Differences in Preoperative Gastric Ultrasound Findings Between Old and Young Surgical Patients: A Retrospective Case-Control Study

Background: Most gastric ultrasound studies have been conducted in young middle-aged patients. Although age is known to influence gastric ultrasound, comparisons of gastric ultrasound in elderly patients with young patients have not been well elucidated. This study aimed to 1) compare gastric ultrasound assessments between young and elderly patients, 2) determine whether the CSA cutoff values for elderly and young patients should be different, and 3) suggest CSA cutoff values for elderly patients.Methods: This retrospective case-control study evaluated the data of 120 patients who underwent elective surgery under general anesthesia between July 2019 and August 2020. Demographic and gastric ultrasound assessment data were retrieved. Patients were divided into the elderly group (n = 58, age: ≥65 years) and young group (n = 62, age: <65 years). The antral cross-sectional area (CSA) in the supine and right lateral decubitus positions (RLDP), semiquantitative three-point Perlas grade (grades 0, 1, and 2), and gastric volume were determined. CSAs according to different Perlas grades were compared between the two groups. The CSA cutoff values for predicting a high risk of pulmonary aspiration in both the groups were determined. Results: Among patients with Perlas grade 0 (empty stomach), the CSA supine and CSA RLDP were greater in the elderly group than in the young group (CSA supine: 5.12 ± 1.99 cm2 vs. 3.92 ± 0.19 cm2, P = 0.002, and CSA RLDP: 6.24 ± 0.43 cm2 vs. 4.58 ± 0.21 cm2, P = 0.002). The specificity, positive predictive value, and accuracy of the CSA decreased when the CSA cutoff value for the young group (CSA RLDP: 6.92 cm2) was applied to the elderly group. The CSA cutoff values for the elderly group were: CSA supine, 6.92 cm2 and CSA RLDP, 10.65 cm2.Conclusions: The CSA of the empty stomach was greater in elderly patients than in young patients. The CSA cutoff values for predicting pulmonary aspiration risk in elderly and young patients should be differentiated. We suggest that the following CSA cutoff values should be used for predicting pulmonary aspiration risk in elderly patients: CSA supine, 6.92 cm2 and CSA RLDP, 10.65 cm2.