<PAGE>
                                                                   Exhibit 10.45


                                SEVENTH AMENDMENT
                                     TO THE
                      FISHER SCIENTIFIC INTERNATIONAL INC.
                                 RETIREMENT PLAN

      WHEREAS, Fisher Scientific International Inc. (the "Company") has
established and maintains the Fisher Scientific International Inc. Retirement
Plan (the "Plan"); and

      WHEREAS, the Fisher Scientific International Inc. Administrative and
Investment Committee (the "Committee") has the authority pursuant to Section
10.1 of the Plan to amend the Plan; and

      WHEREAS, the Committee desires to amend the Plan to authorize the use of a
retroactive annuity starting date for certain distributions and clarify the
marriage requirements for spousal benefits under the Plan;

      NOW, THEREFORE, be it resolved as follows:

      RESOLVED, the Plan shall be amended effective January 1, 2004 as follows:

1.    Section 1.7 of Article I of the Plan shall be amended in its entirety to
      read as follows:

      1.7   "ANNUITY STARTING DATE" means the first day of the first period for
which an amounts is paid or due to be paid under the Plan; provided, however,
that such date shall not constitute a Retroactive Annuity Starting Date unless
the requirements of Section 7.14 of the Plan are satisfied.

2.    A new definition is hereby added to Article I of the Plan to read as
      follows:

            "RETROACTIVE ANNUITY STARTING DATE" means an Annuity Starting Date
elected by a Participant that predates the furnishing of a Qualified Joint and
Survivor Annuity explanation and meets the requirements of Section 7.14 of the
Plan.

3.    Section 7.1(b) of the Plan is hereby amended in its entirety to read as
      follows:

      (b)   The Committee shall notify the Participant in writing concerning the
            right to elect an optional form of benefit and to designate a
            Beneficiary. Such notification will be made at least thirty (30)
            days but not more than ninety (90) days prior to the Annuity
            Starting Date unless the Participant affirmatively elects a
            Retroactive Annuity Starting Date as set forth in Section 7.14.

4.    The last sentence of Section 7.3 is hereby amended in its entirety to read
      as follows:

      "Election Period" shall mean, with respect to a Qualified Joint and
Survivor Annuity, the 90-day period ending on the Annuity Starting Date unless
the Participant affirmatively elects a

<PAGE>

Retroactive Annuity Starting Date as described in Section 7.14 (with the consent
of the Spouse, as applicable).

5.    A new Section 7.14 is hereby added to the Plan to read as follows:

      7.14. ELECTION TO USE RETROACTIVE ANNUITY STARTING DATE. In accordance
with Treasury Regulations Section 1.417(3)-1, effective as of January 1, 2004, a
Participant may elect, with spousal consent if applicable, a Retroactive Annuity
Starting Date subject to the following conditions:

      (a)   NO APPLICATION TO LUMP SUM FORM OF DISTRIBUTION. A Participant may
            not elect a Retroactive Annuity Starting Date if the Participant
            elects or has elected to receive a lump sum distribution under the
            Plan.

      (b)   DETERMINATION OF RETROACTIVE ANNUITY STARTING DATE. A Participant
            may elect a Retroactive Annuity Starting Date that is not earlier
            than the latest of (i) the date as of which the Participant could
            have otherwise started receiving benefits under the Plan, or (ii)
            the date the Participant applies to the Plan Administrator, in
            writing, to commence benefit distributions.

      (c)   AFFIRMATIVE ELECTION BY PLAN PARTICIPANT REQUIRED. A Participant
            must affirmatively elect to commence distributions as of a
            Retroactive Annuity Starting Date. In the absence of such election,
            distributions shall be determined as of and commence in accordance
            with the Annuity Starting Date.

      (d)   SPOUSAL CONSENT REQUIRED. If a Participant elects a Retroactive
            Annuity Starting Date, the Participant's Spouse must consent to the
            Participant's election. In the absence of such spousal consent,
            distributions shall be determined as of and commence in accordance
            with the Annuity Starting Date. If the Participant's Spouse as of
            the Retroactive Annuity Starting Date would not be the Participant's
            Spouse determined as if the date distributions commence was the
            Participant's Annuity Starting Date, consent of the former spouse is
            not required unless otherwise provided under a qualified domestic
            relations order.

      (e)   MAKE-UP PAYMENTS AND INTEREST CALCULATION. If a Participant elects a
            Retroactive Annuity Starting Date, the Participant shall receive a
            make-up payment to reflect any missed payment or payments for the
            period from the Retroactive Annuity Starting Date to the date of the
            actual make-up payment with an appropriate adjustment for interest.
            Interest on such make-up payments shall be calculated using the
            interest rate for determination of the actuarial equivalence for a
            lump sum distribution as set forth in Section 1.4 of the Plan.

      (f)   TIMING OF NOTICE AND CONSENT REQUIREMENTS FOR RETROACTIVE ANNUITY
            STARTING DATE. In the case of a Retroactive Annuity Starting Date,
            the written explanation required by Code Section 417(a)(3)(A) and
            Sections 7.1 and 7.3 must be provided no less than 30 days and no
            more than 90 days before the date of the

<PAGE>

            first actual payment of benefits based on the Retroactive Annuity
            Starting Date. The written explanation may be provided less than 30
            days prior to the first actual payment of benefits subject to the
            requirements of Section 7.1(c).

      (g)   NO ELECTION OF RETROACTIVE ANNUITY STARTING DATE BY SURVIVING SPOUSE
            OR BENEFICIARY. A Surviving Spouse or Beneficiary of a Participant
            may not elect a Retroactive Annuity Starting Date under the Plan.

5.    The definition of "Annuity Starting Date" in Section 1 of Part I of
Schedule A to the Plan (the "Fisher Component") is hereby amended in its
entirety to read as follows:

      "Annuity Starting Date" means (i) the first day of the first period for
which a benefit is payable as an annuity, or (ii) in the case of a benefit not
payable in the form of an annuity, the first day on which all events have
occurred which entitle the Participant to such benefit; provided, however, that
such date shall not constitute a Retroactive Annuity Starting Date unless the
requirements of Section 6.3.1 of the Fisher Component are satisfied.

6.    A new definition of "Retroactive Annuity Starting Date" is hereby added to
Section 1 of Part I of the Fisher Component to read as follows:

      "Retroactive Annuity Starting Date" means an Annuity Starting Date elected
by a Participant that predates the furnishing of a Joint and Survivor Annuity
explanation and meets the requirements of Section 6.3.1 of the Fisher Component.

7.    The first sentence of the third paragraph of Section 6.3 of the Fisher
Component is hereby amended in its entirety to read as follows:

      A Participant may elect, in writing, at any time at least 30 days but not
more than 90 days prior to the Annuity Starting Date, to reject the Joint and
Survivor Benefit and receive the normal form or an optional form of benefit
unless the Participant affirmatively elects a Retroactive Annuity Starting Date
as set forth in Section 6.3.1. The Participant may elect to waive the 30-day
notice period prior to the Annuity Starting Date if distribution commences more
than seven days after such explanation is provided.

8.    A new Section 6.3.1 is hereby added to the Fisher Component to read as
follows:

      6.3.1. Election to Use Retroactive Annuity Starting Date. In accordance
with Treasury Regulations Section 1.417(3)-1, effective as of January 1, 2004, a
Participant may elect, with spousal consent if applicable, a Retroactive Annuity
Starting Date subject to the following conditions:

      (a)   No Application to Lump Sum Form of Distribution. A Participant may
            not elect a Retroactive Annuity Starting Date if the Participant
            elects or has elected to receive a lump sum distribution under the
            Plan.

<PAGE>

      (b)   Determination of Retroactive Annuity Starting Date. A Participant
            may elect a Retroactive Annuity Starting Date that is not earlier
            than the latest of (i) the date as of which the Participant could
            have otherwise started receiving benefits under the Plan, or (ii)
            the date the Participant applies to the Plan Administrator, in
            writing, to commence benefit distributions.

      (c)   Affirmative Election by Plan Participant Required. A Participant
            must affirmatively elect to commence distributions as of a
            Retroactive Annuity Starting Date. In the absence of such election,
            distributions shall be determined as of and commence in accordance
            with the Annuity Starting Date.

      (d)   Spousal Consent Required. If a Participant elects a Retroactive
            Annuity Starting Date, the Participant's Eligible Spouse must
            consent to the Participant's election. In the absence of such
            spousal consent, distributions shall be determined as of and
            commence in accordance with the Annuity Starting Date. If the
            Participant's Eligible Spouse as of the Retroactive Annuity Starting
            Date would not be the Participant's Eligible Spouse determined as if
            the date distributions commence was the Participant's Annuity
            Starting Date, consent of the former spouse is not required unless
            otherwise provided under a qualified domestic relations order.

      (e)   Make-Up Payments and Interest Calculation. If a Participant elects a
            Retroactive Annuity Starting Date, the Participant shall receive a
            make-up payment to reflect any missed payment or payments for the
            period from the Retroactive Annuity Starting Date to the date of the
            actual make-up payment with an appropriate adjustment for interest.
            Interest on such make-up payments shall be calculated using the
            interest rate for determination of the actuarial equivalence for a
            lump sum distribution as set forth in the definition of "Actuarial
            Equivalent" in this Fisher Component.

      (f)   Timing of Notice and Consent Requirements for Retroactive Annuity
            Starting Date. In the case of a Retroactive Annuity Starting Date,
            the written explanation required by Code Section 417(a)(3)(A) and
            Section 6.3 must be provided no less than 30 days and no more than
            90 days before the date of the first actual payment of benefits
            based on the Retroactive Annuity Starting Date. The written
            explanation may be provided less than 30 days prior to the first
            actual payment of benefits subject to the requirements of Section
            6.3.

      (g)   No Election of Retroactive Annuity Starting Date by Surviving Spouse
            or Beneficiary. An Eligible Spouse or Beneficiary of a Participant
            may not elect a Retroactive Annuity Starting Date under the Plan.

9.    The definition of "Eligible Spouse" in Section 1.21 of Part II of Schedule
A to the Plan (the "Clinical Division Component") is hereby amended in its
entirety to read as follows:

      1.21. "Eligible Spouse" means the spouse of a Participant to whom the
Participant has been legally married for at least one (1) year prior to the
Participant's death.

<PAGE>

10.   The second paragraph of Section 6.3(b) of the Clinical Division Component
shall be amended in its entirety to read as follows:

      The written explanation shall be provided at least 30 days but not more
than 90 days prior to the first date on which he is entitled to payment from the
Fund unless the Participant affirmatively elects a Retroactive Annuity Starting
Date as defined and set forth in Section 6.3(c) of the Clinical Division
Component. The Participant may elect to waive the 30-day notice period prior to
the date of payment if distribution commences more than seven days after such
explanation is provided.

11.   A new subsection (c) is hereby added to Section 6.3 of the Clinical
Division Component to read as follows:

      (c)   Election to Use Retroactive Annuity Starting Date. In accordance
with Treasury Regulations Section 1.417(3)-1, effective as of January 1, 2004, a
Participant may elect, with spousal consent if applicable, a Retroactive Annuity
Starting Date subject to the following conditions:

            (1)   Definition of Retroactive Annuity Starting Date. A
                  "Retroactive Annuity Staring Date" means a date for payment
                  from the Clinical Division Component elected by a Participant
                  that predates the furnishing of a joint and survivor annuity
                  explanation and meets the requirements of this Section.

            (2)   No Application to Lump Sum Form of Distribution. A Participant
                  may not elect a Retroactive Annuity Starting Date if the
                  Participant elects or has elected to receive a lump sum
                  distribution under the Plan.

            (3)   Determination of Retroactive Annuity Starting Date. A
                  Participant may elect a Retroactive Annuity Starting Date that
                  is not earlier than the latest of (A) the date as of which the
                  Participant could have otherwise started receiving benefits
                  under the Plan, or (B) the date the Participant applies to the
                  Plan Administrator, in writing, to commence benefit
                  distributions.

            (4)   Affirmative Election by Plan Participant Required. A
                  Participant must affirmatively elect to commence distributions
                  as of a Retroactive Annuity Starting Date. In the absence of
                  such election, distributions shall be determined as of and
                  commence in accordance with the normal payment commencement
                  date.

            (5)   Spousal Consent Required. If a Participant elects a
                  Retroactive Annuity Starting Date, the Participant's Eligible
                  Spouse must consent to the Participant's election. In the
                  absence of such spousal consent, distributions shall be
                  determined as of and commence in accordance with the normal
                  payment commencement date. If the Participant's Eligible

<PAGE>

                  Spouse as of the Retroactive Annuity Starting Date would not
                  be the Participant's Eligible Spouse determined as if the date
                  distributions commence was the Participant's normal payment
                  commencement date, consent of the former spouse is not
                  required unless otherwise provided under a qualified domestic
                  relations order.

            (6)   Make-Up Payments and Interest Calculation. If a Participant
                  elects a Retroactive Annuity Starting Date, the Participant
                  shall receive a make-up payment to reflect any missed payment
                  or payments for the period from the Retroactive Annuity
                  Starting Date to the date of the actual make-up payment with
                  an appropriate adjustment for interest. Interest on such
                  make-up payments shall be calculated using the interest rate
                  for determination of the actuarial equivalence for a lump sum
                  distribution as set forth in the definition of "Actuarial
                  Equivalent" in this Clinical Division Component.

            (7)   Timing of Notice and Consent Requirements for Retroactive
                  Annuity Starting Date. In the case of a Retroactive Annuity
                  Starting Date, the written explanation required by Code
                  Section 417(a)(3)(A) and Section 6.3 must be provided no less
                  than 30 days and no more than 90 days before the date of the
                  first actual payment of benefits based on the Retroactive
                  Annuity Starting Date. The written explanation may be provided
                  less than 30 days prior to the first actual payment of
                  benefits subject to the requirements of Section 6.3(b).

            (8)   No Election of Retroactive Annuity Starting Date by Surviving
                  Spouse or Beneficiary. An Eligible Spouse of a Participant may
                  not elect a Retroactive Annuity Starting Date under the Plan.

12.   Section 8.2(b) of Part III of Schedule A to the Plan (the "Hamilton
Component") shall be amended in its entirety to read as follows:

      (b) No amount shall be payable to a Participant's spouse in accordance
with this Section 8.2 unless she or he presents evidence satisfactory to the
trustees that she or he was legally married to the Participant on the date
retirement benefits are to commence.

13.   The first sentence of Section 8.3(c) of the Hamilton Component shall be
amended in its entirety to read as follows:

      At least thirty (30) days but no more than ninety (90) days prior to a
Participant's expected date of commencement of benefits, or otherwise consistent
with such regulations as the Secretary of the Treasury may prescribe, the
Employer shall give written notice of the terms and conditions of a Joint and
Survivor Annuity to the Participant unless the Participant affirmatively elects
a Retroactive Annuity Starting Date as defined and set forth in Section 8.3.1 of
the Hamilton Component. The Participant may elect to waive the 30-day notice
period prior to the

<PAGE>

date of payment if distribution commences more than seven days after such
explanation is provided.

14.   A new Section 8.3.1 is hereby added to the Hamilton Component to read as
follows:

     8.3.1. Election to Use Retroactive Annuity Starting Date. In accordance
with Treasury Regulations Section 1.417(3)-1, effective as of January 1, 2004, a
Participant may elect, with spousal consent if applicable, a Retroactive Annuity
Starting Date subject to the following conditions:

            (a)   Definition of Retroactive Annuity Starting Date. A
                  "Retroactive Annuity Staring Date" means a date for payment
                  from the Clinical Division Component elected by a Participant
                  that predates the furnishing of a joint and survivor annuity
                  explanation and meets the requirements of this Section.

            (b)   No Application to Lump Sum Form of Distribution. A Participant
                  may not elect a Retroactive Annuity Starting Date if the
                  Participant elects or has elected to receive a lump sum
                  distribution under the Plan.

            (c)   Determination of Retroactive Annuity Starting Date. A
                  Participant may elect a Retroactive Annuity Starting Date that
                  is not earlier than the latest of (i) the date as of which the
                  Participant could have otherwise started receiving benefits
                  under the Plan, or (ii) the date the Participant applies to
                  the Plan Administrator, in writing, to commence benefit
                  distributions.

            (d)   Affirmative Election by Plan Participant Required. A
                  Participant must affirmatively elect to commence distributions
                  as of a Retroactive Annuity Starting Date. In the absence of
                  such election, distributions shall be determined as of and
                  commence in accordance with the normal payment commencement
                  date.

            (e)   Spousal Consent Required. If a Participant elects a
                  Retroactive Annuity Starting Date, the Participant's spouse
                  must consent to the Participant's election. In the absence of
                  such spousal consent, distributions shall be determined as of
                  and commence in accordance with the normal payment
                  commencement date. If the Participant's spouse as of the
                  Retroactive Annuity Starting Date would not be the
                  Participant's spouse determined as if the date distributions
                  commence was the Participant's normal payment commencement
                  date, consent of the former spouse is not required unless
                  otherwise provided under a qualified domestic relations order.

            (f)   Make-Up Payments and Interest Calculation. If a Participant
                  elects a Retroactive Annuity Starting Date, the Participant
                  shall receive a make-up payment to reflect any missed payment
                  or payments for the period from the Retroactive Annuity
                  Starting Date to the date of the actual make-up

<PAGE>

                  payment with an appropriate adjustment for interest. Interest
                  on such make-up payments shall be calculated using the
                  interest rate for determination of the actuarial equivalence
                  for a lump sum distribution as set forth in the definition of
                  "Actuarial Equivalent" in this Clinical Division Component.

            (g)   Timing of Notice and Consent Requirements for Retroactive
                  Annuity Starting Date. In the case of a Retroactive Annuity
                  Starting Date, the written explanation required by Code
                  Section 417(a)(3)(A) and Section 6.3 must be provided no less
                  than 30 days and no more than 90 days before the date of the
                  first actual payment of benefits based on the Retroactive
                  Annuity Starting Date. The written explanation may be provided
                  less than 30 days prior to the first actual payment of
                  benefits subject to the requirements of Section 6.3(b).

            (h)   No Election of Retroactive Annuity Starting Date by Surviving
                  Spouse or Beneficiary. An Eligible Spouse or Beneficiary of a
                  Participant may not elect a Retroactive Annuity Starting Date
                  under the Plan.

      RESOLVED, FINALLY, that all other provisions of the Plan shall remain in
full force and effect.

      IN WITNESS WHEREOF, the Fisher Scientific International Inc. Retirement
Plan is amended this 14th day of April, 2004.

                                                   ADMINISTRATIVE AND INVESTMENT
                                                   COMMITTEE

                                                   /s/ Paul M. Meister
                                                   _____________________________
                                                   Paul M. Meister


                                                   /s/ Todd M. DuChene
                                                   _____________________________
                                                   Todd M. DuChene