EXHIBIT 8.1

                              RIORDAN & McKINZIE
                            300 South Grand Avenue
                             Los Angeles, CA 90071



                                August 3, 1998


                                                                       6-849-002



River Holding Corp.
599 Lexington Avenue, 18/th/ Floor
New York, New York 10022

Hudson Respiratory Care Inc.
27711 Diaz Road
Temecula, California 92589

     Re:  River Holding Corp. and Hudson Respiratory Care Inc. on Form S-4 File
          ---------------------------------------------------------------------
          No. 333-56135
          -------------

Dear Ladies and Gentlemen:

     You have requested our opinion concerning certain material federal income
tax considerations expected to result on the exchange of 11 1/2% Series B Senior
Exchangeable PIK Preferred Stock due 2010 (Liquidation Preference $100 per
share) of River Holding Corp. (the "Issuer"), which have been registered under
the Securities Act of 1933, as amended, for outstanding Senior Exchangeable PIK
Preferred Stock due 2010 (Liquidation Preference $100 per share) of the Issuer,
in connection with the Registration Statement on Form S-4 filed with the
Securities and Exchange Commission (the "Commission") on June 5, 1998 (File No.
333-56135), as amended by Amendment No. 1 filed with the Commission on August
3, 1998 (as amended, the "Registration Statement").

     The facts, as we understand them, and upon which we rely in rendering the
opinion expressed herein, are as set forth in the Registration Statement.  Based
on such facts, it is our opinion that the U.S. federal income tax considerations
set forth under the heading "Certain U.S. Federal Income Tax Considerations" in
the Registration Statement are accurate in all material respects.  No opinion is
expressed as to any matter not discussed therein.

     This opinion is based on various statutory provisions, regulations
promulgated thereunder and interpretations thereof by the Internal Revenue
Service and the courts having jurisdiction over 

 
Hudson Respiratory Care Inc.
August 3, 1998
Page 2




such matters, all of which are subject to change either prospectively or
retroactively. Also, any variation or difference in the facts from those set
forth in the Registration Statement may affect the conclusion stated herein.

     This opinion is rendered to you solely for use in connection with the
Registration Statement.  We consent to your filing this opinion as an exhibit to
the Registration Statement.

                              Very truly yours,


                              Riordan & McKinzie