[1][2][3] In most jurisdictions, Station Outlets are required to be equipped with safety systems that prevent cross-connection errors, such as connecting a Medical air flowmeter to an Oxygen port.
Hospitals mainly use DISS connections, though a wide variety of quick-connect adapters, based on male strikers and female outlet ports, are still in use today.
The Diameter Index Safety System, or DISS, was designed by the Compressed Gas Association specifically for medical gases at 200 psig or less.
Persistent attempts to remove equipment while keeping the button pressed has potential to result in damage leading to latching/connection malfunctions.
The flat outlet ports ensure no injury if a patient or health-care worker should fall into the wall; a consideration when dealing with the mentally ill or those with neuro- or musculodegenerative disorders.