You can call around to all the hospitals in the area, and ask if the peson has been admitted. You have to ask it in just this way: Do you have a mr. or ms, so and so admitted within the past (number of hours or days)? AND if so, then ask if they are allowed visitors.
If the person was involved in an accident you can contact the police or the ambulance squad to find out which hosptial they were transported to.
In the old days and still today in very small towns, hosptal admissions were printed in the paper. But in LA, they are not going to do that for privacy reasons and sheer volumn.