If the hea rate does not improve after 30 sec with bag-and-mask (or endotracheal) ventilation and remains below 100 beats/min, ventilation is continued and chest compression should be initiated over the lower third of the sternum at a rate of 90 compressions/min. The ratio of compressions to ventilation is 3 : 1 (90 compressions:30 breaths). If the hea rate remains <60 beats/min despite effective compressions and ventilation, administration of epinephrine should be considered.Ref: Nelson; 20th edition; Page no: 845