Why are there 30 compressions and 2 breaths in CPR?
Because in 2005 when the International Liaison Committee on Resuscitation (ILCOR) updated a lot of the old procedures. The old standard of 15 compressions and 2 breaths was changed to 30 compressions to 2 breaths. The American Heart Association adopted the recommended changes also.
Some of the reasons for changing included making it easier for one person to perform CPR. It also created less interruptions to blood flow, which maintained blood pressure longer. It also allowed for 3 sets of 30:2 in 1 minute. Which means if you do the math, you could deliver 90 compressions in that one minute.
With the old standard of 15:2 the most sets you could complete in one minute was 4. Which means you could only deliver 60 compressions in that one minute. The 30 compressions created better perfusion of blood carrying oxygen to the heart. This became a much more efficient way to deliver compressions and breaths for conventional CPR.
These 30 compressions should be delivered at a rate of 100-120 compressions per minute. Which is very quick. I hear a lot of people suggest you should sing “Stayin Alive” by the Bee Gees to help keep rhythm with your compressions.
This is impractical in real life. You need to be counting to keep track of your compressions. Singing will totally confuse you. It would work if you were performing hands-only CPR where you were delivering continuous compressions with no interruptions and counting is unnecessary.