{'fraction_non_alphanumeric': 0.018664333624963548, 'fraction_numerical': 0.0014581510644502771, 'mean_word_length': 4.913793103448276, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Be aware of the fatal risk of air embolism

THE ENDOSCOPIC APPROACH to the biliary tract in patients with surgically altered anatomy, such as a Roux-en-Y anastomosis, has been challenging. Doubleballoon endoscopy has greatly facilitated the endoscopic management of biliary problems in such patients. In this issue of Digestive Endoscopy, Peter et al. report on a patient with bleeding arteriovenous malformations (AVM) at the site of a hepaticojejunostomy successfully treated endoscopically. This is an educational case in several regards. First of all, surgery can cause pathological conditions that lead to medical problems such as bleeding. In this case, it is suspected that the AVM arose as a result of the alteration of the blood supply at the site of the hepaticojejunostomy. Therefore, in patients with obscure gastrointestinal bleeding who have surgically altered anatomy, abnormalities at the anastomotic site should always be suspected as a possible bleeding source. This case also demonstrates that double-balloon enteroscopy is useful in exploring the afferent limb of a Roux-en-Y anastomosis. Dual treatment using a combination of argon plasma coagulation (APC) and clip placement was successfully done in this patient with a good outcome. Although endoscopic hemostasis was successfully carried out in this patient, the risk of complications in such patients should be carefully considered. Although air embolism is a very rare complication of endoscopy, it has the potential to be severe and even fatal. Air embolism is most commonly associated with endoscopic retrograde cholangiopancreatography (ERCP). Previous interventions or surgery of the biliary tract are described as major risk factors for air embolism following ERCP. Cholangioscopy with air insufflation directly into the bile duct appears to be a particularly strong risk factor for the development of an air embolism. As the portal vein runs parallel to the biliary tree, adjacent to each other in the liver, injury to the bile ducts with air insufflation can cause air to leak into the portal system very easily. It would be prudent to assume that vascular abnormalities close to a hepaticojejunostomy are closely related to the portal venous system. Endoscopic interventions such as APC and clipping of vascular lesions can lead to bleeding through an injury to the vessel wall. Air insufflation can become excessive in the presence of bleeding to maintain the endoscopic view. In addition, intraluminal air pressure can become excessive in the afferent limb of a Roux-en-Y anastomosis because the lumen has a blind end.As the liver is a solid organ, a ‘check valve’ phenomenon cannot be expected to prevent the backflow of air into the venous system, in contrast to the gastrointestinal tract. For these reasons, I would like to caution readers to be aware of the risk of this potentially fatal complication. I recommend the following steps to minimize the risk of air embolism in this type of procedure. 1. Use CO2 insufflation instead of air insufflation. 2. Use a transparent hood at the tip of the endoscope to maintain the endoscopic view without insufflation. 3. In case of bleeding at the site of a hepaticojejunostomy, or in the bile ducts, use water instead of air to maintain the endoscopic view. 4. Hemostasis using gentle pressure with forceps, a balloon catheter or the tip of the hood is the safest technique to stop the bleeding.