A Flow Visualization Model of Gastric Emptying in the Intrathoracic Stomach After Esophagectomy

Background. Our goal was to verify surgical factors that affect gastric emptying after esophagectomy through the use of a flow visualization model to mimic an intrathoracic gastric tube. Methods. The route and length of the gastric tube model was determined from postoperative computed tomography (CT) images of 5 patients who underwent esophagectomy with gastric interposition. Transparent tubes of various sizes (20, 40 and 60 mm in diameter) were fabricated cylindrically for comparison. 200 mL of liquid with a different viscosity were poured through the gastric tube, and the flow was recorded with a high-speed camera. Transit time to pass the pylori of different sizes (7.5 and 15 mm in diameter) was measured by analyzing the video clips. Results. For the small pylorus setting, emptying times in the 20-, 40-, and 60-mm tubes were 3.17 +/- 0.07, 6.55 +/- 0.28, and 7.60 +/- 0.69 seconds for water (p < 0.000), and 15.56 +/- 0.55, 19.75 +/- 0.47, and 23.28 +/- 0.32 seconds for glycerine (p < 0.000). For the large pylorus setting, emptying times were 2.66 +/- 0.10, 2.93 +/- 0.05, and 3.37 +/- 0.10 seconds for water (p < 0.000) and 9.95 +/- 0.18, 11.18 +/- 0.33, and 10.95 +/- 0.16 seconds for glycerin (p < 0.000). For any given tube size and liquid setting, emptying times for the small pylorus model were always significantly longer than those for the large one (p < 0.000). Conclusions. This fluid mechanics study demonstrates a narrow gastric tube or pyloric drainage procedure, or both, improves gastric emptying. This finding may help reduce the incidence of delayed gastric emptying after esophagectomy with gastric interposition. (Ann Thorac Surg 2011;91:1039-45) (C) 2011 by The Society of Thoracic Surgeons