Is it possible for a nonmedicated saline nasal spray to get stuck in the nasal cavity and cause of ear infection in a five-year-old?

Ear infection causes: Ear infections are caused by bacteria or viruses. Noses are full of bacteria anyway. Saline rinses away a few bacteria; if the bottle is dirty, saline may add a few bacteria to the nose, but they won't often travel to the ear because the Eustachian tube is a tiny passage, esp in children. Droplets of water sprayed in nose are only in the nose a few minutes. Squeeze bottle irrigation CAN hurt ears.

No: The cause of the congestion also decreases Eustachian tube drainage which predisposed to ear infections. Common germs from the throat climb up the dysfunctional Eustachian tube to cause ear infections. It doesn't matter what you stick in the nose, the sites are located in separate parts of the head & not connected.