Obesity & Anesthesia: How Is It Different?

| January 24, 2013 | 9 Comments

Obesity is at the forefront of many health discussions in the United States.

According to 2012 US statistics from the American Heart Association, over 149 million men and women age 20 and older are considered overweight or obese. This means they have a BMI (body mass index) of 25 and higher.

About 75 million are classified as obese (BMI of 30 or higher).

What’s even more concerning, the trends show that Americans are getting fatter and it’s happening earlier on in life. About 1 in 3 kids are now considered overweight or obese. These numbers are about 5 times higher than they were in the early 1970’s.

These statistics, no doubt, have far-reaching implications as drivers of increasing health care costs.

But what about looking at this issue in the short-term? What are the risks for someone who is obese and is in need of surgery? What are some of the issues that may arise when someone suffering from obesity has to undergo anesthesia?

In this article, we will take a close look at the potential difficulties and complications that may arise when someone who is obese needs anesthesia. Just because someone is overweight (or obese even) doesn’t mean they will have issues with everything listed here.

There are different levels of obesity, different weight distributions, and personal medical profiles that will make each individual’s situation unique. This list is meant as a discussion of the potential difficulties that may arise in someone that is obese.

Let’s get started…

IV’s, Monitors, & Tables

Obesity increases the likelihood of having a difficult IV placement. Veins can be more difficult to visualize, making IV placement more difficult. In some instances, if a peripheral IV can not be placed, a “central line” may need to be placed in the neck, upper chest, or groin area. This can add to stress and discomfort prior to surgery.

It may also be a challenge finding a blood pressure cuff that fits properly (your anesthesiologist regularly monitors your vital signs throughout your procedure. This basic monitoring has greatly contributed to the safety of anesthesia). If an appropriately fitting cuff is not possible, your anesthesiologist may need to place an arterial line to monitor your blood pressure.

An arterial line is a small catheter, similar to the IV catheter, that is usually placed in an artery in your wrist that provides close monitoring of blood pressure. Additionally, small samples of blood can be taken and analyzed during surgery to more closely monitor a patient.

*** Arterial lines are also placed for other reasons that may be related to other issues in a patient’s medical history or related to the type of surgery performed (ie. larger, more complex surgeries).

A larger patient also creates some challenges when it comes to positioning for surgery.

First of all, the “everyday” OR tables have weight limitations that may be exceeded by morbidly obese patients. In these instances, a special table will have to be used.

Your anesthesiologist and the rest of the OR team take great care to protect and pad pressure points during surgery. This can be more challenging in an obese patient. And depending on the position necessary for the surgery and the length of time in the operating room, there may be an increased risk of nerve injuries related to positioning.

Luckily, most of these injuries resolve over days, weeks, and sometimes months in the event that they occur.

The Airway

Anesthesiologists are the experts of “the airway”. It is constantly on our mind when a patient is under our care as this is what keeps a patient alive: breathing in oxygen, breathing out carbon dioxide.

Obese patients may have a challenging or difficult airway.

There can be increased soft tissue surrounding the mouth, throat, and neck. As anesthesia is given and a patient loses his/her airway reflexes and ability to breathe on their own, this increased soft tissue can make it more difficult to keep the airway open and deliver oxygen to the patient.

And when it comes time to  intubate a patient (place a breathing tube in the windpipe), this too may be more challenging. All the extra soft tissue can make it more difficult to visualize the breathing tube going into the windpipe.

After reviewing the medical history, an anesthesiologist will assess the patient’s airway during their physical exam. He/she will then make a plan for delivering anesthesia in as safe a way as possible.

Sometimes this will involve having a video laryngoscope available in the operating room. In this case, you will hardly notice a difference as this tool is typically used after you are “asleep”.

But sometimes your anesthesiologist may determine that the safest course is to proceed with an “awake fiberoptic intubation”. This method of placing a breathing tube can be more uncomfortable to a patient, and this is not lost on your physician.

Understand that if this is recommended for you, your anesthesiologist is doing it with your safety in mind. He/she will attempt to make the process as tolerable as possible. But ultimately it’s your life and safety that is foremost on their mind.

Once the breathing tube is properly placed, anesthesia will be induced as quickly as possible (usually within seconds).

Obstructive Sleep Apnea

Obese patients have a higher likelihood of suffering from obstructive sleep apnea (OSA).

This is a condition where the soft tissue surrounding your airway begins to narrow. This can cause frequent episodes of apnea (stopped breathing) when asleep, causing the person to wake up in the middle of sleep. This can lead to day time sleepiness, impaired concentration, memory problems, morning headaches, etc.

These changes can also lead to an increased sensitivity to respiratory effects of general anesthetics and other medicines that may be used as part of your anesthetic plan (eg. narcotic pain medicines).

Over time, OSA can lead to serious effects on the heart and the lungs. Be sure to tell your anesthesiologist if you have been diagnosed with OSA (though many have OSA and have not yet been diagnosed).

The Lungs

Fat accumulation on the chest and the abdomen makes it more difficult for the lungs to function properly. Without getting too technical, this can cause an increase in oxygen needs and more difficulty in the lungs delivering that oxygen to the body.

Carbon dioxide production is also increased due to the metabolic needs of the excess fat.

You can start to see the potential issues as an increased need for oxygen develops, while at the same time, it becomes more challenging to maintain an airway and deliver that oxygen.

Yet another reason your anesthesiologist has gone through four years of residency training to develop the skill and expertise to properly evaluate more challenging patient scenarios and guide them safely through their perioperative experience.

The Heart

Cardiac output goes up with increased weight, making the heart work harder.

Over time, as this process worsens, strain is placed on many parts of the heart. If not corrected, this can eventually lead to heart failure.

Obesity also accelerates atherosclerosis, or the build up of plaque within blood vessels. This compounds the problem as the narrowing (and sometimes blockage) of blood vessels prevents the delivery of oxygen and nutrients as the need continues to increase.

Gastrointestinal System

There may be an increase in volume of fluid in the stomach; and the fluid is often more acidic as well. The stomach may also be prone to delayed emptying. This can put obese patients at risk for gastric aspiration.

There liver is also prone to fatty infiltration and inflammation. It is not always clear, however, how this might affect (if at all) the metabolism in the liver of drugs used during surgery and anesthesia.

Kidneys and Endocrine System

Obese patients may have impaired glucose tolerance and/or a higher chance of type II diabetes.

This has implications related to the functioning of the heart, impaired wound healing, and other issues that will have to wait for its own article.

The kidneys are also impacted by weight gain, and it can eventually lead to impaired kidney function and contribute to the development of high blood pressure.

Drugs (Pharmacology) 

This can get highly technical very fast.

The bottom line is that increased adipose tissue may alter/affect the way a medicine works. This often depends, not only on the patient’s characteristics, but the various properties of the drug itself.

Your anesthesiologist is balancing all of this information when deciding which medicines to give, when to give them, and how much to give.


Your anesthesiologist is trained to evaluate and care for patients of all shapes and sized. Certain conditions may make our job more challenging.

The best course is to be upfront with him/her about all of your medical conditions and any concerns you might have about the anesthesia plan for your planned procedure.

Know that we are doing all we can to make your experience as safe and as comfortable as possible.


Now it’s your turn. Please share any questions and/or experiences below (or in our forum).


What General Anesthesia Side Effect have you experienced, if any?

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Category: Anesthesia Topics, General Anesthesia, operating room

Comments (9)

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  1. Jenn says:

    I did have a question for you. I’m an obese person and I’m going under general anesthesia for a D&C. I was at a consult with an anesthesiologist recently to determine if they were going to do my surgery at the day clinic or if I would need to have it in the hospital. During this consult, the anesthesiologist checked me out, looked down my throat, felt around, and determined I’d be an ‘easy tube,’ he didn’t think there’d be any issue that way (I guess that’s good, right?!) I know the procedure of a D&C is quick – one of my biggest fears, to be honest, is waking up with the tube in my throat. I’d freak out, just being honest. 🙂 Do they normally remove the tube prior to you actually being lucid enough to know what’s going on? Other than being a large person, I’m healthy. I don’t smoke, do drugs, I hit the gym four times a week.

    Kind of a side note – I’ve read some of the forums where folks get put out just by an injection in their IV, for the same procedure I’m having done. Maybe they just don’t realize they were intubated, I’m not sure, but they swear they just went to sleep, woke up, went home an hour later.

    The thought of going under is terrifying to be, and being fat just adds another layer of risk. I’m grateful the D&C is a quick procedure that you’re basically in and out for, but going under general is scary. The thought of being intubated freaks me out, even though I’m not awake for it, but I don’t want to wake up and be alert and have some foreign plastic tube down my throat.

    • DrJoe says:

      Great questions! I am so glad you asked them because I know many other people are thinking the same things….

      First of all, I am glad you were able to meet with an anesthesiologist prior to your surgery. The fact that he / she was able to examine your airway is an added bonus. This is done to try and help predict whether or not you will be a difficult intubation once general anesthesia is induced.

      You are right, D & C procedures are usually quick. But you will still be asleep under general anesthesia. This means you will not remember any part of the procedure, you will not feel it, and you will not know you are there.

      On the day of surgery, you will meet with the anesthesiologist prior to the procedure. Once you are in the operating room, IV medicine will be given to you to get you off to sleep. At this point, it is up to the discretion of the anesthesiologist as to how to proceed. Some will place a breathing tube, others will place an LMA, and some anesthesiologists will have you breathing on your own without any breathing device. It just depends and you should definitely ask the anesthesiologist the plan if you are concerned on the day of your procedure.

      You should not remember or feel the breathing tube while it is in place during the surgery. If you do have a breathing tube in place for the procedure, it will be removed as you are waking up. Because the general anesthesia doesn’t go from “on” to “off” in seconds, it will be removed while you still have sedating anesthesia medicine in your system. I cannot promise that you will not remember the breathing tube coming out, but it would be very unlikely for you to be aware of this. And if for some reason you were aware of the tube coming out, it would be even more unlikely for it to be uncomfortable (because sedating medicines would still be in your system).

      When I underwent general anesthesia 17 years ago, all I remember was talking to the surgeon before the case in the pre-operative area and then waking up later that day at home. And in the current era, our medicines are even faster acting and faster to leave your system.

      If it makes you feel any better, a lot of people are nervous about the same things. Try and talk to some friends or family members who have gone through general anesthesia. Our hope is that folks will post their experiences on our forum as well. Posts on the forum can be made anonymously.

      I really hope this helps. Talk to you soon!

      • Jenn says:

        One other question, if you don’t mind – the guy asked me about sleep apnea. Pretty sure I don’t have anything funky going on – I never wake up restless. I do know, when I’ve napped just flat on my back I wake myself up snoring sometimes. Usually don’t lay on my back flat to sleep. With this procedure, obviously, I will be. No two ways around it. 😛 If I’m at a slight incline? Like pillows or something underneath my shoulderblades or what have you – totally no snoring. Or sometimes if I just turn my head to the side? Good to go. Is this something i should mention to them?

        • DrJoe says:

          You should definitely mention this to the anesthesiologist. This will better help them decide how to administer the general anesthetic. Do not worry about snoring while you are under anesthesia, but don’t hesitate to tell the anesthesiologist that you do snore at night.

          By the way, I forgot to mention that you should read the final comments on the breathing tube post. Someone addressed your exact concern……

  2. Trisha says:

    Is it safer for an obese patient to have a spinal anesthesia instead of being put “under”? I have read that it is. What is your opinion? I have to have a D & C, a hysteroscopy, and a polypectomy performed and am petrified to be unconscious!

    • David Draghinas says:


      That type of procedure can be performed with general anesthesia or with spinal anesthesia.

      What’s “safest” for you and the best anesthetic plan will be designed by your anesthesiologist after considering your entire medical history.

      Definitely let him/her know about your anesthesia fears and this will be taken into consideration.

      All the best to you,

      Dr Dave

  3. Ann says:

    I had a cold knife cone procedure 2 days ago (1/28/2016) at the hospital under general anesthesia. It was an hour long procedure. I don’t remember the tube being placed inside my throat or being removed. However, I did tell them I have a latex allergy and I’m not sure if the tubing was latex free or not but when I awoke in recovery the right side of my lower lip was very swollen with raised bumps inside which was not there before surgery and the muscles in my neck on both sides hurt from inside my throat to the outside. I expected a little raspy soreness in my throat from the tube but it’s like the inside of my throat is smaller and it’s a little difficult and painful to swallow. It’s not affecting my breathing. I took 800 mg of IBP thinking it may help with inflammation but it seemed to not help very much. Maybe I may take some Benadryl and call the Dr tomorrow morning if not improved.

  4. Annie says:

    I need to have all four of my wisdom teeth removed because they keep getting infected and I’m always in pain from it. I’m 26, female, and technically considered obese on my BMI. I do snore at night and I don’t know if I have sleep apnea or not. On top of all that, I have multiple sclerosis. I am petrified to be put under anastesia for fear I will die, but I also don’t want to be awake during the removal. Any thoughts?

  5. shannon says:

    i am a bit obese i am over 200 lbs but under 300 lbs and i don’t smoke and don’t drink alcohol since i do not do these things does that decrease my risk for complications during a D&C procedure

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