Point of Care Ultrasound for Diagnosis of Abdominal Free Air

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

Official Title
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Utility of Bedside Ultrasound for Diagnosis of Intraperitoneal Free Air

Conditions
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Free Air in Abdomen

Intervention / Treatment
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* Diagnostic Test: Pre-Operative Transabdominal Ultrasound
* Diagnostic Test: Post-Operative Transabdominal Ultrasound


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Subjects scheduled for elective laparoscopic surgery Age 18 or greater Exclusion Criteria: Age less than 18 Pregnant unable to provide consent

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Participants undergoing laparoscopy<br>Participants undergoing laparoscopic abdominal surgery with surgical insufflation receiving pre-operative transabdominal ultrasound and post-operative transabdominal ultrasound. | Diagnostic Test: Pre-Operative Transabdominal Ultrasound<br>* Pre-Operative Transabdominal Ultrasound evaluation of the right upper quadrant of the abdomen. Examination with be performed with low frequency curvilinear transducer and high frequency linear transducer at 5 standardized locations along the right costal margin followed by a 10 second sweep along the costal margin from the xyphoid process to the mid-axillary line<br>Diagnostic Test: Post-Operative Transabdominal Ultrasound<br>* Post-Operative Transabdominal Ultrasound evaluation of the right upper quadrant of the abdomen. Examination with be performed with low frequency curvilinear transducer and high frequency linear transducer at 5 standardized locations along the right costal margin followed by a 10 second sweep along the costal margin from the xyphoid process to the mid-axillary line<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Presence of Free Air Artifact on Ultrasound | Hyperechoic echo originating from peritoneal stripe | Following completion of laparoscopic surgery, average of 2 hours, up to 1 day. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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laparoscopic surgery, transabdominal ultrasound, Free air