The Types of Anesthesia: Your Definitive 5 Minute Guide

| February 25, 2013 | 2 Comments

Curious about the different types of anesthesia?  What is the difference between local anesthesia, general anesthesia, and conscious sedation? How about nerve blocks, spinals, and epidural anesthesia? And exactly how much alcohol is in a bier block? (spoiler alert: none, sorry) We will break down all these modes of anesthesia so you can better understand what your options are.

There are millions of surgeries in the United States each year. Add to this anesthesia for other kinds of procedures (colonoscopies, dental procedures, MRI scans, etc) and the anesthetics that are provided for labor & delivery and c-sections, and you start to get a picture of how important anesthesia care is to the field of medicine.

But there are so many different types of anesthesia that it can get confusing. These include general anesthesia, local anesthesia, IV sedation, regional anesthesia and nerve blocks, spinal anesthesia, and epidural anesthesia.  In just a few minutes, you will understand the difference between all of the types of anesthesia.

Let’s start with one basic premise, though.  For each of these types of anesthesia, anesthesiologists are trained to select the best option(s) for you (taking into consideration the procedure, your medical history, etc) and then use standard monitors of your vital signs to keep you as safe as possible.  They will use a blood pressure cuff, a pulse oximeter, and an EKG tracing, for example.  An exception may be made in the dentist’s office, if local anesthesia is used.  However, your vital signs should be checked before the anesthetic injection and vital sign monitoring capability will be close by.

Now for the types of anesthesia from least sedating to most sedating:

Local Anesthesia

Most of us have probably received local anesthesia at one time in our lives.  This includes local anesthetic injections into your mouth at the dentist office or lidocaine injections into your skin to provide comfort when a skin laceration is sutured.  It is often used in the dermatologist’s office when taking care of skin cancers, in plastic surgeon’s offices, and really anytime it can be safely used to keep someone comfortable during a procedure.

I went to see an endodontist a few months ago to have the dreaded root canal and he used local anesthesia.  My entire cheek was numb while he worked and I could not feel a thing.  I actually fell asleep while he was doing the root canal because my tooth didn’t hurt for the first time in a couple of weeks.  The local anesthesia was that good.

How do these medicines work?  They block sodium channels in the nerves that provide the sensation to various parts of our bodies.  Depending on where the local anesthetic is placed (more on this later), topical anesthesia to the skin can be obtained or an entire extremity can be rendered pain-free.  There are two types of local anesthetics, aminoamides and aminoesters.  Both types can be used in a patient depending on the clinical need.  The synthetic local anesthetics that are used are structurally similar to cocaine (although they lack the abuse potential).

But we have to make an important distinction.  If local anesthetics are placed into the central nervous system (i.e. the spinal or epidural space), this takes on a new classification of anesthetic.  In other words, bupivicaine is a local anesthetic that can be injected underneath your skin to make it numb while a laceration is being repaired.  Also, bupivicaine can be injected into the epidural space to numb your lower body for knee surgery or even a c-section.

Sometimes Epinephrine is added to a local anesthetic in order to prolong the numbness. If a fair amount of the epinephrine (ie. adrenaline) gets into a blood vessel, the patient may feel like their heart is racing. This can be accompanied by heart palpitations, increased heart rate, and increased blood pressure.

This is the normal reaction of “epi” in the blood stream. Some who have had this experience mistakenly think this is an allergic reaction to epinephrine.

Bier Block

The Bier Block was invented many years ago.  It is also known as “IV regional anesthesia”.  This type of anesthesia can be used for upper extremity surgery, most commonly finger, hand, and wrist surgery.  I enjoy placing Bier Blocks in our anesthesia practice :)

With a successful Bier Block, the arm will be numb for around an hour, which is enough time for short surgeries to be performed.  In order for a Bier Block to work, local anesthesia is placed into the arm (via an intravenous catheter) while a blood pressure cuff type device (or tourniquet) is inflated around the arm.  This keeps the local anesthesia in the area of the arm that is distal to the inflated cuff.  Due to diffusion of the local anesthetic into the tissues, the arm will become numb (pain-free) for a short time.

In order to keep the local anesthesia in the arm, the arm cuff must remained inflated during the procedure.   Sometimes this inflated cuff can be uncomfortable and IV sedation medicine can be provided to keep the patient comfortable.  When it is safe to stop the anesthesia and the procedure is complete, the cuff on the arm is deflated and the local anesthesia will wash out of the arm.

The beauty of a Bier Block is that short surgeries can be performed under this technique with minimal IV sedation needed to keep a patient comfortable.  This can mean less chance of post operative nausea and vomiting, quicker discharge from the hospital, earlier ability to ambulate, and potentially earlier ability to tolerate food after the procedure.  Also, for patients who have severe cardiovascular or pulmonary disease, a Bier Block can be more safe.

As with any anesthetic, though, a Bier Block can carry certain risks in addition to its benefits.  One significant risk with a bier block is that of local anesthetic toxicity. Your anesthesiologist continues to monitor you throughout the procedure, even with a bier block, to ensure your safety. These risks are taken into account along with your medical history, type of surgery, surgeon preference, and of course, patient preference to decide if a Bier Block is best for you.

Regional Anesthesia

This type of anesthesia includes nerve blocks.  Fortunately, nerve blocks are becoming more common in the world of surgery and anesthesia.  In this type of anesthesia, local anesthetic medicines are injected near nerves or nerve bundles to make an extremity numb and pain free for a period of time.

For instance, we commonly place brachial plexus nerve blocks for pain relief during and after shoulder surgery.  Another common place for nerve blocks is in foot and ankle surgery. Significant knee surgery can also benefit from certain nerve blocks of the lower extremity.

In some cases, the nerve block can be used by itself to keep a patient pain free for surgery.  However, due to many other factors, including length of surgery, patient preference, and type of surgery, nerve blocks are usually combined with general anesthesia.  The general anesthesia keeps the person “asleep and comfortable” for the duration of the procedure (surgery can involve the need for a patient to maintain a certain body position without movement for hours of time). And the nerve block provides pain relief not only during the surgery (while the patient is asleep) but also for hours to days afterwards.

Please see this post to read about several people’s experiences with nerve blocks.

Epidural Anesthesia

Epidural anesthesia is used to keep patients pain free for a variety of surgeries on the lower extremities, hips, and abdominal area.  Specifically, labor epidural anesthesia is used to keep women comfortable during the delivery of babies.  Labor epidurals can also be used for anesthesia for c-sections.   For more about potential side effects of epidurals during labor, see this post.

For major abdominal surgery, epidural anesthesia can be combined with general anesthesia to provide for pain relief post-operatively.  Your anesthesiologist may place an epidural for a variety of orthopedic surgeries on the lower extremities including hip, knee, ankle, and foot surgery.

With epidural anesthesia, local anesthetic medicine is placed into the central nervous system by way of your back.  The placement of an IV catheter is usually more uncomfortable for the patient than the placement of epidural anesthesia.  When the epidural medicine is working well, a patient’s lower extremities and abdomen will feel numb or asleep for a certain period of time.  This will keep this area of the body pain free while the epidural is in place.

Spinal Anesthesia

Spinal anesthesia is similar to epidural anesthesia in that local anesthesia medicines are placed into the central nervous system by way of your back.  However,  spinal anesthesia is distinct from epidural anesthesia in that the medicine is placed into a different part of the central nervous system.

This type of anesthesia will cause a patient to have a more speedy onset of numbness in the lower extremities and abdomen.  In many cases, the spinal block may be more dense (more numb) than with epidural anesthesia.  Please see this post for a complete description of spinal anesthesia and what it may mean for you.

If a patient has had spinal anesthesia, they will not be able to move their legs for a certain period of time until the medicine wears off.  But this means that the medicine is working well!  Depending on a variety of factors, your anesthesiologist may decide to utilize spinal anesthesia for your procedure or surgery.

IV sedation

With this type of anesthesia, medicine is given through your IV to keep you comfortable for a procedure.  This can range from a small dose just to help you relax or a larger dose to cause you to take more of a nap.  It just depends on so many different factors.  However, if you are taken deep enough with IV sedation, you may be taken under general anesthesia.

There are many terms used for IV sedation that can make this confusing for people, even for some that work in hospitals. I have heard about: conscious sedation, light sedation, moderate sedation, deep sedation, etc.

Think of IV anesthesia as a continuum, from minimal sedation all the way to deep sedation and general anesthesia. You can progress from light sedation all the way to general anesthesia using the same medicines. What matters is the dosing, timing, and perhaps combinations of medicines used. And each person will react uniquely to this medicine, depending on their sensitivities and medical history.

Once you enter the realm of deep sedation and general anesthesia, a person’s ability to breath on their own may be affected and the medicines used may start affecting the cardiovascular system. This is why I would insist on having an anesthesiologist take care of me if I had to have such a procedure.

Because each patient is unique, it can be very easy to think a patient is under “moderate sedation” and then slip into a deeper state of sedation and even general anesthesia. This may also be a reason why some patients complain of having  “too little anesthesia” for their procedure. If the person taking care of them is not an anesthesiologist, he/she may not feel comfortable giving more sedating medicine and having the patient slip into a deeper level of anesthesia where they are not qualified to properly and safely take care of that patient.

General Anesthesia

With general anesthesia, you will be completely asleep for the procedure.  You will lose consciousness as well as your airway reflexes. This is the deepest level of sedation that is provided by anesthesiologists.  It means that while the medicine is being given, you will be unconscious and unaware of what’s going on.  But don’t worry because you will be monitored the entire time to ensure that you are as safe and comfortable as possible.

If you ask a friend or family member what general anesthesia felt like, most likely they won’t have much to say!  Read about my experience with general anesthesia when I was 16 here.

Parting Thoughts

I hope this has cleared up the different types of anesthesia for you.  When your anesthesiologist talks about different kinds of anesthesia, and perhaps combining several types of anesthesia, you will be better equipped to understand what it all means.

Please leave your questions or comments below.  Also, don’t forget to visit our forum and learn more about what others have to say about anesthesia.  And as always, thanks for visiting anesthesiamyths.com.

Dr. Joe

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Category: Anesthesia Medicines, Anesthesia Topics, General Anesthesia, Obstetric Anesthesia, Pediatric Anesthesia, Regional Anesthesia, The IV

Comments (2)

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  1. Natasha law says:

    I have svt will it affect me having a general anaesthetic ?

    • David Draghinas says:

      Hi Natasha,

      Arrhythmias such as SVT could impact your anesthetic. It would be a good idea to meet with your anesthesiologist some time before your procedure so that he/she can evaluate that and any other medical conditions. They might recommend you see your cardiologist prior to having surgery.

      All the best,

      Dr Dave

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