During reanimation procedures an attempt to intubate trachea was made. Neither glottis nor epiglottis can be visualized via laryngoscopy. What tactics should be chosen in this case?

Answer options

1. Insert a laryngeal mask
2. Temporarily cease the chest compressions to make intubation easier
3. Perform a bag-valve-mask ventilation with Ambu bag
4. Continue the attempts until the intubation is successful
5. Discontinue the attempts for mechanical ventilation