(a) Patient means a person who is receiving diagnostic or preventive health services or who is under observation or treatment for illness or injury or care during and after pregnancy. (1) Inpatient. An inpatient means a person who has been formally admitted for observation, diagnosis or treatment and who is expected to remain overnight or longer.(2) Outpatient. An outpatient means a person who has been registered or accepted for care but not formally admitted as an inpatient and who does not remain over 24 hours.(3) Ambulatory. Ambulatory means a patient who is capable of demonstrating the mental competence and physical ability to leave a building without assistance or supervision of any person under emergency conditions.(4) Nonambulatory. Nonambulatory means a patient who is unable to leave a building unassisted under emergency conditions. It includes, but is not limited to, those persons who depend upon mechanical aids such as crutches, walkers or wheelchairs, profoundly or severely mentally retarded persons and shall include totally deaf persons.Cal. Code Regs. Tit. 22, § 71051