IV bags hard to find. Rigs to deliver solution to pt still harder to find. Knowledge of how to rig same, IF YOU HAVE BOTH...priceless.
Alt B might be sacrifice drinking bladder and hose and use Pedialyte or Gatorade or Powerade and give pt an enema.
Necessity is the mother of invention.
Starter sets can be had on Amazon. The IV bags are hard to find. It is important to note that oral rehydration is better than IV any day of the week. IV's are useful for rapid fluid resuscitation, when there is a significant loss of blood or the dehydratee is unconscious.
An enema is a legit way to replace fluids.
Pedialyte is great. Better than Gatorade/Powerade.