A male patient suddenly became tachypneic, hypoxic, and febrile after few hours of anesthesia during an abdominal surgery. Mendelson's syndrome is suspected. What can be the cause in this patient to develop this syndrome?

Mendelson's syndrome: It is a chemical pneumonitis, results from regurgitation of stomach contents and aspiration of chemical material, usually acidic gastric juices. Pulmonary inflammation--including the destruction of the alveolar lining, with transudation of fluid into the alveolar space--occurs with remarkable rapidity. Typically this syndrome develops within hours, often following anesthesia when the gag reflex is depressed. The patient becomes tachypneic, hypoxic, and febrile. The leukocyte count may rise, and the chest x-ray may evolve suddenly from normal to a complete bilateral "whiteout" within 8-24 h. Sputum production is minimal. The pulmonary signs and symptoms can resolve quickly with symptom-based therapy. Antibiotic therapy is not indicated unless bacterial infection supervenes. Ref: Cohen-Poradosu R., Kasper D.L. (2012). Chapter 164. Infections Due to Mixed Anaerobic Organisms. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison's Principles of Internal Medicine, 18e.