<PAGE>

                                                                   EXHIBIT 10.23

                                     SUBSIDIARY GUARANTEE AGREEMENT dated as of
                               May 14, 2002, among each of the subsidiaries
                               listed on Schedule Ihereto (each such subsidiary
                               individually, a "Guarantor" and collectively, the
                               "Guarantors") of HUDSON RESPIRATORY CARE INC., a
                               California corporation (the "Borrower"), and
                               DEUTSCHE BANK TRUST COMPANY AMERICAS (f/k/a
                               Bankers Trust Company), a New York banking
                               corporation, as collateral agent (the "Collateral
                               Agent") for the Secured Parties (as defined in
                               the Credit Agreement referred to below).

     Reference is made to the Credit Agreement dated as of April 7, 1998 (as
amended, supplemented or otherwise modified from time to time, the "Credit
Agreement"), among the Borrower, the lenders from time to time party thereto
(the "Lenders"), Bankers Trust Company, as administrative agent for the Lenders
(in such capacity, the "Administrative Agent"), Collateral Agent and issuing
bank (in such capacity, the "Issuing Bank"). Capitalized terms used herein and
not defined herein shall have the meanings assigned to such terms in the Credit
Agreement.

     The Lenders have agreed to make Loans to the Borrower, and the Issuing Bank
has agreed to issue Letters of Credit for the account of the Borrower, pursuant
to, and upon the terms and subject to the conditions specified in, the Credit
Agreement. Each of the Guarantors is a wholly owned Subsidiary of the Borrower
and acknowledges that it will derive substantial benefit from the making of the
Loans by the Lenders, and the issuance of the Letters of Credit by the Issuing
Bank. The obligations of the Lenders to make Loans and of the Issuing Bank to
issue Letters of Credit are conditioned on, among other things, the execution
and delivery by the Guarantors of a Guarantee Agreement in the form hereof. As
consideration therefor and in order to induce the Lenders to make Loans and the
Issuing Bank to issue Letters of Credit, the Guarantors are willing to execute
this Agreement.

     Accordingly, the parties hereto agree as follows:

     Section 1.  Guarantee. Each Guarantor unconditionally guarantees, jointly
with the other Guarantors and severally, as a primary obligor and not merely as
a surety, (a) the due and punctual payment of (i) the principal of and premium,
if any, and interest (including interest accruing during the pendency of any
bankruptcy, insolvency, receivership or other similar proceeding, regardless of
whether allowed or allowable in such proceeding) on the Loans, when and as due,
whether at maturity, by acceleration, upon one or more dates set for prepayment
or otherwise, (ii) each payment required to be made by the Borrower under the
Credit Agreement in respect of any Letter of Credit, when and as due, including
payments in respect of reimbursement of disbursements, interest thereon and
obligations to provide cash collateral and (iii) all other monetary obligations,
including fees, costs, expenses and indemnities, whether primary, secondary,
direct, contingent, fixed or otherwise (including monetary obligations incurred
during the pendency of any bankruptcy, insolvency, receivership or other similar
proceeding, regardless of whether allowed or allowable in such proceeding), of
the Borrower to the Secured Parties under the Credit Agreement and the other
Credit Documents and (b) unless otherwise agreed upon in writing by the
applicable Lender party thereto, all monetary obligations


                                        1

<PAGE>

of the Borrower under each Interest Rate Protection Agreement entered into with
a counterparty that was a Lender at the time such Interest Rate Protection
Agreement was entered into (all the monetary obligations referred to in the
preceding clauses (a) through (b) being collectively called the "Obligations").
Each Guarantor further agrees that the Obligations may be extended or renewed,
in whole or in part, without notice to or further assent from it, and that it
will remain bound upon its guarantee notwithstanding any extension or renewal of
any Obligation.

     Anything contained in this Agreement to the contrary notwithstanding, the
obligations of each Guarantor hereunder shall be limited to a maximum aggregate
amount equal to the greatest amount that would not render such Guarantor's
obligations hereunder subject to avoidance as a fraudulent transfer or
conveyance under Section 548 of Title 11 of the United States Code or any
provisions of applicable state law (collectively, the "Fraudulent Transfer
Laws"), in each case after giving effect to all other liabilities of such
Guarantor, contingent or otherwise, that are relevant under the Fraudulent
Transfer Laws (specifically excluding, however, any liabilities of such
Guarantor (a) in respect of intercompany indebtedness to the Borrower or
Affiliates of the Borrower to the extent that such indebtedness would be
discharged in an amount equal to the amount paid by such Guarantor hereunder and
(b) under any Guarantee of senior unsecured indebtedness or Indebtedness
subordinated in right of payment to the Obligations which Guarantee contains a
limitation as to maximum amount similar to that set forth in this clause,
pursuant to which the liability of such Guarantor hereunder is included in the
liabilities taken into account in determining such maximum amount) and after
giving effect as assets to the value (as determined under the applicable
provisions of the Fraudulent Transfer Laws) of any rights to subrogation,
contribution, reimbursement, indemnity or similar rights of such Guarantor
pursuant to (i) applicable law or (ii) any agreement providing for an equitable
allocation among such Guarantor and other Affiliates of the Borrower of
obligations arising under Guarantees by such parties (including the Indemnity,
Subrogation and Contribution Agreement).

     Section 2.  Obligations Not Waived. To the fullest extent permitted by
applicable law, each Guarantor waives presentment to, demand of payment from and
protest to the Borrower of any of the Obligations, and also waives notice of
acceptance of its guarantee and notice of protest for nonpayment. To the fullest
extent permitted by applicable law, the obligations of each Guarantor hereunder
shall not be affected by (a) the failure of the Collateral Agent or any other
Secured Party to assert any claim or demand or to enforce or exercise any right
or remedy against the Borrower or any other Guarantor under the provisions of
the Credit Agreement, any other Credit Document or otherwise, (b) any
rescission, waiver, amendment or modification of, or any release from any of the
terms or provisions of this Agreement, any other Credit Document, any Guarantee
or any other agreement, including with respect to any other Guarantor under this
Agreement or (c) the failure to perfect any security interest in, or the release
of, any of the security held by or on behalf of the Collateral Agent or any
other Secured Party.

     Section 3.  Security. Each of the Guarantors authorizes the Collateral
Agent and each of the other Secured Parties, to (a) take and hold security for
the payment of this Guarantee and the Obligations and exchange, enforce, waive
and release any such security, (b) apply such security and direct the order or
manner of sale thereof as they in their sole discretion may determine and (c)
release or substitute any one or more endorsees, other guarantors of other
obligers.


                                        2

<PAGE>

     Section 4.  Guarantee of Payment. Each Guarantor further agrees that its
guarantee constitutes a guarantee of payment when due and not of collection, and
waives any right to require that any resort be had by the Collateral Agent or
any other Secured Party to any of the security held for payment of the
Obligations or to any balance of any deposit account or credit on the books of
the Collateral Agent or any other Secured Party in favor of the Borrower or any
other person.

     Section 5.  No Discharge or Diminishment of Guarantee. The obligations of
each Guarantor hereunder shall not be subject to any reduction, limitation,
impairment or termination for any reason (other than the indefeasible payment in
full in cash of the Obligations), including any claim of waiver, release,
surrender, alteration or compromise of any of the Obligations, and shall not be
subject to any defense or setoff, counterclaim, recoupment or termination
whatsoever by reason of the invalidity, illegality or unenforceability of the
Obligations or otherwise. Without limiting the generality of the foregoing, the
obligations of each Guarantor hereunder shall not be discharged or impaired or
otherwise affected by the failure of the Collateral Agent or any other Secured
Party to assert any claim or demand or to enforce any remedy under the Credit
Agreement, any other Credit Document or any other agreement, by any waiver or
modification of any provision of any thereof, by any default, failure or delay,
willful or otherwise, in the performance of the Obligations, or by any other act
or omission that may or might in any manner or to any extent vary the risk of
any Guarantor or that would otherwise operate as a discharge of each Guarantor
as a matter of law or equity (other than the indefeasible payment in full in
cash of all the Obligations).

     Section 6.  Defenses of Borrower Waived. To the fullest extent permitted by
applicable law, each of the Guarantors waives any defense based on or arising
out of any defense of the Borrower or the unenforceability of the Obligations or
any part thereof from any cause, or the cessation from any cause of the
liability of the Borrower, other than the final and indefeasible payment in full
in cash of the Obligations. The Collateral Agent and the other Secured Parties
may, at their election, foreclose on any security held by one or more of them by
one or more judicial or nonjudicial sales, accept an assignment of any such
security in lieu of foreclosure, compromise or adjust any part of the
Obligations, make any other accommodation with the Borrower or any other
guarantor or exercise any other right or remedy available to them against the
Borrower or any other guarantor, without affecting or impairing in any way the
liability of any Guarantor hereunder except to the extent the Obligations have
been fully, finally and indefeasibly paid in cash. Pursuant to applicable law,
each of the Guarantors waives any defense arising out of any such election even
though such election operates, pursuant to applicable law, to impair or to
extinguish any right of reimbursement or subrogation or other right or remedy of
such Guarantor against the Borrower or any other Guarantor or guarantor, as the
case may be, or any security.

     Section 7.  Agreement to Pay; Subordination. In furtherance of the
foregoing and not in limitation of any other right that the Collateral Agent or
any other Secured Party has at law or in equity against any Guarantor by virtue
hereof, upon the failure of the Borrower or any other Credit Party to pay any
Obligation when and as the same shall become due, whether at maturity, by
acceleration, after notice of prepayment or otherwise, each Guarantor hereby
promises to and will forthwith pay, or cause to be paid, to the Collateral Agent
or such other Secured Party as designated thereby in cash the amount of such
unpaid Obligations. Upon payment by any


                                        3

<PAGE>

Guarantor of any sums to the Collateral Agent or any Secured Party as provided
above, all rights of such Guarantor against the Borrower arising as a result
thereof by way of right of subrogation, contribution, reimbursement, indemnity
or otherwise shall in all respects be subordinate and junior in right of payment
to the prior indefeasible payment in full in cash of all the Obligations. In
addition, any indebtedness of the Borrower now or hereafter held by any
Guarantor is hereby subordinated in right of payment to the prior payment in
full of the Obligations. If any amount shall erroneously be paid to any
Guarantor on account of (i) such subrogation, contribution, reimbursement,
indemnity or similar right or (ii) any such indebtedness of the Borrower, such
amount shall be held in trust for the benefit of the Secured Parties and shall
forthwith be paid to the Collateral Agent to be credited against the payment of
the Obligations, whether matured or unmatured, in accordance with the terms of
the Credit Documents.

     Section 8.  Information. Each of the Guarantors assumes all responsibility
for being and keeping itself informed of the Borrower's financial condition and
assets, and of all other circumstances bearing upon the risk of nonpayment of
the Obligations and the nature, scope and extent of the risks that such
Guarantor assumes and incurs hereunder, and agrees that none of the Collateral
Agent or the other Secured Parties will have any duty to advise any of the
Guarantors of information known to it or any of them regarding such
circumstances or risks.

     Section 9.  Representations and Warranties. Each of the Guarantors
represents and warrants as to itself that all representations and warranties
relating to it contained in the Credit Agreement are true and correct.

     Section 10.  Termination. The Guarantees made hereunder (a) shall terminate
when all the Obligations (other than inchoate indemnification and expense
reimbursement obligations) have been indefeasibly paid in full and the Lenders
have no further commitment to lend under the Credit Agreement, the L/C Exposure
has been reduced to zero and the Issuing Bank has no further obligation to issue
Letters of Credit under the Credit Agreement and (b) shall continue to be
effective or be reinstated, as the case may be, if at any time payment, or any
part thereof, of any Obligation is rescinded or must otherwise be restored by
any Secured Party or any Guarantor upon the bankruptcy or reorganization of the
Borrower, any Guarantor or otherwise.

     Section 11.  Binding Effect; Several Agreement; Assignments. Whenever in
this Agreement any of the parties hereto is referred to, such reference shall be
deemed to include the successors and assigns of such party; and all covenants,
promises and agreements by or on behalf of the Guarantors that are contained in
this Agreement shall bind and inure to the benefit of each party hereto and
their respective successors and assigns. This Agreement shall become effective
as to any Guarantor when a counterpart hereof executed on behalf of such
Guarantor shall have been delivered to the Collateral Agent, and a counterpart
hereof shall have been executed on behalf of the Collateral Agent, and
thereafter shall be binding upon such Guarantor and the Collateral Agent and
their respective successors and assigns, and shall inure to the benefit of such
Guarantor, the Collateral Agent and the other Secured Parties, and their
respective successors and assigns, except that no Guarantor shall have the right
to assign its rights or obligations hereunder or any interest herein (and any
such attempted assignment shall be void). If all of the capital stock of a
Guarantor is sold, transferred or otherwise disposed of pursuant to a
transaction permitted by Section 6.05 of the Credit Agreement, such Guarantor
shall be released


                                        4

<PAGE>

from its obligations under this Agreement without further action. This Agreement
shall be construed as a separate agreement with respect to each Guarantor and
may be amended, modified, supplemented, waived or released with respect to any
Guarantor without the approval of any other Guarantor and without affecting the
obligations of any other Guarantor hereunder.

     Section 12.  Waivers; Amendment. (a) No failure or delay of the Collateral
Agent in exercising any power or right hereunder shall operate as a waiver
thereof, nor shall any single or partial exercise of any such right or power, or
any abandonment or discontinuance of steps to enforce such a right or power,
preclude any other or further exercise thereof or the exercise of any other
right or power. The rights and remedies of the Collateral Agent hereunder and of
the other Secured Parties under the other Credit Documents are cumulative and
are not exclusive of any rights or remedies that they would otherwise have. No
waiver of any provision of this Agreement or consent to any departure by any
Guarantor therefrom shall in any event be effective unless the same shall be
permitted by clause (b), and then such waiver or consent shall be effective only
in the specific instance and for the purpose for which given. No notice or
demand on any Guarantor in any case shall entitle such Guarantor to any other or
further notice or demand in similar or other circumstances.

     (b) Neither this Agreement nor any provision hereof may be waived, amended
or modified except pursuant to a written agreement entered into between the
Guarantors with respect to which such waiver, amendment or modification relates
and the Collateral Agent, with the prior written consent of the Required Lenders
(except as otherwise provided in the Credit Agreement).

     Section 13.  Governing Law. THIS AGREEMENT SHALL BE GOVERNED BY, AND
CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK WITHOUT REGARD
TO PRINCIPLES OF CONFLICTS OF LAWS.

     Section 14.  Notices. All communications and notices hereunder shall be in
writing and given as provided in Section 9.01 of the Credit Agreement. All
communications and notices hereunder to each Guarantor shall be given to it at
its address set forth in Schedule 1.

     Section 15.  Survival of Agreement; Severability. (a) All covenants,
agreements, representations and warranties made by the Guarantors herein and in
the certificates or other instruments prepared or delivered in connection with
or pursuant to this Agreement or any other Credit Document shall be considered
to have been relied upon by the Collateral Agent and the other Secured Parties
and shall survive the making by the Lenders of the Loans and the issuance of the
Letters of Credit by the Issuing Bank regardless of any investigation made by
the Secured Parties or on their behalf, and shall continue in full force and
effect as long as the principal of or any accrued interest on any Loan or any
other fee or amount payable under this Agreement or any other Credit Document is
outstanding and unpaid or the L/C Exposure does not equal zero and as long as
the Commitments and the L/C Commitment have not been terminated.

     (b)  In the event any one or more of the provisions contained in this
Agreement or in any other Credit Document should be held invalid, illegal or
unenforceable in any respect, the validity, legality and enforceability of the
remaining provisions contained herein and therein shall not in any way be
affected or impaired thereby (it being understood that the invalidity of a


                                        5

<PAGE>

particular provision in a particular jurisdiction shall not in and of itself
affect the validity of such provision in any other jurisdiction). The parties
shall endeavor in good-faith negotiations to replace the invalid, illegal or
unenforceable provisions with valid provisions the economic effect of which
comes as close as possible to that of the invalid, illegal or unenforceable
provisions.

     Section 16.  Counterparts. This Agreement may be executed in counterparts,
each of which shall constitute an original, but all of which when taken together
shall constitute a single contract, and shall become effective as provided in
Section 11. Delivery of an executed signature page to this Agreement by
facsimile transmission shall be as effective as delivery of a manually executed
counterpart of this Agreement.

     Section 17.  Rules of Interpretation. The rules of interpretation specified
in Section 1.02 of the Credit Agreement shall be applicable to this Agreement.

     Section 18.  Jurisdiction; Consent to Service of Process. (a) Each
Guarantor hereby irrevocably and unconditionally submits, for itself and its
property, to the nonexclusive jurisdiction of any New York State court or
Federal court of the United States of America sitting in New York City, and any
appellate court from any thereof, in any action or proceeding arising out of or
relating to this Agreement or the other Credit Documents, or for recognition or
enforcement of any judgment, and each of the parties hereto hereby irrevocably
and unconditionally agrees that all claims in respect of any such action or
proceeding may be heard and determined in such New York State or, to the extent
permitted by law, in such Federal court. Each of the parties hereto agrees that
a final judgment in any such action or proceeding shall be conclusive and may be
enforced in other jurisdictions by suit on the judgment or in any other manner
provided by law. Nothing in this Agreement shall affect any right that the
Collateral Agent or any other Secured Party may otherwise have to bring any
action or proceeding relating to this Agreement or the other Credit Documents
against any Guarantor or its properties in the courts of any jurisdiction.

     (b) Each Guarantor hereby irrevocably and unconditionally waives, to the
fullest extent it may legally and effectively do so, any objection that it may
now or hereafter have to the laying of venue of any suit, action or proceeding
arising out of or relating to this Agreement or the other Credit Documents in
any New York State or Federal court. Each of the parties hereto hereby
irrevocably waives, to the fullest extent permitted by law, the defense of an
inconvenient forum to the maintenance of such action or proceeding in any such
court.

     (c) Each party to this Agreement irrevocably consents to service of process
in the manner provided for notices in Section 14. Nothing in this Agreement will
affect the right of any party to this Agreement to serve process in any other
manner permitted by law.

     Section 19.  Waiver of Jury Trial. EACH PARTY HERETO HEREBY WAIVES, TO THE
FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY RIGHT IT MAY HAVE TO A TRIAL BY
JURY IN RESPECT OF ANY LITIGATION DIRECTLY OR INDIRECTLY ARISING OUT OF, UNDER
OR IN CONNECTION WITH THIS AGREEMENT OR THE OTHER CREDIT DOCUMENTS. EACH PARTY
HERETO (A) CERTIFIES THAT NO REPRESENTATIVE, AGENT OR ATTORNEY OF ANY OTHER
PARTY HAS REPRESENTED, EXPRESSLY OR OTHERWISE,


                                        6

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THAT SUCH OTHER PARTY WOULD NOT, IN THE EVENT OF LITIGATION, SEEK TO ENFORCE THE
FOREGOING WAIVER AND (B) ACKNOWLEDGES THAT IT AND THE OTHER PARTIES HERETO HAVE
BEEN INDUCED TO ENTER INTO THIS AGREEMENT AND THE OTHER CREDIT DOCUMENTS, AS
APPLICABLE, BY, AMONG OTHER THINGS, THE MUTUAL WAIVERS AND CERTIFICATIONS IN
THIS SECTION 19.

     Section 20.  Additional Guarantors. Pursuant to Section 5.11 of the Credit
Agreement, each Restricted Subsidiary of the Borrower that was not in existence
on the date of the Credit Agreement is required to enter into this Agreement as
a Guarantor upon becoming a Restricted Subsidiary. Upon execution and delivery
after the date hereof by the Collateral Agent and such a Subsidiary of an
instrument in the form of Annex 1, such Subsidiary shall become a Guarantor
hereunder with the same force and effect as if originally named as a Guarantor
herein. The execution and delivery of any instrument adding an additional
Guarantor as a party to this Agreement shall not require the consent of any
other Guarantor hereunder. The rights and obligations of each Guarantor
hereunder shall remain in full force and effect notwithstanding the addition of
any new Guarantor as a party to this Agreement.

     Section 21.  Right of Setoff. If an Event of Default shall have occurred
and be continuing, each Secured Party is hereby authorized at any time and from
time to time, to the fullest extent permitted by law, to set off and apply any
and all deposits (general or special, time or demand, provisional or final) at
any time held and other Indebtedness at any time owing by such Secured Party to
or for the credit or the account of any Guarantor against any or all the
obligations of such Guarantor now or hereafter existing under this Agreement and
the other Credit Documents held by such Secured Party, irrespective of whether
or not such Secured Party shall have made any demand under this Agreement or any
other Credit Document and although such obligations may be unmatured. The rights
of each Secured Party under this Section 21 are in addition to other rights and
remedies (including other rights of setoff) which such Secured Party may have.

     Section 22.  Certain Other Rights. (a) The Guarantor authorizes the
Collateral Agent, without notice or demand and without affecting its liability
hereunder, from time to time, either before or after revocation hereof, to (i)
renew, compromise, extend, accelerate, or otherwise change the time for payment
of, or otherwise change the terms of the indebtedness or any part thereof,
including increase or decrease of the rate of interest thereon; (ii) receive and
hold security for the payment of the Obligations, and exchange, enforce, waive,
release, fail to perfect, sell, or otherwise dispose of any such security; (iii)
apply such security and direct the order or manner of sale thereof as the
Collateral Agent in its discretion may determine; and (iv) release or substitute
any one or more of the endorsers or guarantors.

     (b) The Guarantor waives any right to require the Collateral Agent to (i)
proceed against the Borrower; (ii) proceed against or exhaust any security held
from the Borrower; or (iii) pursue any other remedy in the Collateral Agent's
power whatsoever. The Guarantor waives any defense arising by reason of any
disability or other defense of the Borrower, or the cessation from any cause
whatsoever of the liability of the Borrower, or any claim that the Guarantor's
obligations exceed or are more burdensome than those of the Borrower. Until the
indebtedness shall have been paid in full, even though the indebtedness is in
excess of the Guarantor's liability


                                        7

<PAGE>

hereunder, the Guarantor will not pursue any right of subrogation,
reimbursement, indemnification, and contribution (contractual, statutory, or
otherwise) including, without limitation, any claim or right of subrogation
under the Bankruptcy Code (Title 11, United States Code) or any successor
statute, arising from the existence or performance of this Guarantee Agreement,
and until such payment in full, the Guarantor will not pursue any right to
enforce any remedy which the Collateral Agent and the Lenders now have or may
hereafter have against the Borrower and will not pursue any benefit of, and any
right to participate in, any security now or hereafter held by the Collateral
Agent. The Guarantor waives all presentments, demands for performance, notices
of nonperformance, protests, notices of protest, notices of dishonor, and
notices of acceptance of this Guarantee Agreement and of the existence,
creation, or incurring of new or additional indebtedness.

     (c)(i) The Guarantor understands and acknowledges that if the Collateral
Agent forecloses, either by judicial foreclosure or by exercise of power of
sale, any deed of trust securing the Obligations, that foreclosure could impair
or destroy any ability that the Guarantor may have to seek reimbursement,
contribution, or indemnification from the Borrower or others based on any right
the Guarantor may have of subrogation, reimbursement, contribution, or
indemnification for any amounts paid by the Guarantor under this Guarantee
Agreement. The Guarantor further understands and acknowledges that in the
absence of this paragraph, such potential impairment or destruction of the
Guarantor's rights, if any, may entitle the Guarantor to assert a defense to
this Guarantee Agreement based on Section 580d of the California Code of Civil
Procedure as interpreted in Union Bank v. Gradsky, 265 Cal. App. 2d 40 (1968).
By executing this Guarantee Agreement, the Guarantor freely, irrevocably, and
unconditionally: (A) waives and relinquishes that defense and agree that the
Guarantors will be fully liable under this Guarantee Agreement even though the
Collateral Agent may foreclose, either by judicial foreclosure or by exercise of
power of sale, any deed of trust securing the Obligations; (B) agrees that the
Guarantor will not assert that defense in any action or proceeding which the
Collateral Agent may commence to enforce this Guarantee Agreement; (C)
acknowledges and agrees that the rights and defenses waived by the Guarantor in
this Guarantee Agreement include any right or defense that the Guarantor may
have or be entitled to assert based upon or arising out of any one or more of
Sections 580a, 580b, 580d, or 726 of the California Civil Code; and (iv)
acknowledges and agrees that the Collateral Agent and the Lenders are relying on
this waiver in creating the indebtedness, and that this waiver is a material
part of the consideration which the Collateral Agent and the Lenders are
receiving for creating the indebtedness.

          (ii) The Guarantor waives any rights and defenses that are or may
become available to the Guarantor by reason of Sections 2787 to 2855, inclusive,
of the California Civil Code.

          (iii) The Guarantor waive all rights and defenses that the Guarantor
may have because any of the indebtedness is secured by real property. This
means, among other things: (A) the Collateral Agent may collect from the
Guarantor without first foreclosing on any real or personal property collateral
pledged by the Borrower; and (B) if the Collateral Agent forecloses on any real
property collateral pledged by the Borrower: (x) the amount of the indebtedness
may be reduced only by the price for which that collateral is sold at the
foreclosure sale, even if the collateral is worth more than the sale price, and
(y) the Collateral Agent may collect from the Guarantor even if the Collateral
Agent, by foreclosing on the real property collateral, has


                                        8

<PAGE>

destroyed any right the Guarantor may have to collect from the Borrower. This is
an unconditional and irrevocable waiver of any rights and defenses the Guarantor
may have because any of the indebtedness is secured by real property. These
rights and defenses include, but are not limited to, any rights or defenses
based upon Section 580a, 580b, 580d, or 726 of the California Code of Civil
Procedure.

          (iv) The Guarantor waives any right or defense they may have at law or
equity, including California Code of Civil Procedure Section 580a, to a fair
market value hearing or action to determine a deficiency judgment after a
foreclosure.

          (v) No provision or waiver in this Guarantee Agreement shall be
construed as limiting the generality of any other waiver contained in this
Guarantee Agreement.

     (d) The Guarantor acknowledges and agrees that it shall have the sole
responsibility for obtaining from the Borrower such information concerning the
Borrower's financial conditions or business operations as the Guarantor may
require, and that the Collateral Agent has no duty at any time to disclose to
the Guarantor any information relating to the business operations or financial
conditions of the Borrower.


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<PAGE>

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

                                          IH HOLDING LLC,

                                          By:  HUDSON RESPIRATORY CARE INC., its
                                               Managing Member

                                          By:
                                               ---------------------------------
                                               Name:
                                               Title:


                                       S-1

<PAGE>

                                          DEUTSCHE BANK TRUST COMPANY
                                          AMERICAS, as Collateral Agent,

                                          by
                                               ---------------------------------
                                               Name:
                                               Title:


                                       S-2

<PAGE>

                                                               Schedule I to the
                                                             Guarantee Agreement

<TABLE>
<CAPTION>
                Guarantor                                    Address
               ---------                                     -------
<S>                                         <C>
IH Holding LLC                              27711 Diaz Road, P.O. Box 9020
                                            Temecula, CA 92589-9020
</TABLE>


                                       S-2

<PAGE>


                                                                  Annex I to the
                                                  Subsidiary Guarantee Agreement

                                            SUPPLEMENT NO. ________dated as of
                                    __________, to the Subsidiary Guarantee
                                    Agreement dated as of April [ ], 1998, among
                                    each of the subsidiaries listed on Schedule
                                    I thereto (each such subsidiary
                                    individually, a "Guarantor" and
                                    collectively, the "Guarantors") of HUDSON
                                    RESPIRATORY CARE INC., a California
                                    corporation (the "Borrow"), and DEUTSCHE
                                    BANK TRUST COMPANY AMERICAS, a New York
                                    banking corporation, as collateral agent
                                    (the "Collateral Agent") for the Secured
                                    Parties (as defined in the Credit Agreement
                                    referred to below).

     A.  Reference is made to the Credit Agreement dated as of April [ ],1998
(as amended, supplemented or otherwise modified from time to time, the "Credit
Agreement"), among the Borrower, the lenders from time to time party thereto
(the "Lenders"), Bankers Trust Company, as administrative agent for the Lenders
(in such capacity, the "Administrative Agent"), Collateral Agent and issuing
bank (in such capacity, the "Issuing Bank").

     B.  Capitalized terms used herein and not otherwise defined herein shall
have the meanings assigned to such terms in the Guarantee Agreement and the
Credit Agreement.

     C.  The Guarantors have entered into the Guarantee Agreement in order to
induce the Lenders to make Loans and the Issuing Bank to issue Letters of
Credit. Pursuant to Section 5.11 of the Credit Agreement, each Subsidiary of the
Borrower that was not in existence or not a Subsidiary on the date of the Credit
Agreement is required to enter into the Guarantee Agreement as a Guarantor upon
becoming a Subsidiary. Section 20 of the Guarantee Agreement provides that
additional Subsidiaries of the Borrower may become Guarantors under the
Guarantee Agreement by execution and delivery of an instrument in the form of
this Supplement. The undersigned Subsidiary of the Borrower (the "New
Guarantor") is executing this Supplement in accordance with the requirements of
the Credit Agreement to become a Guarantor under the Guarantee Agreement in
order to induce the Lenders to make additional Loans and the Issuing Bank to
issue additional Letters of Credit and as consideration for Loans previously
made and Letters of Credit previously issued.

     Accordingly, the Collateral Agent and the New Guarantor agree as follows:

     Section 1.  In accordance with Section 20 of the Guarantee Agreement, the
New Guarantor by its signature below becomes a Guarantor under the Guarantee
Agreement with the same force and effect as if originally named therein as a
Guarantor and the New Guarantor hereby (a) agrees to all the terms and
provisions of the Guarantee Agreement applicable to it as a Guarantor thereunder
and (b) represents and warrants that the representations and warranties made by
it as a Guarantor thereunder are true and correct on and as of the date hereof.
Each


                                       S-2

<PAGE>

reference to a "Guarantor" in the Guarantee Agreement shall be deemed to include
the New Guarantor. The Guarantee Agreement is hereby incorporated herein by
reference.

     Section 2.  This Supplement may be executed in counterparts, each of which
shall constitute an original, but all of which when taken together shall
constitute a single contract. This Supplement shall become effective when the
Collateral Agent shall have received counterparts of this Supplement that, when
taken together, bear the signatures of the New Guarantor and the Collateral
Agent. Delivery of an executed signature page to this Supplement by facsimile
transmission shall be as effective as delivery of a manually executed
counterpart of this Supplement.

     Section 3.  Except as expressly supplemented hereby, the Guarantee
Agreement shall remain in full force and effect.

     Section 4.  THIS SUPPLEMENT SHALL BE GOVERNED BY, AND CONSTRUED IN
ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK WITHOUT REGARD TO PRINCIPLES
OF CONFLICTS OF LAWS.

     Section 5.  In case any one or more of the provisions contained in this
Supplement should be held invalid, illegal or unenforceable in any respect, the
validity, legality and enforceability of the remaining provisions contained
herein and in the Guarantee Agreement shall not in any way be affected or
impaired thereby (it being understood that the invalidity of a particular
provision hereof in a particular jurisdiction shall not in and of itself affect
the validity of such provision in any other jurisdiction). The parties hereto
shall endeavor in good-faith negotiations to replace the invalid, illegal or
unenforceable provisions with valid provisions the economic effect of which
comes as close as possible to that of the invalid, illegal or unenforceable
provisions.

     Section 6.  All communications and notices hereunder shall be in writing
and given as provided in Section 14 of the Guarantee Agreement. All
communications and notices hereunder to the New Guarantor shall be given to it
at the address set forth under its signature below, with a copy to the Borrower.

     Section 7.  The New Guarantor agrees to reimburse the Collateral Agent for
its out-of-pocket expenses in connection with this Supplement, including the
fees, disbursements and other charges of counsel for the Collateral Agent.


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<PAGE>

         IN WITNESS WHEREOF, the New Guarantor and the Collateral Agent have
duly executed this Supplement to the Guarantee Agreement as of the day and year
first above written.

                                        [Name Of New Guarantor],

                                          by
                                               ---------------------------------
                                               Name:
                                               Title:
                                               Address:


                                        DEUTSCHE BANK TRUST COMPANY
                                        AMERICAS, as Collateral Agent,

                                          by
                                               ---------------------------------

                                               Name:
                                               Title:


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