Our Story

Richard H. Koehler MD FACS has acquired a unique understanding about the limitations of personal protective equipment, both in warfare and in peacetime. He set out twelve years ago to solve this problem.  

Dr. Koehler has been a board-certified surgeon for over 30 years, experiencing some of the most extreme urgent care events in recent history. He was a surgeon on the frontlines of Desert Storm and Desert Shield, operating directly on combat casualties. His units received advanced training on personal protective strategies during chemical and biological warfare. He was also on the frontlines of the 1989 San Francisco earthquake, stationed at the Naval Hospital, Oakland CA. While there, he was an Assistant Clinical Professor of Surgery at the University of California – East bay.  

Over the past five years, Dr. Koehler has become a leader addressing the effectiveness of respirator masks in healthcare settings.  He holds four U.S. patents on respirator and face-seal technology, as well as five foreign patents.

He has collaborated with Sergey A. Grinshpun PhD, Director of the University of Cincinnati’s Center for Health-Related Aerosol Studies. Professor Grinshpun is recognized internationally, as one of the top authorities on healthcare aerosol research. They have published multiple peer-reviewed studies proving the effectiveness of Dr. Koehler ‘s design for a novel N95 respirator mask face seal. Their findings have been presented at major conferences nationally and internationally.

Leveraging this research and expertise, Critical Technologies has assembled a team to build the next generation of N95 respirator masks that will significantly improve the safety of healthcare workers.

Richard Koehler, MD

Founder | Chairman | Inventor


Dr. Koehler is a graduate of Tufts University School of Medicine and is currently a Laparoscopic Surgeon at Martha’s Vineyard hospital. He is also a Clinical Associate in Surgery at Massachusetts General Hospital, in Boston, where he teaches both advanced trauma life support and advanced trauma operative management to the surgical residents.

His work has been featured in: 

  • The integration of FDA and NIOSH processes to evaluate respiratory protective devices for healthcare workers
  • Journal of The International Society for Respiratory Protection
  • Journal of Aerosol Science & Technology
  • The Chartered Society for Worker Health Protection

Our Team

Terence Fowler
Co-Founder
Sergey Grinshun, Ph.D.
Collaborator
Richard Koehler, MD FACS
Founder
Terence Fowler
Co-Founder
Sergey Grinshun, Ph.D.
Collaborator
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