Health services delivered on an inpatient basis in hospitals, nursing homes, or other inpatient institutions, and by health maintenance organizations; but may also refer to services delivered on an outpatient basis by departments or other organizational units of or sponsored by such institutions. The National Health Planning and Resources Development Act of 1974, (section 1531(5) of the PTIS Act) defines them as services and facilities subject under HEIW rules to section 1122 review, and requires that all institutional, but not non-institutional, health services be subject to certificate-of-need review and periodic review for appropriateness.