SACRAMENTO, Calif. — Dr. Anna Nguyen spoke with none of the five patients she treated on a recent weekday morning. She didn’t even leave her dining room. The emergency physician nevertheless helped a pregnant Ohio woman handle hip pain, examined a Michigan man’s sore throat and texted a mom whose son became sick during a family trip to Mexico. Welcome to the latest wrinkle in health care convenience: the chat diagnosis. Nguyen’s company, CirrusMD, can connect patients with a doctor in less than a minute.