<< Is it sufficient to just have the guard rails of the gurney raised on both sides of the cart? >>
No. It may seem fairly secure, but if the ambulance were involved in even a minor MVC or the gurney started to tip, imagine what could happen. Taking a few seconds to strap the pt to the ambulance gurney is cheap insurance. I usually do this as we're rolling the patient from the rear of the 105 towards the ambulance (don't like to keep anyone near the rear of the a/c any longer than absolutely necessary - tail rotor + exhaust fumes).
If the gurney straps aren't long enough to fit around the aircraft litter AND the patient, then simply strap the aircraft litter itself to the gurney (with the pt still strapped to the litter, of course), and you are all set.
If too-short stretcher straps seem to be a recurring problem, then the ambulance service you use most often may be willing to put longer straps on their gurneys, especially if your program offers to buy them - they are quite cheap and it takes all of about 30 seconds to change them. Or you may simply carry short ones of your own to use as extensions.
Good luck.
