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                                 EXHIBIT 10.23
 
                     CHANGE IN CONTROL EMPLOYMENT AGREEMENT
 
     This Change in Control Employment Agreement (the "Agreement") is hereby
made and entered into effective as of December 9, 1994, by and between Aequitron
Medical, Inc., a Minnesota corporation (the "Company"), and Jeffrey A. Blair
("Executive").
 
                                    Recitals
 
     1. Executive is currently employed by the Company as Company's Senior Vice
President of Sales and Marketing under the terms and conditions of a written
agreement dated September 9, 1993 and executed by Executive approximately
September 14, 1993 and by a representative of the Company on September 9, 1993.
 
     2. Company desires to provide Executive with assurances justifying
Executive's continued employment at a time when Company anticipates that there
may be offers for its acquisition by outside third parties.
 
                                   Agreement
 
     1. Employment.  The Company agrees to continue to employ Executive as its
Senior Vice President of Sales and Marketing upon the terms and conditions set
forth in the September 9, 1993 Agreement between the Company and Executive.
 
     2. Benefits Available to Executive When Employment Termination Results
Subsequent to a Change in Control.
 
     a. If, at any time, subsequent to the date of this Agreement, the Company
undergoes a "change in control" as hereinafter defined and thereafter Executive
is terminated without cause or if Executive voluntarily resigns within one year
after such "change in control," Executive shall receive two times the total of
his base compensation and two times the amount of target bonus pursuant to the
Company's approved management incentive plan in effect at the time of the change
in control. Within ten (10) days from the date of termination of Executive's
employment or Executive's voluntary resignation, all sums due the Executive for
his base compensation and target bonus under this Agreement shall be paid in one
lump sum (subject to applicable deductions and withholding for FICA and state
and federal income taxes) unless a schedule specifying dates upon which such
payments will be made has been agreed to by the Executive in writing. Executive
will also receive the health benefits in effect at the time of termination for a
period of two years or until he attains new employment and qualifies for similar
health coverage, whichever occurs earlier. The health coverage to be received
will be consistent with the Aequitron Medical, Inc. policy for full-time
employees in effect on the date a "change in control" occurs. In addition, all
outstanding stock options on the date of resignation or termination to the
extent they are not then vested will become vested immediately, and Executive
shall thereafter have the right to exercise all such options for a period of
three months after Executive is terminated or voluntarily resigns.
 
     b. A change in control shall be deemed to have occurred if: (i) any person
or entity becomes the beneficial owner of 35% or more of the Company's
outstanding securities in conjunction with a "change in the Board of Directors
composition": (ii) any person or entity increased his or her or its ownership of
the Company by an amount equal to 25% of the Company's outstanding securities in
conjunction with a "change in the Board of Directors composition"; (iii) the
consummation of a merger, acquisition or consolidation of the Company into or
with any other entity; (iv) the consummation of a plan of complete liquidation
of the Company or the sale of substantially all of the Company's assets; or (v)
a "change in the Board of Directors composition."
 
     c. A "change in the Board of Directors composition" shall be deemed to have
occurred if, at any time, while Executive is employed by the Company a numerical
majority of the Company's Board of Directors is comprised of persons whose
nomination was not approved by vote of at least two-thirds of the Company's
directors.
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     3. Except for the specific occurrence of a "change in control" or a "change
in the composition of the Board of Directors" of Company as defined herein,
Executive's employment with Company shall continue to be on an at will basis and
such other Company employment policies as are from time to time approved and
adopted for Company's full-time employees.
 
     IN WITNESS WHEREOF, the parties have hereto executed this Change in Control
Employment Agreement as of the day and year first written above.
 
                                          AEQUITRON MEDICAL, INC.
 
                                                 /s/ JAMES B. HICKEY, JR.
                                          By: ------------------------------
                                                    Its President and CEO
 

                                                 /s/ JEFFREY A. BLAIR
                                              ------------------------------
                                                        Executive