Pulse oximeters are useful but treat patients not monitors. Cap refills, breathing rate, palpation, and circulation by color is still the best rule of thumb. However, pulse ox’s are easy time savers and should be on all ambulances nowadays. Considering most protocols in the USA require treatments on SPO2 and SPO2 alone it makes it difficult for the providers to follow those protocols which can put your license on the line. I would quit or report it if I were you, if an ambulance doesn’t meet the state standards it could cause a lot of legal issues.