Color as an index of gastric-content acidity.
D000768:Anesthesia, General / Q000009:adverse effects; D001646:Bile / Q000032:analysis; D003116:Color; D005745:Gastric Acidity Determination; D005764:Gastroesophageal Reflux / Q000209:etiology; D006863:Hydrogen-Ion Concentration; D008722:Methods