis of
 pneumoperitoneum will be calculated considering CT or surgery as gold standard. Furthermore
 intra and interobserver agreement and the accuracy of each ultrasonographic sign and scan
 will be calculated.
Inclusion Criteria:

 -  All patients more than 18 years with acute abdominal pain

 Exclusion Criteria:

 -  Refused consent

 -  Less than 18 years old

 -  Not possible to perform ultrasonography