Does the air pumped into the colon also inflate the small intestine? what part of the intestine is likely to be involved in a inguinal hernia?

Yes.: Insufflated air from colonoscopy does pass the ileocecal valve and to a degree insufflate small bowel. An inguinal hernia sac may contain omentum (fatty tissue over bowel), small intestine, or colon.

Mimimal: The air used may enter into the small intestine, but it would be expected to be a minimal amount & not likely irritate an inguinal hernia. Unless the hernia was already quite large prior to the colonoscopy. Hernias can contain fat, small intestine & less often colon unless the hernia is quite large & the hernia was present for a long time.

Small amount of air: During a colonoscopy a small amount of air can pass from the colon. A right inguinal hernia can have cecum, appendix, omentum & bladder. Left is usually sigmoid colon, small bowell, bladder, omentum.