Friday, October 19, 2012

Put me to Sleep: Anesthesiology


I'm so pleased to host a new guest blogger, Dr. Kate O'Reilley, anesthesiologist extraordinaire. Today, she's talking about an anesthesiologist's main job-- putting you to sleep-- in a good way!
 
Welcome, Kate!
 

Anesthesia is all about passing gas (no pun intended!)  The most common anesthesia gases administered in operating rooms today include Sevoflurane, Desflurane, Isoflurane, and Halothane.  The gases, which are also referred to as volatile anesthetics, can be given to a patient in one of two ways. The first method involves the anesthesiologist simply holding a mask over the patient’s face and having the patient spontaneously breathe in a mixture of gas and oxygen. The second method employs the use of a ventilator that is attached to a breathing tube inserted into a patient’s airway.  Similar to the first method, the ventilator delivers a mixture of volatile anesthetic and oxygen to the patient’s lungs.

All of the anesthetic gases have similar effects. They cause sedation, muscle relaxation and amnesia – the three components to an ideal general anesthetic. The gases have slight differences in how they are metabolized, toxicities, dosages, and degree of cardiovascular depression.

Induction of anesthesia is simply the process of taking a patient from an awake, conscious state to a state of unconsciousness. With adults, this process is usually achieved through the intravenous administration of a series of drugs. Once the patient is unconscious and a breathing tube is placed, the anesthesiologist turns on one of the gases to an appropriate concentration, and uses the gas to maintain anesthesia during the operation.

With children, we rarely have the luxury of a preoperative intravenous line. It’s simply too difficult and traumatizing to place an IV in the little rascals while they’re awake. As a result, anesthesia in children is often induced with gas instead of drugs. Once the child is asleep, an OR nurse places and IV and surgery commences.

Watching a patient being anesthetized by gas alone is an interesting process. It’s the only time one is able to see the distinct stages of anesthesia. The first stage of anesthesia is a state of voluntary excitation and euphoria. It lasts from when the patient is awake until they are rendered unconscious.  Until the patient is unconscious, their movements are purposeful and they can follow commands.  Stage 2 of anesthesia is a stage of involuntary excitation. In this stage, patients my flail their arms and legs, giving the appearance of being combative or agitated. However, they are completely unaware of their actions. When parents accompany their children to the operating room for induction, this stage is usually unsettling for them to witness. The third stage of anesthesia is the stage of surgical anesthesia. In this stage, the patient has reduced muscle tone and will not respond to surgical stimulation. This is the stage where we want patients to be during the operation.  Stage 4 of anesthesia is where we aim not to be. It is the stage where there is severe cardiovascular and respiratory depression. If allowed to persist, this stage could result in death.

So once the patient’s surgery is done, how do we get rid of the gases? We simply turn the gas off.  Over time, the patient breathes off the gas and eliminates it from their bloodstream. Often times, as patients wake up, we will see the stages of anesthesia in reverse. As patients pass through the second stage, they often need to be restrained in order to protect them and the operating room staff from injury. Once a patient returns to stage 1, they may continue to be groggy and somewhat disoriented, but they should be able to follow simple commands. Only once a patient has returned to stage 1 is it safe to remove a breathing tube.

I hope that helps explain a little about anesthesia gases and how they work.  If there are any questions, always feel free to email me at kateoreilley@gmail.com.
 
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Kate O’Reilley, M.D. is a practicing anesthesiologist in the Rocky Mountain region.  In addition to being a physician, she has also written two books, both of which are medical thrillers.  She plans on releasing her first book, “It’s Nothing Personal” in the near future. When not writing, blogging or passing gas, Kate spends her time with her daughter and husband. Together, they enjoy their trips to Hawaii and staying active. Please visit her at her website, http://www.kateoreilley.com/ , and her blog www.katevsworld.com.

 

10 comments:

  1. That was Very interesting. Thank you for sharing this! I remember at age 18 I was put under when they removed my wisdom teeth.
    I woke up and asked, "How did you wake me up? Why do I feel so good?" I remember feeling extra good lol. It was my first and only time under the mask.
    :-)

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    1. Actually, in the dentist's office you only receive intravenous sedatives. It feels like you're asleep for hours, when in reality it's just a few minutes. In that setting, there are no gases and no intubation.

      I'm glad you enjoyed yourself though.

      Best,

      Kate

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  2. I've only been under anaesthetic once, when I was about 4 - I needed gromits for glue ear - and it was a bit of an anticlimax. My older brother had had the same operation, and was full of tales of masks and gas, but they used an IV for me, and got round the problem of sticking the needle in while I was awake by doing it when I was asleep.
    I went to bed the night before, and woke up with a huge needle taped into my hand, to be told I'd had the operation already.

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    1. It's always interesting to hear things from the patient's perspective. It almost seems like anesthesia magic, doesn't it.

      Thanks for reading my post and have a great day,

      Kate

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  3. I have been anaesthetised for colonoscopies a number of times. One minute they're putting the mask on, the next you're in the recovery room wondering how you got there.:-)

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    1. Yeah, our drugs work wonders for messing with your mind. It's pretty interesting stuff.

      One fascinating point is that we still don't know how anesthesia gases exert their effects. There are multiple theories, but after all these years, none have been proven as conclusive. It's like sleep -- we know we need it but the scientists have yet to figure out why.

      Best,

      Kate

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  4. This is interesting, as I have not experienced being given anesthesia. Non that I remember of, atleast. But I see my mom being given that using a vaccine. And it looks like it hurts. Yikes!

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    1. Hi Connor,

      I'm glad you liked the post. Anesthesia doesn't hurt, but getting the intravenous line placed sometimes does.

      Take care,

      Kate

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  5. Thanks for all the great comments! It was great hearing everyone's anesthetic stories.

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    1. Hey Jordyn,

      You are a sweetheart for being so kind as to host me as a guest blogger on your site. Your subscribers are lucky to have found you! Keep up the awesome work.

      Kate

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