<p>We need a 3D printer, that can print with plastic suitable for medical applications. We have about $5000 for the printer. What printers can we choose? I am not a specialist in 3D printing, so please answer in detail. </p>

<p>We need to print breathing tubes with cuffs. The tubes should be flexible, but rigid enough in order not to collapse. The cuff material should be thin and collapsible, but very strong. Breathing tubes are inserted through the mouth and stay in contact with mucous membrane for many hours.</p>

I am not an expert but I think you will find that because 3D printers use a layer by layer construction method, and the boundary between the layers creates grooves along the surface or leaves a rough texture on the surface. That the textured surface left by 3D printer construction would trap microbes and make 3D printed objects not suitable for medical applications where you need the product to be sterile.
It might be possible to treat the printed object or post process it. By vapor smoothing or painting/coating, but I doing think this would work for flexible materials.
If you are considering 3D printing because of the ability to customize the design, then I would suggest considering combining 3D printing with molding or casting. You could then use a cheap 3D printer to create the mold and use a flexible resin to create the object you want.
I have heard of SLA 3D printing being used to create molds for casting fake teeth. There 3D printing is used to create a custom shape and the print is used to make a mold and the final product is cast using the mold to get the quality and finish needed.
And I have head of FDM printing being used in used in remote areas to print clamps for umbilical cords. But I believe this was because not no other option was available.