Portable medical support system with ancillary viewing mode and method of operation thereof

A medical ventilator, comprising:

• a first user interface having a touch-sensitive primary display having a first display area;
• a hard key (HK) interface including a display select key;
• a unitary display coupler configured to couple a remote user interface to the medical ventilator;
• and
• at least one controller which is configured to:
• determine whether the remote user interface having a touch-sensitive remote display is coupled to the medical ventilator,
• respond to the display select key of the HK interface to toggle an active display between the touch-sensitive primary display and the touch-sensitive remote display, wherein the medical ventilator is configured to directly provide DC power through the unitary display coupler to the touch-sensitive remote display while the medical ventilator is running on AC power,
• enable the first user interface when it is determined that the remote user interface is not coupled to the medical ventilator and enable the remote user interface when it is determined that the remote user interface is coupled to the medical ventilator,
• and sense when the medical ventilator switches from an external power source to an internal power source and in response,
• disable the remote user interface after the remote user interface is enabled and enable the first user interface after the first user interface is disabled.