Medicine is science and as such is always evolving. I recently got certified in CPR and defibrillator use. Turns out that CPR guidelines keep changing as scien

Medicine is science and as such is always evolving. I recently got certified in CPR and defibrillator use. Turns out that CPR guidelines keep changing as scientific research advances our knowledge of what is actually going on. One of the reasons why a first responder should keep getting re-certified every year or so.