Ethel was admitted to the Heritage Care Center. Subsequently, she was transferred to Hospital after ingesting an overdose of Tolbutamide, a diabetic medication. An intravenous device was inserted in the dorsum area of her right foot to treat the coma. Gangrene later developed in the same foot, which eventually required an above-the-knee amputation. P, Ethel's sister, brought a suit against P. The presentation of the case followed a res ipsa loquitur pattern of proof. D demurrered to the evidence, and the trial court directed a verdict for D. The trial court ruled that D's evidence fell short of establishing a negligence claim because her proof failed to show all the requisite foundational elements for res ipsa loquitur. The Court of Civil Appeals affirmed.