Because of the risk of pneumothorax and subcutaneous or mediastinal emphysema,<unk>  ventilation should not be used when you are able to secure the airway using more conventional and non-invasive means. In addition, it should not be used if there is:
Damage to the trachea or tracheal rupture: pressurized air would escape into the soft tissues
Severe obstruction of the airway above the cricothyroid membrane: patient would be unable to exhale and risk of pneumothorax would increase
Damage to the trachea or tracheal rupture: pressurized air would escape into the soft tissues
Severe obstruction of the airway above the cricothyroid membrane: patient would be unable to exhale and risk of pneumothorax would increase
Pediatric jet ventilation
Bag valve mask ventilation
Extracorporeal membrane oxygenation
Mechanical ventilation 
Neonatal resuscitation
High frequency oscillation ventilation
Oxygen therapy
Noninvasive ventilation