As used in sections four-a to four-j in this article the following terms shall have the respective meanings ascribed thereto:
(a) "Records" means and includes without restriction, those medical histories, records, reports, summaries, diagnoses, and prognoses, records of treatment and medication ordered and given, notes, entries, X-rays, and other written or graphic data prepared, kept, made or maintained in hospitals that pertain to hospital confinements or hospital services rendered to patients admitted to hospitals or receiving emergency room or outpatient care. Such records shall not, however, include ordinary business records pertaining to patients' accounts or the administration of the institution.
(b) "Custodian" means and includes the medical record librarian and the administrator or other chief officer of a duly licensed hospital in this state and its proprietor, as well as their deputies and assistants and any other persons who are official custodians or depositories of records.