What are the different types of anesthesia?

For most people, anesthesia is one of the more mysterious branches of medicine.  What we do for patients is done, generally, when they are asleep.  You the patient don’t exactly know what we are going to do, or how it’s done, but you put yourselves in our hands willingly.  It’s sort of a weird relationship we have with other humans.  We have done our job right if our patients don’t remember most of what we did.

There are actually several types of anesthesia, the two most common being general anesthesia and monitored anesthesia care.  But the two are really just different degrees on the continuum of awake and asleep.  On the lightest end, monitored anesthesia care (MAC), drugs are given to you to make you more or less “sleepy” depending on what you are having done and the surgeon preference and, to some degree, your preference.  General anesthesia is usually done with some of the same drugs, but in greater doses, for a more deep sleep that generally requires that the anesthesiologist breathe for you in some way or another. If 1 is awake and 10 is asleep, MAC is more towards the 1 (small hammer) and general is more towards the 10 (big hammer). If someone asks you “have you had general anesthesia before”  you may say yes even thought you really had a MAC because often patients can’t tell the difference.

The thing to remember about MAC is that the goal is not to make you completely asleep, although you probably will feel like you were.  So if you are a little awake or hear or remember a few things, that’s normal and nothing to worry about.  A MAC can be “heavy” or “light,” and just like in other parts of medicine, every patient is a little different.  There’s no set formula or dosage that will work on every person.  It’s a little more of an art than a science in that respect.  You have to trust the anesthesiologist to work with you to make you comfortable.

In general anesthesia, the goal is to make you totally asleep for the duration of the surgical procedure.  Usually this requires that we put some sort of device in your throat to help you breathe while you’re asleep.  This is because the drugs we use, in small doses for MAC, are used in high doses and are strong enough to cause you to stop breathing.  So we breathe for you.  So if you are having general anesthesia the anesthesiologist will probably stop you from breathing, then breathe for you until he/she wakes you up.  Another way in which we have a weird relationship to other humans.

So with MAC you may be a little aware, with general you will not be at all. A word about awareness under anesthesia.  People ask me about this all the time.  It very rarely occurs and when it does we don’t really understand why.  In fact it occurs so rarely I’ve never seen it.  This is not to discount or make light of your anxiety about the possibility but to reassure you that the possibility is vanishingly small.  Remember what I said about every patient being slightly different.   People handle drugs different ways and have different tolerances.  Medicine is not an exact science.  We spend 4 years in residency to learn how to figure out whether you are awake or asleep.  We almost always get it right.  Don’t go see the movie.

Other kinds of anesthesia concern blocking the nerves to a specific area of the body, rather than blocking all of them, which is essentially what general anesthesia does.  So if you are having hand surgery we can block the nerves to the hand by putting a novocaine-like substance around the nerves that lead to your hand.  If you are having a baby, we can put that substance around the spinal cord and block the nerves that lead to the lower half of your body.  Sometimes we combine nerve blocking with either MAC or general.  We will tell you what your case is “booked as,” meaning what is usually done for your specific type of surgery, and what we recommend, but you will always have input and we will always have a conversation with you ahead of time to make sure your goals and our goals are the same.

Each person and each case is different, and there is no cookbook. You have to trust us to make you comfortable and safe.  After you’ve only met us for 5 minutes.  Now that is a weird relationship between humans.

Shirie Leng is an anesthesiologist who blogs at medicine for real.

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