Purpose <p>Postoperative ileus(POI) occurs in 10–19% of colorectal surgeries. The identification of patients at-risk for POI is a key for nasogastric tube(NGT) placement. Point-of-care ultrasound(POCUS) has shown potential in predicting POI by assessing gastric volume, but its role has never been explored. The aim was to evaluate the association between the ratio of gastric volume on postoperative day (POD)2/POD0, measured by Point-of-care ultrasound(POCUS), and the risk of vomiting, postoperative ileus(POI) and the need for nasogastric tube(NGT) insertion after colorectal surgery.</p> Methods <p>This prospective monocentric study included 112 patients who underwent colorectal resection with or without anastomosis between August 2020 and April 2023. Gastric volume was measured using POCUS at POD0 and POD2. The primary outcome was the ratio of POD2/POD0. Area under the ROC curve based on multivariate model was estimated for the prediction of the need for NGT insertion was calculated.</p> Results <p>Among the 112 patients included in the study, 22 had postoperative nausea (19.6%), 16 experimented POI (14.3%) and 13 needed postoperative NGT insertion(11.6%). A larger POD2/POD0 ratio was significantly associated with nausea, POI and postoperative NGT insertion. In multivariate analysis, the POD2/POD0 ratio was an independent factor associated with the risk of postoperative nausea and postoperative NGT insertion. Finally, the POD2/POD0 ratio predicted the risk for postoperative NGT insertion with an area under ROC curve at 0.79(95%CI:0.67–0.91).</p> Conclusion <p>POCUS of the gastric volume is a promising tool to select patient requiring NGT insertion after colorectal surgery.</p> Clinical trial registry <p>NCT04461067.</p>