What are the elements of a professional negligence claim?

To succeed on a professional negligence claim, the plaintiff must prove the following elements: "'(1) a duty to use such skill, prudence, and diligence as other members of the profession commonly possess and exercise; (2) a breach of the duty; (3) a proximate causal connection between the negligent conduct and the injury; and (4) resulting loss or damage.' [Citation.]" (Lattimore v. Dickey (2015) 239 Cal.App.4th 959, 968.)

Where, as here, "the conduct required of a medical professional is not within the common knowledge of laymen, a plaintiff must present expert witness testimony to prove a breach of the standard of care. [Citations.] [The] [p]laintiff also must show that [the defendant's] breach of the standard of care was the cause, within a reasonable medical probability, of his injury. [Citation.]" (Bushling v. Fremont Medical Center (2004) 117 Cal.App.4th 493, 509 (Bushling).)