Free Air in Abdomen Clinical Trial
Official title:
Utility of Bedside Ultrasound for Diagnosis of Intraperitoneal Free Air
This study evaluates the ability of ultrasound to identify intraperitoneal free air. The study will consist of blinded review of abdominal ultrasound images of patients before and after laparoscopic surgery, a procedure which results in the introduction of air into the peritoneal cavity.
Free peritoneal air is a marker of potential intraabdominal catastrophe, reflecting
perforation of a hollow viscous organ such as stomach or intestine. While definitively
identified by computed tomography, this diagnostic test can be delayed. Presence of air
beneath the diaphragm on an upright chest or abdominal radiograph can allow for faster
diagnosis, but again can present limitations in terms of timing.
Bedside clinician performed ultrasound has become standard practice in emergency medicine and
critical care settings. Traditionally, air is not conducive to diagnostic ultrasound, but the
artifacts it creates can be used to give clues about certain conditions. Recently this
artifact has been proposed as a means to identify free peritoneal air. Several small studies
have shown promise for the technique, but further investigation is warranted.
In this study the investigators will generate a database of standardized abdominal ultrasound
images in subjects undergoing laparoscopic surgery. During this surgery, the peritoneal
cavity is intentionally insufflated with air. The majority of this is removed at the end of
the case, but small volumes of air remain, as evidence by the presence of air on CT scan when
performed shortly after surgery.
The investigators will obtain a standardized set of images preoperatively and post
operatively which will then be reviewed in a blinded fashion by three expert reviewers, one
each from radiology, surgery and emergency medicine, with data analysis to determine
sensitivity and specificity of ultrasound for free air.
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