Which theory does NOT support a medical malpractice lawsuit?

Informed consent does not support a medical malpractice lawsuit in the same manner as the other theories mentioned. The concept of informed consent primarily refers to the obligation of healthcare providers to inform patients about the risks, benefits, and alternatives of a proposed treatment or procedure. While failing to obtain informed consent can lead to liability, it is not a theory of negligence in itself; rather, it is a duty that physicians must fulfil to ensure patients are adequately informed before proceeding with medical interventions.

In contrast, the other theories—negligence, vicarious liability, and res ipsa loquitur—are foundational elements in establishing a medical malpractice case. Negligence focuses on the failure of the healthcare provider to meet the required standard of care. Vicarious liability holds an employer responsible for the actions of its employees during the course of their employment. Res ipsa loquitur is a doctrine that allows for the presumption of negligence when the incident causing harm is inherently dangerous and typically would not occur without negligence. Therefore, while informed consent is a critical part of the patient care process, it does not serve as a standalone theory for a malpractice lawsuit.