Document:

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                                                                   Exhibit 10.33

                            PATENT SECURITY AGREEMENT
                            -------------------------

          This PATENT SECURITY AGREEMENT (this "Agreement"), dated as of October
7, 2003, is executed and delivered by and between HUDSON RESPIRATORY CARE INC.,
a California corporation ("Debtor"), and MW POST ADVISORY GROUP, LLC, a Delaware
limited liability company, as administrative agent for the Lenders (in such
capacity, together with its successors and assigns, if any, in such capacity,
"Agent"), with reference to the following:

          WHEREAS, Debtor, the Lenders (such Lenders, together with Agent,
individually and collectively, the "Lender Group"), and Agent have entered into
that certain Loan and Security Agreement, dated as of even date herewith (as
amended, restated, modified, supplemented, refinanced, renewed, or extended from
time to time, the "Loan Agreement"), pursuant to which the Lender Group has
agreed to make certain financial accommodations to Debtor, and pursuant to which
Debtor has granted to Agent for the benefit of the Lender Group security
interests in (among other things) all general intangibles of Debtor; and

          WHEREAS, to induce the Lender Group to make the financial
accommodations provided to Debtor pursuant to the Loan Agreement, Debtor has
agreed to execute and deliver this Agreement to Agent for filing with the PTO
and with any other relevant recording systems in any domestic or foreign
jurisdiction, and as further evidence of and to effectuate Agent's existing
security interests in the patents and other general intangibles described
herein.

          NOW, THEREFORE, for valuable consideration, the receipt and adequacy
of which is hereby acknowledged, Debtor hereby agrees in favor of Agent, for the
benefit of the Lender Group, as follows:

          1.   Definitions; Interpretation.

               (a)  Certain Defined Terms. As used in this Agreement, the
following terms shall have the following meanings:

          "Agent" has the meaning ascribed to such term in the preamble to this
Agreement.

          "Agreement" has the meaning ascribed to such term in the preamble to
this Agreement.

          "Debtor" has the meaning ascribed to such term in the preamble to this
Agreement.

          "Debtor's Patents" has the meaning set forth in Section 4.

                                      -1-

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          "Event of Default" means any Event of Default under the Loan
Agreement.

          "Excluded Collateral" has the meaning ascribed to such term in the
Loan Agreement.

          "Lender Group" has the meaning ascribed to such term in the recitals
to this Agreement.

          "Lenders" means, individually and collectively, each of the lenders
identified on the signature pages of the Loan Agreement, and any other person
made a party thereto in accordance with the provisions of Section 14 thereof
(together with their respective successors and assigns).

          "Loan Agreement" has the meaning ascribed to such term in the recitals
to this Agreement.

          "Patent Collateral" has the meaning ascribed to such term in Section
2.

          "Patents" has the meaning ascribed to such term in Section 2.

          "Proceeds" means whatever is receivable or received from or upon the
sale, lease, license, collection, use, exchange or other disposition, whether
voluntary or involuntary, of any Patent Collateral, including "proceeds" as
defined in the UCC, and all proceeds of proceeds. Proceeds shall include (i) any
and all accounts, chattel paper, instruments, general intangibles, cash and
other proceeds, payable to or for the account of Debtor, from time to time in
respect of any of the Patent Collateral, (ii) any and all proceeds of any
insurance, indemnity, warranty or guaranty payable to or for the account of
Debtor from time to time with respect to any of the Patent Collateral, (iii) any
and all claims and payments (in any form whatsoever) made or due and payable to
Debtor from time to time in connection with any requisition, confiscation,
condemnation, seizure or forfeiture of all or any part of the Patent Collateral
by any Person acting under color of governmental authority, and (iv) any and all
other amounts from time to time paid or payable under or in connection with any
of the Patent Collateral or for or on account of any damage or injury to or
conversion of or infringement of rights in any Patent Collateral by any Person.

          "PTO" means the United States Patent and Trademark Office and any
successor thereto.

          "Secured Obligations" means all liabilities, obligations (including
the Obligations), or undertakings owing by Debtor to the Lender Group of any
kind or description arising out of or outstanding under, advanced or issued
pursuant to, or evidenced by the Loan Agreement, this Agreement, or any of the
other Loan Documents, irrespective of whether for the payment of money, whether
direct or indirect, absolute or contingent, due or to become due, voluntary or
involuntary, whether now existing or hereafter arising, and including all
interest, costs, fees (including attorneys fees), and expenses (including
interest, costs, fees, and expenses

                                       -2-

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that, but for the provisions of the Bankruptcy Code, would have accrued) and any
and all other amounts which Debtor is required to pay pursuant to any of the
foregoing, by law, or otherwise.

          "UCC" shall mean the Uniform Commercial Code as in effect from time to
time in the State of California.

          "United States" and "U.S." shall each mean the United States of
America.

               (b)  Terms Defined in UCC. Where applicable and except as
otherwise defined herein, terms used in this Agreement shall have the meanings
ascribed to them in the UCC.

               (c)  Interpretation. In this Agreement, except to the extent the
context otherwise requires:

                    (i)    Any reference to a Section or a Schedule is a
     reference to a section hereof, or a schedule hereto, respectively, and to a
     subsection or a clause is, unless otherwise stated, a reference to a
     subsection or a clause of the Section or subsection in which the reference
     appears.

                    (ii)   The words "hereof," "herein," "hereto," "hereunder"
     and the like mean and refer to this Agreement as a whole and not merely to
     the specific Section, subsection, paragraph or clause in which the
     respective word appears.

                    (iii)  The meaning of defined terms shall be equally
     applicable to both the singular and plural forms of the terms defined.

                    (iv)   The words "including," "includes" and "include" shall
     be deemed to be followed by the words "without limitation."

                    (v)    References to agreements and other contractual
     instruments shall be deemed to include all subsequent permitted amendments,
     restatements, supplements, refinancings, renewals, extensions, and other
     modifications thereto and thereof.

                    (vi)   References to statutes or regulations are to be
     construed as including all statutory and regulatory provisions
     consolidating, amending or replacing the statute or regulation referred to.

                    (vii)  Any captions and headings are for convenience of
     reference only and shall not affect the construction of this Agreement.

                    (viii) Capitalized words not otherwise defined herein shall
     have the respective meanings assigned to them in the Loan Agreement.

                                       -3-

<PAGE>

                    (ix)   In the event of a direct conflict between the terms
     and provisions of this Agreement and the Loan Agreement, it is the
     intention of the parties hereto that such documents shall be read together
     and construed, to the fullest extent possible, to be in concert with each
     other. In the event of any actual, irreconcilable conflict between this
     Agreement and the Loan Agreement, that cannot be resolved as aforesaid, the
     terms and provisions of the Loan Agreement shall control and govern;
     provided, however, that the inclusion herein of additional obligations on
     the part of the Debtor and supplemental rights and remedies in favor of
     Agent (whether under federal law or applicable California law), in each
     case in respect of the Patent Collateral, shall not be deemed a conflict
     with the Loan Agreement.

          2.   Security Interest.

               (a)  Assignment and Grant of Security Interests. As security for
the prompt payment and performance of the Secured Obligations, Debtor hereby
grants, assigns, transfers, and conveys to Agent, for the benefit of the Lender
Group, continuing security interests in all of such Debtor's right, title and
interest in, to and under the following property, whether now existing or
hereafter acquired or arising and whether registered or unregistered
(collectively, the "Patent Collateral"):

                    (i)    all letters patent of the U.S. or any other country,
     all registrations and recordings thereof, and all applications for letters
     patent of the U.S. or any other country, owned, held, or used by Debtor in
     whole or in part, including all existing U.S. patents and patent
     applications of Debtor which are described on Schedule A hereto, as the
     same may be amended or supplemented pursuant hereto from time to time, and
     together with and including all patent licenses held by Debtor, including
     such patent licenses which are described on Schedule A hereto, together
     with all reissues, divisions, continuations, renewals, extensions and
     continuations-in-part thereof and the inventions disclosed therein, and all
     rights corresponding thereto throughout the world, including the right to
     make, use, lease, sell and otherwise transfer the inventions disclosed
     therein, and all proceeds thereof, including all license royalties and
     proceeds of infringement suits (collectively, the "Patents");

                    (ii)   all claims, causes of action and rights to sue for
     past, present and future infringement or unconsented use of any of the
     Patents and all rights arising therefrom and pertaining thereto;

                    (iii)  all general intangibles and all intangible
     intellectual or other similar property of Debtor of any kind or nature,
     whether now owned or hereafter acquired or developed, associated with or
     arising out of any of the Patents and not otherwise described above; and

                    (iv)   all products and Proceeds of any and all of the
     foregoing;

     provided, however, that Patent Collateral shall not include Excluded
     Collateral.

                                       -4-

<PAGE>

               (b)  Continuing Security Interests. Debtor agrees that this
Agreement shall create continuing security interests in the Patent Collateral
which shall remain in effect until terminated in accordance with Section 17.

               (c)  Incorporation into Loan Agreement. This Agreement shall be
fully incorporated into the Loan Agreement and all understandings, agreements
and provisions contained in the Loan Agreement shall be fully incorporated into
this Agreement. Without limiting the foregoing, the Patent Collateral described
in this Agreement shall constitute part of the Collateral in the Loan Agreement.

               (d)  Licenses. Debtor may grant licenses of the Patent Collateral
in the ordinary course of business in accordance with the terms of the Loan
Agreement.

          3.   Further Assurances; Appointment of Agent as Attorney-in-Fact.
Debtor at its expense shall execute and deliver, or cause to be executed and
delivered, to Agent any and all documents and instruments, in form and substance
satisfactory to Agent, and take any and all action, which Agent, in the exercise
of its discretion, may request from time to time, to perfect and continue
perfected, maintain the priority of or provide notice of Agent's security
interests in the Patent Collateral and to accomplish the purposes of this
Agreement. If Debtor refuses to execute and deliver, or fails timely to execute
and deliver, any of the documents it is requested to execute and deliver by
Agent in accordance with the foregoing, Agent shall have the right to, in the
name of Debtor, or in the name of Agent or otherwise, without notice to or
assent by Debtor, and Debtor hereby irrevocably constitutes and appoints Agent
(and any of Agent's officers or employees or agents designated by Agent) as
Debtor's true and lawful attorney-in-fact with full power and authority, (i) to
sign the name of Debtor on all or any of such documents or instruments, and
perform all other acts, that Agent, in its reasonable discretion, deems
necessary or advisable in order to perfect or continue perfected, maintain the
priority or enforceability of or provide notice of Agent's security interests
in, the Patent Collateral, and (ii) to execute any and all other documents and
instruments, and to perform any and all acts and things for and on behalf of
Debtor, which Agent, in its reasonable discretion, may deem necessary or
advisable to maintain, preserve and protect the Patent Collateral and to
accomplish the purposes of this Agreement, including (A) upon the occurrence and
during the continuance of any Event of Default, to defend, settle, adjust or
institute any action, suit or proceeding with respect to any Patent Collateral,
(B) upon the occurrence and during the continuance of any Event of Default, to
assert or retain any rights under any license agreement for any Patent
Collateral, including any rights of Debtor arising under Section 365(n) of the
Bankruptcy Code, and (C) upon the occurrence and during the continuance of any
Event of Default, to execute any and all applications, documents, papers and
instruments for Agent to use any Patent Collateral, to grant or issue any
exclusive or non-exclusive license with respect to any Patent Collateral, and to
assign, convey or otherwise transfer title in or dispose of the Patent
Collateral. The power of attorney set forth in this Section 3, being coupled
with an interest, is irrevocable so long as this Agreement shall not have
terminated in accordance with Section 17; provided that the foregoing power of
attorney shall terminate when all of the Secured Obligations have been fully and
finally repaid and performed and the Lender Group's obligation to extend credit
under the Loan

                                       -5-

<PAGE>

Agreement is terminated. The Agent acknowledges that the exercise of the powers
granted in this Section 3 may at some times be subject to the provisions of the
Intercreditor Agreement.

          4.   Representations and Warranties. Debtor represents and warrants to
each member of the Lender Group, in each case, to the best of its knowledge,
information, and belief, as follows:

               (a)  No Other Patents. A true and correct list of all Patents
owned by Debtor, in whole or in part, is set forth on Schedule A (collectively,
the "Debtor's Patents"). Schedule A also sets forth a true and correct list of
all of the Patents that Debtor holds (by reason of license or otherwise) from a
third party.

               (b)  Validity. Each of the Debtor's Patents listed on Schedule A
is subsisting and has not been adjudged invalid or unenforceable, in whole or in
part, all maintenance fees required to be paid on account of any Patents have
been timely paid for maintaining such Patents in force, and, to the best of
Debtor's knowledge, each of the Patents is valid and enforceable.

               (c)  Title. (i) Debtor has rights in and good and defensible
title to the Patent Collateral in respect of the Patents it owns, (ii) Debtor is
the sole and exclusive owner of such Patent Collateral, free and clear of any
Liens and rights of others (other than Permitted Liens), including licenses
(other than licenses entered into as permitted herein), shop rights and
covenants by Debtor not to sue third persons and (iii) with respect to any
Patent for which Debtor is either a licensor or a licensee pursuant to a license
or licensee agreement regarding such Patent, each such license or licensing
agreement is in full force and effect, such Debtor is not in material default of
any of its obligations thereunder and no other Person is known by such Debtor to
have any rights in or to any of the Patent Collateral, other than (A) the
parties to such licenses or licensing agreements, or (B) in the case of any
non-exclusive license or license agreement entered into by Debtor or any such
licensor regarding such Patent Collateral, the parties to any other such
non-exclusive licenses or license agreements entered into by Debtor or any such
licensor with any other Person.

               (d)  No Infringement. To the best of Debtor's knowledge, (i) no
material infringement or unauthorized use presently is being made of any of the
Patent Collateral by any Person, and (ii) neither the past nor the present use
of the Patent Collateral by Debtor has or does infringe upon or violate any
right, privilege or license agreement of or with any other Person or give such
Person the right to terminate any such license agreement.

               (e)  Powers. Debtor has the unqualified right, power and
authority to pledge and to grant to Agent, for the benefit of the Lender Group,
security interests in all of the Patent Collateral pursuant to this Agreement,
and to execute, deliver and perform its obligations in accordance with the terms
of this Agreement, without the consent or approval of any other Person except as
already obtained.

          5.   Covenants. Debtor covenants that so long as this Agreement shall
be in effect, Debtor shall:

                                       -6-

<PAGE>

               (a)  comply with all of the covenants, terms and provisions of
this Agreement, the Loan Agreement, and the other Loan Documents;

               (b)  promptly give Agent written notice of the occurrence of any
event that could have a material adverse effect on any of the Patents or the
Patent Collateral (except as to such Patent or Patents, which alone or in the
aggregate, the absence of which would not reasonably be expected to materially
impair the conduct of the business), including any petition under the Bankruptcy
Code filed by or against any licensor of any of the Patents for which Debtor is
a licensee, provided, however, that Debtor shall not be required to preserve,
protect and maintain, and may abandon, in whole or in part, any Patent as Debtor
deems appropriate in the exercise of Debtor's reasonable business judgment, so
long as the absence of such Patent or Patents, alone or in the aggregate, would
not reasonably be expected to materially impair the conduct of Debtor's business
or the Patent Collateral;

               (c)  on a continuing basis, make, execute, acknowledge and
deliver, and file and record in the proper filing and recording places, all such
instruments and documents, including appropriate financing and continuation
statements and security agreements, and take all such action as may be necessary
or advisable or may be requested by Agent, in the exercise of its Permitted
Discretion, to carry out the intent and purposes of this Agreement, or for
assuring, confirming or protecting the grant or perfection of the security
interests granted or purported to be granted hereby, to ensure Debtor's
compliance with this Agreement or to enable Agent to exercise and enforce its
rights and remedies hereunder with respect to the Patent Collateral. Without
limiting the generality of the foregoing sentence, Debtor:

                    (i)    hereby authorizes Agent in its sole discretion if
     Debtor refuses to execute and deliver, or fails timely to execute and
     deliver, any of the documents it is requested to execute and deliver by
     Agent, to modify this Agreement without first obtaining Debtor's approval
     of or signature to such modification by amending Schedule A hereof to
     include a reference to any right, title or interest in any existing Patent
     Collateral or Patent Collateral acquired or developed by Debtor after the
     execution hereof, or to delete any reference to any right, title or
     interest in any Patent Collateral in which Debtor no longer has or claim
     any right, title or interest; and

                    (ii)   hereby authorizes Agent, in its sole discretion, to
     file one or more financing or continuation statements, or if Debtor refuses
     to execute and deliver, or fails timely to execute and deliver, any such
     amendment thereto it is requested to execute and deliver by Agent, any
     amendments thereto, relative to all or any portion of the Patent
     Collateral, without the signature of Debtor where permitted by law;

               (d)  comply, in all material respects, with all applicable
statutory and regulatory requirements in connection with any and all Patent
Collateral and give such notice of patent, prosecute such material claims, and
do all other acts and take all other measures which, in Debtor's reasonable
business judgment, may be necessary or desirable to preserve, protect and
maintain Patent Collateral and all of Debtor's rights therein, including the
diligent prosecution of any patent application pending as of the date of this
Agreement or thereafter;

                                       -7-

<PAGE>

               (e)  comply with each of the terms and provisions of this
Agreement, and not enter into any agreement (for example, a license agreement)
which is inconsistent with the obligations of Debtor under this Agreement
without Agent's prior written consent, which consent shall not be unreasonably
withheld or delayed; and

               (f)  not permit the inclusion in any contract to which Debtor
becomes a party of any provision that could or might impair or prevent the
creation of a security interest in favor of Agent (for the benefit of the Lender
Group) in Debtor's rights and interest in any property included within the
definition of Patent Collateral acquired under such contracts.

          6.   Future Rights. If and when Debtor shall obtain rights to any new
patentable inventions, or become entitled to the benefit of any Patent, or any
reissue, division, continuation, renewal, extension or continuation-in-part of
any Patent or Patent Collateral or any improvement thereof (whether pursuant to
any license or otherwise), the provisions of this Agreement shall automatically
apply thereto and Debtor shall give to Agent prompt notice thereof, within 20
days after obtaining such rights, reissuance, division, continuation, renewal,
extension or any improvement thereof. Debtor shall do all things deemed
necessary or advisable by Agent, in its discretion, to ensure the validity,
perfection, priority and enforceability of the security interests of Agent in
such future acquired Patent Collateral. Debtor hereby authorizes Agent to
modify, amend or supplement the Schedules hereto and to re-execute this
Agreement from time to time on Debtor's behalf and as its attorney-in-fact to
include any future patents which are or become Patent Collateral and to cause
such re-executed Agreement or such modified, amended or supplemented Schedules
to be filed with the PTO.

          7.   Events of Default. The occurrence of any "Event of Default" under
the Loan Agreement shall constitute an Event of Default hereunder.

          8.   Remedies. Upon the occurrence and during the continuance of an
Event of Default, and subject to the Intercreditor Agreement, Agent shall have
all rights and remedies available to it under the Loan Agreement and applicable
law (which rights and remedies are cumulative) with respect to the security
interests in any of the Patent Collateral or any other Collateral. Debtor agrees
that such rights and remedies include the right of Agent as an Agent to sell or
otherwise dispose of its Collateral after default, pursuant to the UCC. Debtor
agrees that Agent shall at all times have such non-exclusive, royalty free
licenses, to the extent permitted by law, for any Patent Collateral that is
reasonably necessary to permit the exercise of any of Agent's rights or remedies
upon the occurrence and during the continuation of an Event of Default with
respect to (among other things) any tangible asset of Debtor in which Agent has
a security interest, including Agent's rights to sell inventory, tooling or
packaging which is acquired by Debtor (or its successor, assignee or trustee in
bankruptcy). In addition to and without limiting any of the foregoing, upon the
occurrence and during the continuance of an Event of Default, Agent shall have
the right but shall in no way be obligated to bring suit, or to take such other
action as Agent, in its discretion, deems necessary or advisable, in the name of
Debtor or Agent, to enforce or protect any of the Patent Collateral, in which
event Debtor shall, at the request of Agent, do any and all lawful acts and
execute any and all documents required by Agent in aid of such enforcement. To
the extent that Agent shall elect not to bring suit to enforce

                                       -8-

<PAGE>

such Patent Collateral, upon the occurrence and during the continuation of an
Event of Default, Debtor, in the exercise of its reasonable business judgment,
agrees to use all reasonable measures and diligent efforts, whether by action,
suit, proceeding or otherwise, to prevent the infringement, misappropriation or
violations thereof by others and for that purpose agrees diligently to maintain
any action, suit or proceeding against any Person necessary to prevent such
infringement, misappropriation or violation.

          9.   Binding Effect. This Agreement shall be binding upon, inure to
the benefit of and be enforceable by Debtor and Agent for the benefit of the
Lender Group and their respective successors and assigns.

          10.  Notices. All notices and other communications hereunder shall be
in writing and shall be mailed, sent or delivered in accordance with the Loan
Agreement.

          11.  Governing Law. This Agreement shall be governed by, and construed
and enforced in accordance with, the laws of the State of California, except to
the extent that the validity or perfection of the security interests hereunder
in respect of the Patent Collateral are governed by federal law, in which case
such choice of California law shall not be deemed to deprive Agent of such
rights and remedies as may be available under federal law.

          12.  Entire Agreement; Amendment. This Agreement and the other Loan
Documents, together with the Schedules hereto and thereto, contain the entire
agreement of the parties with respect to the subject matter hereof and
supersedes all prior drafts and communications relating to such subject matter.
Neither this Agreement nor any provision hereof may be modified, amended or
waived except by the written agreement of the parties, as provided in the Loan
Agreement. Notwithstanding the foregoing, Agent may re-execute this Agreement or
modify, amend or supplement the Schedules hereto as provided in Section 6
hereof.

          13.  Severability. If one or more provisions contained in this
Agreement shall be invalid, illegal or unenforceable in any respect in any
jurisdiction or with respect to any party, such invalidity, illegality or
unenforceability in such jurisdiction or with respect to such party shall, to
the fullest extent permitted by applicable law, not invalidate or render illegal
or unenforceable any such provision in any other jurisdiction or with respect to
any other party, or any other provisions of this Agreement.

          14.  Counterparts; Telefacsimile Execution. This Agreement may be
executed in any number of counterparts and by different parties hereto in
separate counterparts, each of which when so executed shall be deemed to be an
original and all of which taken together shall constitute but one and the same
agreement. Delivery of an executed counterpart of this Agreement by
telefacsimile shall be equally as effective as delivery of an original executed
counterpart of this Agreement. Any party delivering an executed counterpart of
this Agreement by telefacsimile also shall deliver an original executed
counterpart of this Agreement but the failure to deliver an original executed
counterpart shall not affect the validity, enforceability, and binding effect of
this Agreement

                                       -9-

<PAGE>

          15.  Loan Documents. Debtor acknowledges that the rights and remedies
of Agent with respect to the security interests in the Patent Collateral granted
hereby are more fully set forth in the Loan Agreement and the other Loan
Documents and all such rights and remedies are cumulative.

          16.  No Inconsistent Requirements. Debtor acknowledges that this
Agreement and the other Loan Documents may contain covenants and other terms and
provisions variously stated regarding the same or similar matters, and Debtor
agrees that all such covenants, terms and provisions are cumulative and all
shall be performed and satisfied in accordance with their respective terms.

          17.  Termination. Upon the indefeasible payment in full of the Secured
Obligations, including the cash collateralization, expiration, or cancellation
of all Secured Obligations, if any, consisting of letters of credit, and the
full and final termination of any commitment to extend any financial
accommodations under the Loan Agreement, this Agreement shall terminate and
Agent shall execute and deliver such documents and instruments and take such
further action reasonably requested by Debtor and at Debtor's expense as shall
be necessary to evidence termination of the security interests granted by Debtor
to Agent for the benefit of the Lender Group hereunder, including cancellation
of this Agreement by written notice from Agent to the PTO.

          18.  Duties of Agent and the Lender Group. Notwithstanding any
provision contained in this Agreement, none of Agent or any other member of the
Lender Group shall have any duty to exercise any of the rights, privileges or
powers afforded to it and shall not be responsible to Debtor for any failure to
do so or delay in doing so. Except for the accounting for moneys actually
received by Agent, any other member of the Lender Group, hereunder or in
connection herewith, none of Agent or any other member of the Lender Group,
shall have any duty to exercise or preserve any rights, privileges or powers
pertaining to the Patent Collateral.

                            [Signature page follows]

                                      -10-

<PAGE>

          IN WITNESS WHEREOF, the parties have duly executed this Agreement, as
of the date first above written.

                                      HUDSON RESPIRATORY CARE INC.,
                                      a California corporation

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

                                      MW POST ADVISORY GROUP, LLC,
                                      a Delaware limited liability
                                      company, as Agent

                                      By:
                                          --------------------------------------
                                      Name: Lawrence Post
                                      Title: Chief Executive Officer

                  [Signature Page to Patent Security Agreement]

<PAGE>

                                   SCHEDULE A

                         Patents and Patent Applications
                         -------------------------------

                                 [see attached]

                                       -1-

<PAGE>

                                 Patent Licenses
                                 ---------------

                                      None

                                       -2-<PAGE>

                                                                   Exhibit 10.34

                          TRADEMARK SECURITY AGREEMENT
                          ----------------------------

          This TRADEMARK SECURITY AGREEMENT (this "Agreement"), dated as of
October 7, 2003, is executed and delivered by and between HUDSON RESPIRATORY
CARE INC., a California corporation ("Debtor"), and MW POST ADVISORY GROUP, LLC,
a Delaware limited liability company, as administrative agent for the Lenders
(in such capacity, together with its successors and assigns, if any, in such
capacity, "Agent"), with reference to the following:

          WHEREAS, Debtor, the Lenders (such Lenders, together with Agent,
individually and collectively, the "Lender Group"), and Agent have entered into
that certain Loan and Security Agreement, dated as of even date herewith (as
amended, restated, modified, supplemented, refinanced, renewed, or extended from
time to time, the "Loan Agreement"), pursuant to which the Lender Group has
agreed to make certain financial accommodations to Debtor, and pursuant to which
Debtor has granted to Agent for the benefit of the Lender Group security
interests in (among other things) all general intangibles of Debtor; and

          WHEREAS, to induce the Lender Group to make the financial
accommodations provided to Debtor pursuant to the Loan Agreement, Debtor has
agreed to execute and deliver this Agreement to Agent for filing with the PTO
and with any other relevant recording systems in any domestic or foreign
jurisdiction, and as further evidence of and to effectuate Agent's existing
security interests in the trademarks and other general intangibles described
herein.

          NOW, THEREFORE, for valuable consideration, the receipt and adequacy
of which is hereby acknowledged, Debtor hereby agrees in favor of Agent, for the
benefit of the Lender Group, as follows:

          1.  Definitions; Interpretation.

               (a) Certain Defined Terms. As used in this Agreement, the
following terms shall have the following meanings:

          "Agent" has the meaning ascribed to such term in the preamble to this
Agreement.

          "Agreement" has the meaning ascribed to such term in the preamble
hereto.

          "Debtor" has the meaning ascribed to such term in the preamble to this
Agreement.

          "Debtor's Trademarks" has the meaning set forth in Section 4.

          "Event of Default" has the meaning ascribed to such term in the Loan
Agreement.

          "Excluded Collateral" has the meaning ascribed to such term in the
Loan Agreement.

                                       -1-

<PAGE>

          "Lender Group" has the meaning ascribed to such term in the recitals
to this Agreement.

          "Lenders" means, individually and collectively, each of the lenders
identified on the signature pages of the Loan Agreement, and any other person
made a party thereto in accordance with the provisions of Section 14 thereof
(together with their respective successors and assigns).

          "Loan Agreement" has the meaning ascribed to such term in the recitals
to this Agreement.

          "Proceeds" means whatever is receivable or received from or upon the
sale, lease, license, collection, use, exchange or other disposition, whether
voluntary or involuntary, of any Trademark Collateral, including "proceeds" as
such term is defined in the UCC, and all proceeds of proceeds. Proceeds shall
include (i) any and all accounts, chattel paper, instruments, general
intangibles, cash and other proceeds, payable to or for the account of Debtor,
from time to time in respect of any of the Trademark Collateral, (ii) any and
all proceeds of any insurance, indemnity, warranty or guaranty payable to or for
the account of Debtor from time to time with respect to any of the Trademark
Collateral, (iii) any and all claims and payments (in any form whatsoever) made
or due and payable to Debtor from time to time in connection with any
requisition, confiscation, condemnation, seizure or forfeiture of all or any
part of the Trademark Collateral by any Person acting under color of
governmental authority, and (iv) any and all other amounts from time to time
paid or payable under or in connection with any of the Trademark Collateral or
for or on account of any damage or injury to or conversion of or infringement of
rights in any Trademark Collateral by any Person.

          "PTO" means the United States Patent and Trademark Office and any
successor thereto.

          "Secured Obligations" means all liabilities, obligations, or
undertakings owing by Debtor to the Lender Group of any kind or description
arising out of or outstanding under, advanced or issued pursuant to, or
evidenced by the Loan Agreement, this Agreement, or any of the other Loan
Documents, irrespective of whether for the payment of money, whether direct or
indirect, absolute or contingent, due or to become due, voluntary or
involuntary, whether now existing or hereafter arising, and including all
interest, costs, fees (including attorneys fees), and expenses (including
interest, costs, fees, and expenses that, but for the provisions of the
Bankruptcy Code, would have accrued) and any and all other amounts which Debtor
is required to pay pursuant to any of the foregoing, by law, or otherwise.

          "Trademark Collateral" has the meaning set forth in Section 2.

          "Trademarks" has the meaning set forth in Section 2.

          "UCC" means the Uniform Commercial Code as in effect from time to time
in the State of California.

          "United States" and "U.S." each mean the United States of America.

                                       -2-

<PAGE>

               (b) Terms Defined in UCC. Where applicable and except as
otherwise defined herein, terms used in this Agreement shall have the meanings
ascribed to them in the UCC.

               (c) Interpretation. In this Agreement, except to the extent the
context otherwise requires:

                    (i)    Any reference to a Section or a Schedule is a
     reference to a section hereof, or a schedule hereto, respectively, and to a
     subsection or a clause is, unless otherwise stated, a reference to a
     subsection or a clause of the Section or subsection in which the reference
     appears.

                    (ii)   The words "hereof," "herein," "hereto," "hereunder"
     and the like mean and refer to this Agreement as a whole and not merely to
     the specific Section, subsection, paragraph or clause in which the
     respective word appears.

                    (iii)  The meaning of defined terms shall be equally
     applicable to both the singular and plural forms of the terms defined.

                    (iv)   The words "including," "includes" and "include" shall
     be deemed to be followed by the words "without limitation."

                    (v)    References to agreements and other contractual
     instruments shall be deemed to include all subsequent permitted amendments,
     restatements, supplements, refinancings, renewals, extensions, and other
     modifications thereto and thereof.

                    (vi)   References to statutes or regulations are to be
     construed as including all statutory and regulatory provisions
     consolidating, amending or replacing the statute or regulation referred to.

                    (vii)  Any captions and headings are for convenience of
     reference only and shall not affect the construction of this Agreement.

                    (viii) Capitalized words not otherwise defined herein shall
     have the respective meanings ascribed to them in the Loan Agreement.

                    (ix)   In the event of a direct conflict between the terms
     and provisions of this Agreement and the Loan Agreement,it is the intention
     of the parties hereto that such documents shall be read together and
     construed, to the fullest extent possible, to be in concert with each
     other. In the event of any actual, irreconcilable conflict that cannot be
     resolved as aforesaid, the terms and provisions of the Loan Agreement shall
     control and govern; provided, however, that the inclusion herein of
     additional obligations on the part of Debtor and supplemental rights and
     remedies in favor of Agent (whether under federal law or applicable state
     law), in each case in respect of the Trademark Collateral, shall not be
     deemed a conflict with the Loan Agreement.

          2.  Security Interest.

                                       -3-

<PAGE>

               (a) Assignment and Grant of Security in respect of the Secured
Obligations. To secure the prompt payment and performance of the Secured
Obligations, Debtor hereby grants, assigns, transfers and conveys to Agent, for
the benefit of the Lender Group, a continuing security interest in all of
Debtor's right, title and interest in and to the following property, whether now
existing or hereafter acquired or arising and whether registered or unregistered
(collectively, the "Trademark Collateral"):

                    (i)    all state(including common law)and federal
     trademarks, service marks and trade names, corporate names, company names,
     business names, fictitious business names, trade styles, trade dress,
     logos, other source or business identifiers, designs and general
     intangibles of like nature, now existing or hereafter adopted or acquired,
     together with and including all licenses therefor held by Debtor, and all
     registrations and recordings thereof, and all applications filed or to be
     filed in connection therewith, including registrations and applications in
     the PTO, any State of the United States (but excluding each application to
     register any trademark, service mark, or other mark prior to the filing
     under applicable law of a verified statement of use (or the equivalent) for
     such trademark or service mark) and all extensions or renewals thereof,
     including without limitation any of the foregoing identified on Schedule A
     hereto (as the same may be amended, modified or supplemented from time to
     time), and the right (but not the obligation) to register claims under any
     state or federal trademark law or regulation and to apply for, renew and
     extend any of the same, to sue or bring opposition or cancellation
     proceedings in Debtor's name or in the name of Agent for past, present or
     future infringement or unconsented use thereof, and all rights arising
     therefrom throughout the world (collectively, the "Trademarks");

                    (ii)   all claims, causes of action and rights to sue for
     past, present or future infringement or unconsented use of any Trademarks
     and all rights arising therefrom and pertaining thereto;

                    (iii)  all general intangibles related to or arising out of
     any of the Trademarks and all the goodwill of Debtor's business symbolized
     by the Trademarks or associated therewith; and

                    (iv)   all Proceeds of any and all of the foregoing;

provided, however, that Trademark Collateral shall not include any Excluded
Collateral.

               (b) Continuing Security Interest. Debtor hereby agrees that this
Agreement shall create a continuing security interest in the Trademark
Collateral which shall remain in effect until terminated in accordance with
Section 18.

               (c) Incorporation into Loan Agreement. This Agreement shall be
fully incorporated into the Loan Agreement and all understandings, agreements
and provisions contained in the Loan Agreement shall be fully incorporated into
this Agreement. Without limiting the foregoing, the Trademark Collateral
described in this Agreement shall constitute part of the Collateral in the Loan
Agreement.

                                       -4-

<PAGE>

               (d) Licenses. Debtor may grant licenses of the Trademark
Collateral in the ordinary course of business in accordance with the terms of
the Loan Agreement.

          3.  Further Assurances; Appointment of Agent as Attorney-in-Fact.
Debtor at its expense shall execute and deliver, or cause to be executed and
delivered, to Agent any and all documents and instruments, in form and substance
reasonably satisfactory to Agent, and take any and all action, which Agent, in
the exercise of its discretion, may request from time to time, to perfect and
continue the perfection or to maintain the priority of, or provide notice of the
security interest in the Trademark Collateral held by Agent for the benefit of
the Lender Group and to accomplish the purposes of this Agreement. If Debtor
refuses to execute and deliver, or fails timely to execute and deliver, any of
the documents it is requested to execute and deliver by Agent in accordance with
the foregoing, Agent shall have the right, in the name of Debtor, or in the name
of Agent or otherwise, without notice to or assent by Debtor, and Debtor hereby
irrevocably constitutes and appoints Agent (and any of Agent's officers or
employees or agents designated by Agent) as Debtor's true and lawful
attorney-in-fact with full power and authority, (i) to sign the name of Debtor
on all or any of such documents or instruments and perform all other acts that
Agent in the exercise of its discretion deems necessary in order to perfect or
continue the perfection of, maintain the priority or enforceability of or
provide notice of the security interest in the Trademark Collateral held by
Agent for the benefit of the Lender Group, and (ii) to execute any and all other
documents and instruments, and to perform any and all acts and things for and on
behalf of Debtor, that Agent, in the exercise of its discretion, may deem
necessary or advisable to maintain, preserve and protect the Trademark
Collateral and to accomplish the purposes of this Agreement, including (A) after
the occurrence and during the continuance of any Event of Default, to defend,
settle, adjust or institute any action, suit or proceeding with respect to the
Trademark Collateral, (B) after the occurrence and during the continuation of
any Event of Default, to assert or retain any rights under any license agreement
for any of the Trademark Collateral, and (C) after the occurrence and during the
continuance of any Event of Default, to execute any and all applications,
documents, papers and instruments for Agent to use the Trademark Collateral, to
grant or issue any exclusive or non-exclusive license with respect to any
Trademark Collateral, and to assign, convey or otherwise transfer title in or
dispose of the Trademark Collateral. The power of attorney set forth in this
Section 3, being coupled with an interest, is irrevocable so long as this
Agreement shall not have terminated in accordance with Section 18; provided that
the foregoing power of attorney shall terminate when all of the Secured
Obligations have been fully and finally repaid and performed and the Lender
Group's obligation to extend credit under the Loan Agreement is terminated. The
Agent acknowledges that the exercise of the powers granted in this Section 3 may
at some times be subject to the provisions of the Intercreditor Agreement.

          4.  Representations and Warranties. Debtor represents and warrants to
each member of the Lender Group, in each case to the best of its knowledge,
information, and belief, as follows:

               (a) No Other Trademarks. Schedule A sets forth a true and correct
list of all of Debtor's existing Trademarks that are registered, or for which
any application for registration has been filed with the PTO or any
corresponding or similar trademark office of any other U.S. jurisdiction, and
that are owned or held and used by Debtor (collectively, the

                                       -5-

<PAGE>

"Debtor's Trademarks"). Schedule A also sets forth a true and correct list of
all of the Trademarks Debtor holds by reason of license from a third party.

               (b) Trademarks Subsisting. Each of Debtor's Trademarks is
subsisting and has not been adjudged invalid or unenforceable, in whole or in
part, and, to the best of Debtor's knowledge, each of the Trademarks set forth
on Schedule A is valid and enforceable.

               (c) Ownership of Trademark Collateral; No Violation. (i) Debtor
has rights in and good and defensible title to the Trademark Collateral in
respect of the Trademarks that it owns, (ii) Debtor is the sole and exclusive
owner of such Trademark Collateral, free and clear of any Liens and rights of
others (other than Permitted Liens), including licenses (other than licenses
entered into as permitted herein), registered user agreements and covenants by
Debtor not to sue third persons, and (iii) with respect to any Trademarks for
which Debtor is either a licensor or a licensee pursuant to a license or
licensing agreement regarding such Trademark, each such license or licensing
agreement is in full force and effect, Debtor is not in material default of any
of its obligations thereunder and, to the best of Debtor's knowledge other than
(A) the parties to such licenses or licensing agreements, or (B) in the case of
any non-exclusive license or license agreement entered into by Debtor or any
such licensor regarding such Trademark, the parties to any other such
non-exclusive licenses or license agreements entered into by Debtor or any such
licensor with any other Person, no other Person has any rights in or to any of
such Trademark Collateral, other than licenses entered into as permitted herein.
To the best of Debtor's knowledge, neither the past nor the present use of the
Trademark Collateral by Debtor has or does infringe upon or violate any right,
privilege or license agreement of or with any other Person or give any such
Person the right to terminate any such right, privilege or license agreement.

               (d) No Infringement. To the best of Debtor's knowledge, (i) no
material infringement or unauthorized use presently is being made of any of the
Trademark Collateral by any Person, and (ii) neither the past nor the present
use of the Trademark Collateral by Debtor has or does infringe upon or violate
any right, privilege, or license arrangement of or with any other Person or give
such Person the right to terminate any such license arrangement.

               (e) Powers. Debtor has the unqualified right, power and authority
to pledge and to grant to Agent, for the benefit of the Lender Group, security
interests in the Trademark Collateral pursuant to this Agreement, and to
execute, deliver and perform its obligations in accordance with the terms of
this Agreement, without the consent or approval of any other Person except as
already obtained.

          5.  Covenants. So long as any of the Secured Obligations remain
unsatisfied, Debtor agrees: (i) that it will comply in all material respects
with all of the covenants, terms and provisions of this Agreement, and (ii) that
it will promptly give Agent written notice of the occurrence of any event that
could have a material adverse effect on any of the Trademarks and the Trademark
Collateral (except as to such Trademark or Trademarks, which alone or in the
aggregate, the absence of which would not reasonably be expected to materially
impair the conduct of the business), including any petition under the Bankruptcy
Code filed by or against any licensor of any of the Trademarks for which Debtor
is a licensee, provided, however, that Debtor shall not be required to preserve,
protect and maintain, and may abandon, in whole or in

                                       -6-

<PAGE>

part, any Trademark as Debtor deems appropriate in the exercise of Debtor's
reasonable business judgment, so long as the absence of such Trademark or
Trademarks, alone or in the aggregate, would not reasonably be expected to
materially impair the conduct of Debtor's business or the Trademark Collateral.

          6.  Future Rights. For so long as any of the Secured Obligations shall
remain outstanding, or, if earlier, until Agent shall have released or
terminated, in whole but not in part, its interest in the Trademark Collateral,
if and when Debtor shall obtain rights to any new Trademarks, or any reissue,
renewal or extension of any Trademarks, the provisions of Section 2 shall
automatically apply thereto and Debtor shall give to Agent prompt notice
thereof, within 20 days after obtaining such rights, reissuance, renewal, or
extension. Debtor shall do all things reasonably deemed necessary by Agent in
the exercise of its discretion to ensure the validity, perfection, priority and
enforceability of the security interests of Agent in such future acquired
Trademark Collateral. If Debtor refuses to execute and deliver, or fails timely
to execute and deliver, any of the documents it is requested to execute and
deliver by Agent in connection herewith, Debtor hereby authorizes Agent to
modify, amend or supplement the Schedules hereto and to re-execute this
Agreement from time to time on Debtor's behalf and as its attorney-in-fact to
include any future Trademarks which are or become Trademark Collateral and to
cause such re-executed Agreement or such modified, amended or supplemented
Schedules to be filed with the PTO.

          7.  Duties of Agent and the Lender Group. Notwithstanding any
provision contained in this Agreement, none of Agent or any other member of the
Lender Group shall have any duty to exercise any of the rights, privileges or
powers afforded to it and shall not be responsible to Debtor for any failure to
do so or delay in doing so. Except for the accounting for moneys actually
received by Agent, any other member of the Lender Group hereunder or in
connection herewith, none of Agent or any other member of the Lender Group shall
have any duty to exercise or preserve any rights, privileges or powers
pertaining to the Trademark Collateral.

          8.  Events of Default. The occurrence of any "Event of Default" under
the Loan Agreement shall constitute an Event of Default hereunder.

          9.  Remedies. From and after the occurrence and during the
continuation of an Event of Default, and subject to the Intercreditor Agreement,
Agent shall have all rights and remedies available to it under the Loan
Agreement, the other Loan Documents, and applicable law (which rights and
remedies are cumulative) with respect to the security interests in any of the
Trademark Collateral. Debtor hereby agrees that such rights and remedies include
the right of Agent as a secured party to sell or otherwise dispose of the
Trademark Collateral after default, pursuant to the UCC. Debtor hereby agrees
that Agent shall at all times have such royalty-free licenses, to the extent
permitted by law and the other Loan Documents, for any Trademark Collateral that
is reasonably necessary to permit the exercise of any of Agent's rights or
remedies upon or after the occurrence of (and during the continuance of) an
Event of Default with respect to (among other things) any tangible asset of
Debtor in which Agent has a security interest, including Agent's rights to sell
inventory, tooling or packaging which is acquired by Debtor (or their successor,
assignee or trustee in bankruptcy). In addition to and without limiting any of
the foregoing, upon the occurrence and during the continuance of an Event of
Default, Agent shall

                                       -7-

<PAGE>

have the right but shall in no way be obligated to bring suit, or to take such
other action as Agent, in the exercise of its discretion, deems necessary, in
the name of Debtor or Agent, to enforce or protect any of the Trademark
Collateral, in which event Debtor shall, at the request of Agent, do any and all
lawful acts and execute any and all documents required by Agent in aid of such
enforcement. To the extent that Agent shall elect not to bring suit to enforce
such Trademark Collateral, Debtor, in the exercise of its reasonable business
judgment, agrees to use all reasonable measures and its diligent efforts,
whether by action, suit, proceeding or otherwise, to prevent the infringement,
misappropriation or violation thereof by others and for that purpose agrees
diligently to maintain any action, suit or proceeding against any Person
necessary to prevent such infringement, misappropriation or violation.

          10. Binding Effect. This Agreement shall be binding upon, inure to the
benefit of and be enforceable by Debtor and Agent for the benefit of the Lender
Group and their respective successors and assigns.

          11. Notices. All notices and other communications hereunder shall be
in writing and shall be mailed, sent or delivered in accordance with the Loan
Agreement.

          12. Governing Law. This Agreement shall be governed by, and construed
and enforced in accordance with, the laws of the State of California, except to
the extent that the validity or perfection of the security interests hereunder
in respect of the Trademark Collateral are governed by federal law, in which
case such choice of California law shall not be deemed to deprive Agent of such
rights and remedies as may be available under federal law.

          13. Entire Agreement; Amendment. This Agreement and the other Loan
Documents, together with the Schedules hereto and thereto, contains the entire
agreement of the parties with respect to the subject matter hereof and supersede
all prior drafts and communications relating to such subject matter. Neither
this Agreement nor any provision hereof may be modified, amended or waived
except by the written agreement of the parties to this Agreement.
Notwithstanding the foregoing, Agent may reexecute this Agreement or modify,
amend or supplement the Schedules hereto as provided in Section 6 hereof.

          14. Severability. If one or more provisions contained in this
Agreement shall be invalid, illegal or unenforceable in any respect in any
jurisdiction or with respect to any party, such invalidity, illegality or
unenforceability in such jurisdiction or with respect to such party shall, to
the fullest extent permitted by applicable law, not invalidate or render illegal
or unenforceable any such provision in any other jurisdiction or with respect to
any other party, or any other provisions of this Agreement.

          15. Counterparts; Telefacsimile Execution. This Agreement may be
executed in any number of counterparts and by different parties hereto in
separate counterparts, each of which when so executed shall be deemed to be an
original and all of which taken together shall constitute but one and the same
agreement. Delivery of an executed counterpart of this Agreement by
telefacsimile shall be equally as effective as delivery of an original executed
counterpart of this Agreement. Any party delivering an executed counterpart of
this Agreement by telefacsimile also shall deliver an original

                                       -8-

<PAGE>

executed counterpart of this Agreement but the failure to deliver an original
executed counterpart shall not affect the validity, enforceability, and binding
effect of this Agreement.

          16. Loan Documents. Debtor acknowledges that the rights and remedies
of Agent with respect to the security interest in the Trademark Collateral
granted hereby are more fully set forth in the Loan Agreement and the other Loan
Documents and all such rights and remedies are cumulative.

          17. No Inconsistent Requirements. Debtor acknowledges that this
Agreement, the Loan Agreement, and the other Loan Documents may contain
covenants and other terms and provisions variously stated regarding the same or
similar matters, and Debtor agrees that all such covenants, terms and provisions
are cumulative and all shall be performed and satisfied in accordance with their
respective terms.

          18. Termination. Upon the indefeasible payment and performance in full
of the Secured Obligations, including the cash collateralization, expiration, or
cancellation of all Secured Obligations, if any, consisting of letters of
credit, and the full and final termination of any commitment to extend any
financial accommodations under the Loan Agreement, this Agreement shall
terminate, and Agent shall execute and deliver such documents and instruments
and take such further action reasonably requested by Debtor, at Debtor's
expense, as shall be necessary to evidence termination of the security interest
granted by Debtor to Agent for the benefit of the Lender Group hereunder,
including cancellation of this Agreement by written notice from Agent to the
PTO.

                            [Signature page follows]

                                       -9-

<PAGE>

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

                                        HUDSON RESPIRATORY CARE INC.,
                                        a California corporation

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

                                        MW POST ADVISORY GROUP, LLC,
                                        a Delaware limited liability company,
                                        as Agent

                                        By:
                                           -------------------------------------
                                        Name: Lawrence Post
                                        Title: Chief Executive Officer

                                                                  Signature Page
                                                    Trademark Security Agreement

<PAGE>

                                   SCHEDULE A
                                   ----------

                              Trademarks of Debtor
                              --------------------

                                 [see attached]

                                       -1-

<PAGE>

                               Trademark Licenses
                               ------------------

                                      None

                                       -2-

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