The county hospital board shall select and employ a competent chief executive officer whom they shall vest with general managerial powers over the operation of the hospital property, subject to the provisions of this act and subject to the rules and regulations for the conduct of the hospital affairs as formulated by the hospital board and approved by the board of county commissioners, together with such assistant or assistants as the board may find necessary or convenient to the efficient and successful operation of the hospital property. The board shall fix a salary to be paid to the chief executive officer and to any assistant chief executive officer or chief executive officers, and shall be authorized to contract with competent persons for such services for such period as the board may authorize. The chief executive officer shall be responsible for the employment, supervision, direction, assignment and discharge of all operating employee personnel. Payment for such services shall be according to the scale of wages as fixed by the hospital board and in effect at the time. The hospital board shall have the power to change, by increase or decrease, the scale of wages to be paid at any time.