About IES

Ambassadors in ED Excellence

Integrative Emergency Services (IES) was created to manage all of the nonclinical functions of emergency medicine physician groups. Drawing on a foundation of excellence comprised of clinical, financial, academic, business intelligence and philanthropic platforms, IES provides comprehensive management services in pursuit of the highest quality healthcare in the industry.

Our mission is to help physician groups preserve their culture and strengthen the relationships they have with the hospitals and communities they serve through partnerships and incentive alignment.

  • We are committed to furthering the ED’s role in value-based healthcare delivery.
  • We are dedicated to doing the right thing.
  • We promote practice intelligence through quality program reporting, operational initiatives and education.
  • We develop, implement and disseminate best practices and processes which improve quality and access for patients and the populations we serve.
  • We embrace emerging technologies to improve the caliber of ED services and the manner in which they are delivered.

Core Services

Clinical Intelligence

data analytics

customized reporting

research and education

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Financial Management



revenue cycle management

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Practice Administration

provider services

human resources


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Advisory & Strategy

legal and compliance

contract negotiation/management

pay plan analysis

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Key Relationships

Thought Leadership Gatherings

IES is committed to the advancement of clinical education and dissemination of information. At the annual IES Quality Summit, our team brings together hundreds of industry leaders including hospital administrators, physicians, industry associations and emergency medicine employees to share outcomes, explore industry trends, inspire collaboration and develop synergies. Dedicated to improving quality of care in emergency medicine, this signature conference features an array of hands-on educational sessions and keynote speakers and is the largest of its kind in Texas. IES also hosts Clinical Integration Forums throughout the year on a variety of topics related to emergency medicine.

Corporate Leadership

Nick Zenarosa
Nick Zenarosa, MD, FACEP
Founder and Chief Medical Officer
Bob Timmermann
Bob Timmermann
President and Chief Executive Officer
Victoria Feather
Victoria Feather
Chief Integration Officer
Clare Elizabeth Graca
Clare Elizabeth Graca
Chief Operating Officer
Matt Innes
Matt C. Innes
In-house Counsel
Jose Alberto Loza
Jose Alberto Loza
Chief Revenue Cycle Officer
Christopher Welch
Christopher Welch
Chief Financial Officer

Clinical Leadership

Steve Arze
Steve Arze, MD, MBA, FACEP
Executive Vice President
Liz Fagan
Elizabeth Fagan, MD, FACEP
Director of Education
John Garrett
John S. Garrett, MD, FACEP
Vice Chief Quality Officer
Dahlia Hassani, MD, MBA, FACEP
Dahlia Hassani, MD, MBA, FACEP
Executive Vice President
Ron Jensen
Ronald J. Jensen, DO, MSHM
Executive Vice President
Judy Keller
Judith A. Keller, RN, DNP, CEN
Chief Nursing Officer
Kevin Marcum
Kevin S. Marcum, PA-C, MPAS
System Director of Advanced Practice Providers and Operations
Bob Risch
Robert M. Risch, MD, MBA, FACEP
Chief Quality Officer
Jose Robert Rosillo, MD
Jose Robert Rosillo, MD, FACEP
Regional Quality Officer, Central Texas
Chet Schrader, MD, FACEP
Chet Schrader, MD, FACEP
Executive Vice President
IES News

Explore news and insights related to emergency medicine.

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IES Events
Take part in our thought leadership gatherings throughout the year.

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Job Listings
Explore corporate and clinical career opportunities with IES.

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