An anesthesiologist in scrubs.The Department of Anesthesia, Critical Care and Pain Medicine at Massachusetts General Hospital offers answers to patients' frequently asked questions about anesthesia.

Patients and families often have many questions about what to expect and how to prepare for anesthesia during a surgical procedure. As always, it is recommended to also review your questions with your surgeon and anesthesia provider.

Anesthesia is a group of medical treatments that allow for patients to undergo surgical procedures without feeling pain. There are different types of anesthetic medications, and they work in different ways. Some anesthetics numb specific parts of the body, allowing for surgery to comfortably take place while the patient is conscious, and others induce a loss of consciousness, so that the patient is asleep throughout surgery. All anesthetics block pain so that the patient’s complete comfort is ensured.

The different types of anesthetics include:

  • General anesthesia
  • Regional anesthesia
  • Local anesthesia
  • Sedation

Anesthesia providers at Massachusetts General Hospital answer commonly asked questions that patients have about their anesthesia care.

What is general anesthesia?

General anesthesia allows for patients to be unconscious, unaware, and insensitive to pain during surgery. General anesthesia is administered as either an inhaled gas or through a vein (IV). Many invasive operations require general anesthesia. 

There are many benefits to general anesthesia, including that it:

  • Allows for the anesthesia provider to control your breathing more easily
  • Can be used with muscle relaxants to keep you very still during certain procedures
  • Puts you to sleep so you will not be aware of anything or feel pain during surgery

If you receive general anesthesia:

  • You may arrive to the OR awake but will be unconscious once the procedure starts
  • You will not hear or feel anything once you are asleep, and you won't remember what happened while you were asleep
  • You may breathe on your own or you may have a tube put in your nose or throat so that oxygen can be given to you
  • An anesthesia provider will carefully monitor your breathing, heart function, and how deeply you are asleep during the procedure

Video Resources: General Anesthesia

What is regional anesthesia?

Regional anesthesia blocks pain in a specific area of the body. A regional anesthetic may be combined with another type of anesthetic. With regional anesthesia, patients are often conscious during surgery, yet insensitive to pain.

There are several different types of regional anesthesia, including:

Peripheral Nerve Blocks

Peripheral nerve blocks are injections of medication that numb areas of the body that are near peripheral nerves (i.e., nerves are responsible for transmitting pain signals to the brain). Peripheral nerve blocks can be used alone to block pain while you are conscious, or combined with general anesthesia to induce a state of sleep.

Peripheral nerve blocks may be used for arm and shoulder surgery, dental procedures, and more.

Spinal Anesthesia

Spinal anesthesia is a procedure in which medication is injected into the spinal fluid to numb the nerves. Spinal anesthesia is most often used for surgical procedures involving the lower body.

Epidural Anesthesia

Epidural anesthesia refers to injections that numb the nerves coming out of the spine. This is done by inserting a small plastic tube into the back which stays in place while the medications are administered. Epidural anesthesia is most often used for labor and delivery as well as surgical procedures involving the chest or lower body. The tube may be left in place after the surgery to provide continued pain control.

There are many benefits to regional anesthesia, including that it:

  • Blocks pain without putting you to sleep
  • Can be used along with general anesthesia to provide long-lasting pain relief after surgery
  • Is safer to use during pregnancy, as the medication stays near where it is injected
  • Uses lower doses of medication than general anesthesia

Video Resources: Regional Anesthesia

What is local anesthesia?

Local anesthesia is used to block sensation in a small part of the body, and is most often used for procedures that are on or just under the skin. Local anesthesia can be safely administered by surgeons, dentists, and other clinicians who are not anesthesia providers.

What is monitored anesthesia care (MAC)?

Other terms for MAC include:

  • Twilight sleep
  • Procedural sedation
  • Conscious sedation

To induce sedation, anesthetic medications are used to make patients sleepy and calm, provide mild pain relief, and reduce awareness without causing a loss of consciousness. Many procedures, such as colonoscopies, are often done using sedation. During surgery, the anesthesia team closely watches the patient’s vital functions so that the surgeon can focus on the operation.

If you receive sedation or monitored anesthesia care:

  • You may be drowsy, lightly sleeping or awake and relaxed, depending on the type and amount of medication you receive

  • You will usually receive local or regional anesthesia along with sedation, so you should not feel any pain. Depending on the procedure, you may still be able feel pressure or motion

  • You will breathe on your own during the procedure, usually through an oxygen mask or tube under your nose

  • If you are lightly sedated, you may or may not hear and see things happening in the room during the procedure

  • After the procedure, you may or may not remember things that happened while you were sedated

What are the side effects of anesthesia?

If you have any questions about potential risks, please consult with your doctor and anesthesiologist.

Side Effects of General Anesthesia

General anesthesia is usually very safe, and may result in some side effects that are common and temporary. Serious or permanent effects are rare.

Common side effects of general anesthesia include:

  • Body aches
  • Constipation
  • Dry mouth
  • Grogginess or confusion
  • Injury to your lips
  • Nausea or vomiting
  • Shivering and feeling cold
  • Sore throat

Less common side effects of general anesthesia include:

  • Damage to your teeth
  • Delirium or cognitive dysfunction (mental fuzziness)
  • Eye injury or loss of vision
  • Slow wake-up

You may have a higher or lower risk for side effects or complications based on your health. Your anesthesia team will do everything possible to manage your risks and keep you safe and comfortable during your surgery.

Video: Safety of general anesthesia

Side Effects of Regional Anesthesia

Common side effects of regional anesthesia include:

  • Soreness or bruising from the injection

Less common side effects of regional anesthesia include:

  • Spinal headache (post dural-puncture headache) which can happen if a spinal or epidural needle accidentally punctures a sac in your spine
  • Bleeding, sometimes leading to a build-up of clotted blood called a hematoma

You may have a higher or lower risk for side effects or complications based on your health. Your anesthesia team will do everything possible to manage your risks and keep you safe and comfortable during your surgery.

Video: Safety of regional anesthesia

Is anesthesia safe for pregnancy?

Our team of highly skilled obstetricians, midwives, nurses, and anesthesiologists work together to make the birth experience as safe and comfortable as possible for you and your baby. Obstetric anesthesia services at Mass General are available on the labor and delivery floor 24 hours per day.

Read answers to FAQs about obstetric anesthesia

How can I prepare for anesthesia?

You may be asked to participate in a conversation about anesthesia before surgery either by phone or an in-clinic visit. At this appointment, a health care provider will ask you specific questions about your health and medical history. This is important for planning your anesthesia care.

Ahead of surgery, below are examples of steps that you can take to assist your care team:

  • If asked, please complete all medical tests (such as blood tests, urine tests, electrocardiograms, and MRIs) or other medical appointments prior to surgery
  • Ask your doctor for instructions regarding medications. Some can be taken as usual before surgery, but others should be stopped or taken at a different dose
  • Speak up, ask questions, and express concerns

Your anesthesia providers may not have records from external hospitals unless you or your care team requested a copy. It is recommended to provide the below to your anesthesia and surgical care team:

  • A list of your previous surgeries including the type of surgery, the year you had it, and where you had it done
  • A list of any previous medical tests or imaging including the type of test, the year it was done, where you had it done
  • The name and phone number of your primary care provider and/or specialists

Tell your anesthesia provider about your health and lifestyle, including:

  • Any health conditions you have such as asthma, diabetes, or heart disease
  • If you or anyone in your family has had a bad reaction to anesthesia in the past
  • Allergies to food, medications or latex
  • Any routine prescription or over-the-counter medications
  • Any routine herbal or nutritional supplements
  • Any recent changes in your health including recent illnesses as well as new symptoms, like trouble breathing or chest pain
Can I eat or drink before my surgery?

The general rule is to stop eating all foods eight hours before surgery and to stop drinking clear liquids two hours before surgery. Clear liquids include water, juice, and coffee or tea without milk. Please refrain from chewing gum at least two hours before your surgery.

We recommend that you drink plenty of water throughout the week before your surgery. If you are diabetic, ask your doctor if it is okay to bring a can of clear juice to the hospital in case you feel sick on the morning of surgery.

You may get different instructions from your care team about when to stop eating and drinking depending on your health and the type of surgery. Always follow the instructions that your doctor gives you. Otherwise, your surgery may be delayed or rescheduled.

Should I stop taking or change the dose of my medication before my procedure?

Some medications and vitamins should be taken as usual the morning of your surgery, while others should be stopped altogether or taken at a different dose. You will be given specific directions about your medications based on your health and the type of surgery. Always follow the instructions that your doctor gives you. Otherwise, your surgery may be delayed or rescheduled.

Should I temporarily stop smoking before my procedure?

You can reduce the chance of serious surgical complications by quitting smoking, even temporarily. The effects of smoking on the body are not limited to your lungs—they have also been linked to delayed wound healing and increased risk of infection at the surgical site. Furthermore, anesthesia is much safer and more predictable in those who do not smoke as the heart, lungs, and blood vessels function better in non-smokers.

The benefits of quitting begin the day you quit. Improved heart and lung function begins as early as 12 hours after quitting. In less than a day, carbon monoxide and nicotine levels drop and blood flow improves. The longer you quit, the more benefits you gain.

View our smoking cessation programs

Can I drive home from the hospital?

After receiving anesthesia, your decision-making and reaction time may be impaired for up to 24 hours. You should not drive during this time. You should plan to have someone meet you at the hospital who will make sure you get home safely.

What should I avoid wearing on the day of surgery?

In order to ensure a safe and effective procedure, it is recommended that you do not wear any of the following:

  • Hair products (gel, mousse, hair spray, etc.)
  • Jewelry
  • Lotion
  • Makeup
  • Nail polish
  • Perfume

In order to monitor oxygen levels in your blood, we apply a special sensor to your fingertip, which works by passing a light through your nail and skin. This sensor may be less effective in the presence of nail polish or acrylic nails, especially when dark colors are used. Additionally, cosmetics may be flammable and increase the risk of burns, as various heat sources are used during surgery. Also, eye makeup, especially mascara, may cause eye injury while you are under anesthesia, since you will not have your blink reflex.

Why did my doctor ask me about my alcohol and drug use?

Alcohol and certain drugs can alter the effectiveness of anesthesia, and cause health problems by negatively interacting with the anesthetics. We encourage you to answer questions from your anesthesia provider as honestly as you can so that we can keep you safe.

Why did my doctor ask me about other injuries, rashes, cuts and blisters?

Each surgical procedure requires you to be in a specific position to give the surgeon the best access to the surgical site. Your team will always make sure that your body is supported and padded. If you have sensitive areas, your care team can also take extra measures to protect them. For example, if we know you have a bad shoulder, we won't extend your arm very far.

Some cuts and rashes can pose a big risk for infection, especially if they are near the surgical site. This can lead to serious health complications and a longer hospital stay. To prevent this, we will look at any skin problems you have and decide if they need to be treated before your surgery.

Who will give me anesthesia?

At Mass General, your anesthesia will be supervised by a board-eligible anesthesiologist, which is a doctor who has completed advanced training in anesthesia. The anesthesiologist will often work with either a certified registered nurse anesthetist (CRNA) or an anesthesia resident.

CRNAs are registered nurses (RNs) who have critical care experience and have completed graduate training in anesthesia. Anesthesia residents are doctors who have completed medical school and are doing their advanced training in anesthesia under the supervision of anesthesiologists.

Anesthesiologists, CRNAs, and residents are all anesthesia providers, and together they make up your anesthesia team. All of them are highly trained in advanced life support, resuscitation, and airway management.

What should I expect before the procedure?

You will likely be scheduled for an anesthesia phone screening before your surgery or procedure. These appointments are often referred to as the pre-procedural evaluation (PPE) or preadmission testing.

Before your screening, you should create a Patient Gateway account or ask your Mass General primary care provider to create one for you. Then, you should log in and complete the necessary online forms as instructed by your provider.

During your phone appointment, you will be asked about your medical, medication and anesthetic history. You will also review instructions for when to stop eating and drinking before the procedure and which medications to change or stop.

An anesthesiologist will contact you after your initial phone appointment if there are further questions about the best anesthesia plan for you.

Learn more about what to expect before surgery

What should I expect on the day of the procedure?

Your doctor's office will tell you when to arrive at the hospital. On the day of your procedure, please go to the Center for Perioperative Care (CPC).

Prior to your procedure, you will:

  • Change into a hospital gown and remove your dentures or eyeglasses
    • If you are not staying overnight in the hospital, you will be assigned a locker to store your clothes and other items
    • If you are staying overnight, you will give your clothes and other items to someone who will place everything in a labeled bag and deliver it to your hospital room
  • Be given very tight socks (compression stockings) to wear as protection from the unlikely event of a blood clot
  • Be asked for your name and type of surgery by different staff members—this is a normal safety measure to make sure you receive the right care
  • Have the area of your body where you are having surgery marked
  • Have your vital signs checked and receive some tests, such as a finger prick to check blood sugar
  • Be asked to open your mouth. They will check for any loose or chipped teeth, and will get an idea of how easy it will be to put in a breathing tube if you need one
  • Meet with your anesthesia team to have an opportunity to ask them questions, receive medication and receive an IV, which is a thin tube that goes inside one of your veins and provides you with fluids

When you are brought to the operating room (OR), the team will place monitors on you to check your heart rate, blood pressure, and oxygen levels. You may notice safety checks being done before the procedure starts. Equipment in the OR is carefully checked and counted before the procedure.

Learn more about what to expect on the day of surgery

What should I expect after the procedure?

When your surgeon has finished the operation, your anesthesia provider will stop any medication that kept you asleep in order to wake you up. This is called emergence and it is very different than waking up from normal sleep. You may feel groggy, confused or cold for a short time. Some people become agitated or tearful as they wake up, but this doesn't usually last very long and most people don't remember it.

Depending on your body and the medication you received, you may or may not remember parts of this time. Noises, like people talking, are often the first thing that patients remember. This is normal. You will then be transported to the recovery room.

Possible symptoms of recovery include:

  • Awareness of some pain, which you should let the nurses know about as soon as you begin to feel it
  • Nausea, which can be treated by medication or other methods
  • Cold or chills
  • Sore throat, if you had a breathing tube during surgery

Before you leave the recovery room, you will be evaluated to ensure that you are ready for discharge. We will check your vital signs, assess your pain level and make sure that any nausea is controlled.

If you are being discharged on the same day, a staff member will return your belongings and give you discharge instructions and prescriptions from your surgeon. Your family can join you at this point, they are waiting in the hospital. If someone is going to pick you up, a staff member will call them.

If you are going to be admitted to the hospital after the surgery, please be aware that you may be in the recovery room for several hours until a room on the floor is available. Again, your family can join you at this point.

Learn more about what to expect after surgery

I have had side effects in the past after anesthesia. Will it happen again?

If you have had side effects from anesthesia in prior procedures, please inform your anesthesia provider prior to surgery.

Your anesthesia provider will ask you about prior experiences with anesthesia to understand how your body reacted in the past. Make sure to share your history of anesthesia care, your expectations and your concerns. In particular, please inform your anesthesia provider if you are prone to motion sickness and if anyone in your family has ever experienced complications with anesthesia.

Despite our best efforts, some patients still experience unpleasant side effects of anesthesia. The good news is that we have medications to treat these symptoms if they occur, and we will work with the nursing team in the recovery room to keep you comfortable and safe.