In a 56-year-old man with a history of proximal gastrectomy and chronic reflux, a transnasally inserted 18-Fr midesophageal Foley catheter was used during high-risk sedated upper endoscopy. The catheter balloon was inflated with 20 mL of saline to close the esophageal lumen, and the drainage port was connected to suction at -20 kPa to remove the refluxate. After deepening sedation with propofol and alfentanil (MOAA/S score ≤ 2) without endotracheal intubation, the balloon was gradually deflated endoscopically under direct visual control without observation of reflux or leakage of gastric contents. The eight-minute procedure took place without hypoxemia, cough, or signs of aspiration, and the patient recovered without complications. The esophageal balloon occlusion technique with vacuum suction allowed safe deep sedation in a patient at high risk of aspiration. It serves as a simple, minimally invasive alternative to endotracheal intubation or awake endoscopy for airway protection.