FOURTH AMENDMENT TO EMPLOYMENT AGREEMENT

                                                                    Exhibit 10.9

                              FOURTH AMENDMENT TO
                              EMPLOYMENT AGREEMENT

          This Fourth Amendment to Employment Agreement (the "Fourth Amendment")
is made as of July 18, 2001 by and between Xxxxxxx Xxxxxx ("Employee") and Data
Critical Corporation, a Delaware corporation (the "Company").


                                  WITNESSETH

          WHEREAS, Employee and the Company are parties to an Employment
Agreement dated as of June 14, 1999 (the "Original Employment Agreement") and to
an Amendment of Employment Agreement dated as of February 24, 2000 (the "First
Amendment") and to a Second Amendment to Employment Agreement dated as of March
11, 2001 (the "Second Amendment") and to a Third Amendment to Employment
Agreement dated as of July 2, 2001 (the "Third Amendment") (the Original
Employment Agreement, as amended by the First Amendment, Second Amendment and
Third Amendment, is herein referred to as the "Employment Agreement");

          WHEREAS, Employee and the Company wish to amend the Employment
Agreement as set forth in this Amendment;

          NOW, THEREFORE, in consideration of the mutual consideration,
promises, representations and covenants set forth herein, the receipt and
sufficiency of which are hereby acknowledged, Employee and the Company agree as
follows:

                                   AGREEMENT

          1.   Section 4(c)(v) of the Employment Agreement hereby is deleted in
its entirety.

          2.   The first sentence of Section 5(b)(i) of the Employment Agreement
hereby is amended by the deletion of the reference to Section 4(c)(v) therein.

          3.   This Fourth Amendment may be executed in one or more
counterparts, all of which shall be considered one and the same agreement.


          IN WITNESS WHEREOF, the parties hereto have executed this FOURTH
AMENDMENT TO EMPLOYMENT AGREEMENT as of the date and year first above written.

                                 DATA CRITICAL CORPORATION

                                 By:     /s/ Xxxxxxx X. Xxxxxxx
                                     --------------------------------
                                 Name:  Xxxxxxx X. Xxxxxxx
                                 Title: Chief Executive Officer

                                 Address:  00000 Xxxxx Xxxxx Xxxxxxx
                                           Xxxxx 000
                                           Xxxxxxx, XX  00000


                                 XXXXXXX X. XXXXXX

                                         /s/ Xxxxxxx X. Xxxxxx
                                     --------------------------------

                                 Address:  0000 00xx Xxxxxx XX
                                           Xxxxxxxx, XX  00000

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