Philips V24CT User's Reference Manual page 35

The arrow keys consist of up/down/left/right keys. They only function
when illuminated. The arrow keys allow you to move between areas on
operating screens to enable you to change or adjust settings, perform
procedures, or make changes to the screen display.
Key
Confirm
This key functions only when it is illuminated. A prompt message "...press
CONFIRM..." appears on the screen when you need to use it.
Airway Gases/Ventilation
ventilator waves and numerics.
- (CMS only) Press to view airway gases or
The CMS and V24 and V26 Patient Monitors 1-13
Introduction