Dramatic body cam footage shows the chilling moment a Florida sheriff deputy rescued an infant from a mangled car wreck -- and her survival is being attributed to his CPR.

As you can see in the footage, Charlotte County Deputy Sgt. Dave Musgrove was cruising along the state highway near Englewood on the night of Feb. 8 when a motorcycle sped past over 100 mph and crashed into another vehicle up ahead seconds later.

Upon arriving at the scene ... Musgroves wastes no time removing the toddler from the booster seat, handing the child over to the passenger of another vehicle he flags down -- this as the baby's mother pleads for him to help her kid.

He then gets to work removing the six-month-old infant from the car seat ... but it proves more of a challenge with the motorcyclist wedged directly on top.

Of course, the situation is every parent's worst nightmare ... evident by the panicked background shrieks of the mother asking whether her child is alive or not.

It quickly becomes clear the baby isn't breathing -- and once he officially gets the baby out of the car, Deputy Musgroves begins performing chest compressions on her in a race against time ... and thankfully, there's soon a pulse!!

Fort Myer's WBBH reported that the baby is now in ICU at a St. Petersburg hospital with a brain injury. The baby's mom, Kayleigh Foley, praised Musgrove as a hero, gushing to the publication, "He is such a genuine person."

Sheriff Bill Prummell also praised Musgraves ... saying in a statement, "The actions of Sgt. Musgrove are to be commended. His poise and calm demeanor in a scene of chaos and tragedy ultimately saved the life of a beautiful child."

Unfortunately, the motorcyclist didn't survive.