Colo. Rev. Stat. § 38-27-102
Such lien shall take effect if, prior to any such judgment, settlement, or compromise, a written notice of lien containing the name and address of the injured person, the date of the accident, the name and location of the hospital, and the name of the person alleged to be liable to the injured person for the injuries received is filed by the hospital in the office of the secretary of state. Hospital liens properly recorded with the division of insurance prior to July 1, 1994, shall be valid and enforceable without filing with the office of the secretary of state. Within ten days after such filing, the hospital shall mail by certified mail, return receipt requested, a copy of said notice to such injured person at the last address provided to the hospital by such person, to his or her attorney, if known, to the persons alleged to be liable to such injured person for the injuries sustained, if known, and to the insurance carriers, if known, which have insured such persons alleged to be liable against such liability. If an action for damages on account of such injuries or death is pending, the requirements of notice contained in this section shall be satisfied by the filing of the said notice of lien in the pending action, with copies thereof to the attorneys of record for the parties thereto.
C.R.S. § 38-27-102