CPR without the R?

Here's an interesting article that says CPR can be more effective with just chest compressions.

Only 5 percent of cardiac arrest victims survived if nobody performed CPR. In those receiving standard CPR (alternating between 30 compressions and 2 breaths), survival was marginally higher at 6 percent. In contrast, 11 percent survived if bystanders kept pumping on their chest and did not stop for mouth-to-mouth breaths until emergency medical services arrived.

These trends were even more pronounced in those patients facing the highest survival chance to begin with due to the specific nature of their cardiac arrest, namely those whose collapse was witnessed and whose heart was in a rhythm that is most likely to respond to a shock from a defibrillator. In those, the survival rate was 17 percent without bystander CPR, 19 percent with standard CPR and 32 percent with continuous chest compressions.

That's a big difference. But I notice the stats are for one person CPR. Since you're not getting fresh oxygen to the victim I can't help wondering how much good circulating the blood does. Has anyone compared neurological deficits of just compressions vs regular CPR? I'm also guessing if you've got two people then you definitely want to do the whole thing, with one person doing compressions and one breathing.