<PAGE>   1
SILICON VALLEY BANK

                          AMENDMENT TO LOAN AGREEMENT

BORROWER:  VITALCOM INC., A DELAWARE CORPORATION

ADDRESS:   15222 DEL AMO AVENUE
           TUSTIN, CA 92780

DATE:      MARCH 21, 2000

THIS AMENDMENT TO LOAN AGREEMENT is entered into between SILICON VALLEY BANK
("Silicon") and the borrower named above (the "Borrower").

     The Parties agree to amend the Loan and Security Agreement between them
dated February 26, 1993, as amended by that Amendment to Loan Agreement dated
December 21, 1993, as amended by that Amendment to Loan Agreement dated April
27, 1994, as amended by that Amendment to Loan Agreement dated May 5, 1995, as
amended by that Amendment to Loan Agreement dated May 30, 1995, as amended by
that Amendment to Loan Agreement dated December 27, 1995, as amended by that
Amendment to Loan Agreement dated August 6, 1996, as amended by that Amendment
to Loan Agreement dated September 25, 1996, as amended by that Amendment to
Loan Agreement dated August 6, 1997, as amended by that Amendment to Loan
Agreement dated December __, 1998 and as otherwise amended or modified from
time to time (the "Loan Agreement": terms defined in the Loan Agreement are
used herein as therein defined), as follows, effective as of the date hereof.

     1.   AMENDED SCHEDULE. The Schedule to the Loan Agreement is amended,
effective as of the date hereof, to read as set forth on the Amended Schedule
attached hereto.

     2.   MODIFIED SECTION 2.2. Section 2.2 of the Loan Agreement is hereby
deleted in its entirety and replaced with the following:

     "2.2 GRANT OF SECURITY INTEREST IN COLLATERAL. Upon the making of any
     Loans, the following shall be considered to be immediately and fully
     effective, without any further action on the part of Silicon or Borrower:
     Borrower hereby grants Silicon a continuing security interest in all of
     Borrower's interest in the Collateral (as defined below in Section 2.2A)
     as security for all Obligations (such grant of a security interest is
     referred to herein as the "Grant"). Notwithstanding the foregoing, no
     Loans shall be made unless and until Silicon has acquired a perfected
     security interest in the Collateral, including but not limited to the
     filing of any UCC-1 financing statements as required by Silicon in its
     discretion: Borrower agrees to take such actions and execute such
     documentation as Silicon determines is necessary or desirable in order to
     allow Silicon to perfect its security interest in the Collateral at such
     time as the Grant becomes effective.

     2.2A COLLATERAL. The following is referred to as the "Collateral": (a) All
     accounts, contract rights, chattel paper, letters of credit, documents,
     securities, money, and instruments, and all other obligations now or in
     the future owing to the Borrower; (b) All inventory, goods, merchandise,
     materials, raw materials, work in process, finished



                                      -1-
<PAGE>   2
SILICON VALLEY BANK                                  AMENDMENT TO LOAN AGREEMENT
--------------------------------------------------------------------------------


     goods, farm products, advertising, packaging and shipping materials,
     supplies, and all other tangible personal property which is held for sale
     or lease or furnished under contracts of service or consumed in the
     Borrower's business, and all warehouse receipts and other documents; and
     (c) All equipment, including without limitation all machinery, fixtures,
     trade fixtures, vehicles, furnishings, furniture, materials, tools, machine
     tools, office equipment, computers and peripheral devices, appliances,
     apparatus, parts, dies, and jigs; (d) All general intangibles, including,
     but not limited to, deposit accounts, goodwill, names, trade names,
     drawings, blueprints, customer lists, security deposits, loan commitment
     fees, federal, state and local tax refunds and claims, all rights in all
     litigation presently or hereafter pending for any cause or claim (whether
     in contract, tort or otherwise), and all judgments now or hereafter arising
     therefrom, all claims of Borrower against Silicon, all rights to purchase
     or sell real or personal property, all rights as a licensor or licensee of
     any kind, all royalties, licenses, processes, telephone numbers,
     proprietary information, purchase orders, and all insurance policies and
     claims (including without limitation credit, liability, property and other
     insurance), and all other rights, privileges and franchises of every kind;
     (e) All books and records, whether stored on computers or otherwise
     maintained; and (f) All substitutions, additions and accessions to any of
     the foregoing, and all products, proceeds and insurance proceeds of the
     foregoing, and all guaranties of and security for the foregoing; and all
     books and records relating to any of the foregoing; provided, however, that
     "Collateral" shall not include Intellectual Property (as defined below).

     As used herein the term "Intellectual Property" means (a) any and all
     copyright rights, copyright applications, copyright registrations and like
     protections; (b) any trademark and servicemark rights, whether registered
     or not, applications to register and registrations of the same and like
     protections; (c) all patents, patent applications and like protections; and
     (d) all mask work or similar rights available for the protection of
     semiconductor chips."

     3.   SECTION 3.7 OF THE LOAN AGREEMENT. Section 3.7 of the Loan Agreement
is hereby amended in its entirety to read as follows:

     "3.7 FINANCIAL CONDITION AND STATEMENTS. All financial statements now or in
     the future delivered to Silicon have been, and will be, prepared in
     conformity with generally accepted accounting principles and now and in the
     future will completely and accurately reflect the financial condition of
     the Borrower, at the times and for the periods therein stated subject to
     normal year-end adjustments. Since the last date covered by any such
     statement, there has been no material adverse change in the financial
     condition or business of the Borrower. The Borrower is now and will
     continue to be solvent. The Borrower will provide Silicon: (i) Within 30
     days after the end of each calendar month in which, as of the end of such
     month, Borrower's Remaining Months Liquidity (as defined in the Schedule
     hereto) is equal to or less than 12 months, a monthly financial statement
     prepared by Borrower and a Compliance Certificate in such form as Silicon
     shall reasonably specify, signed by the Chief Financial Officer of the
     Borrower, certifying that throughout such month the Borrower was in full
     compliance with all of the terms and conditions of this Agreement, and
     setting forth calculations showing compliance with the financial covenants
     set forth on the Schedule and such other information as Silicon shall
     reasonably request (a "Compliance Certificate"); (ii) Within 5 days after
     the earlier of the date the report 10-Q is filed or is required to be filed
     with the Securities and Exchange Commission ("SEC") with respect to
     Borrower, such 10-Q report, a quarterly financial statement prepared by
     Borrower, and a Compliance Certificate for


                                      -2-

<PAGE>   3
SILICON VALLEY BANK                     AMENDMENT TO LOAN AGREEMENT
-----------------------------------------------------------------------

     Such quarter; (iii) within 5 days after the earlier of the date the report
     10-K is filed or is required to be filed with the Securities and Exchange
     Commission with respect to Borrower, such 10-K report, complete annual
     financial statements, certified by Deloitte & Touche or other independent
     certified public accountants acceptable to Silicon, and a Compliance
     Certificate for the quarter then ended; provided, however, with respect to
     the 10-Q and 10-K reports referred to above, if (x) Borrower applies for
     and obtains an extension from the SEC for the delivery of such reports to
     the SEC, (y) Borrower provides Silicon with evidence of the SEC's grant of
     such extension, and (z) such extension is not 30 days beyond the regular
     submission date for such reports, then the required dates for the
     submission of financial information and reports set forth in this Section
     3.7 shall be deemed to be modified to the date of the extension so granted
     by the SEC*.


     *; AND, FINALLY, WITHIN 20 DAYS AFTER THE END OF EACH CALENDAR MONTH IN
     WHICH, AT ANY TIME DURING SUCH MONTH THERE WERE ANY OBLIGATIONS
     OUTSTANDING, (a) A BORROWING BASE CERTIFICATE SIGNED BY THE CHIEF EXECUTIVE
     OFFICER, PRESIDENT, CHIEF FINANCIAL OFFICER OR CONTROLLER OF BORROWER IN
     FORM AND SUBSTANCE ACCEPTABLE TO SILICON, (b) AN ACCOUNTS RECEIVABLE AGING
     FOR SUCH MONTH, AGED BY INVOICE DATE, (c) AN ACCOUNTS PAYABLE AGING FOR
     SUCH MONTH, AGED BY INVOICE DATE, AND (d) OUTSTANDING OR HELD CHECK
     REGISTERS, IF ANY, WITH RESPECT TO SUCH MONTH."


     4.   SECTION 4.5 OF THE LOAN AGREEMENT. Section 4.5 of the Loan Agreement
is hereby amended in its entirety to read as follows:

     "4.5 ACCESS TO COLLATERAL, BOOKS AND RECORDS. At all reasonable times, and
     upon *notice, Silicon, or its agents, shall have the right to inspect the
     Collateral, and the right to audit and copy the Borrower's accounting
     books and records and Borrower's books and records relating to the
     Collateral. Silicon shall take reasonable steps to keep confidential all
     information obtained in any such inspection or audit, but Silicon shall
     have the right to disclose any such information to its auditors, regulatory
     agencies, and attorneys, and pursuant to any subpoena or other legal
     process. The foregoing audits shall be at Silicon's expense, except that
     the Borrower shall reimburse Silicon for its reasonable out of pocket costs
     for semi-annual accounts receivable audits by third parties retained by
     Silicon, and Silicon may debit Borrower's deposit accounts with Silicon for
     the cost of such semi-annual accounts receivable audits (in which event
     Silicon shall send notification thereof to the Borrower). Notwithstanding
     the foregoing, after the occurrence of an Event of Default all audits shall
     be at the Borrower's expense**

     *THREE BUSINESS DAYS'

     **AND MAY BE PERFORMED ON ONE BUSINESS DAY'S NOTICE."


     5.   REFERENCES IN LOAN AGREEMENT: Until such time as the Grant has become
effective, Borrower and Silicon hereby agree that all references to the
security interest or lien of Silicon in the Collateral are deemed not to be in
effect; provided that, upon the effectiveness of the Grant, such provisions and
such references shall immediately be deemed to be in full force and effect,
without any further action or notice to any person by Silicon or Borrower or by
any other person.

     6.   FEE. Borrower shall pay to Silicon a fee the amount of $25,000 in
connection herewith such amount includes the $5,000 fee Borrower has paid in
connection with the letter dated March 15, 2000 from Silicon to Borrower; such
fees shall be in addition to interest and to all amounts payable to Silicon
under the Loan Agreement.




                                     - 3 -
<PAGE>   4
          SILICON VALLEY BANK                        AMENDMENT TO LOAN AGREEMENT


     7.   GENERAL PROVISIONS. This Amendment, the Loan Agreement, any prior
written amendments to the Loan Agreement signed by Silicon and the Borrower,
and the other written documents and agreements between Silicon and the Borrower
set forth in full all of the representations and agreements of the parties with
respect to the subject matter hereof and supersede all prior discussions,
representations, agreements and understandings between the parties with respect
to the subject hereof. Except as herein expressly amended, all of the terms and
provisions of the Loan Agreement, and all other documents and agreements
between Silicon and the Borrower shall continue in full force and effect and the
same are hereby ratified and confirmed. This Amendment shall be controlling in
the event of any conflicts between any prior written agreements and amendments
between Silicon and the Borrower, on the one hand, and this Amendment.

Borrower:                               Silicon:

VITALCOM INC.                           SILICON VALLEY BANK


By: /s/ FRANK T. SAMPLE                 By: /s/ [Signature Illegible]
   ------------------------------          ----------------------------------
    President or Vice President         Title: VP

By: /s/ JOHN ROBERT GRAHAM
   ------------------------------
    Secretary or Ass't Secretary



                                     - 4 -
<PAGE>   5
SILICON VALLEY BANK

                              AMENDED SCHEDULE TO

                          LOAN AND SECURITY AGREEMENT

BORROWER:      VITALCOM INC., A DELAWARE CORPORATION

ADDRESS:       15222 DEL AMO AVENUE
               TUSTIN, CA 92780

DATE:          MARCH 21, 2000

CREDIT LIMIT
(Section 1.1):      An amount not to exceed the lesser of (and subject to the
                    proviso that follows):

                    (1) $5,000,000 at any one time outstanding; or

                    (2) the sum of:

                        (a) Loans (the "Formula Loans") in an amount not to
                            exceed 80% of the Net Amount of Borrower's accounts,
                            which Silicon in its discretion deems eligible for
                            borrowing; plus

                        (b) If the Liquidity Covenant (as defined in section 4.1
                            of this Schedule below) is satisfied, and only
                            during such period that the Liquidity covenant
                            remains satisfied including after taking into
                            account the amount of any and all contemplated
                            Non-Formula Loans, the following Loans will also be
                            made available to the Borrower: Loans (referred to
                            herein as the "Non-Formula Loans") in an aggregate
                            amount not to exceed at any time the sum of
                            $5,000,000 minus the aggregate amount of Formula
                            Loans outstanding from time to time;

                        PROVIDED in no event shall the aggregate amount of Loans
                        outstanding plus the aggregate face amount of all
                        outstanding Letters of Credit exceed $5,000,000.

                        "Net Amount" of an account means the gross amount of the
                        account, minus all applicable sales, use, excise and
                        other similar taxes and minus all discounts, credits and
                        allowances of any nature granted or claimed.

                        Without limiting the fact that the determination of
                        which accounts are eligible for borrowing is a matter of
                        Silicon's discretion, the following will not be deemed
                        eligible for borrowing: accounts outstanding for more
                        than 90 days from the invoice date, accounts subject to
                        any contingencies, accounts owing from any government
                        agency (unless, with


<PAGE>   6
          SILICON VALLEY BANK                        AMENDMENT TO LOAN AGREEMENT
--------------------------------------------------------------------------------

                              respect to United States or any department, agency
                              or instrumentality thereof, there has been
                              compliance, to Silicon's satisfaction, with the
                              United States Assignment of Claims Act), accounts
                              owing from an account debtor outside the United
                              States (unless pre-approved by Silicon in its
                              discretion, or backed by a letter of credit
                              satisfactory to Silicon, or FCIA insured
                              satisfactory to Silicon), accounts owing from one
                              account debtor to the extent they exceed 25%* of
                              the total eligible accounts outstanding, accounts
                              owing from an affiliate of Borrower, and accounts
                              owing from an account debtor to whom Borrower is
                              or may be liable for goods purchased from such
                              account debtor or otherwise. In addition, if more
                              than 50% of the accounts owing from an account
                              debtor are outstanding more than 90 days from the
                              invoice date or are otherwise not eligible
                              accounts, then all accounts owing from that
                              account debtor will be deemed ineligible for
                              borrowing.

                              *provided that in the case of Datascope
                              Instruments and Quinton Instrument Company as
                              account debtors, this percentage figure shall be
                              40%.

LETTERS OF CREDIT             Silicon, in its reasonable discretion, will from
                              time to time during the term of this Agreement
                              issue letters of credit for the account of the
                              Borrower ("Letters of Credit"), in an aggregate
                              amount at any one time outstanding not to exceed
                              $500,000, upon the request of the Borrower,
                              provided that, on the date the Letters of Credit
                              are to be issued, Borrower has available to it
                              Loans in an amount equal to or greater than the
                              face amount of the Letters of Credit to be issued.
                              Prior to the issuance of any Letters of Credit,
                              Borrower shall execute and deliver to Silicon
                              Applications for Letters of Credit and such other
                              documentation as Silicon shall specify (the
                              "Letter of Credit Documentation"). Fees for the
                              Letters of Credit shall be as provided in the
                              Letter of Credit Documentation.

                              The Loans available under this Agreement at any
                              time shall be reduced by the face amount of
                              Letters of Credit from time to time outstanding.

INTEREST RATE (Section 1.2):  A rate equal to the "Prime Rate" in effect from
                              time to time plus .50%. Interest shall be
                              calculated on the basis of a 360-day year for the
                              actual number of days elapsed. "Prime Rate" means
                              the rate announced from time to time by Silicon as
                              its "prime rate;" it is a base rate upon which
                              other rates charged by Silicon are based, and it
                              is not necessarily the best rate available at
                              Silicon. The interest rate applicable to the
                              Obligations shall change on each date there is a
                              change in the Prime Rate.

MATURITY DATE
(Section 5.1):                March __, 2001

PRIOR NAMES OF BORROWER
(Section 3.2):                ACCUCORE, Inc., Pacific Communications, Inc.


                                       2
<PAGE>   7

SILICON VALLEY BANK                SCHEDULE TO LOAN AGREEMENT
--------------------------------------------------------------------------------

TRADE NAMES OF BORROWER
(Section 3.2):                     Accucore

OTHER LOCATIONS AND ADDRESSES
(Section 3.3):                     None

MATERIAL ADVERSE LITIGATION
(Section 3.10):                    None

NEGATIVE COVENANTS-EXCEPTIONS
(Section 4.6):                     Without Silicon's prior written consent,
                                   Borrower may do the following, provided
                                   that, after giving effect thereto, no Event
                                   of Default has occurred and no event has
                                   occurred which, with notice or passage of
                                   time or both, would constitute an Event of
                                   Default, and provided that the following are
                                   done in compliance with all applicable laws,
                                   rules and regulations; (i) repurchase shares
                                   of Borrower's stock, provided that the total
                                   amount paid by Borrower for such stock does
                                   not exceed $500,000 in any fiscal year.

FINANCIAL COVENANTS
  (Section 4.1):                   Borrower shall comply with all of the
                                   following covenants. Compliance shall be
                                   determined as of the end of each required
                                   period for the delivery of a compliance
                                   certificate as set forth in section 3.7 of
                                   the Loan Agreement, except as otherwise
                                   specifically provided below:

LIQUIDITY COVENANT:                Borrower shall maintain the greater of (i)
                                   at least Six (6) months Remaining Months
                                   Liquidity or (ii) cash on hand, cash
                                   equivalents and marketable securities less
                                   restricted cash of at least two multiplied
                                   times the principal amount of the
                                   Non-Formula Loans outstanding (collectively
                                   being referred to herein as the "Liquidity
                                   Covenant"). "Remaining Months Liquidity" is
                                   defined as cash on hand, cash equivalents
                                   and marketable securities less restricted
                                   cash, divided by Cash Burn. "Cash Burn" is
                                   defined as cash (prior period) minus cash
                                   (current period) plus increases in short and
                                   long term borrowings plus increases in
                                   equity (or subordinated debt) on a mean
                                   monthly average basis with respect to the
                                   immediately preceding three month to month
                                   periods.

DEBT TO TANGIBLE
NET WORTH RATIO:                   Borrower shall maintain a ratio of total
                                   liabilities to tangible net worth of not
                                   more than 1.00 to 1.

PROFITABILITY:                     Borrower shall not incur a net loss (after
                                   taxes) for:

                                   (i) the fiscal quarter ending March 31, 2000
                                   in excess of $2,600,000;

                                   (ii) the fiscal quarter ending June 30, 2000
                                   in excess of $2,000,000;

                                   (iii) the fiscal quarter ending September
                                   30, 2000 in excess of $1,000,000; and


                                       3


<PAGE>   8
SILICON VALLEY BANK                                   SCHEDULE TO LOAN AGREEMENT
--------------------------------------------------------------------------------

                    (iv) the fiscal year ending December 31, 2000 in excess of
                    $4,800,000.

                    Thereafter, Borrower shall not incur a loss (after taxes in
                    any fiscal year.

DEFINITIONS:        "Current assets" and "current liabilities" shall have the
                    meaning ascribed thereto in accordance with generally
                    accepted accounting principles.

                    "Tangible net worth" means the excess of total assets over
                    total liabilities, determined in accordance with generally
                    accepted accounting principles, excluding however all assets
                    which would be classified as intangible assets under
                    generally accepted accounting principles, including without
                    limitation goodwill, licenses, patents, trademarks, trade
                    names, copyrights and franchises.

SUBORDINATED DEBT:  "Liabilities", for purposes of the foregoing covenants, do
                    not include indebtedness which is subordinated to the
                    indebtedness to Silicon under a subordination agreement in
                    form specified by Silicon or by language in the instrument
                    evidencing the indebtedness which is acceptable to Silicon."

                    "Net loss", for purposes of the foregoing covenants, shall
                    not include no-cash charges incurred in connection with any
                    acquisitions by Borrower of another corporation and up to
                    $250,000 in write-offs relating to goodwill.

OTHER COVENANTS
(Section 4.1):      Borrower shall at all times comply with all of the following
                    additional covenants:

                    1. BANKING RELATIONSHIP; MUTUAL FUND ACCOUNT. Borrower shall
                    at all times maintain its primary operating banking
                    relationship with Silicon. Further, Borrower shall maintain
                    with Silicon or with a Silicon-designated institution a
                    money market mutual fund account having a minimum balance of
                    $2,500,000 at all times.

                    2. INDEBTEDNESS. Without limiting any of the foregoing terms
                    or provisions of this Agreement, Borrower shall not in the
                    future incur indebtedness for borrowed money, except for (i)
                    indebtedness to Silicon, (ii) indebtedness incurred in the
                    future for the purchase price of or lease of equipment and
                    (iii) trade debt incurred in the ordinary course of
                    business.

                    3. UCC-1 FINANCING STATEMENTS. Borrower is concurrently
                    herewith delivering to Silicon UCC-1 financing statements,
                    and it is understood and agreed that such financing
                    statements shall not be considered effective unless and
                    until the Grant becomes effective. At such time Silicon
                    shall be permitted to file such financing statements
                    immediately.

                    4. COLLATERAL EXAMINATION. Prior to the making of the
                    initial Formula Loan hereunder, Silicon shall (A) conduct a
                    collateral examination and audit under section 4.5 of the
                    Loan


<PAGE>   9

SILICON VALLEY BANK                                  SCHEDULE TO LOAN AGREEMENT
-------------------------------------------------------------------------------

                     Agreement and (B) determine that the results thereof are
                     acceptable to Silicon for loan purposes in its discretion.

                     BORROWER:

                              VITALCOM INC.


                              By /s/ FRANK T. SAMPLE
                                ----------------------------------------
                                President or Vice President

                              By /s/ JOHN ROBERT GRAHAM
                                ----------------------------------------
                                Secretary or Ass't Secretary

                     SILICON:

                              SILICON VALLEY BANK


                              By [SIGNATURE ILLEGIBLE]
                                ----------------------------------------
                              Title VP
                                   -------------------------------------


<PAGE>   10
SILICON VALLEY BANK
CERTIFIED RESOLUTION

BORROWER:      VITALCOM INC., A CORPORATION
               ORGANIZED UNDER THE LAWS OF THE
               STATE OF DELAWARE

ADDRESS:       15222 DEL AMO AVENUE
               TUSTIN, CA 92780

DATE:          MARCH __, 2000

     I, the undersigned, Secretary or Assistant Secretary of the above-named
borrower, a corporation organized under the laws of the state set forth above,
do hereby certify that the following is a full, true and correct copy of
resolutions duly and regularly adopted by the Board of Directors of said
corporation as required by law, and by the by-laws of said corporation, and
that said resolutions are still in full force and effect and have not been in
any way modified, repealed, rescinded, amended or revoked.

     RESOLVED, that this corporation borrow from Silicon Valley Bank
     ("Silicon"), from time to time, such sum or sums of money as, in the
     judgment of the officer or officers hereinafter authorized hereby, this
     corporation may require.

     RESOLVED FURTHER, that any of the Chairman, President, Chief Executive
     Officer, Chief Financial Officer or Secretary of this corporation be, and
     he or she is hereby authorized, directed and empowered, in the name of
     this corporation, to execute and deliver to Silicon, and Silicon is
     requested to accept, the loan agreements, security agreements, notes,
     financing statements, and other documents and instruments providing for
     such loans and evidencing and/or securing such loans, with interest
     thereon, and said authorized officers are authorized from time to time to
     execute renewals, extensions and/or amendments of said loan agreements,
     security agreements, and other documents and instruments.

     RESOLVED FURTHER, that said authorized officers be and they are hereby
     authorized, directed and empowered, as security for any and all
     indebtedness of this corporation to Silicon, whether arising pursuant to
     this resolution or otherwise, to grant, transfer, pledge, mortgage,
     assign, or otherwise hypothecate to Silicon, or deed in trust for its
     benefit, any property of any and every kind, belonging to this
     corporation, including, but not limited to, any and all real property,
     accounts, inventory, equipment, general intangibles, instruments,
     documents, chattel paper, notes, money, deposit accounts, furniture,
     fixtures, goods, and other property of every kind, and to execute and
     deliver to Silicon any and all grants, transfers, trust receipts, loan or
     credit agreements, pledge agreements, mortgages, deeds of trust, financing
     statements, security agreements and other hypothecation agreements, which
     said instruments and the note or notes and other instruments referred to
     in the proceeding paragraph may contain such provisions, covenants,
     recitals and agreements as Silicon may require and said authorized
     officers may approve, and the execution thereof by said authorized
     officers shall be conclusive evidence of such approval.




                                      -1-
<PAGE>   11
        The undersigned further certifies that the following persons are the
duly elected and acting officers of the corporation named above as borrower and
that the following are their actual signatures:

<TABLE>
<CAPTION>
       NAME                                OFFICE(S)                              ACTUAL SIGNATURES
       ----                                ---------                              -----------------
<S>                           <C>                                             <C>
Frank T. Sample               Chairman, President, CEO & Acting CFO           /s/ FRANK T. SAMPLE
----------------------        -------------------------------------           -------------------------

John Robert Graham             V.P. Corporate Alliances, Secretary            /s/ JOHN ROBERT GRAHAM
----------------------        -------------------------------------           -------------------------

----------------------        -------------------------------------           -------------------------

----------------------        -------------------------------------           -------------------------
</TABLE>

        IN WITNESS WHEREOF, I have hereunto set my hand as such Secretary or
Assistant Secretary on the date set forth above.


                                        /s/ JOHN ROBERT GRAHAM
                                        ----------------------------------------
                                        Secretary or Assistant Secretary


<PAGE>   12
                           NEGATIVE PLEDGE AGREEMENT

     This Negative Pledge Agreement is made as of March 21, 2000 by and between
Vitalcom Inc. ("Borrower") and Silicon Valley Bank ("Silicon").

     In connection with, among other documents, the Loan and Security Agreement
between Borrower and Silicon dated February 26, 1993 (as amended, the "Loan
Agreement"; the Loan Agreement and all related instruments, documents and
agreements may be collectively referred to herein as the "Loan Documents"), and
without limitation of the terms and provisions of the Loan Documents, Borrower
agrees it will not sell, transfer, assign, mortgage, pledge, lease, grant a
security interest in, or encumber any of Borrower's Intellectual Property (as
defined below), provided that the foregoing shall not restrict licenses of
Borrower's Intellectual Property in the ordinary course of business consistent
with past business practices.

     As used herein the term "Intellectual Property" means (a) any and all
copyright rights, copyright applications, copyright registrations and like
protections; (b) any trademark and servicemark rights, whether registered or
not, applications to register and registrations of the same and like
protections; (c) all patents, patent applications and like protections; and (d)
all mask work or similar rights available for the protection of semiconductor
chips.

     It shall be an event of default under the Loan Documents between Borrower
and Silicon if there is a breach of any term of this Negative Pledge Agreement.

BORROWER:

VITALCOM INC.

By: /s/ FRANK T. SAMPLE
    --------------------------

Name: Frank T. Sample
      ------------------------

Title: CEO
       -----------------------


SILICON:

SILICON VALLEY BANK

By: /s/ GARY REAGAN
    --------------------------

Name: Gary Reagan
      ------------------------

Title: VP
       -----------------------