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                                                                    Exhibit 10.8

                              THIRD AMENDMENT TO
                             EMPLOYMENT AGREEMENT
                           Dated as of July 2, 2001

     THIS THIRD AMENDMENT TO EMPLOYMENT AGREEMENT (this "Amendment") is entered
into as of July 2, 2001 (the "Effective Date") between Data Critical Corporation
("Data Critical" or the "Company") and Michael E. Singer ("you" or the
"Executive").

                                  WITNESSETH:

     WHEREAS, the Company and the Executive have entered into a certain
employment agreement dated as of June 14, 1999, an Amendment of Employment
Agreement dated as of February 24, 2000 and a Second Amendment to Employment
Agreement dated as of March 11, 2001 (collectively, the "Original Employment
Agreement") setting forth certain agreements with respect to terms of the
Executive's employment with the Company; and

     WHEREAS, in connection with the Company's acquisition of VitalCom, Inc. and
as a result of the related consolidation and move of the Company's operations to
Tustin, California, the parties hereto wish to amend the terms of the Original
Employment Agreement as hereinafter set forth (the Original Employment
Agreement, as amended by this Amendment, being collectively, the "Employment
Agreement");

     NOW THEREFORE, in consideration of the mutual premises set forth herein and
for other good and valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, the parties hereto hereby agree as follows:

     SECTION 1.  Amendments.  The Original Employment Agreement is hereby
amended as follows:

          Section 5(b)(ii) of the Original Employment Agreement is hereby
     amended and restated in its entirety to read as follows:

               "(ii) Termination Without Cause.  Based on overall Company policy
          and as an Officer of the Company and pursuant to Section 1, after
          August 24, 2001, the Company may not terminate Employee's employment
          with the Company without cause unless it provides Employee at least
          thirty (30) days' advance written notice of such termination.  In
          addition, in the event that at any time prior to December 30, 2001:

                    (a) the Company terminates your employment at any point in
               time without cause, or

                    (b) as a requirement of your continued employment with the
               Company, the Company requires you to permanently relocate to
               Tustin, California and rather than relocate, you elect to
               voluntarily terminate your employment with the Company (which
               event shall be deemed a termination without cause),

          then in either such case as an Officer of the Company and based on
          stated company policy, the Company will pay you $19,000 per month
          (subject to customary withholding) for a period of two months after
          such termination in accordance with the Company's standard payroll
          procedures.

     SECTION 2.  Effect on Original Employment Agreement.  This Amendment amends
the Original Employment Agreement and all terms of this Amendment shall be
deemed incorporated
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into and made a part of the Original Employment Agreement. Except as and to the
extent specifically modified by the terms of this Amendment, all terms of the
Original Employment Agreement shall remain in full force and effect. All
references to the Employment Agreement in any other agreement or document, and
all references in the Employment Agreement to "this Agreement," "hereof,"
"hereunder," or "hereto" or words of similar import shall be deemed to be
references to the Original Employment Agreement as amended hereby.

     SECTION 3.  Miscellaneous Provisions.

     3.1  Choice of Law.  The validity, interpretation, construction and
performance of this Amendment shall be governed by the laws of the State of
Washington, without giving effect to the principles of conflict of laws.

     3.2  Counterparts.  This Amendment may be executed in counterparts, each of
which shall be deemed an original, but all of which together will constitute one
and the same instrument.

     3.3  Advice of Counsel.  EACH PARTY TO THIS AMENDMENT ACKNOWLEDGES THAT, IN
EXECUTING THIS AMENDMENT, SUCH PARTY HAS HAD THE OPPORTUNITY TO SEEK THE ADVICE
OF INDEPENDENT LEGAL COUNSEL, AND HAS READ AND UNDERSTOOD ALL OF THE TERMS AND
PROVISIONS OF THIS AMENDMENT.  NEITHER THE ORIGINAL EMPLOYMENT AGREEMENT NOR
THIS AMENDMENT SHALL BE CONSTRUED AGAINST ANY PARTY BY REASON OF THE DRAFTING OR
PREPARATION HEREOF.

                           [Signature Page Follows]

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     The parties have executed this Amendment on the date first written above.

                                 DATA CRITICAL CORPORATION


                                 By:     /s/ Richard L. Earnest
                                    ----------------------------------
                                 Name:  Richard L. Earnest
                                 Title: Chief Executive Officer


                                 MICHAEL E. SINGER


                                 Signature:   /s/ Michael E. Singer
                                           ---------------------------

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