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Guide to General Anesthesia: What You Need to Know Before Going Under

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I am a board-certified anesthesiologist in Lake Tahoe, California. I write from the perspective of both a doctor and a patient.

Your anesthesiologist monitors vital signs and adjusts anesthetic throughout your surgery.

Your anesthesiologist monitors vital signs and adjusts anesthetic throughout your surgery.

General Anesthesia: What You Need to Know

For some procedures and surgeries, you may have a choice regarding the type of anesthesia used. Many times, though, the only good choice will be general anesthesia.

In this article, I will give you a broad introduction to terminology, procedure, and what to expect.

What to Expect Before Surgery

After checking in with a nurse and having an IV placed, you will meet your anesthesiologist to discuss your anesthetic. Midazolam or other sedatives are often given prior to other medications to "take the edge off." You may get this type of drug before you even leave the pre-op room. These drugs kick in within a minute and make you forget anything that happens for a period of time afterward, although the effect varies from person to person. For this reason, you may have no recollection (or only vague memories) of entering the operating room.

After you go to the operating room, you will be given oxygen to breathe and will have monitors such as a blood pressure cuff, an oxygen monitor, and EKG stickers placed.

Agents for Induction

Most commonly, your general anesthetic is induced with medicines injected into your IV. Anesthesia providers use a combination of medications that function as sedatives, pain relievers, and hypnotics for the induction (getting you to sleep) phase of general anesthesia. You may or may not remember this if you were given a sedative in the pre-op phase.

After You Are "Sleeping"

Once you are unconscious, your anesthesiologist will make sure you are getting enough oxygen and anesthesia. To do this, they may need to use a breathing device to help keep your airway open. There are various ways to do this, including using just an oxygen mask, an LMA (a soft rubber mask that sits inside of your mouth, just over the opening to your windpipe), or a breathing tube that slides into the windpipe between the vocal cords. The decision regarding the type of airway device is based on many factors, including any medical problems that you have and the type of surgery planned.

(Note: Although we use the word "sleeping," anesthesia is not like sleep in that you cannot be awakened until the drugs are removed from or metabolized by your body. Recent studies reiterate that it is better thought of as a controlled, reversible, coma-like state.)

Oxygen levels are monitored and maintained the whole time you are "asleep."

Oxygen levels are monitored and maintained the whole time you are "asleep."

Maintenance of General Anesthesia

"Maintenance" refers to the process of keeping you "asleep"/"under" for the entire surgery. Usually, a combination of gas, IV hypnotics and strong pain medication are used for this important stage.

During this phase, your anesthesiologist stays with you, carefully monitoring your vital signs and keeping you safe. Your anesthesia is adjusted throughout the operation based on what is going on in the surgery. For example, it will be "lighter" during the time that the nurse is washing the surgical area with sterilizing soap—you need less because this is not painful or disruptive for your body. Too much anesthesia when it is not needed causes the heart rate and blood pressure to drop. When the surgeons are ready to begin, your anesthesiologist will make adjustments to make sure you have enough.

Your unconsciousness is maintained by watching your heart rate, blood pressure, and breathing rate. Medications are increased or decreased based on your specific needs during that surgery. In other words, every anesthetic is customized to the needs of the patient.

Emergence ("Waking Up")

When the surgery is over, the anesthesia gases are allowed to dissipate. Titration of pain medication continues so that you do not wake up in pain. You will move through stages of consciousness until, at last, you are awake and the breathing mask or tube is removed. Don't worry; you won't likely remember this, though. Most people don't realize they are awake until some time later in the recovery room.


Our anesthetics are much shorter-acting than those of ten years ago, but they are still going to make you feel pretty sleepy for the rest of the day after your surgery. General anesthetics have the unfortunate side effect of nausea and vomiting. If you are particularly prone to nausea (for example, from motion sickness), make sure to tell the nurses and doctors in the pre-op area. There are meds they can give you to minimize this side effect.

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The pain medicines you will take after surgery have many of the same side effects. So, if you are still sleepy and experiencing nausea a couple of days after your surgery, it more likely results from narcotic pain medicines than the anesthetic.

How Do You Know I’m Asleep?

Anesthesiologists monitor all of your vital signs continuously throughout the surgery. Increases in heart rate, breathing rate, and blood pressure all signal "light" anesthesia. Changes do not mean you are awake. Your autonomic nervous system reacts to the stressful stimuli of surgery long before you wake up. You actually move involuntarily as a reaction to the surgery while still unconscious, as well.

What Is Anesthesia Awareness?

Anesthesia awareness is an unfortunate situation where you are not fully unconscious during the surgery. People with true anesthesia awareness later report that they heard some of what was going on in the operating room. Usually, they can't feel anything but may be very scared. Rarely, they can feel the surgery but can't move or speak. People who have medical or surgical issues where giving deep anesthesia is dangerous are at more risk for true anesthesia awareness.

Why Do You Say “True” Anesthesia Awareness?

There are many, many cases when people think they have been awake during general anesthesia, but in fact, they are mistaken. The most common scenario involves a surgery where they had sedation anesthesia or sedation in combo with a spinal, epidural, or regional anesthetic. Those types of anesthesia do not and are not supposed to induce unconsciousness. It is absolutely normal to have memories and be at least partially awake with these types, but memories may be fuzzy due to the drugs used.

Could You Use a Brain Monitor to Prevent Anesthesia Awareness?

Brain monitors have not been shown to provide protection from anesthesia awareness, but don't worry; your anesthesiologist knows what to look for. Monitoring for sweating, tearing, increases in heart rate, breathing, and blood pressure are much more reliable. Brain monitors may provide other valuable information, so your anesthesiologist may use one, but not to prevent awareness.

Why Do I Have to Have General Anesthesia for This Surgery?

Many types of surgery simply cannot be done with other types of anesthesia. Obvious examples are brain and heart operations, but others, such as laparoscopic abdominal surgeries, require more explanation.

When you have laparoscopic surgery, the surgeons use skinny tubes with cameras and instruments on the ends to do the operation. This causes less pain than large incisions, but in order to see into the abdominal cavity with cameras, the surgeons need to make room to operate. To do this, they inflate the abdomen with gas, usually carbon dioxide, to create a domed space in which to work. The other types of anesthesia—epidurals and spinals—that used to be used for abdominal surgery just don't cover enough of the abdomen to keep you comfortable. Also, the table is often adjusted into a "head-down" position to improve working conditions even more. The combination of an inflated belly and laying head down makes it very difficult to take deep breaths and keep your oxygen level adequate. With you asleep under general anesthesia, we can use the ventilator to make sure your lungs are fully inflated, making oxygenation easier and safer.

Why Can’t I Eat or Drink Anything After Midnight Before My Surgery?

When you go under anesthesia, it's not like normal nighttime sleep. At the point at which you become unconscious, you also lose the protective reflexes that normally keep your airway clear. For example, while awake, if something irritates your vocal cords, they would reflexively close and you would cough to clear the irritant. While unconscious with anesthesia, you may be more prone to regurgitation of stomach contents, and your vocal cords and the rest of your throat can't react to prevent the material from entering your windpipe and your lungs. This can lead to a dangerous condition called aspiration pneumonitis or aspiration pneumonia. Damage to or infection of the lungs causes serious complications in some people.

So the food and water you have in your stomach could end up in your lungs. While some studies show that the usual eight-hour fast before surgery may be overly cautious, and some institutions are shortening the NPO (nil per os, Latin for "nothing by mouth") interval, some will not for another reason: Surgeries sometimes cancel or get moved around. If you are lucky enough to have your surgery moved earlier in the day, but you have eaten within the NPO interval, the operating staff will not be able to move your surgery earlier. And if they move someone else up, you may end up getting delayed even later.

For Information on Other Types of Anesthesia . . .

  • Insider's Guide to Spinal Anesthesia
    Your anesthesiologist may recommend, or give you the option of, spinal anesthesia for your surgery. Learn the uses, benefits, and risks of spinal anesthesia.

This content is for informational purposes only and does not substitute for formal and individualized diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed medical professional. Do not stop or alter your current course of treatment. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.

Barbara Roth on December 12, 2019:

Is it ok for a person who has dementia/Alzheimer’s to receive anesthesia? Will it make the situation worse?

George on January 28, 2019:

Am having a melanoma removed from lower back. I am 86 year old male with some memory loss and history od heart problems 17 years ago, Surgeon wants to use general anathesia. Can local be used.

Becca on May 10, 2018:

am having a Breast augmentation and having GA . I can't lie flat on my back as I get a post nasal drip and it's thick and can wake me up with a start at night coughing. How will my Anastetic doc sort this so I don't choke on the table .


Melody52 on April 12, 2018:

I am having a total hip in 2 weeks by the anterior approach. I have 2 herniated discs, can I have a spinal? If so, is an EKG necessary, I'm 65, no heart problems at all.

babs on February 25, 2018:

will the anesthesiologist put my iv in for me when i am under sedation because i am scared of needles

Kathy on December 03, 2017:

I recently had foot surgery. I’ve have been under anesthesia at least 10 times. This time as the anesthesiologist administered the drugs into my IV I had a horrible taste of like powdered medicine in my mouth that made me start coughing just before I lost consciousness. Why?

Scott Burkholder on September 13, 2017:

On opiate pain meds is there a concern I should know about before going under,getting 12 teeth pulled.

Lia Moncada on September 05, 2017:

I had a 20 hrs surgery, what I would like to ask is it possible loosen memory of things you plan in doing , or said something and don't remember saying it, or place something's secure spot and not be confused where put it

Also be running out breath , meanings if i carrying a bag or something else to take a breath ?

My bones hurts every morning ,

After 2 days of surgery a couldn't catch any air , couldn't breath , i lost conscience , but drs where there , because the person watching me run for help

Then I couldn't hold my own weigh, feeling frágil I was sent to convalescent home starter walk with a waker and still felt insecure .this was feb28/17 today I lose my balance and still short of breath walking a block

Is this because part of prolong anesthesia? Because I am afraid and I am Schedulle for another surgery in a month ( had breast cancer) reason for all this surgeries

Thank you on August 23, 2017:

i have congestion in my lungs . am having camera down the thoart will have local is it dangerous for me

KiVah on August 08, 2017:

Is it possible to be talking when your under anesthesia? Was given anesthesia before my operation but then woke up realizing I was talking the whole time I was unconscious. I felt very confused.

Teri on June 19, 2017:

I am having mortons neuroma surgery but I am having bouts of vertigo. Do I need to postpone surgery? I only get vertigo when I first lie down or get up from sleeping.

Harvey Borodkin on June 04, 2017:

i am due to have kidney removed due to TSS in renal pelvis.This is to be laproscopic. I had quintuple bypass 2 years ago and am fine from that. Since i am 81 and taking the above into account,is there anything i should be aware of prior to surgery.I understand that many inhalation drugs are bad for the liver,kidneys and heart.Do i have to worry?

Ammie on June 04, 2017:

2 year old is needing dental work,he is not cooperative at general dental visits, pediatric dentist recommended doing work in children's hospital, under general anesthesia to do work, I have had general anesthesia 1 time, help this mom be confident in having general anesthesia at his age...

Lisa Highley on December 04, 2016:

I am 55 and im facing surgery for two hernias,gallbladder and scar tissue removal from the small intestine and i was diagnosed with Mitral Valve Prolasp in 1990 but dont take medication for this dont really have any problems except flutters.My question is how safe is general anesthesia on the heart with Mitral Valve Prolasp im really unhappy about being under general do i have another option?

noplaybarbie on August 30, 2016:

Hi...I recently had my second hip replacement in less than 3 months time. My first hip replacement was done under general anesthesia because they said in the OR that I couldn't have spinal anesthesia because of multi-level spinal stenosis. Now for my second surgery, different anesthesiologist he insisted that he can give me a spinal anesthesia with a nerve block. This time approximately 17 hours after my surgery time I awoke in ICU on a ventilator. I was told that I aspirated at the end of my surgery and that I had to be put on a ventilator and that they also had to do a bronchoscopic procedure to suck the contents out of my lungs. I had to stay on the vent the rest of the night with no sedation because they said they could not sedate me as my blood pressure was way to low. It was one horrible night. I also caught aspiration pneumonia. I did not eat or drink anything for over 12 hours prior to surgery with the exception of a small sip of water to take my blood pressure medication the morning of surgery. I am curious to what could have caused this. One doctor said maybe I am diabetic and it takes diabetic people longer to digest food. My blood sugar level is good, so that is not it. I just want to know what happened to me and wonder why I was completely out for so many hours. I have no recollection of anything that went on until I awoke at almost midnight that night, my surgery was at 7:30am....Thanks....Just curious....

Karen Bal-e Eduarde on August 11, 2016:

Why it is important to a doctor or nurse to know the percentage of an anesthethic before performing an surgery?

Meri on August 01, 2016:

Hello. I have a big concern. Please, help me. After 9 days is my operation with full anesthesia, but I started to cough. Some months ago when I went to checking, my doctor said that if I cough they can't do the operation. It was over, but now suddenly I got cold and started to cough. I have to do the operation abroad and at this moment I can't get in touch with the doctor and my flight is in 4 days. Please, help me and advise me what if my cough lightens, as now I take a lot of medicine for recovery, will it be possible to do the operation. And if no, what can be the risks?

Thanks a lot in advance.

redhed on December 14, 2015:

I had a partial nephrectomy 6 weeks ago to remove a large ( thankfully benign ) tumour ( angiomyolipoma ). I have me/cfs ( chronic fatigue syndrom ) which the anesthetist was aware of . I had a lot of anxiety before the surgery, so the anaesthetist prescribed an ativan tablet pre surgery. I went into the surgery aproximately 8 am and the surgeon tried to call my spouse at aproximately 1:00 ( he'd forgotten to turn his cell back on as not to have on in hospital ). I did not get to my room in the ward until 5:15 pm. My husband kept asking why the delay and nursing staff just said, not to worry she'll be up soon. On my follow up visit to my surgeon I was so worried about the results of pathology I didn't even think to ask about why I was in recovery so long. ( is 4 hours excessively long ? ) I'm wondering if anything went wrong or if there is anything I should be aware of in case of needing anaesthesia in the future. I have suffered shortness of breath but seems to be improving since doing breathing exercises.

thomas on November 04, 2015:

Three months ago I had a pace maker implanted,now I am experiencing ,an odor in my hair,on my breath ,and my skin has this smell of medicine coming from the pores of my skin.Is this a side effect from anesthesia?

sakinah on July 05, 2015:

Very informative hub. I liked how you explained why laparascopies are done under general anesthesia, even for surgeries performed below the belly button. I cannot say I feel at ease about general anesthesia, and will probably do whatever I can to avoid it, but it certainly helps to have an idea as to what to expect, coming from a professional. on January 26, 2015:

To be a soccer mom is equivalent to having some sort of part-time job that has a demanding program. My top ten soccer mama ideas will probably hopefully be useful for finding balance that you saw and while doing so help improve your son or daughter's soccer ability.

Feeonavictoria on December 02, 2014:

So I had a lump removed from my breast under General anaesthetic four days ago, not sure what pain killers I had but I know they put some in me before they put the anaesthetic in. Ever since I have random spurts of itching which is mostly down the arm that I had the anaesthetic put in and my legs (still wearing the stockings they give you for blood clots) and also my face. I was wondering when will this stop it is very irritating.

I have also got this mucus cough after I eat :/ never had it before but I have to cough til the mucus has gone for it to stop. Is this normal?

kuma508 on November 29, 2014:

Should they able to tell if water is around lungs and heart in pre op day before surgery

shoaibkhatri on November 23, 2014:

This is a wonderful article, Given so much info in it, These type of articles keeps the users interest in the website, and keep on sharing more ... good

sharon dass on November 04, 2014:

Hello I had surgery 2 days ago and quite traumatised by it first conscious memory was the nurse advising me I need oxygen through my nose as my oxygen levels were low. .also my blood pressure..they took me to the ward after recovery ward and I still was out to it..some 6 hours later the nurse tried to take me to the toilet but i could barely walk and felt so dizzy I felt like I was going to pass out..I didnt wake up properly till 1am that morning and my surgery had been 1pm that day my blood pressure was still down the whole day..ive had surgeries before and it never took me that long before.

shreekanth on August 19, 2014:

my wife had an cesarean delivery and some times she feel some fear in her mind and not get sleep and also not talk smooth and not have food and I need reason and answer to come out from this complications and u can help me by mail

shreekanth on August 19, 2014:

my wife had an cesarean delivery and some times she feel some fear in her mind and not get sleep and also not talk smooth and not have food and I need reason and answer to come out from this complications

Lynda Derks on August 06, 2014:

I have to have a complete hysterectomy 8-30. I just had a D@C and was put to sleep the middle of last month. I have Meniere's disease and since the last surgery my dizziness has gotten worse. Do you think the next surgery will add to this? How save is it to have 2 in a month and half?

babs74 on May 28, 2014:

Is thrashing around a side effect of Propoful...I had a follow up colonoscopy and was told by nurse after awakening from anesthesia.

I did not have this reaction 3 months earlier under the same anesthetic.

Is this a common reaction.

India Collins on May 13, 2014:

I'm getting ready to under general anthesia for the 4th time I'm having laporscoptic assisted vaginal hysterectomy since this surgery takes so long do they have to give me more of the anesthesia to keep under I have had gall bladder removal bladder procedure and dental surgery in OR and usually what is the time frame for this surgery very nervous thank you for your time

Clyon on April 08, 2014:

Very good information! About ten years ago I had a cesarean under anesthesia. My husband did not tell me until later (he forgot in the excitement of the baby) that they had been very scared for a while because a nurse came out and told my family they were having a hard time getting me out of anesthesia. I remember waking up in extreme pain and the staff seemed very frantic... The staff never explained what happened & I have always wondered if I should get my medical records from that hospital (I have since moved states) in case I have to go under again & they should know about the possible? Complications. Is this common & what are the possible causes?

Amommy on March 25, 2014:

Yesterday was my surgey! I am doing well resting at home. I just wanted to say thank you for your response and all your information. I was given versed, I guess something to take the edge off, right before heading into the operating room. Once there I guess I was given proforol through an IV and I could hear someone say you will get very sleepy soon and next thing I knew I was being awaken by a nurse asking me if I was in any pain. The surgery was over! It was as though I had closed my eyes for 5 seconds! Again Thank you!

Sara on March 05, 2014:

Thank you so much for posting this blog. I'm getting ready to have my very first surgery ( a tonsillectomy) at the age of 25 and I am petrified. I know in the grand scheme of things, it's a very simple procedure, but like you mentioned, it's the fear of the anesthesia that gets to me. I don't like the fact that for those 45 ish minutes, I will be giving all control up to a stranger (a very very educated and smart stranger, but still a stranger). I do get panic attacks prior to anything very there something they could give me to calm me down before surgery and/or make me not aware that I'm going into the OR? I'm perfectly healthy (the sickest I've ever been in my life was just the stomach virus). Everyone in my family has had some kind of surgery with some type of anesthesia and no one has ever had any problems. Based on that, are the chances pretty good that I too won't have any problems with the anesthesia? Sorry for all of the questions- I'm just really nervous and am trying to get as much information as possible.

Amommy on February 26, 2014:

Thank you so much for your reply. I did ask if an epidural or other local anesthesia would be an option for me and the answer was no. The surgery requires GA. Uncomfortable and I will need breathing tube. I am still apprehensive about it all but I am slowly coming around to the idea that all will be well. Will keep you and your readers posted! The fear of general anesthesia is not easy to overcome. So I know I am not alone in this. Again Thank you.

TahoeDoc (author) from Lake Tahoe, California on February 23, 2014:

Hi Amommy.

I have been both a patient and a doctor with anesthesia. I honestly believe the best thing is usually to go with the 'norm'- what the doctors and nurses are most used to doing for a particular procedure. In this case, that is going to be general anesthesia.

Laparoscopy has been done with epidural on very rare occasions when there was an overwhelming reason (like medical issues that made general anesthesia unsafe) BUT it is NOT ideal. It is very difficult to get the epidural to cover / prevent pain in all of the areas needed for a laparoscopic surgery. I would not advise it as a doctor, nor would I accept it as a patient. While the surgery will not take long, it would still be quite uncomfortable due to the gas that has to be put into the abdomen and the position in which you have to lay while they are operating. General anesthesia does a much better job of this.

You can ask to speak to someone from the Anesthesia department there long before your surgery to get more info. It will likely help you feel better.

General anesthesia is more scary because you have to give up control to become unconscious- you are not aware of what is going on, but in this case, I believe the discomfort and the risk to you and the level of difficulty for the surgeons are all minimized by general anesthesia.

You could ask your doctor about the possibility of doing something to avoid general anesthesia, but I imagine you will get a similar answer.

I have had 5 surgeries, all with general anesthesia. I also have young children (I had a 4 month old baby when I had my 1st surgery) and it's a protective momma instinct to fear that you won't be able to care for them, but if you are otherwise healthy, general anesthesia should be very safe.

*standard disclaimer- no guarantees are made or implied and this comment nor any information contained on this site or any other should be a substitute for personal medical interaction with a qualified professional medical provider*