Hi newlife,
I'm sorry to hear that your wife needs an endoscopy. Please tell her that her windpipe is protected by rings of cartilage which cannot collapse while the endoscopy is going down her oesophagus. I looked this up in an encyclopedia online: 'The
esophagus, which passes food from the pharynx to the stomach, is about 25 cm (10 inches) in length; the width varies from 1.5 to 2 cm (about 1 inch).' That means the endoscope is not too big for the throat, either.
Let us all pray that as the day approaches, she will feel calm and hopeful, and even happy that she is receiving appropriate care which will lead to her recovery, or, reassurance that all is well. May she be reassured of God's love for her and feel thankful towards Him for His protection.
Blessings, brother. :)