CO2 vs. Air Insufflation for Endoscopic Ultrasound
CO2 vs. Air Insufflation for Endoscopic Ultrasound
The insufflation of air in the viscera is indispensable during endoscopy. However, the
 distension of the bowel that follows is often the cause of abdominal discomfort.

 Carbon dioxide (CO2) has been widely used for insufflation in endoscopy. CO2 insufflation is
 demonstrated in the literature to cause lower abdominal discomfort as it is quickly
 reabsorbed by the body.

 Endoscopic ultrasonography (EUS) is a method in which you associate the endoscopic view and
 the ultrasound vision obtained from the inside of the viscera.

 The diagnostic accuracy of EUS is undermined by the visual artifacts caused by the presence
 of air between the probe and the organ to be studied.

 Although the use of CO2 is already widely applied by many endoscopists, there are no studies
 to date concerning the use of CO2 during EUS from the point of view of the abdominal
 discomfort related to the procedure and/or the quality of the images obtained.

 The main purpose of the study is to assess whether the insufflation of CO2 results in a
 reduction of discomfort of the patients undergoing EUS. The study design is observational
 because no randomization or other interventions are planned; participants will be assigned to
 either air or CO2 insufflation according to the endoscopic room equipment (one room is
 equipped with CO2 insufflation while another endoscopic room is equipped just with air
 insufflation) and the results of the two groups will be compared. Among the secondary goals
 the investigators want to evaluate whether insufflation of CO2 is associated with a reduction
 in the dose required for patients sedation. Finally, the investigators want to clarify
 whether the use of CO2 is able to produce less visual artifacts than air and thus improve the
 quality of EUS images.
The insufflation of air in the viscera during endoscopy is indispensable in order to allow
 the advancement of endoscopic probe, to visualize the mucosa and to avoid injury to the
 gastrointestinal wall. However, the distension of the bowel that follows is often the cause
 of abdominal discomfort since the air blown appears to be slightly absorbable and therefore
 it needs a long time to be expelled.

 Carbon dioxide (CO2) is a gas that has already been widely used for insufflation in
 endoscopy. CO2 insufflation is demonstrated in the literature to cause lower abdominal
 discomfort as it is quickly reabsorbed by the body. This gas is at the same time devoid of
 side effects.

 Studies in the literature focus mainly on the intensity of abdominal discomfort after the
 insufflation of CO2 vs. air while performing colonoscopy, endoscopic retrograde
 cholangiopancreatography (ERCP) and enteroscopy.

 Endoscopic ultrasonography (EUS) is a method in which you associate the endoscopic view and
 the ultrasound vision obtained from the inside of the viscera. The main indications to EUS
 are represented by the study of the biliary pancreatic diseases, the staging of the digestive
 tract tumors and the differential diagnosis of submucosal tumors.

 The diagnostic accuracy of EUS is undermined by the visual artifacts caused by the presence
 of air between the probe and the organ to be studied; during the procedure the endoscopist
 must ensure, by means of repeated suctions, that the least possible amount of air is present
 inside the viscera.

 Although the use of CO2 is already widely applied by many endoscopists, there are no studies
 to date concerning the use of CO2 during EUS from the point of view of the abdominal
 discomfort related to the procedure and/or the quality of the images obtained.

 At the moment, with regard to EUS, there are no recommendations regarding the use of a gas
 rather than the other; the choice is in fact at the discretion of the operator and also it
 depends on the availability in the individual endoscopic units of the instrumentation for CO2
 insufflation.

 At Our Endoscopic Unit, CO2 or air insufflation is decided upon the availability of the
 equipment in the endoscopic room; in particular, in Suite 1, patients receive air
 insufflation and in Suite 2 they receive CO2 insufflation. The assignment into one or the
 other endoscopic room is purely casual according to scheduling the next free available slot.

 The main purpose of the study is to assess whether there is any difference between CO2 and
 air insufflation in inducing discomfort of the patients undergoing EUS. The study design is
 observational because no randomization or other intervention modifications are planned;
 participants will be assigned to either air or CO2 insufflation according to the endoscopic
 room equipment (one room is equipped with CO2 insufflation while another endoscopic room is
 equipped just with air insufflation) and the results of the two groups will be compared.
 Among the secondary goals the investigators want to evaluate whether insufflation of CO2 is
 associated with a reduction in the dose required for patients sedation. Finally, the
 investigators want to clarify whether the use of CO2 is able to produce less visual artifacts
 than air and thus improve the quality of EUS images.
Inclusion Criteria:

 • Consecutive patients referred for EUS

 Exclusion Criteria:

 -  Age <18

 -  Pregnancy

 -  Unwillingness to participate