Exhibit
4.12


SUPPLEMENTAL
INDENTURE NO. 6


THIS SUPPLEMENTAL
INDENTURE NO. 6 (this “Supplemental Indenture”), dated as of November 28,
2006, is among Electrolyte Acquisition Subsidiary, Inc., a Delaware corporation
(the “Guaranteeing Subsidiary”), subsidiary of EmCare, Inc., a Delaware
corporation, the Issuers (as defined in the Indenture referred to herein), the
other Guarantors (as defined in the Indenture) and U.S. Bank Trust National
Association, as trustee under the Indenture referred to below (the “Trustee”).


W I T N E S S E T
H


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


WHEREAS, the
Indenture provides that under certain circumstances the Guaranteeing Subsidiary
shall execute and deliver to the Trustee a supplemental indenture pursuant to
which the Guaranteeing Subsidiary shall unconditionally guarantee all of the
Issuers’ Obligations under the Notes and the Indenture on the terms and
conditions set forth herein (the “Subsidiary Guarantee”); and


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


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


1.             Capitalized Terms.  Capitalized terms used herein without
definition shall have the meanings assigned to them in the Indenture.


2.             Agreement to Guarantee.  The Guaranteeing Subsidiary hereby agrees as
follows:


(a)           Along with all other Guarantors, to
jointly and severally unconditionally Guarantee to each Holder of a Note
authenticated and delivered by the Trustee and to the Trustee and its
successors and assigns, irrespective of the validity and enforceability of the
Indenture, the Notes or the obligations of the Issuers hereunder or thereunder,
that:


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











 


(ii)           in case of any extension of time of
payment or renewal of any Notes or any of such other obligations, that same
will be promptly paid in full when due or performed in accordance with the
terms of the extension or renewal, whether at stated maturity, by acceleration
or otherwise.  Failing payment when due
of any amount so guaranteed or any performance so guaranteed for whatever
reason, the Guarantors shall be jointly and severally obligated to pay the same
immediately.  Each Guarantor agrees that
this is a guarantee of payment and not a guarantee of collection.


(b)           The obligations hereunder shall be
unconditional, irrespective of the validity, regularity or enforceability of
the Notes or the Indenture, the absence of any action to enforce the same, any
waiver or consent by any Holder of the Notes with respect to any provisions
hereof or thereof, the recovery of any judgment against the Issuers, any action
to enforce the same or any other circumstance which might otherwise constitute
a legal or equitable discharge or defense of a Guarantor.  Subject to Section 6.06 of the Indenture,
each Guarantor hereby waives diligence, presentment, demand of payment, filing
of claims with a court in the event of insolvency or bankruptcy of an Issuer,
any right to require a proceeding first against an Issuer, protest, notice and
all demands whatsoever and covenant that this Subsidiary Guarantee shall not be
discharged except by complete performance of the obligations contained in the
Notes and the Indenture.


(c)           If any Holder or the Trustee is
required by any court or otherwise to return to the Issuers, the Guarantors, or
any Custodian, Trustee, liquidator or other similar official acting in relation
to either the Issuers or the Guarantors, any amount paid by either to the
Trustee or such Holder, this Subsidiary Guarantee, to the extent theretofore
discharged, shall be reinstated in full force and effect.


(d)           The Guaranteeing Subsidiary shall not
be entitled to any right of subrogation in relation to the Holders in respect
of any obligations guaranteed hereby until payment in full of all obligations
guaranteed hereby.  The Guaranteeing
Subsidiary further agrees that, as between the Guarantors, on the one hand, and
the Holders and the Trustee, on the other hand, (x) the maturity of the
obligations guaranteed hereby may be accelerated as provided in Article 6 of
the Indenture for the purposes of this Subsidiary Guarantee, notwithstanding
any stay, injunction or other prohibition preventing such acceleration in
respect of the obligations guaranteed hereby, and (y) in the event of any
declaration of acceleration of such obligations as provided in Article 6 of the
Indenture, such obligations (whether or not due and payable) shall forthwith become
due and payable by the Guarantors for the purpose of this Subsidiary
Guarantee.  The Guarantors shall have the
right to seek contribution from any non-paying Guarantor so long as the
exercise of such right does not impair the rights of the Holders under the
Guarantee.


(e)           Pursuant to Section 11.03 of the
Indenture, after giving effect to any maximum amount and any other contingent
and fixed liabilities that are relevant under any applicable Bankruptcy or
fraudulent conveyance laws, and after giving effect to any collections from,
rights to receive contribution from or payments made by or on behalf of any
other Guarantor in respect of the obligations of such other Guarantor under
Article 11 of the Indenture shall result in the obligations of such Guarantor
under its Subsidiary Guarantee not constituting a fraudulent transfer or
conveyance.











 


3.             Execution and Delivery.  Each Guaranteeing Subsidiary agrees that the
Subsidiary Guarantees shall remain in full force and effect notwithstanding any
failure to endorse on each Note a notation of such Subsidiary Guarantee.


4.             Releases.


(a)           The Subsidiary Guarantee of a
Subsidiary Guarantor shall be released:


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


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


(iii)          in connection with any transaction
which results in a Subsidiary Guarantor ceasing to be a Restricted Subsidiary
of an Issuer, if the transaction is not in violation of the applicable
provisions of the Indenture;


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


(v)           if a Subsidiary Guarantor has no
outstanding Indebtedness after giving effect to such release other than
pursuant to clause (2), (4), (5), (6) (with respect to Permitted Refinancing
Indebtedness in respect of Indebtedness initially incurred under clause (2) or
(5) only), (7), (10), (11), (12), (13), (14) or (15) of Section 4.09 of the Indenture
or pursuant to clause (9) of Section 4.09 of the Indenture (with respect to
Indebtedness incurred under any of the foregoing clauses) and an Officers’
Certificate certifying the foregoing is presented to the Trustee together with
a request to release such Subsidiary Guarantor from its Subsidiary Guarantee.


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


(b)           Any Subsidiary Guarantor not released
from its obligations under its Subsidiary Guarantee shall remain liable for the
full amount of principal of and interest on the Notes and for the other
obligations of any Guarantor under the Indenture as provided in Article 11 of
the Indenture.











 


5.             No Recourse Against Others.  No past, present or future director, officer,
employee, incorporator, stockholder or agent of Parent or the Guaranteeing
Subsidiary, as such, shall have any liability for any obligations of the
Issuers, Parent or any Guaranteeing Subsidiary under the Notes, any Guarantees,
the Indenture or this Supplemental Indenture or for any claim based on, in
respect of, or by reason of, such obligations or their creation.  Each Holder of the Notes by accepting a Note
waives and releases all such liability. 
The waiver and release are part of the consideration for issuance of the
Notes.  Such waiver may not be effective
to waive liabilities under the federal securities laws and it is the view of
the SEC that such a waiver is against public policy.


6.             NEW YORK LAW TO GOVERN.  THE INTERNAL LAW OF THE STATE OF NEW YORK
SHALL GOVERN AND BE USED TO CONSTRUE THIS SUPPLEMENTAL INDENTURE BUT WITHOUT
GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT
THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.


7.             Counterparts. 
The parties may sign any number of copies of this Supplemental
Indenture.  Each signed copy shall be an
original, but all of them together represent the same agreement.


8.             Effect of Headings.  The Section headings herein are for
convenience only and shall not affect the construction hereof.


9.             The Trustee. 
The Trustee shall not be responsible in any manner whatsoever for or in
respect of the validity or sufficiency of this Supplemental Indenture or for or
in respect of the recitals contained herein, all of which recitals are made
solely by the Guaranteeing Subsidiary and the Issuers.


[Remainder of Page Left Intentionally Blank]











 


IN WITNESS WHEREOF,
the parties hereto have caused this Supplemental Indenture to be duly executed
and attested, all as of the date first above written.


ELECTROLYTE ACQUISITION SUBSIDIARY, INC.


 


	
  By:

  	
   

  	
  /s/ WILLIAM A. SANGER

  	
   

  	
   

  
	
  Name:

  	
   

  	
  William A. Sanger

  	
   

  	
   

  
	
  Title:

  	
   

  	
  President

  	
   

  	
   

  



 


AMR HOLDCO, INC. n/k/a EMSC MANAGEMENT, 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


 


[Signature Page to Sixth
Supplemental Indenture]











 


METROPOLITAN AMBULANCE SERVICE


AMERICAN MEDICAL RESPONSE OF INLAND EMPIRE


DESERT VALLEY MEDICAL TRANSPORT, INC.


SPRINGS AMBULANCE SERVICE, INC.


AMERICAN MEDICAL RESPONSE OF COLORADO, INC.


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.


 


[Signature Page to Sixth
Supplemental Indenture]











 


 


 


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.


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.


[Signature Page to Sixth
Supplemental Indenture]


 











 


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.


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


[Signature Page to Sixth
Supplemental Indenture]


 


 











 


EMS MANAGEMENT LLC


By: EMSC Management, 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.


PROVIDER ACCOUNT MANAGEMENT, INC.


CHARLES T. MITCHELL, M.D., INC.


GLOBAL MEDICAL RESPONSE, INC.


AIR AMBULANCE SPECIALISTS, INC.


EMCARE OF MARYLAND LLC,


By: EmCare Holdings Inc. and EmCare, Inc., its members


 


	
  By:

  	
   

  	
  /s/ WILLIAM A. SANGER

  	
   

  	
   

  
	
  Name:

  	
   

  	
  William A. Sanger

  	
   

  	
   

  
	
  Title:

  	
   

  	
  Chief Executive Officer

  	
   

  	
   

  



 


U.S. BANK TRUST NATIONAL ASSOCIATION, as Trustee


 


	
  By:

  	
   

  	
  /s/ PAUL SCHMALZEL

  	
   

  	
   

  
	
  Name:

  	
   

  	
  Paul Schmalzel

  	
   

  	
   

  
	
  Title:

  	
   

  	
  Vice President

  	
   

  	
   

  



 


[Signature Page to Sixth
Supplemental Indenture]