Thank you for your query on Healthcare Magic.
Is your child drooling
of saliva in the day time also?
Any history of throat infection
Salivation is normal in children in the sleep and nothing to worry.
The breathing pattern may vary in sleeping period depending on the stage of their sleep like deep sleep.
While in waking if respiration are normal, nothing to worry.
But if there is salivation and increased respiration during day time and in awake period consult your Pediatrician
for the examination of your child.
Hope I have answered your query.