Final answer:
A passenger should immediately alert flight attendants if an elderly woman is experiencing chest pain and difficulty breathing, as they are trained for such emergencies and can provide the necessary assistance. It's important to keep the woman comfortable and to not self-administer any treatments unless instructed by a professional.
Step-by-step explanation:
If a 78-year-old woman is complaining of chest pain and difficulty breathing aboard an airplane, immediate action is necessary as these may be signs of a potentially serious medical condition, such as a heart attack or pulmonary issue. The first step should be to notify the flight attendants as they are trained to handle medical emergencies and can use their resources to provide assistance, including the possible use of an onboard automated external defibrillator (AED) and oxygen. The cabin crew can also communicate with medical professionals on the ground or request the help of any medical professionals onboard.
In the meantime, try to keep the woman calm and comfortable. Loosen any tight clothing, ensure she is in a position that helps her breathing, and ask if she has any medications for chest pain, such as nitroglycerin. It is important not to provide any medications yourself unless directed by a medical professional. The crew may make an emergency landing at the nearest airport if the situation is deemed urgent enough.
Do not attempt to treat the woman yourself, as this could worsen her condition or expose you to legal risks. Offer moral support and assist the flight crew as directed until a professional can take over.