Ventilation, Rescue Breathing, and Airway Management
Opening the airway
Head tilt–chin lift is the default for an unresponsive patient without suspected trauma; use a jaw thrust when cervical spine injury is suspected. Remove visible obstruction, suction if available, and insert an oropharyngeal airway (measured from the corner of the mouth to the angle of the mandible) in patients without a gag reflex, or a nasopharyngeal airway (nostril to earlobe) when an OPA is not tolerated.
Delivering breaths
Give each breath over about 1 second, with just enough volume to make the chest rise visibly. In respiratory arrest with a pulse, adults get 1 breath every 6 seconds (10/min); infants and children get 1 breath every 2–3 seconds (20–30/min). Once an advanced airway is in place during arrest, the same rates apply with continuous compressions. Use a bag-mask device with two rescuers when possible - one seals with two hands, the other squeezes - and attach oxygen as soon as it is available.
Traps
Excessive rate or volume is the most common ventilation error: it raises intrathoracic pressure, reduces venous return and coronary perfusion, and causes gastric inflation with regurgitation and aspiration. If the chest does not rise, the answer is reposition the head and reseal the mask - not push harder. For foreign body airway obstruction, adults and children get abdominal thrusts, infants get back slaps alternating with chest thrusts; an unresponsive victim gets CPR, and you remove a object only if you can see it.
Rule of thumb
If you can see the chest rise, that is enough - one breath per second of squeeze, then let the patient exhale before the next breath.