The latest CPR guidelines recommend single person CPR for adults, children, and infants, with a compression rate of 100-120/minute and a compression to ventilation ratio of 30:2. That is, 30 chest compressions and 2 artificial respirations alternately. For children, use both hands or one hand to press at the midpoint of the nipple line, i.e., below the sternum; for infants, use two fingers to press 2 cm below the midpoint of the nipple line and press the sternum to a depth of about 4 cm. For artificial respiration, wrap the mouth and nose of the infant and the younger child simultaneously and blow lightly. For two-person CPR, the compression-ventilation ratio is 15:2.