**Exhibit 4.18**

 

**SUPPLEMENTAL INDENTURE NO. 12**

 

THIS SUPPLEMENTAL INDENTURE NO.12 (this “Supplemental Indenture”), dated as of March 28, 2008, isamong River Medical Incorporated, an Arizona corporation and a wholly ownedsubsidiary of Arizona Oasis Acquisition, Inc. (the “GuaranteeingSubsidiary”); the Issuers (as defined in the Indenture referred to herein);the other Guarantors (as defined in the Indenture); and U.S. Bank TrustNational Association, as trustee under the Indenture referred to below (the “Trustee”).

 

W I T N E S SE T H

 

WHEREAS, the Issuers and theGuarantors party thereto have heretofore executed and delivered to the Trusteean indenture (the “Indenture”), dated as of February 10, 2005providing for the issuance of 10% Senior Subordinated Notes due 2015 (the “Notes”);

 

WHEREAS, the Indenture providesthat under certain circumstances the Guaranteeing Subsidiary shall execute anddeliver to the Trustee a supplemental indenture pursuant to which theGuaranteeing Subsidiary shall unconditionally guarantee all of the Issuers’Obligations under the Notes and the Indenture on the terms and conditions setforth herein (the guarantee of the Guaranteeing Subsidiary is referred toherein as a “Subsidiary Guarantee”); and

 

WHEREAS, pursuant to Section 9.01of the Indenture, the Trustee is authorized to execute and deliver thisSupplemental Indenture.

 

NOW THEREFORE, in considerationof the foregoing and for other good and valuable consideration, the receipt ofwhich is hereby acknowledged, the Guaranteeing Subsidiary and the Trusteemutually covenant and agree for the equal and ratable benefit of the Holders ofthe Notes as follows:

 

# 1.             CapitalizedTerms.  Capitalized terms used hereinwithout definition shall have the meanings assigned to them in the Indenture.

#  

# 2.             Agreementto Guarantee.  The GuaranteeingSubsidiary hereby agrees as follows with respect to its Subsidiary Guarantee:

#  

## (a)           Alongwith all other Guarantors, to jointly and severally unconditionally Guaranteeto each Holder of a Note authenticated and delivered by the Trustee and to theTrustee and its successors and assigns, irrespective of the validity andenforceability of the Indenture, the Notes or the obligations of the Issuershereunder or thereunder, that:

##  

### (i)            the principal of and interest on theNotes will be promptly paid in full when due, whether at maturity, byacceleration, redemption or otherwise, and interest on the overdue principal ofand interest on the Notes, if any, if lawful, and all other obligations of theIssuers to the Holders or the Trustee hereunder or thereunder will be promptlypaid in full or performed, all in accordance with the terms hereof and thereof;and

 

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### (ii)           in case of any extension of time ofpayment or renewal of any Notes or any of such other obligations, that samewill be promptly paid in full when due or performed in accordance with theterms of the extension or renewal, whether at stated maturity, by accelerationor otherwise.  Failing payment when dueof any amount so guaranteed or any performance so guaranteed for whateverreason, the Guarantors shall be jointly and severally obligated to pay the sameimmediately.  Each Guarantor agrees thatthis is a guarantee of payment and not a guarantee of collection.

###  

## (b)           Theobligations hereunder shall be unconditional, irrespective of the validity,regularity or enforceability of the Notes or the Indenture, the absence of anyaction to enforce the same, any waiver or consent by any Holder of the Noteswith respect to any provisions hereof or thereof, the recovery of any judgmentagainst the Issuers, any action to enforce the same or any other circumstancewhich might otherwise constitute a legal or equitable discharge or defense of aGuarantor.  Subject to Section 6.06of the Indenture, each Guarantor hereby waives diligence, presentment, demandof payment, filing of claims with a court in the event of insolvency orbankruptcy of an Issuer, any right to require a proceeding first against anIssuer, protest, notice and all demands whatsoever and covenant that this SubsidiaryGuarantee shall not be discharged except by complete performance of theobligations contained in the Notes and the Indenture.

##  

## (c)           Ifany Holder or the Trustee is required by any court or otherwise to return tothe Issuers, the Guarantors, or any Custodian, Trustee, liquidator or othersimilar official acting in relation to either the Issuers or the Guarantors,any amount paid by either to the Trustee or such Holder, this SubsidiaryGuarantee, to the extent theretofore discharged, shall be reinstated in fullforce and effect.

##  

## (d)           TheGuaranteeing Subsidiary shall not be entitled to any right of subrogation inrelation to the Holders in respect of any obligations guaranteed hereby untilpayment in full of all obligations guaranteed hereby.  The Guaranteeing Subsidiary further agreesthat, as between the Guarantors, on the one hand, and the Holders and theTrustee, on the other hand, (x) the maturity of the obligations guaranteedhereby may be accelerated as provided in Article 6 of the Indenture forthe purposes of this Subsidiary Guarantee, notwithstanding any stay, injunctionor other prohibition preventing such acceleration in respect of the obligationsguaranteed hereby, and (y) in the event of any declaration of accelerationof such obligations as provided in Article 6 of the Indenture, suchobligations (whether or not due and payable) shall forthwith become due andpayable by the Guarantors for the purpose of this Subsidiary Guarantee.  The Guarantors shall have the right to seekcontribution from any non-paying Guarantor so long as the exercise of suchright does not impair the rights of the Holders under the Guarantee.

##  

## (e)           Pursuantto Section 11.03 of the Indenture, after giving effect to any maximumamount and any other contingent and fixed liabilities that are relevant underany applicable Bankruptcy or fraudulent conveyance laws, and after givingeffect to any collections from, rights to receive contribution from or paymentsmade by or on behalf of any other Guarantor in respect of the obligations ofsuch other Guarantor under Article 11 of the Indenture 

 

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## shall result in theobligations of such Guarantor under its Subsidiary Guarantee not constituting afraudulent transfer or conveyance.

##  

# 3.                                      Execution and Delivery.  The Guaranteeing Subsidiary agrees that theSubsidiary Guarantee shall remain in full force and effect notwithstanding anyfailure to endorse on each Note a notation of such Subsidiary Guarantee.

#  

# 4.                                      Releases.

##  

## (a)           TheSubsidiary Guarantee of a Subsidiary Guarantor shall be released:

##  

### (i)            in connection with any sale or otherdisposition of all or substantially all of the assets of that SubsidiaryGuarantor (including by way of merger or consolidation), if the Issuer thatdirectly or indirectly owns such Subsidiary Guarantor applies the Net Proceedsof such sale or other disposition, in accordance with the applicable provisionsof the Indenture;

###  

### (ii)           in connection with the sale of all ofthe capital stock of a Subsidiary Guarantor, if the Issuer that directly orindirectly owns such Subsidiary Guarantor applies the Net Proceeds of thatsale, in accordance with the applicable provisions of the Indenture;

###  

### (iii)          in connection with any transactionwhich results in a Subsidiary Guarantor ceasing to be a Restricted Subsidiaryof an Issuer, if the transaction is not in violation of the applicableprovisions of the Indenture;

###  

### (iv)          if an Issuer designates any RestrictedSubsidiary of such Issuer that is a Subsidiary Guarantor as an UnrestrictedSubsidiary, in accordance with the applicable provisions of the Indenture; or

###  

### (v)           if a Subsidiary Guarantor has nooutstanding Indebtedness after giving effect to such release other thanpursuant to clause (2), (4), (5), (6) (with respect to PermittedRefinancing Indebtedness in respect of Indebtedness initially incurred underclause (2) or (5) only), (7), (10), (11), (12), (13), (14) or (15) ofSection 4.09 of the Indenture or pursuant to clause (9) of Section 4.09of the Indenture (with respect to Indebtedness incurred under any of theforegoing clauses) and an Officers’ Certificate certifying the foregoing ispresented to the Trustee together with a request to release such SubsidiaryGuarantor from its Subsidiary Guarantee.

###  

Upon delivery by the Issuers tothe Trustee of an Officers’ Certificate and an Opinion of Counsel to the effectthat such sale or other disposition was made by the Issuers in accordance withthe provisions of the Indenture, including without limitation Section 4.10of the Indenture, the Trustee shall execute any documents reasonably requiredin order to evidence the release of any Subsidiary Guarantor from itsobligations under its Subsidiary Guarantee.

 

## (b)           AnySubsidiary Guarantor not released from its obligations under its SubsidiaryGuarantee shall remain liable for the full amount of principal of and intereston the 

 

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## Notes and for theother obligations of any Guarantor under the Indenture as provided in Article 11of the Indenture.

##  

# 5.             NoRecourse Against Others.  No past,present or future director, officer, employee, incorporator, stockholder oragent of Parent or the Guaranteeing Subsidiary, as such, shall have anyliability for any obligations of the Issuers, Parent or the GuaranteeingSubsidiary under the Notes, any Guarantees, the Indenture, or this SupplementalIndenture or for any claim based on, in respect of, or by reason of, suchobligations or their creation.  EachHolder of the Notes by accepting a Note waives and releases all suchliability.  The waiver and release arepart of the consideration for issuance of the Notes.  Such waiver may not be effective to waiveliabilities under the federal securities laws and it is the view of the SECthat such a waiver is against public policy.

#  

# 6.             NEWYORK LAW TO GOVERN.  THE INTERNAL LAWOF THE STATE OF NEW YORK SHALL GOVERN AND BE USED TO CONSTRUE THIS SUPPLEMENTALINDENTURE BUT WITHOUT GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OFLAW TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTIONWOULD BE REQUIRED THEREBY.

#  

# 7.             Counterparts.  The parties may sign any number of copies ofthis Supplemental Indenture.  Each signedcopy shall be an original, but all of them together represent the sameagreement.

#  

# 8.             Effectof Headings.  The Section headingsherein are for convenience only and shall not affect the construction hereof.

#  

# 9.             TheTrustee.  The Trustee shall not beresponsible in any manner whatsoever for or in respect of the validity orsufficiency of this Supplemental Indenture or for or in respect of the recitalscontained herein, all of which recitals are made solely by the Guaranteeing Subsidiaryand the Issuers.

 

*{Signature Page Follows}*

 

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IN WITNESS WHEREOF, the partieshereto have caused this Supplemental Indenture to be duly executed andattested, all as of the date first above written.

 

 
| RIVER MEDICAL INCORPORATED                                      |                    |
|-----------------------------------------------------------------|-------------------------|
|                                                            |                    |   |
| By:                                                             | /s/ William A. Sanger   |   |
| Name:                                                           | William A. Sanger       |   |
| Title:                                                          | Chief Executive Officer |   |
|                                                            |                    |   |
|                                                            |                    |   |
| AMR HOLDCO, INC.                                                |                    |
|                                                            |                    |   |
| By:                                                             | /s/ William A. Sanger   |   |
| Name:                                                           | William A. Sanger       |   |
| Title:                                                          | Chief Executive Officer |   |
|                                                            |                    |   |
|                                                            |                    |   |
| EMCARE HOLDCO, INC.                                             |                    |
|                                                            |                    |   |
| By:                                                             | /s/ William A. Sanger   |   |
| Name:                                                           | William A. Sanger       |   |
| Title:                                                          | Chief Executive Officer |   |
|                                                            |                    |   |
|                                                            |                    |   |
| EMERGENCY MEDICAL SERVICES L.P.                                 |                    |
| By: Emergency Medical Services Corporation, its general partner |                    |
|                                                            |                    |   |
|                                                            |                    |   |
| By:                                                             | /s/ William A. Sanger   |   |
| Name:                                                           | William A. Sanger       |   |
| Title:                                                          | Chief Executive Officer |   |
|                                                            |                    |   |
|                                                            |                    |   |
| AMERICAN MEDICAL RESPONSE, INC.                                 |
| HANK’S ACQUISITION CORP.                                   |
| FOUNTAIN AMBULANCE SERVICE, INC.                                |
| MEDLIFE EMERGENCY MEDICAL SERVICE, INC.                         |
| AMERICAN MEDICAL RESPONSE NORTHWEST, INC.                       |
| AMERICAN MEDICAL RESPONSE WEST                                  |
| METROPOLITAN AMBULANCE SERVICE                                  |
| AMERICAN MEDICAL RESPONSE OF INLAND EMPIRE                      |
| DESERT VALLEY MEDICAL TRANSPORT, INC.                           |
| SPRINGS AMBULANCE SERVICE, INC.                                 |
| AMERICAN MEDICAL RESPONSE OF COLORADO, INC.                     |

 

 

[Signature Page to Supplemental Indenture No. 12]

 

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| INTERNATIONAL LIFE SUPPORT, INC.                        |
|---------------------------------------------------------|
| MEDEVAC MIDAMERICA, INC.                                |
| MEDEVAC MEDICAL RESPONSE, INC.                          |
| AMERICAN MEDICAL RESPONSE OF OKLAHOMA, INC.             |
| AMERICAN MEDICAL RESPONSE OF TEXAS, INC.                |
| KUTZ AMBULANCE SERVICE, INC.                            |
| AMERICAN MEDICAL RESPONSE HOLDINGS, INC.                |
| AMERICAN MEDICAL RESPONSE MANAGEMENT, INC.              |
| A1 LEASING, INC.                                        |
| FLORIDA EMERGENCY PARTNERS, INC.                        |
| MOBILE MEDIC AMBULANCE SERVICE, INC.                    |
| METRO AMBULANCE SERVICE, INC.                           |
| METRO AMBULANCE SERVICE (RURAL), INC.                   |
| MEDIC ONE AMBULANCE SERVICES, INC.                      |
| AMERICAN MEDICAL RESPONSE OF SOUTH CAROLINA, INC.       |
| AMERICAN MEDICAL RESPONSE OF NORTH CAROLINA, INC.       |
| AMERICAN MEDICAL RESPONSE OF GEORGIA, INC.              |
| TROUP COUNTY EMERGENCY MEDICAL SERVICES, INC.           |
| RANDLE EASTERN AMBULANCE SERVICE, INC.                  |
| MEDI-CAR SYSTEMS, INC.                                  |
| MEDI-CAR AMBULANCE SERVICE, INC.                        |
| AMERICAN MEDICAL RESPONSE OF TENNESSEE, INC.            |
| PHYSICIANS & SURGEONS AMBULANCE SERVICE, INC.  |
| AMERICAN MEDICAL RESPONSE OF ILLINOIS, INC.             |
| MIDWEST AMBULANCE MANAGEMENT COMPANY                    |
| PARAMED, INC.                                           |
| MERCY AMBULANCE OF EVANSVILLE, INC.                     |
| TIDEWATER AMBULANCE SERVICE, INC.                       |
| AMERICAN MEDICAL RESPONSE OF CONNECTICUT,  INCORPORATED |
| AMERICAN MEDICAL RESPONSE OF MASSACHUSETTS, INC.        |
| AMERICAN MEDICAL RESPONSE MID-ATLANTIC, INC.            |
| AMBULANCE ACQUISITION, INC.                             |
| METRO AMBULANCE SERVICES, INC.                          |
| BROWARD AMBULANCE, INC.                                 |
| ATLANTIC AMBULANCE SERVICES ACQUISITION, INC.           |
| ATLANTIC/KEY WEST AMBULANCE, INC.                       |
| ATLANTIC/PALM BEACH AMBULANCE, INC.                     |
| SEMINOLE COUNTY AMBULANCE, INC.                         |
| LIFEFLEET SOUTHEAST, INC.                               |
| AMERICAN MEDICAL PATHWAYS, INC.                         |
| ADAM TRANSPORTATION SERVICE, INC.                       |
| ASSOCIATED AMBULANCE SERVICE, INC.                      |
| PARK AMBULANCE SERVICE INC.                             |
| FIVE COUNTIES AMBULANCE SERVICE, INC.                   |
| SUNRISE HANDICAP TRANSPORT CORP.                        |

 

 

[Signature Page to Supplemental Indenture No. 12]

 

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| STAT HEALTHCARE, INC.                                                      |
|----------------------------------------------------------------------------|
| LAIDLAW MEDICAL TRANSPORTATION, INC.                                       |
| MERCY, INC.                                                                |
| AMERICAN INVESTMENT ENTERPRISES, INC.                                      |
| LIFECARE AMBULANCE SERVICE, INC.                                           |
| TEK, INC.                                                                  |
| MERCY LIFE CARE                                                            |
| HEMET VALLEY AMBULANCE SERVICE, INC.                                       |
| AMERICAN MEDICAL RESPONSE OF SOUTHERN  CALIFORNIA  MEDIC ONE OF COBB, INC. |
| PUCKETT AMBULANCE SERVICE, INC.                                            |
| AMERICAN MEDICAL RESPONSE DELAWARE VALLEY, LLC                             |
| By: American Medical Response Mid-Atlantic, Inc., its sole  member    |
| REGIONAL EMERGENCY SERVICES, LP                                            |
| By: Florida Emergency Partners, Inc., its general partner             |
| PROVIDACARE, L.L.C.                                                        |
| By: American Medical Pathways, Inc., its sole member                  |
| AMR BROCKTON, L.L.C.                                                       |
| By: American Medical Response of Massachusetts, Inc., its  manager    |
|                                                                       |
|                                                                       |
| By:                                                                        | /s/ Randel G. Owen |   |
| Name:                                                                      | Randel G. Owen |   |
| Title:                                                                     | Vice President |   |
|                                                                       |
|                                                                       |
| EMCARE HOLDINGS INC.                                                       |
| EMCARE, INC.                                                               |
| EMCARE OF ALABAMA, INC.                                                    |
| EMCARE CONTRACT OF ARKANSAS, INC.                                          |
| EMCARE OF ARIZONA, INC.                                                    |
| EMCARE OF CALIFORNIA, INC.                                                 |
| EMCARE OF COLORADO, INC.                                                   |
| EMCARE OF CONNECTICUT, INC.                                                |
| EMCARE OF FLORIDA, INC.                                                    |
| EMCARE OF GEORGIA, INC.                                                    |
| EMCARE OF HAWAII, INC.                                                     |
| EMCARE OF INDIANA, INC.                                                    |
| EMCARE OF IOWA, INC.                                                       |
| EMCARE OF KENTUCKY, INC.                                                   |
| EMCARE OF LOUISIANA, INC.                                                  |
| EMCARE OF MAINE, INC.                                                      |
| EMCARE OF MICHIGAN, INC.                                                   |
| EMCARE OF MINNESOTA, INC.                                                  |
| EMCARE OF MISSISSIPPI, INC.                                                |
| EMCARE OF MISSOURI, INC.                                                   |

 

 

[Signature Page to Supplemental Indenture No. 12]

 

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| EMCARE OF NEVADA, INC.                                              |
|---------------------------------------------------------------------|
| EMCARE OF NEW HAMPSHIRE, INC.                                       |
| EMCARE OF NEW JERSEY, INC.                                          |
| EMCARE OF NEW MEXICO, INC.                                          |
| EMCARE OF NEW YORK, INC.                                            |
| EMCARE OF NORTH CAROLINA, INC.                                      |
| EMCARE OF NORTH DAKOTA, INC.                                        |
| EMCARE OF OHIO, INC.                                                |
| EMCARE OF OKLAHOMA, INC.                                            |
| EMCARE OF OREGON, INC.                                              |
| EMCARE OF PENNSYLVANIA, INC.                                        |
| EMCARE OF RHODE ISLAND, INC.                                        |
| EMCARE OF SOUTH CAROLINA, INC.                                      |
| EMCARE OF TENNESSEE, INC.                                           |
| EMCARE OF TEXAS, INC.                                               |
| EMCARE OF VERMONT, INC.                                             |
| EMCARE OF VIRGINIA, INC.                                            |
| EMCARE OF WASHINGTON, INC.                                          |
| EMCARE OF WEST VIRGINIA, INC.                                       |
| EMCARE OF WISCONSIN, INC.                                           |
| EMCARE PHYSICIAN PROVIDERS, INC.                                    |
| EMCARE PHYSICIAN SERVICES, INC.                                     |
| EMCARE SERVICES OF ILLINOIS, INC.                                   |
| EMCARE SERVICES OF MASSACHUSETTS, INC.                              |
| EMCARE ANESTHESIA SERVICES, INC.                                    |
| ECEP, INC.                                                          |
| COORDINATED HEALTH SERVICES, INC.                                   |
| EM-CODE REIMBURSEMENT SOLUTIONS, INC.                               |
| EMERGENCY MEDICINE EDUCATION SYSTEMS, INC.                          |
| EMERGENCY SPECIALISTS OF ARKANSAS, INC. II                          |
| FIRST MEDICAL/EMCARE, INC.                                          |
| HEALTHCARE ADMINISTRATIVE SERVICES, INC.                            |
| OLD STAT, INC.                                                      |
| REIMBURSEMENT TECHNOLOGIES, INC.                                    |
| STAT PHYSICIANS, INC.                                               |
| THE GOULD GROUP, INC.                                               |
| TIFTON MANAGEMENT SERVICES, INC.                                    |
| TUCKER EMERGENCY SERVICES, INC.                                     |
| EMERGENCY MEDICAL SERVICES CORPORATION                              |
| EMS MANAGEMENT LLC                                                  |
| By: AMR Holdco, Inc. and EmCare Holdco, Inc., its members |
| HELIX PHYSICIANS MANAGEMENT, INC.                                   |
| NORMAN BRUCE JETTON, INC.                                           |
| PACIFIC EMERGENCY SPECIALISTS MANAGEMENT, INC.                      |
| AMERICAN EMERGENCY PHYSICIANS MANAGEMENT, INC.                      |
| PHYSICIAN ACCOUNT MANAGEMENT, INC.                                  |

 

 

[Signature Page to Supplemental Indenture No. 12]

 

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| PROVIDER ACCOUNT MANAGEMENT, INC.                           |
|-------------------------------------------------------------|
| CHARLES T. MITCHELL, M.D., INC.                             |
| GLOBAL MEDICAL RESPONSE, INC.                               |
| AIR AMBULANCE SPECIALISTS, INC.                             |
| EHR MANAGEMENT CO.                                          |
| EMCARE OF MARYLAND LLC,                                     |
| By: EmCare Holdings Inc. and EmCare, Inc., its members |
| NEVADA RED ROCK HOLDINGS, INC.                              |
| NEVADA RED ROCK AMBULANCE, INC.                             |
| MEDICWEST HOLDINGS, INC.                                    |
| MEDICWEST AMBULANCE, INC.                                   |
| MISSION CARE  SERVICES, LLC                                 |
| By: American  Medical Response, Inc., its manager      |
| MISSION CARE  OF ILLINOIS, LLC                              |
| By: Mission  Care Services, Inc., its manager          |
| By: American  Medical Response, Inc., its manager      |
| MISSION CARE  OF MISSOURI, LLC                              |
| By: Mission  Care Services, Inc., its manager          |
| By: American  Medical Response, Inc., its manager      |
| ACCESS2CARE,  LLC                                           |
| By: Mission  Care Services, Inc., its manager          |
| By: American  Medical Response, Inc., its manager      |
| ABBOTT  AMBULANCE, INC.                                     |
| ARIZONA  OASIS ACQUISITION, INC.                            |
| RADIOLOGY  STAFFING SOLUTIONS, INC.                         |
| RADSTAFFING  MANAGEMENT SOLUTIONS, INC.                     |
|                                                        |
|                                                        |
| By:                                                         | /s/ William A. Sanger |   |
| Name:                                                       | William A. Sanger |   |
| Title:                                                      | Chief Executive Officer |   |
|                                                        |
|                                                        |
| U.S. BANK TRUST NATIONAL ASSOCIATION, as Trustee            |
|                                                        |   |   |
|                                                        |   |   |
| By:                                                         | /s/ John J. Doherty |   |
| Name:                                                       | John J. Doherty |   |
| Title:                                                      | Vice President |   |

 

 

[Signature Page to Supplemental Indenture No. 12]

 

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