My apologies, what I was trying to say was that if that is its original design, I don't believe it would be intended for field use as it would be overly cumbersome if not impossible for a two person carry. Having used period litters for living history events and modern military litters for real world, I completely agree that a four person carry is the way to go. At least with the standard design wood handles, you could do a two person carry for short movements where as yours looks like it would be too cumbersome.
I also agree it was probably used with an ambulance.
I would also mention that my 1946 Lentz catalog shows the standard 90" interwar litter (USMD #7844000)as a Lawrence Carrying Stretcher "used by most transportation companies, hospitals and clinics". If yours is purpose built, maybe there is patent for it somewhere.
IMO ... yours looks like it was modified rather than purpose built. However, I have certainly been wrong before
. Either way, I think it is an interesting piece. Thanks for sharing!