If at any time you determine that the child or infant is experiencing a life-threatening emergency, support breathing and cardiovascular function immediately. This usually means providing high-quality CPR. While it is important to recognize and respond to the particular cause of the problem, the time required to determine the problem should not interfere with perfusion and oxygenation for the child or the infant. As you maintain breathing and circulation for them, determine if they are primarily experiencing respiratory distress/arrest, bradycardia, tachycardia, shock, or cardiac arrest. Individual PALS protocols for each of these clinical situations are provided throughout this handbook.