Is it procedural to have a swallow test done or pj drains put in to drain blood from hiatal hernia repair? also to rule out any possible blockages that could occur?

I am not sure you use the procedure term correctly. Swallowing test is to evaluate if patient has any difficulty with swallowing but after hiatal hernia repair, surgeon or GI doc may order barium swallowing test to see if the surgery is successful, no more hernia and no leak. JP drain is used to drain the blood out after the procedure if there is significant extravasation during the procedure.