Your family doesn't need to know CPR to save you. All they need to do is remove you from suspension.
Non-vital brain regions can endure serious damage before vital areas die. It doesn't take long for brain damage to occur but it does take a long time for the brain to fully die/kill you.
This means that there is a significant window of time where others can save you but you will live with traumatic brain injuries. The severity of these injuries can range from minor cognitive, language, & personality impairments all the way to full loss of autonomy (what people call being a "vegetable" AKA disorders of consciousness) or even pain (e.g., difficulties breathing, nervous system dysregulation, musculoskeletal pain from motor impairments, etc)
I can't stress enough how important it is to avoid being discovered if you wish to avoid permanent injuries.
Properly deliberated and planned exits are always a good idea. Spontaneous ones are often poorly thought out with much higher rates of injury + there are greater odds of recovery/remission/regret among people who have not thoroughly deliberated and planned. Reach out if you'd like to chat about any of this
I support your decision, but I wonder what sort of deliberation and circumstances you face where you feel compelled to attempt suicide within your family's home. Notwithstanding the trauma they will face, it is an incredibly risky choice.
Wishing you peace in living or dying
-R