Every year, an estimated one in five Americans needs to seek care at least once at a hospital emergency department. A national survey reported by the federal Centers for Disease Control and Prevention found that there were nearly 145.6 million ED visits in 2016. Moreover, national trends show an increasing number of visits every year. This has led to increased crowding and longer waiting times.

As an emergency department physician, I can tell you that nobody likes to wait. I also can tell you that there are plenty of mysteries and misconceptions about visiting the ED.

So here are some of the most common questions I hear from my patients, with answers that might help you better understand what to expect when you visit the ED.

1. What should I bring?

Above all, if you think you are having a life-threatening emergency, call 911 and get yourself to the hospital as rapidly as possible. Nothing matters more than getting here quickly if you may be having a stroke, heart attack, or other critical episode.

However, if you have more time, or a family member is available, the most useful thing to bring is an updated list of your medications. Knowing what you take – and the doses – helps your doctor quickly understand your medical conditions and their severity, while making sure you get the dose you need at the proper time. Even if all your doctors belong to the same health system, do not assume that the electronic records are up-to-date with all of your medications.

Additionally, bring whatever you need to keep yourself entertained for several hours. Be aware that cell phone service may be poor or nonexistent, as many emergency departments have thick walls to protect against fires and irradiation from scanners. Ask staff for a phone if you need to make a call. Bring chargers for your devices, but know that outlets can be scarce.

2. Can my family or friends visit me?

The emergency department is a crowded and confined space, with little extra room for visitors. If possible, bring one family member or friend with you, preferably one who is familiar with your medical history, and who can speak on your behalf (or quickly contact your power of attorney) if you are injured, sedated, or unable to communicate.

If you have elderly family members and small children who don’t need medical services themselves, it’s best if they avoid visiting the ED as they are more vulnerable to potentially life-threatening infections, like influenza and MRSA.

3. When can I eat?

This is the question patients ask the most. The answer is: It depends.

Having food in your belly puts you at high risk for anesthesia complications, such as vomiting and aspiration, if we find you need an immediate operation. Additionally, there are many medical conditions, such as bowel obstructions and high blood sugar levels, that can be made worse by eating and drinking. That’s why you may be asked to refrain from eating or even drinking anything until your medical workup is complete. This may take up to six hours, or longer, on a busy day. If you have a medical condition that requires you to eat, however, please let a staff member know.

4. How much longer will I have to wait?

The average time spent in the ED is two to four hours, according to the CDC. Generally, Monday evenings are the busiest days for ED visits, and overnight hours and early mornings are the fastest times to be seen.

It is undoubtedly frustrating to watch as patients who arrived after you are called in to see the doctor before you are. Please know that this does not mean you’ve been forgotten.

In general, patients are seen on a first-come, first-served basis. But patients who are more medically unstable may have to be skipped ahead of the line to the next available bed.

Triage is a method of rapid medical assessment that helps us categorize the severity of patients’ emergencies. Every emergency department has its own variant of the triage system, but they all work similarly. When you arrive in the ED, you are seen immediately by a health-care provider who will assign you a “severity score” based on your presenting complaint, your initial vital signs, and a brief medical evaluation. Your severity score takes into consideration potentially dangerous findings, like elevated heart rates, high fever, low blood pressure, or low oxygen levels. Provided your condition is stable, you will then be sent back to the waiting room until a bed is available.

Even while you are in the waiting room, you’re being monitored. In many hospitals, the triage staff will order blood work, X-ray imaging, or electrocardiograms for you while you are waiting for a bed. If there is a concerning finding, such as evidence of a heart attack on your ECG, you go to the front of the line immediately.

If you fear you’ve been forgotten, it’s OK to see the staffer at the front desk and confirm you’re in the queue. But don’t be surprised to learn that no one has forgotten you and that, unfortunately, it’s a busy time at the ED.

Matthew Trifan, M.D., is a resident physician in emergency medicine at Jefferson University Hospital.