Oklahoma Leadership

2024-2025 Chapter Leadership

The Oklahoma chapter of HFMA continues to function based on the volunteer efforts of our members. Below are the chapter’s current elected officers, directors and committee chairs. If you would like to volunteer your time and efforts in any capacity, please reach out to any of these chapter leaders.


Phillip Smith


Phillip is INSURICA’s Healthcare Practice Group Leader. From his years of experience in the Healthcare industry, Phillip protects the assets of healthcare professionals, hospitals, and facilities through risk management and insurance solutions. Phillip is also an adjunct instructor at the University of Central Oklahoma and Mid-America Christian University where he teaches insurance and risk management, healthcare policy, management and leadership, and organizational behavior with a key focus on business ethics.

Darren Walkup

Commerce Healthcare

Darren Walkup is a Sr. Vice President in the Commercial Bank at Commerce Bank and leads the Commerce Healthcare division for Oklahoma. Darren’s primary responsibilities include relationship management of current relationships as well as expanding Commerce’s Healthcare service offerings to all healthcare institutions across the State of Oklahoma. He received his BA in Finance from the University of Oklahoma in Norman and has an MBA in Accounting from Rockhurst University in Kansas City, MO. Before attending college, he served 5 years active duty in the United States Army. Darren currently serves on the Board of OK HFMA as well as the Board for the Community Food Bank of Eastern Oklahoma and is a past Board member for Tulsa Historical Society and the Arts & Humanities Council of Tulsa (now known as AHHA). 

Mike Lorenz


Mike is a recent transplant to the Oklahoma City area when he joined INTEGRIS Health in 2019 and is the Director of Revenue Cycle for hospital and physician clinic operations.  He has over 20 years’ experience in the accounts receivable arena of which the last nine years have been in acute care hospitals and long term care facilities.  Mike enjoys spending his spare time with his wife and family exploring the area or travelling to favorite destinations.  He also has been producing off-road motorcycle racing events for over 30 years and enjoys participating in races with the two youngest of his three children. 

Lisa Postelwait

OU Health

Lisa Postelwait is Vice President of Finance at OU Health and has primary responsibility for the financial planning and analytics functions.  Lisa has been a member of HFMA for over 20 years and new to the Oklahoma chapter after relocating from Texas.  In her spare time, Lisa enjoys gardening, home improvement projects and spending time with family and friends.

Karen Todd

Stillwater Medical Center

Karen is the Director of Patient Financial Services for Stillwater Medical in Stillwater, Oklahoma.  She loves all things accounts receivable and is passionate about the patient billing experience.  She is also passionate about her poodles, her new old-house fixer-upper, and the latest RPDR franchise.

Tyler Bernier

Eide Bailly

Tyler is a partner with Eide Bailly in Oklahoma City, Oklahoma. When he’s not working on behalf of his clients, you’ll often find Tyler watching Disney movies, playing with toys and chasing after his two kids. When he’s traveling-either for work or pleasure-he likes to take in new sights, try new restaurants and sample the local craft beers.


Jessica Elsberry

Forvis Mazars

Jessica is a Director with Forvis Mazars in Tulsa, Oklahoma working as an auditor alongside her hospital and healthcare clients throughout the state.  She enjoys traveling with friends and family and especially trying new and unique restaurants on her journey.  But when she’s not out on the town, you can find her on the couch reading and cuddling with her two cats, Tonks and Minerva.

Priacilla Leatherman

Northeastern Health System

Priacilla is the Vice President of Finance at Northeastern Health System and has over 25 years’ experience in the healthcare industry.  She has been a member of HFMA for over 8 years.  Priacilla enjoys spending time with family and traveling.  In her spare time, you will often find her at the ballfields watching her nephews play or at the lake.

Scott Blair


Scott is a Director of Revenue Cycle with INTEGRIS Health in Oklahoma City. He spent 12 years as an Air Force officer and was stationed in exotic locations such as Kansas and New Jersey with brief visits to much less exciting places like Hawaii, Germany, and Afghanistan. He holds an MBA and MLS in Healthcare Law from the University of Oklahoma. When not working, he’s likely planning his next vacation to Disney World with his wife and youngest son or coaching youth sports.

Rostina Swindall

Oklahoma Heart Hospital

Rostina Swindall has 30 years of experience in the medical and health field and is currently a Business Office Manager at Oklahoma Heart Hospital, overseeing account collections, post-authorization processing and reviewing denials, and appeals for both physicians and facilities.  Rostina represents the hospital on the board of the Oklahoma Healthcare Financial Management Association (OKHFMA).  Rostina Swindall’s career includes roles such as Corporate Billing/Patient Accounts Director and Director of Billing and Collections in past healthcare organizations.  She also served as Director of Billing and Collection for two hospitals an ASC and eight bed inpatient hospital, where she managed admissions and medical records. Additionally, Rostina have ten years of experience with the Oklahoma Medicaid Information System and a diverse background also includes retail sales and marketing, demonstrating my adaptability and comprehensive knowledge in healthcare administration.

Cori Loomis

Christensen Law Group

Cori is a healthcare attorney representing hospitals and physicians with regulatory, compliance, and transactional issues for over 30 years. Cori participates in Rotary and serves on the board of a couple of nonprofit entities. For fun, she enjoys spending time with her family and friends, attending Acts 2 UMC, traveling, exercising, going to movies and supporting OU sports and Thunder basketball. Cori enjoys planning unique entertainment and travel experiences for family and friends and always enjoys a creative theme!

George Kruger

Comanche County Memorial Hospital

George is a CPA with almost 35 years experience in healthcare finance. He loves the service and educational aspects of his position.

Throughout his career George has worked for both for-profit and not-for-profit organizations. For the last nine years he has worked as Chief Financial Officer of Comanche County Hospital Authority, a medium sized Healthcare System serving communities throughout Southwest Oklahoma.

In his spare time George loves music, traveling and spending time with his family. A native of New Orleans, he has a BS in Accounting from the University of New Orleans and an MBA from the University of North Florida.

Mitzi McCullock

Oklahoma Hospital Association

Mitzi has over 20 years of experience, specializing in managed care insurance contracting, revenue integrity and payer strategies.  Mitzi is responsible for monitoring regulatory issues related to Medicare, Medicaid, managed care, and workers’ compensation, determining their impact on Oklahoma hospitals, and informing Oklahoma hospitals about their implications. She is an active member of the Oklahoma HFMA chapter and the Oklahoma Hospital Managed Care Association.


Katharine Johnston
Certification Chair

Rostina Swindall
Certification Co-Chair
Oklahoma Heart Hospital

William Rodgers
Communications Chair
HBCS Revenue Cycle

Cassie Walden
Founders Points Contact
Knowtion Health

Tiffany Alvey
Membership Chair
Eide Bailly

Cassie Walden
Membership Co-Chair
Knowtion Health

Mike Lorenz
Program Chair

Darren Walkup
Program Co-Chair
Commerce Healthcare

Karen Todd
Social Chair
Stillwater Medical Center

Jessica Elsberry
Sponsorship Chair
Forvis Mazars

Louise Kiper
Sponsorship Co-Chair
American Collections


Shannon Cleburn
Region 9 Representative
Knowtion Health

Tamie Young
Region 9 Representative
Stillwater Medical Center


Erin Thompson
Region 9 Treasurer
Forvis Mazars


Scott Sanders
Region 9 Regional Executive



  • Katharine Johnston | Weaver | Co-Chair
  • Rostina Swindall | Oklahoma Heart Hospital | Co-Chair


  • William Rodgers | HBCS Revenue Cycle | Chair
  • Tanya Mitchell                       
  • Phillip Smith | INSURICA
  • Tyler Bernier | Eide Bailly


  • Tiffany Alvey | Eide Bailly | Chair
  • Cassie Walden | Knowtion Health | Co-Chair
  • Stephanie Anderson | FORVIS
  • Angela Wright | Norman Regional Health


  • Mike Lorenz | INTEGRIS | Chair
  • Darren Walkup | Commerce Healthcare | Co-Chair
  • Phillip Smith | INSURICA                               
  • Tyler Bernier | Eide Bailly
  • Louise Kiper | American Collection Services
  • Scott Sanders | Friday Health Plans
  • Karen Knight | Face Rock Enterprises
  • Priacilla Leatherman | Northeastern Health System  
  • Tamie Young | Stillwater Medical Center
  • Jessica Elsberry | Forvis
  • Bill Rodgers | HBCS Revenue Cycle
  • Rostina Swindall | Oklahoma Heart Hospital
  • Robert Dudley | BOK Financial
  • Mitzi McCullock | Oklahoma Hospital Association
  • Amanda Martinez-Reyes | LifeCare              
  • Shannon Cleburn | Knowtion Health


  • Karen Todd | Stillwater Medical Center | Chair
  • Shannon Cleburn | Knowtion Health
  • Rostina Swindall | Oklahoma Heart Hospital


  • Jessica Elsberry | Forvis | Chair
  • Louise Kiper | American Collection Services | Co-Chair
  • Mike Lorenz | INTEGRIS Health        
  • Tyler Bernier | Eide Bailly
  • Scott Sanders | Aetna
  • Phillip Smith | INSURICA
Tyler BernierEide Bailly2023-2024
Louise KiperAmerican Collection Services, Inc.2022-2023
Scott SandersOklahoma Heart Hospital2021
Scott SandersOklahoma Heart Hospital2020
Andrew HejtmanekBKD2019
Anne AdamsChapman Foundation Management, LLC2018
Julie WardNortheastern Health System2017
William ClarkBKD, LLC2016
Jeff MincherNorman Regional Health System2015
Shannon FullerWorks & Lentz, Inc2014
Sherry CollinsEide Bailly LLPæ2013
Carley WilliamsBKD, LLP2012
Erin HillBKD, LLP2011
Amy MarshINTEGRIS Baptist Regional Health Center2010
Karen ReynoldsINTEGRIS Marshall County Medical Center2009
Tamie OsburnGustafson & Associates, Inc.2008
Karen HendrenStillwater Medical Center2007
Becky SpeightTulsa Regional Medical Center2006
Rick KellySaint Francis Home æ Medical Equip.2005
Lloyd HaggardBKD, LLP2004
Ann L. PaulæAetna Health, Inc.2003
Jerry GardnerIntegris Health2002
Steven MattachioneMercy Health System2001
Kevin GoreBKD, LLP2000
Jack ConklingSouthwestern Memorial Hospital1999
Linda FarrarRenaissance Center1998
Barry SteichenSaint Francis Health System1997
Richard WagnerMadole Wagner PLLC.1996
Duane CutterPrice Waterhouse1995
Dwayne WorthyCaring Touch Home Care (OKC)1994
Dennis PeareBKD, LLP1993
Robert JungerSaint Francis Hospital1992
John MehargæNorman Regional Hospital1991
Patricia AndersenDuncan Regional Hospitalæ1990
Steve DorsettæBroken Arrow Medical Center1989
Errol MitchellIntegris Baptistæ Medical Center1988
Rory WardValley View Regional Hospital1987
Rollo MaxwellSaint Francis Hospital æ1986
Ron CunninghamMercy Health Center1985
George PoseySt. Mary’s Hospital1984
Boyd TudorSt. Anthony Hospital1983
Gary GunderMuskogee General Hospital1982
Herb TohlenJane Phillips Medical Center1981
Darrell WilsonDoctors Medical Center1980
Sam PriceSt. Anthony Hospital1979
Fred MillsMiami Baptist Hospital1978
Max ArmstrongCommunity Hospital (Kingfisher)1977
Bobby ThompsonArbuckle Memorial Hosp.1976
Ben SchnitziusMemorial Hospital (Collinsville)1975
Thomas GiaudroneMcAlester Reg Health Center1974
Ann HeslarGrand Valley Hospital1973
Ann HeslarGrand Valley Hospital1972
Bob ParmeterJane Phillips Medical Center æ1971
Doyal KnowlesHillcrest Medical Center1970
James PowersValley View Regional Hospital1969
Dan NesomMuskogee General Hospital1968
Dan NesomMuskogee General Hospital1967
Clyde McNuttOklahoma General Hospital1966
George PeterSt. Mary’s Hospitalæ1965
Harry HopkinsæNorman Municipal1964
Marion PickettæWesley Hospital1963
Ralph StumppOU Medical Center1962
Opal CampbellACH Hospital1961
John HensonHillcrest Medical Center1960
John HensonHillcrest Medicalæ Center1959
William MauldinCapital Hill Generalæ Hosp. (OKC)1958
William MauldinNorman Municipal1957
Johnnie KimballSouthwestern Hospital1956
Stanley VossValley View Hospital1955

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