Our Pug Princess, Pheobe (who you met in a blog post from earlier this week) experiences this sometimes. It would freak us out a little, until we found out what it was: some dogs do what is called, "reverse sneezing." She would make a series of snorting sounds, and it seemed like she couldn't breathe for a few seconds, but then she would be okay. If you have a dog that does this, you'll want to read this! Brandy Arnold at dogingtonpost.com writes:

Reverse sneezing, also known as Pharyngeal Gag Reflex or Paroxysmal Respiration, is a relatively widespread respiratory condition in dogs that is normally triggered off by a spasm in the pooch’s soft palate as well as laryngeal area. It is often referred to as “reverse sneeze” because during the event, the dog is gasping air heavily inward, instead of simply expelling it, like in a typical sneeze. Although harmless in and of itself, reverse sneezing can be rather alarming for dog owners to see and can be indicative of a more serious problem.

 

Check out this video for an example of "reverse sneezing," and a veterinarian's advice on causes and treatment:

So don't panic, but if you have concerns, consult your vet!

(via Reverse Sneezing in Dogs | The Dogington Post.)