Rick Santorum, ex American senator, in light of the recent youth-led movement for gun reforms stated that the kids should learn CPR instead of asking for better gun laws.
There is very little the CPR does for a significantly bleeding individual and here is why.
CPR depends on supplying enough blood to the vital organs and especially the heart and the brain. It has two components. The pump which is the heart and the volume which is the blood.
In a bleeding individual CPR is likely not going to be effective as there is not enough blood to go around even if the heart keeps pumping.
As an extension and for the same reasons shocking the heart is not going to work. The thing which has an outside chance in this race against time situation is rapid volume and blood replenishment and control of the bleeding.
The best strategy, however, remains to decrease the odds of bullets ever flying.