Final answer:
There is no set time to perform CPR or PPV before reassessment; continuous and situation-responsive action is recommended until professional help arrives or there is a change in the victim's condition.
Step-by-step explanation:
When providing CPR or oxygenated positive pressure ventilation (PPV), there isn't a specific time limit set before reassessment. The guidelines for resuscitation emphasize continuous assessment and intervention based on the victim's response. However, if after a significant duration (usually this would be several minutes), there is no sign of recovery, emergency services who are more likely to have arrived by this time will take over and utilise more advanced medical support.
In the case of emergencies like carbon monoxide poisoning, administering oxygen drastically reduces the half-life of carbon monoxide in the blood, accelerating recovery. For newborns, the Apgar score, which includes heart rate and respiration rate, is vital to ascertain immediately after birth and five minutes later to decide if medical intervention is necessary.
Therefore, the direct answer to the student's multiple-choice question is not clearly provided by the guidelines, as continuous and situation-responsive CPR or PPV is typically what is recommended until professional help arrives or there is a change in the victim's condition.