Final answer:
Upon the complete emergence of the baby's head during childbirth, the correct action is to turn the baby's head to one side to clear the airways, not to pull or apply pressure on the head. Any loose umbilical cord around the neck should also be removed.
Step-by-step explanation:
When assisting in an emergency childbirth and the baby's head has completely emerged, the appropriate action would be to turn the baby's head to one side. This maneuver is important to ensure that the baby's airways are clear and can help prevent the inhalation of mucus. It is not recommended to pull on the baby's head, as this can cause injury. Applying pressure to avoid explosive delivery is unnecessary and might cause harm. If the cord is wrapped around the neck, it should be carefully removed if it is loose and not causing compression.
After the head is birthed, the rest of the body usually follows quickly, and attention should then be turned to clearing the baby's mouth and nose of any mucus to facilitate the first breath. The next steps involve expulsion of the newborn and the delivery of the placenta, which are part of the natural childbirth stages.