Gastric Ultrasound in Patients Who Have Undergone Bariatric Surgery

Aspiration of gastric contents in the perioperative period is a well-known complication with potentially disastrous consequences. Gastric POCUS is a tool clinicians can utilize to assess stomach fullness and risk stratify prior to induction of anesthesia. There is currently no literature describing how bariatric surgeries impact the location of the stomach and/or the ability of clinicians to obtain gastric POCUS images. Recent increased use of GLP-1 agonists, which delay gastric emptying, has renewed conversations surrounding using gastric POCUS to assess aspiration risk. Case reports have been published showing aspiration events in patients taking GLP-1 agonists despite an adequate fasting period. Additionally, recent studies have shown that these medications can help patients who have undergone bariatric surgery and then regained the weight, lose said weight. Given the possibility that patients may be post-bariatric surgery and currently taking GLP-1 agonists, POCUS is an important skill to utilize that can help anesthesiologists assess aspiration risk. This study will aim to fill a gap in the literature by describing how bariatric surgery can impact the location of the stomach and how to obtain sonographic images of the stomach in a post-bariatric surgery abdomen. The analysis will include description of how the images were obtained (ex: needing to rotate the probe further than expected, or stomach displacement, etc.) and comparison to the procedure used to obtain preoperative images. The measurements will be subjective to the PI who is certified in POCUS use.

Discussions will be held with surgeons who perform bariatric surgery, to determine which patients fit the qualifications to participate in the study. Patients are routinely seen by anesthesiologists for their anesthetic evaluation in the pre-operative holding area on the day of their procedure. After the patient have been evaluated, the patient will have time to discuss the study with the anesthesia team prior to transferring the patient to the OR. Consent will be obtained in the preoperative holding area. There are sequestered rooms in this area where patients can be brought for increased privacy during the consent process. The team will finalize participation and ask the participant to sign the study consent forms. All patient will be provided with copies of the IRB protocol and consent if the patient wish to have it. If agreeable to joining the study, the patient will undergo gastric POCUS after intubation. To perform the gastric POCUS, the patient will be in the supine position and the right lateral decubitus position on the operating room table. A curvilinear ultrasound probe with gel will be placed on the patient just below the xiphoid. A picture is then obtained of the antrum of the stomach. The probe may need to be moved, tilted, or rotated to obtain the clearest image of the antrum of the stomach. The POCUS of the abdomen before abdominal surgery will be done before the surgical team has prepared a sterile field for their surgery. Therefore, there is no need to maintain sterile precautions when using the ultrasound on the abdomen. Once the surgical procedure is complete, the patient will once again undergo gastric POCUS before extubation.

Inclusion criteria

• 18-85 years old
• scheduled to undergo bariatric surgery
• no prior abdominal surgery

Exclusion criteria

• ASA physical status > 3
• Urgent or emergent surgery
• Patient refusal or inability to consent
• Prior abdominal surgery