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Hold on!!!! before adding the filter
Many meds will effect the nitrifying bacteria so you really don;t want a filter in a "hospital"tank. Just an air supply and heater will suffice. You will be doing water changes only as directed by the medication you use. Once the fish has been successfully medicated and it is either kept in a tank under quarantine or needs to be in an unmedicated tank to recover from the trauma, infection or injury for a longer period than hospitalization, THEN you should use a seeded filter for the tank.
Just so you know: A "Hospital" tank should be bare bottomed, clean and contain no decorations that can absorb the medications ( ie calcium based rock or shells, etc). The exact amount of water in the tank should be known so that you medicate for the proper amount of water present. ( i.e. a 10 gal tank does not hold 10 gals of water. Decorations can displace water as well.) Most hospital tanks are 5 or 10 gal tanks so that they are easier to medicate and easy to break down and sterilize once the medicating is over. You always want to sterilize a hospital tank after each use.
A "quarantine" tank can be decorated and maintained as your other tank(s) with the exception that you will not be adding more fish to this tank while your current stock is healing or adjusting to their new home.
Hope this helps.
Hold on!!!! before adding the filter
Many meds will effect the nitrifying bacteria so you really don;t want a filter in a "hospital"tank. Just an air supply and heater will suffice. You will be doing water changes only as directed by the medication you use. Once the fish has been successfully medicated and it is either kept in a tank under quarantine or needs to be in an unmedicated tank to recover from the trauma, infection or injury for a longer period than hospitalization, THEN you should use a seeded filter for the tank.
Just so you know: A "Hospital" tank should be bare bottomed, clean and contain no decorations that can absorb the medications ( ie calcium based rock or shells, etc). The exact amount of water in the tank should be known so that you medicate for the proper amount of water present. ( i.e. a 10 gal tank does not hold 10 gals of water. Decorations can displace water as well.) Most hospital tanks are 5 or 10 gal tanks so that they are easier to medicate and easy to break down and sterilize once the medicating is over. You always want to sterilize a hospital tank after each use.
A "quarantine" tank can be decorated and maintained as your other tank(s) with the exception that you will not be adding more fish to this tank while your current stock is healing or adjusting to their new home.
Hope this helps.
Actually, what I was writing about was for more than just this instance ( i.e the proper use of a hospital tank vs a quarantine tank) however, whenever dealing with a parasitic problem, you want nothing in the tnak for the parasite to adhere to so my comment still stands.
Here is what the main problem with high heat and nitrifying bacteria is ( this was taken from the Fritz Labs page on Nitrifying bacteria Facts Nitrifying Bacteria Facts)
Dissolved Oxygen
Maximum nitrification rates will exist if dissolved oxygen (DO) levels exceed 80% saturation. Nitrification will not occur if DO concentrations drop to 2.0 mg/l (ppm) or less. Nitrobacter is more strongly affected by low DO than NITROSOMONAS.
Whenever using high heat, unless the aquarist is using a DO meter, there is no way to know whether the DO level is sufficient for nitrification. If not, whatever bacteria is in there would start to die off causing more pollution and water quality issues. Putting this together with not giving the parasites places to live and it really is better to not use a filter in a hospital tank situation no matter what you are treating. Quarantine tanks are a whole other story.
Hope this better explains it.
Here is another link about the life cycle of the ich parasite that might help you as well. Using Heat to Treat Ich in Freshwater Tropical Fish - Article at The Age of Aquariums - Tropical Fish
It makes things so much easier when you know exactly what you are dealing with. That article even taught this old dog some new tricks. lol I had always treated ICH with either heat and meds or just meds but now I know WHY the heat worked and how high it needs to be. Proof positive that you never know EVERYTHING when dealing with livestock. 
