Not sure about the kind of bag used by medics in Vietnam, but as far as I know nothing beats elfbait's custom made medic gear items. They range from alcohol swabs to artificial airways.
As you can imagine, these can be quite expensive. My source was Dave (Davinator65 here and on eBay) - check out his auctions and you will find some goodies to put in the medic's bag.
You could also use WWII medic's instruments; they can be found on eBay and several e-tailers as well. While browsing eBay check out Old Joe's Infirmary items too - the last time I looked they had stethoscopes, IV bottles, tubing, bandages and other medic supplies as well.
ACE made some cans of albumin that were also used in the field in Vietnam.
I'd suggest checking out some GI Joe stuff, they have a WWII medic accessory set that comes with a ton of stuff, including a glass-type IV bottle.
Do you have the bags already? This baby can do for an M5 bag in a pinch, with some mods.
A forum community dedicated to One-Sixth scale action figure owners and enthusiasts. Come join the discussion about collections, kitbashs, customizations, displays, models, styles, scales, reviews, accessories, classifieds, and more!