Gas Stop Valve: Reduces Exposure to Waste Anesthetic Gases

Gas Stop, a bypass valve designed for surgical anesthesia masks, controls the flow of anesthetic gas flow at the point of patient delivery, reducing the risk of exposure to hazardous waste anesthetic gases that leak into the operating room environment. The device provides a faster, safer approach to managing anesthetic gas flow in surgical settings.


Operating room personnel—anesthesiologists, nurses, surgeons, scrub techs, etc.—are often exposed to toxic waste anesthetic gases during the routine administration of anesthesia, particularly during pediatric surgeries. This exposure, even in small amounts, represents a significant health risk over long periods of time.

On-and-off control of oxygen and anesthesia at the machine can reduce gas flow during activities like induction and patient repositioning, but are impractical during fast-paced surgeries. When practitioners turn off the anesthesia vaporizer or fresh gas flow, this stops the flow but does not address the problem of anesthesia gases already present in the delivery system.

Stopping the administration of anesthesia at the machine requires an additional step and requires the practitioner to remember to resume oxygen and anesthesia delivery to the patient. A safer, more efficient method is needed to control anesthesia gas flow within a closed system.


By preventing the unintentional escape of gas from the anesthesia circuit, the Gas Stop device reduces inhalational pollution in the operating room during anesthesia delivery. Located on the mask itself rather than the anesthesia machine, the bypass valve allows anesthesiologists to stop gas flow to the mask while at the same time recirculating the gases within the anesthesia circuit, all without leaving the patient’s side. The on-off switch allows personnel to resume flow to the mask as easily as stopping it. The Gas Stop features a minimal amount of moving parts to increase safety during surgery.


  • Reduces the occupational health hazard of waste anesthetic gases in operating room
  • Allows anesthesiologist to focus on the patient during surgery
  • Inexpensive
  • Easy to use


Thomas Templeton, MD, Department of Anesthesiology

Application Fields

Anesthesiology, pediatric surgery

Stage of Development

An initial prototype has been created for preliminary testing.

Patent Status

Patent pending


Anesthesia, anesthetic breathing circuit, waste anesthetic gases, halogenated anesthetics hazards, anesthesia care providers, anesthetic gases, engineering exposure controls, precautionary practices

Purchasing Contact

John Druga, MS, MBA
Licensing Director, Center for Technology Innovation & Commercialization

Ref #: WFU 16-25

Back to Top