<PAGE>   1
                             [VITALCOM LETTERHEAD]
                                                                    EXHIBIT 10.1



                                                                   April 2, 1998



VIA FAX (213) 553-9740
(Follow up with hard copy in mail)


ChaseMellon Shareholder Services
Attn: Mary Ann McElroy
400 South Hope St., 4th Floor
Los Angeles, CA 90071


        Re:    Issuance of VitalCom Inc. Common Stock, Control Number: 11


Dear Mary Ann:

        You are hereby authorized and directed to issue 103,000 shares of Common
Stock of VitalCom Inc. to David L. Schlotterbeck. The shares are being issued to
cover the purchase of shares directly from VitalCom Inc. The stock certificate
should bear the 144 legend and upon issuance sent to my attention at the address
below. The effective date of purchase, pursuant to the Common Stock Purchase
Agreement, is March 26, 1998.

        Should you have any questions, please do not hesitate to contact me at
(714) 247-4082




                                        Sincerely,

                                        /s/ SHELLEY B. THUNEN

                                        Shelley B. Thunen
                                        Chief Financial Officer


<PAGE>   2

                                  VITALCOM INC.

                         COMMON STOCK PURCHASE AGREEMENT


        THIS AGREEMENT is made as of March 26, 1998, between VitalCom Inc., a
Delaware corporation (the "Company"), and David L. Schlotterbeck ("Purchaser").

        WHEREAS in order to provide Purchaser an opportunity to acquire an
equity interest in the Company as Mr. Schlotterbeck provides transition support
to the Company after his resignation from the Company's Board of Directors
effective November 1997, the Company is willing to sell to Purchaser and
Purchaser desires to purchase shares of Common Stock according to the terms and
conditions hereof;

        THEREFORE, the parties agree as follows:

1.      PURCHASE AND SALE OF STOCK. Subject to the terms and conditions of this
Agreement, the Company hereby agrees to sell to Purchaser and Purchaser agrees
to purchase from the Company 103,000 shares of the Company's Common Stock (the
"Stock") at a price of $4.4375 per share, for an aggregate purchase price of
$457,062.50. Payment of the aggregate purchase price shall be by a certified
check in the amount of $10.50 and a non-recourse promissory note in the amount
of $457,052.00 (the "Note") in the form attached hereto as Exhibit A. The Note
shall bear interest at a rate no less than the Company's borrowing rate at
"Prime" at time of purchase (8.50% per annum), and shall be secured by a pledge
of the Stock purchased by the Note pursuant to a Security Agreement in the form
attached hereto as Exhibit B (the "Security Agreement") accompanied by executed
stock powers in the form attached hereto as Exhibit C. Upon such payment, the
Company shall issue a duly executed certificate evidencing the Stock in the name
of Purchaser, said certificate to be held by the Secretary of the Company
subject to the terms and conditions of the Security Agreement. 

2.      RESTRICTIVE LEGENDS AND STOP-TRANSFER ORDERS.

        (a) LEGENDS. The share certificate evidencing the Stock issued hereunder
shall be endorsed with the following legends (in addition to any legends
required under applicable state securities laws):

        THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE BEEN ACQUIRED FOR
        INVESTMENT AND NOT WITH A VIEW TO, OR IN CONNECTION WITH, THE SALE OR
        DISTRIBUTION THEREOF. NO SUCH SALE OR DISPOSITION MAY BE EFFECTED
        WITHOUT AN EFFECTIVE REGISTRATION STATEMENT RELATED THERETO OR AN
        OPINION OF COUNSEL SATISFACTORY TO THE COMPANY THAT SUCH REGISTRATION IS
        NOT REQUIRED UNDER THE SECURITIES ACT OF 1933.


<PAGE>   3



        THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO THE TERMS AND
        CONDITIONS OF A COMMON STOCK PURCHASE AGREEMENT, DATED AS OF MARCH 26,
        1998 BETWEEN THE COMPANY AND PURCHASER. COPIES OF SUCH AGREEMENT MAY BE
        OBTAINED AT NO COST BY WRITTEN REQUEST MADE BY THE HOLDER OF RECORD OF
        THIS CERTIFICATE TO THE COMPANY.

        (B) STOP-TRANSFER NOTICES. Purchaser agrees that, in order to ensure
compliance with the restrictions referred to herein, the Company may issue
appropriate "stop transfer" instructions to its transfer agent, if any, and
that, if the Company transfers its own securities, it may make appropriate
notations to the same effect in its own records.

3.      PURCHASER'S REPRESENTATIONS AND COVENANTS. In connection with the
purchase of the Stock, Purchaser hereby represents and warrants to the Company
as follows:

        (a) INVESTMENT INTENT: CAPACITY TO PROTECT INTERESTS. Purchaser is
purchasing the Stock solely for Purchaser's own account for investment and not
with a view to or for sale in connection with any distribution of the Stock or
any portion thereof and not with any present intention of selling, offering to
sell or otherwise disposing of or distributing the Stock or any portion thereof.
Purchaser also represents that the entire legal and beneficial interest of the
Stock is being purchased, and will be held, for Purchaser's account only, and
neither in whole or in part for any other person. Purchaser either (i) has a
pre-existing business or personal relationship with the Company or at least one
of its officers, directors or controlling persons, or (ii) by reason of
Purchaser's business or financial experience (or the business or financial
experience of Purchaser's professional advisors who are unaffiliated with and
who are not compensated by the Company or any affiliate or selling agent of the
Company, directly or indirectly), can be reasonably assumed to have the capacity
to evaluate the merits and risks of an investment in the Company and to protect
Purchaser's own interests in connection with this transaction.

        (b) RESIDENCE. Purchaser's principal residence is within the State of
California and is located at the address indicated beneath Purchaser's signature
below.

        (c) INFORMATION CONCERNING COMPANY. Purchaser has discussed the Company
and its plans, operations and financial condition with the Company's officers
and has received all such information as Purchaser has deemed necessary and
appropriate to enable Purchaser to evaluate the financial risk inherent in
making an investment in the Stock. Purchaser has received satisfactory and
complete information concerning the business and financial condition of the
Company in response to all inquiries in respect thereof.

        (d) ECONOMIC RISK. Purchaser realizes that the purchase of the Stock
involves a high degree of risk. Purchaser is able, without impairing Purchaser's
financial condition, to hold the Stock for an indefinite period of time and to
suffer a complete loss on Purchaser's investment.


<PAGE>   4

        (e) RESTRICTED SECURITIES. PURCHASER UNDERSTANDS AND ACKNOWLEDGES THAT:

            (i) The Stock has not been registered under the Securities Act of
1933, as amended, in reliance upon a specific exemption therefrom, which
exemption depends upon, among other things, the bona fide nature of Purchaser's
investment intent as expressed herein. In this connection, Purchaser understands
that, in the view of the Securities and Exchange Commission ("SEC"), the
statutory basis for such exemption may be unavailable if Purchaser's
representation was predicated solely upon a present intention to hold the Stock
for the minimum capital gains period specified under tax statutes, for a
deferred sale, for or until an increase or decrease in the market price of the
Stock, or for a period of one year or any other fixed period in the future.

            (ii) The Stock must be held indefinitely unless it is subsequently
registered under the Securities Act or unless an exemption from such
registration is otherwise available. Purchaser further acknowledges and
understands that, except as contemplated by Section 4 of this Agreement, the
Company is under no obligation to register the Stock. In addition, Purchaser
understands that the certificate evidencing the Stock will be imprinted with a
legend which prohibits the transfer of the Stock unless it is registered or such
registration is not required in the opinion of counsel satisfactory to the
Company.

        (f) DISPOSITION UNDER RULE 144. Purchaser understands that:

            (i) The shares of Stock are restricted securities within the meaning
of Rule 144 promulgated under the Securities Act; that the exemption from
registration under Rule 144 will not be available in any event for at least one
(1) year from the date of purchase and payment of the Stock, and then will be
available only if (i) a public trading market then exists for the Common Stock
of the Company, (ii) adequate information concerning the Company is then
available to the public, and (iii) other terms and conditions of Rule 144 are
complied with; and that any sale of the Stock may be made only in limited
amounts in accordance with such terms and conditions of Rule 144;

            (ii) That at the time Purchaser wishes to sell the Stock there may
be no public market upon which to make such a sale; that, even if such a public
market then exists, the Company may not be satisfying the current public
information requirements of Rule 144; and that, in such event, Purchaser would
be precluded from selling the Stock under Rule 144 even if the two (2) year
minimum holding period had been satisfied; and

            (iii) In the event all of the requirements of Rule 144 are not
satisfied, registration under the Securities Act or compliance with Regulation A
or another registration exemption will be required; that, notwithstanding the
fact that Rule 144 is not exclusive, the Staff of the SEC has expressed its
opinion that persons proposing to sell private placement securities other than
in a registered offering or pursuant to Rule 144 will have a substantial burden
of proof in establishing that an exemption from registration is available for
such offers.


<PAGE>   5

            (iv) "SELLING EXPENSES" shall mean all underwriting discounts and
selling commissions applicable to the sale of Registrable Securities and all
fees and disbursements of counsel for the Purchaser other than fees and expenses
of one counsel for the Purchaser in an amount not to exceed $15,000.

        (b) REQUESTED REGISTRATION. At any time, but only once, and so long as
Purchaser is not in default under the Note and the Security Agreement, Purchaser
shall have the right to request in writing that the Company effect a
registration with respect to all of the Registrable Securities. If the Company
shall receive from the Purchaser such written request, the Company will use its
reasonable efforts to effect such registration (including, without limitation,
the execution of an undertaking to file post-effective amendments, appropriate
qualification under applicable blue sky or other state securities laws and
appropriate compliance with applicable regulations issued under the Securities
Act) within a period of 180 days of such request; provided that the Company
shall not be obligated to effect, or take any action to effect, any such
registration pursuant to this Section 4(b):

            (i) In any particular jurisdiction in which the Company would be
required to execute a general consent to service of process in effecting such
registration, qualification or compliance, unless the Company is already subject
to service in such jurisdiction and except as may be required by the Securities
Act or applicable rules or regulations thereunder;

            (ii) After the Company has effected a registration pursuant to this
Section 4(b) and such registration has been declared or ordered effective and
the sales of such Registrable Securities shall have closed;

            (iii) During the period starting with the date sixty (60) days prior
to the Company's good faith estimate of the date of filing of, and ending on a
date one hundred eighty (180) days after the effective date of, a
Company-initiated registration;

            (iv) If (A) in the good faith judgment of the Board of Directors of
the Company, such registration would be seriously detrimental to the Company,
and the Board of Directors of the Company concludes, as a result, that it is
essential to defer the filing of such registration statement at such time, and
(B) the Company shall furnish to the Purchaser a certificate signed by the
Chairman of the Board of the Company stating that in the good faith judgment of
the Board of Directors of the Company, it would be seriously detrimental to the
Company for such registration statement to be filed in the near future and that
it is, therefore, essential to defer the filing of such registration statement,
then the Company shall have the right to defer such filing for a period of not
more than one hundred eighty (180) days after receipt for the request of the
Purchaser; or

            (v) If after the receipt by the Company of Purchaser's request under
this Section 4(b) Purchaser shall become in default under the Note and the
Security Agreement,


<PAGE>   6

in which case, so long as Purchaser fails to cure such default, the Company
shall have no obligation to effect such registration.

            The registration statement filed pursuant to the request of the
Purchaser may include other securities of the Company which are held by officers
or directors of the Company, or which are held by persons who, by virtue of
agreements with the Company, are entitled to include their securities in any
such registration.

        (c) EXPENSES OF REGISTRATION. All Registration Expenses incurred in
connection with any registration, qualification or compliance pursuant to this
Section 4 shall be borne by the Company, and all Selling Expenses shall be borne
by Purchaser; provided, however, that the Company shall not be required to pay
any Registration Expenses if, as a result of the withdrawal of a request for
registration by Purchaser, as applicable, the registration statement does not
become effective, in which case Purchaser shall bear such Registration Expenses.

        (d) REGISTRATION PROCEDURES. In the case of a registration effected by
the Company pursuant to this Section 4, the Company will:

            (i) keep such registration effective for a period of ninety (90)
days, until Purchaser has completed the distribution described in the
registration statement relating thereto or until Purchaser becomes in default
under the Note and the Security Agreement, which default remains uncured for a
period of thirty (30) days, whichever first occurs; provided, however, that such
90-day period shall be extended for a period of time equal to the period during
which Purchaser refrains from selling any securities included in such
registration in accordance with provisions in Section 4(g) hereof; and

            (ii) furnish such number of prospectuses and other documents
incident thereto as each the Purchaser may reasonably request.

        (e) INDEMNIFICATION.

            (i) The Company will indemnify Purchaser with respect to any
registration which has been effected pursuant to this Section 4, and each
underwriter, if any, and each person who controls any underwriter, against all
claims, losses, damages and liabilities (or actions in respect thereof) arising
out of or based on any untrue statement (or alleged untrue statement) of a
material fact contained in any prospectus, offering circular or other document
(including any related registration statement, notification or the like)
incident to any such registration, qualification or compliance, or based on any
omission (or alleged omission) to state therein a material fact required to be
stated therein or necessary to make the statements therein not misleading, and
will reimburse Purchaser, each such underwriter and each person who controls any
such underwriter, for any legal and any other expenses reasonably incurred in
connection with investigating and defending any such claim, loss, damage,
liability or action; provided, however, that the Company will not be liable to
Purchaser in any such case to the extent that any such claim, loss, damage,
liability or expense




<PAGE>   7

arises out of or is based on any untrue statement or omission based upon written
information furnished to the Company by Purchaser and stated to be specifically
for use therein; provided, further that the Company will not be liable to the
underwriter in any such case to the extent that any such claims, loss, damage,
liability or expense arises out of or is based on any untrue statement or
omission based upon written information furnished to the Company by the
underwriter and stated to be specifically for use therein.

            (ii) Purchaser will, if securities held by it are included in the
securities as to which such registration, qualification or compliance is being
effected, indemnify the Company, each of its directors and officers and each
underwriter, if any, of the Company's securities covered by such a registration
statement, each person who controls the Company or such underwriter, against all
claims, losses, damages and liabilities (or actions in respect thereof) arising
out of or based on any untrue statement (or alleged untrue statement) of a
material fact contained in any such registration statement, prospectus, offering
circular or other document made by Purchaser or any omission (or alleged
omission) to state therein a material fact required to be stated therein or
necessary to make the statements by Purchaser therein not misleading, and will
reimburse the Company and directors, officers, partners, persons, underwriters
or control persons for any legal or any other expenses reasonably incurred in
connection with investigating or defending any such claim, loss, damage,
liability or action, in each case to the extent, but only to the extent, that
such untrue statement (or alleged untrue statement) or omission (or alleged
omission) is made in such registration statement, prospectus, offering
curricular or other document in reliance upon and in conformity with written
information furnished to the Company by Purchaser and stated to be specifically
for use therein; provided, however, that the obligations of Purchaser hereunder
shall be limited to an amount equal to the net proceeds to Purchaser of
securities sold as contemplated herein.

            (iii) Each party entitled to indemnification under this Section 4(e)
(the "Indemnified Party") shall give notice to the party required to provide
indemnification (the "Indemnifying Party") promptly after such Indemnified Party
has actual knowledge of any claim as to which indemnity may be sought, and shall
permit the Indemnifying Party to assume the defense of any such claim or
litigation resulting therefrom; provided, however, that counsel for the
Indemnifying Party, who shall conduct the defense of such claim or any
litigation resulting therefrom, shall be approved by the Indemnified Party
(whose approval shall not unreasonably be withheld) and the Indemnified Party
may participate in such defense at such party's expense (unless the Indemnified
Party shall have reasonably concluded that there may be a conflict of interest
between the Indemnifying Party and the Indemnified Party in such action, in
which case the fees and expenses of counsel shall be at the expense of the
Indemnified Party); and provided further that the failure of any Indemnified
Party to give notice as provided herein shall not relieve the Indemnifying Party
of its obligations under this Section 4 unless the Indemnifying Party is
materially prejudiced thereby. No Indemnifying Party, in the defense of any such
claim or litigation shall, except with the consent of each Indemnified Party,
consent to entry of any judgment or enter into any settlement which does not
include as an unconditional term thereof the giving by the claimant or plaintiff
to such Indemnified Party of a release from all liability in respect to such
claim or




<PAGE>   8

litigation. Each Indemnified Party shall furnish such information regarding
itself or the claim in question as an Indemnifying Party may reasonably request
in writing and as shall be reasonably required in connection with the defense of
such claim and litigation resulting therefrom.

            (iv) If the indemnification provided for in this Section 4(e) is
held by a court of competent jurisdiction to be unavailable to an Indemnified
Party with respect to any loss, liability, claim, damage or expenses referred to
herein, then the Indemnifying Party, in lieu of indemnifying such Indemnified
Party hereunder, shall contribute to the amount paid or payable by such
Indemnified Party as a result of such loss, liability, claim, damage or expenses
in such proportion as is appropriate to reflect the relative fault of the
Indemnifying Party on the one hand and of the Indemnified party on the other in
connection with the statements or omissions which resulted in such loss,
liability, claim, damage or expense, as well as any other relevant equitable
considerations. The relative fault of the Indemnifying Party and of the
Indemnified Party shall be determined by reference to, among other things,
whether the untrue (or alleged untrue) statement of a material fact or the
omission (or alleged omission) to state a material fact relates to information
supplied by the Indemnifying Party or by the Indemnified Party and the parties'
relative intent, knowledge, access to information and opportunity to correct or
prevent such statement or omission.

            (v) Notwithstanding the foregoing, to the extent that the provisions
on indemnification and contribution contained in the underwriting agreement
entered into in connection with any underwritten public offering contemplated by
this Agreement are in conflict with the foregoing provisions, the provisions in
such underwriting agreement shall be controlling.

            (vi) The foregoing indemnity agreement of the Company and Purchaser
is subject to the condition that, insofar as they relate to any loss, claim,
liability or damage made in a preliminary prospectus but eliminated or remedied
in the amended prospectus on file with the Securities and Exchange Commission
(the "Commission") at the time the registration statement in question becomes
effective or the amended prospectus filed with the Commission pursuant to
Commission Rule 424(b) (the "Final Prospectus"), such indemnity agreement shall
not inure to the benefit of any underwriter if a copy of the Final Prospectus
was furnished to the underwriter and was not furnished to the person asserting
the loss, liability, claim or damage at or prior to the time such action is
required by the Securities Act.

        (f) INFORMATION BY PURCHASER. Purchaser shall furnish to the Company
such information regarding Purchaser and the distribution proposed by Purchaser
as the Company may reasonably request in writing and as shall be reasonably
required in connection with any registration, qualification or compliance
referred to in this Section 4.

        (g) "MARKET STAND-OFF" AGREEMENT. Purchaser agrees, if requested by the
Company or an underwriter of Common Stock (or other securities) of the Company,
not to sell or otherwise transfer or dispose of, either directly or indirectly,
any Common Stock (or other



<PAGE>   9

securities) of the Company held by such holder during the 90-day period
following the effective date of a registration statement of the Company filed
under the Securities Act.

            If requested by the underwriters, Purchaser shall execute a separate
agreement to the foregoing effect. The Company may impose stop-transfer
instructions with respect to the shares (or securities) subject to the foregoing
restriction until the end of said 90-day period. The provisions of this Section
4(g) shall be binding upon any transferee who acquires Registrable Securities,
whether or not such transferee is entitled to the registration rights provided
hereunder.

        (h) TERMINATION. The registration rights set forth in this Section 4
shall not be available to Purchaser if, in the opinion of counsel to the
Company, all of the Registrable Securities then owned by such Purchaser could be
sold in any 90-day period pursuant to Rule 144 under the Securities Act (without
giving effect to the provisions of Rule 144(k) or pursuant to any similar or
successor rule or exemption from registration).

5.      GOVERNING LAW. This Agreement shall be governed and construed by the
laws of the State of California as applied to agreements made and performed in
California by residents of the State of California.

6.      MISCELLANEOUS.

        (a) FURTHER ASSURANCES. The parties agree to execute such further
instruments and to take such further action as may reasonably be necessary to
carry out the intent of this Agreement.

        (b) NOTICES. Any notice required or permitted hereunder shall be given
in writing and shall be deemed effectively given upon personal delivery
(including by express courier) or upon deposit in the United States Post Office,
by First Class mail with postage and fees prepaid, addressed to Purchaser at his
address shown on the Company's employment records and to the Company at the
address of its principal corporate offices (attention: Secretary) or at such
other address as such party may designate by ten (10) days' advance written
notice to the other party.

        (c) ASSIGNMENT. The Company may assign its rights and delegate its
duties under this Agreement. This Agreement shall inure to the benefit of the
successors and assigns of the Company and, subject to the restrictions on
transfer herein set forth, be binding upon Purchaser, his heirs, executors,
administrators, successors and assigns. The rights of Purchaser under this
Agreement may be assigned only with the prior written consent of the Company.

        (d) WAIVER. Either party's failure to enforce any provision or
provisions of this Agreement shall not in any way be construed as a waiver of
any such provision or provisions, nor prevent that party thereafter from
enforcing each and every other provision of this Agreement. The rights granted
both parties herein are cumulative and shall




<PAGE>   10

not constitute a waiver of either party's right to assert all other legal
remedies available to it under the circumstances.

        (e) ADVICE OF COUNSEL. Purchaser has reviewed this Agreement in its
entirety, has had an opportunity to obtain the advice of counsel prior to
executing this Agreement and fully understands all provisions hereof.

        (f) COUNTERPARTS. This Agreement may be executed in any number of
counterparts, each of which shall be an original and all of which together shall
constitute one instrument.

        (g) ENTIRE AGREEMENT. This Agreement together with the Security
Agreement and the Note represent the entire agreement between the parties with
respect to the purchase of Common Stock by Purchaser, may be modified or amended
only in writing signed by both parties, and satisfies all of the Company's
obligations to Purchaser with regard to the issuance or sale of securities.


<PAGE>   11


        IN WITNESS WHEREOF, the parties hereto have duly executed this Agreement
as of the day and year first above written.




VITALCOM INC.                           DAVID L. SCHLOTTERBECK
a  Delaware corporation


By: /s/ DAVID L. SCHLOTTERBECK          Signature:  /s/ DAVID L. SCHLOTTERBECK
    ---------------------------                    ---------------------------

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



<PAGE>   12

                                    Exhibit A

                          NON-RECOURSE PROMISSORY NOTE



$457,052.00                                                   Tustin, California

                                                              March 26, 1998


        FOR VALUE RECEIVED, the undersigned, David L. Schlotterbeck, promises to
pay to VitalCom Inc., a Delaware corporation (the "Company"), or order, the
principal sum of Four Hundred Fifty Seven Thousand Fifty Two Dollars and No
Cents ($457,052.00), together with interest on the outstanding principal amount
from the date hereof at the rate of 8.50% per annum. The principal amount hereof
and all accrued and unpaid interest on the outstanding principal amount shall be
due and payable to the holder hereof at 15222 Del Amo Avenue, Tustin, California
92780, or such other place as the holder hereof may designate.

        The principal amount, to the extent not sooner paid, shall be due and
payable on August 24, 1998. All accrued and unpaid interest shall be due and
payable on the first day of each fiscal quarter of the Company commencing on
July 1, 1998. Should the undersigned fail to make full payment of principal or
interest for a period of 30 days or more after the due date thereof, the whole
unpaid balance on this Note of principal and interest shall become immediately
due at the option of the holder of this Note. Payments of principal and interest
shall be made in lawful money of the United States of America.

        The undersigned may at any time prepay all or any portion of the
principal or interest owing hereunder.

        This Note is subject to the terms of the Common Stock Purchase
Agreement, dated as of March 26, 1998. This Note is without recourse to the
undersigned, provided that this Note is secured by a pledge of the Company's
Common Stock under the terms of a Security Agreement of even date herewith (a
copy of which is on file with the Secretary of the Company) and is subject to
all the provisions thereof.

        The undersigned hereby waives presentment, protest, demand for payment,
notice of dishonor and all other notices or demands in connection with the
delivery, acceptance, performance, default or endorsement of this Note.

        In the event the Common Stock Purchase Agreement dated March 26, 1998
between the undersigned and the Company shall be terminated for any reason, this
Note shall, at the option of the Company, be accelerated, and the whole unpaid
balance on this Note of principal and accrued interest shall be immediately due
and payable.




<PAGE>   13

        The reasonable costs and attorneys' fees of the holder incurred in the
collection of this Note shall be paid by the undersigned. This Note has been
made and delivered in the State of California and shall be governed and
construed in accordance with the laws of the State of
California.




                                        /s/ DAVID L. SCHLOTTERBECK
                                        ---------------------------------------
                                        David L. Schlotterbeck


<PAGE>   14


                                CONSENT OF SPOUSE


I, GENELL A. SCHLOTTERBECK spouse of David L. Schlotterbeck, have read and
approve the foregoing Agreement. In consideration of the granting to my spouse
of the right to purchase shares of VitalCom Inc., as set forth in the Agreement,
I hereby appoint my spouse as my attorney-in-fact in respect to the exercise of
any rights under the Agreement and agree to be bound by the provisions of the
Agreement insofar as I may have any rights in the Agreement or in any shares
issued pursuant thereto under the community property laws of the State of
California or similar laws relating to marital property in effect in the state
of our residence as of the date of the signing of the Agreement.



Dated:    4-1-98
       --------------------

                                         /s/ GENELLA A. SCHLOTTERBECK
                                         --------------------------------------
                                         (Signature of Spouse)


<PAGE>   15

                                    Exhibit B

                               SECURITY AGREEMENT


        This Security Agreement is made as of March 26, 1998 between VitalCom
Inc., a Delaware corporation ("Pledgee"), and David L. Schlotterbeck
("Pledgor").


                                    Recitals

        Pursuant to Pledgor's election to purchase Stock under the Stock
Purchase Agreement dated March 26, 1998 (the "Agreement") and Pledgor's election
to pay for such shares with a promissory note (the "Note"), Pledgor has
purchased 103,000 shares of Pledgee's Common Stock (the "Stock") at a price of
$4.4375 per share, for a total purchase price of $457,062.50. The Note and the
obligations thereunder are as set forth in Exhibit A to the Agreement.

        NOW, THEREFORE, it is agreed as follows:

        1. Creation and Description of Security Interest. In consideration of
the transfer of the Stock to Pledgor under the Agreement, Pledgor, pursuant to
the California Commercial Code, hereby pledges all of such Stock (herein
sometimes referred to as the "Collateral") represented by certificate number
_________, duly endorsed in blank or with executed stock powers, and herewith
delivers said certificate to the Secretary of Pledgee ("Pledgeholder"), who
shall hold said certificate subject to the terms and conditions of this Security
Agreement.

        The pledged stock (together with an executed blank stock assignment for
use in transferring all or a portion of the Stock to Pledgee if, as and when
required pursuant to this Security Agreement) shall be held by the Pledgeholder
as security for the repayment of the Note, and any extensions or renewals
thereof, to be executed by Pledgor pursuant to the terms of the Agreement, and
the Pledgeholder shall not encumber or dispose of such Stock except in
accordance with the provisions of this Security Agreement.

        2. Pledgor's Representations and Covenants. To induce Pledgee to enter
into this Security Agreement, Pledgor represents and covenants to Pledgee, its
successors and assigns, as follows:

           a. Payment of Indebtedness. Pledgor will pay the principal sum of the
Note secured hereby, together with interest thereon, at the time and in the
manner provided in the Note.

           b. Encumbrances. The Stock is free of all other encumbrances,
defenses and liens, and Pledgor will not further encumber the Stock without the
prior written consent of Pledgee.


<PAGE>   16

           c. Margin Regulations. In the event that Pledgee's Common Stock is
now or later becomes margin-listed by the Federal Reserve Board and Pledgee is
classified as a "lender" within the meaning of the regulations under Part 207 of
Title 12 of the Code of Federal Regulations ("Regulation G"), Pledgor agrees to
cooperate with Pledgee in making any amendments to the Note or providing any
additional collateral as may be necessary to comply with such regulations.

        3. Voting Rights. During the term of this pledge and so long as all
payments of principal and interest are made as they become due under the terms
of the Note, Pledgor shall have the right to vote all of the Stock pledged
hereunder.

        4. Stock Adjustments. In the event that during the term of the pledge
any stock dividend, reclassification, readjustment or other changes are declared
or made in the capital structure of Pledgee, all new, substituted and additional
shares or other securities issued by reason of any such change shall be
delivered to and held by the Pledgee under the terms of this Security Agreement
in the same manner as the Stock originally pledged hereunder. In the event of
substitution of such securities, Pledgor, Pledgee and Pledgeholder shall
cooperate and execute such documents as are reasonable so as to provide for the
substitution of such Collateral and, upon such substitution, references to
"Stock" in this Security Agreement shall include the substituted shares of
capital stock of Pledgor as a result thereof.

        5. Options and Rights. In the event that, during the term of this
pledge, subscription Options or other rights or options shall be issued in
connection with the pledged Stock, such rights, Options and options shall be the
property of Pledgor and, if exercised by Pledgor, all new stock or other
securities so acquired by Pledgor as it relates to the pledged Stock then held
by Pledgeholder shall be immediately delivered to Pledgeholder, to be held under
the terms of this Security Agreement in the same manner as the Stock pledged.

        6. Default. Pledgor shall be deemed to be in default of the Note and of
this Security Agreement in the event:

           a. Payment of principal or interest on the Note shall be delinquent
for a period of 30 days or more;

           b. Pledgor fails to perform any of the covenants set forth in the
Agreement or contained in this Security Agreement for a period of 10 days after
written notice thereof from Pledgee; or

           c. The purchase agreement dated March 26, 1998 between Pledgee and
Pledgor shall be terminated for any reason.

        In the case of an event of Default, as set forth above, Pledgee shall
have the right to accelerate payment of the Note upon notice to Pledgor, and
Pledgee shall thereafter be entitled to pursue its remedies under the California
Commercial Code.


<PAGE>   17

         7. Release of Collateral. Subject to any applicable contrary rules
under Regulation G, there shall be released from this pledge a portion of the
pledged Stock held by Pledgeholder hereunder upon payments of the principal of
the Note. The number of shares of the pledged Stock which shall be released
shall be that number of shares of full Stock which bears the same proportion to
the initial number of shares of Stock pledged hereunder as the payment of
principal bears to the initial full principal amount of the Note.

        8. Withdrawal or Substitution of Collateral. Pledgor shall not sell,
withdraw, pledge, substitute or otherwise dispose of all or any part of the
Collateral without the prior written consent of Pledgee.

        9. Term. The within pledge of Stock shall continue until the payment of
all indebtedness secured hereby, at which time the remaining pledged stock shall
be promptly delivered to Pledgor, subject to the provisions for prior release of
a portion of the Collateral as provided in paragraph 7 above.

        10. Insolvency. Pledgor agrees that if a bankruptcy or insolvency
proceeding is instituted by or against him, or if a receiver is appointed for
the property of Pledgor, or if Pledgor makes an assignment for the benefit of
creditors, the entire amount unpaid on the Note shall become immediately due and
payable, and Pledgee may proceed as provided in the case of default.

        11. Pledgeholder Liability. In the absence of willful or gross
negligence, Pledgeholder shall not be liable to any party for any of his acts,
or omissions to act, as Pledgeholder.

        12. Invalidity of Particular Provisions. Pledgor and Pledgee agree that
the enforceability or invalidity of any provision or provisions of this Security
Agreement shall not render any other provision or provisions herein contained
unenforceable or invalid.

        13. Successors or Assigns. Pledgor and Pledgee agree that all of the
terms of this Security Agreement shall be binding on their respective successors
and assigns, and that the term "Pledgor" and the term "Pledgee" as used herein
shall be deemed to include, for all purposes, the respective designees,
successors, assigns, heirs, executors and administrators.

        14. Governing Law. This Security Agreement shall be interpreted and
governed under the laws of the State of California.


<PAGE>   18

        IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the day and year first above written.


                                     /s/ DAVID L. SCHLOTTERBECK
        "PLEDGOR"                    -------------------------------------
                                     David L. Schlotterbeck

                                     57 Poppy Hills Rd.
                                     -------------------------------------
                                     Address

                                     Laguna Niguel, CA 92677
                                     -------------------------------------

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

        "PLEDGEE"                    VitalCom Inc.



                                     By: /s/ [SIG]
                                         ---------------------------------
                                     Title:  CEO
                                            ------------------------------



                                     /s/ [SIG]
        "PLEDGEHOLDER"               -------------------------------------
                                     Secretary of VitalCom Inc.


<PAGE>   19

                                    Exhibit C

                      ASSIGNMENT SEPARATE FROM CERTIFICATE



        FOR VALUE RECEIVED and pursuant to that certain Security Agreement dated
as of March 26, 1998 (the "Agreement"), David L. Schlotterbeck ("Purchaser")
hereby sells, assigns and transfers unto _______________________________________
___________________________________ (_______) shares of the Common Stock of
VitalCom Inc., a Delaware corporation, standing in the undersigned's name on the
books of said corporation represented by certificate no. ________ herewith, and
does hereby irrevocably constitute and appoint ___________________ attorney to
transfer the said stock on the books of the said corporation with full power of
substitution in the premises. THIS ASSIGNMENT MAY ONLY BE USED AS AUTHORIZED BY
THE AGREEMENT AND THE EXHIBITS THERETO.


Dated:                                  PURCHASER


                                   
                                        Signature: /s/ DAVID L. SCHLOTTERBECK
                                                   ----------------------------
                                                    David L. Schlotterbeck









INSTRUCTION: PLEASE DO NOT FILL IN ANY BLANKS OTHER THAN THE SIGNATURE LINE. THE
PURPOSE OF THIS ASSIGNMENT IS TO ENABLE THE CORPORATION TO ACQUIRE THE SHARES
UPON DEFAULT UNDER PURCHASER'S NOTE WITHOUT REQUIRING ADDITIONAL SIGNATURES ON
THE PART OF THE PURCHASER.