Head throw/chin lift
If the victim is unconscious and the airway is obstructed due to a recessed tongue, you can ensure its patency by simply throwing the victim’s head back and lifting the chin. If the obstruction is caused by tissue swelling, you should call an ambulance immediately as you may not be able to open your airway.
The method of throwing the head back with the chin raised gives the throat a position that prevents the tongue from sinking. If there is a possibility that the victim has suffered other injuries, do not turn him over until you have checked
whether he has breath so as not to cause more harm. If the victim is not breathing, roll him onto his back with one hand while supporting his head and neck with the other hand. Having laid the victim on his back in this way, throw his head back with one hand while raising his chin with the other hand
Squeeze the victim's nostrils and, tightly covering his mouth with yours, blow air into the victim's lungs twice. (The procedure for performing artificial ventilation will be discussed in more detail in the next chapter.) If air flows freely into the lungs, the victim's airways are open.