What would be the standard method of treating a persistent case of viral bronchitis if i went to an er?

Really--No: I f you have a pcp then see that doctor if you have as you describe "a persistent case of viral bronchitis". Viral bronchitis is usually a self limited disease state and usually treated symptomatically with fluids, otc cough & cold meds & observaiton. If you cannot clear an infection, or if fever, shortness of breath or other co-morbid conditons see your pcp. The er should be for emergencies.

Persistent?: Viral bronchitis has no specific therapy and symptoms typically resolve over a week or 2. Antibiotics are not effective so treatment involves symptom control while the virus runs its course. If you have shortness of breath, you should be urgently evaluated since bronchospasm can complicate viral bronchitis and an inhaler or 2 may be needed for the persistent residual cough to completely resolve.