This episode introduces the basics of anesthesia, including its history, types, and the role of anesthesiologists. It explains how anesthesia works to make surgeries pain-free and safe using different techniques and medicines.

Transcript

[00:00] Hello and welcome back to Surgery 101. The podcast series brought to you with the help of the Department of Surgery at the University of Alberta and our partners at Covidien. I’m Jonathan White.

[00:20] broadcasting to you from the Royal Alexandra Hospital in Edmonton, Alberta. It’s been a beautiful summer here and our summer students have been very busy making videos for Surgery 101. You may have seen a few of them already including Lego Can Meds and Lego eRAS. So more of those videos are coming out in the fall but for now we thought

[00:40] we’d start an audio series, which we’ve been looking forward to for quite a while now. It’s a series of episodes focusing on anesthesia, because a lot of our listeners have gotten touched to say, well, we like what you’re doing in surgery, but is there any chance of making a podcast to cover the basics of anaesthesiology? So over the next few weeks, we’ll be introducing the topic, looking at

[01:00] what anaesthesiology is and what anaesthesiologists do. We’ll be looking at how you assess a patient prior to anaesthesia and we’ll be looking at how you induce general anaesthesia during an operation. We’ll also look at local and regional anaesthetic and also consider how they manage post-operative pain. The first step of SODE in the series is brought

[01:20] to us by Danica Kindretuk from the University of Saskatchewan. Danica was one of the very first students who did a Surgery 101 education elective with us. You may recall a couple of excellent episodes she did recently on cataract surgery and in this first episode of Anesthesia 101 she’ll be introducing the topic for us. She’ll be

[01:40] looking at some of the history of anesthesia and looking at the scope of practice of an anesthesiologist. She’ll be defining local, regional and general anesthesia and then she’ll be talking about what is balanced anesthesia as well. So let’s let Danica get us started here as we consider anesthesiology on

[02:00] surgery 101.

[02:20] My name is Danica Kindrachuk. So far on Surgery 101, the team has covered a myriad of interesting topics, ranging from the bowels to the brain, along with some career guidance, health innovation, and patient

[02:40] stories. Up until now, however, we’ve yet to cover the surgical journey from the other side of the drape. That’s right, today we’ll be talking about the role of anesthesia. The objectives of this podcast are to 1. Understand some history of anesthesia and

[03:00] understand its importance. 2. Describe anesthesia and its scope of practice. 3. Understand the differences between and uses of local, regional and general anesthesia. 4.

[03:20] List four main goals of general anesthesia and five. Define the term balanced anesthesia and explain its rationale. When the dreadful steel was plunged

[03:40] into the breast, cutting through veins, arteries, flesh, nerves. I needed no injunction not to restrain my cries. I began a scream that lasted unintermittently during the whole time of the incision and I almost marvel that it rings not in my ears still.

[04:00] So excruciating was the agony. I then felt the knife racking against the breastbone, scraping it. This performed while I yet remained in utterly speechless torture.” That was a quote from an early 19th century woman named Fanny Burke.

[04:20] who underwent a mastectomy. The only anesthetic she received was a bit of wine to calm her nerves. She also needed seven men to hold her down during the procedure. This is a good reminder that prior to the advent of anesthesia many patients would forgo life-saving surgery

[04:40] due to pain. Anesthesia is described in the dictionary as a loss of sensation resulting from pharmacologic depression of nerve function or from neurologic dysfunction. The term is also used to describe the medical specialty of anesthesiology.

[05:00] As with many things in history, there is some debate over who, where and when anesthesia was first used. In the year 1800, Sir Humphry Davy wrote a paper on nitrous oxide, commenting on its capability

[05:20] to destroy physical pain and remarked its potential to be used in surgery. Though cocaine was likely used as a topical anesthetic by some ancient tribes in South America, it was first isolated by Albert Neiman in 1860 and its first recorded use was in 1880.

[05:40] The first public use of anesthesia was in October of 1846 when William Morton used diethyl ether on a patient with a jaw tumor at Harvard Medical School. It was also used for the delivery of Queen Victoria’s child in 1853.

[06:00] Over the years, numerous new agents have been discovered and created and anesthesia has gone from a somewhat risky enterprise to a very safe endeavor. In the year 1950, the death rate from anesthesia was 1 in 1500. In 1995, this was 1 in

[06:20] 250,000. So then, who are anesthesiologists today? Anesthesia as a medical specialty encompasses a broad range of activities and includes operating room management,

[06:40] preoperative assessment, routine day surgery, acute and chronic pain management, resuscitation, obstetrical anesthesia, pediatric anesthesia, clinical pharmacology,

[07:00] patient safety experts. It is in a nutshell physiology and pharmacology live in action. Anesthesia can be broadly categorized into local

[07:20] regional and general. Local anesthesia involves the numbing of a small part of the body. The patient remains conscious. It is mainly used for small procedures where the nerves innervating the area of treatment can be easily reached with

[07:40] injections, drops or ointments. Common procedures performed with local anesthesia are cataract removal, dental procedures and some biopsies. Regional anesthesia is used for slightly larger procedures or for those located deeper in the body. It is a

[08:00] bit of a variant on local anesthesia. The same drugs used for local anesthesia are injected into bundles of nerves as opposed to a single nerve. You may sometimes hear regional anesthesia referred to as a spinal block or epidural. Common procedures performed with regional anesthesia

[08:20] are caesarean sections, hip replacements, or bladder operations. Finally, we have general anesthesia, which probably most resembles the prototypical image that comes to your mind when thinking of anesthesia. General anesthesia is a state of controlled unconsciousness.

[08:40] Patients do not feel anything. This is essential for some operations like laparoscopic surgeries of any type as well as most abdominal surgeries and chest surgeries. General anesthesia is admitted intravenously or through gases inhaled into the lungs. Regardless of

[09:00] mode of delivery, the global mechanism of action is the same. These drugs are carried by the blood to the brain, where they impair the brain’s ability to interpret signals coming from the peripheral nervous system. You may have previously learned that pain is not interpreted as pain until it is recognized as

[09:20] such by the brain. Therefore, by blocking this interpretation, we eliminate its perception. It is also very important to note that the controlled unconsciousness in anesthesia is very very different from non-controlled unconsciousness from other things such as disease, injury and

[09:40] even sleep. As the anesthetic agents wear off, consciousness, perception and pain all begin to return. Here’s a quick tip for the wards. General anesthesia is almost always abbreviated to capital G and capital A. So if you see that on the wards or

[10:00] patient’s chart, now you’ll be one step ahead in the alphabet soup land of medical records. If you are a medical student, you are all too familiar with objectives of the learning type of course. Anesthesia,

[10:20] can also be thought of as having objectives. The four main goals of general anesthesia are, one, amnesia or hypnosis. This means impairment of perceptive awareness. Two, analgesia

[10:40] which is lack of pain sensation, 3. achinesia, meaning lack of motor movement, and 4. homeostasis and autonomic regulation, meaning we want to control sympathetic responses to surgical

[11:00] stimuli. Essentially, we don’t want patients to remember, feel pain, move, or have major physiological responses such as tachycardia or hypertension during their procedures. So then, how do we achieve this? No one agent can be used to achieve all of these objectives.

[11:20] safely. Therefore, we must use a wide variety of pharmacologic agents to reduce toxicities. This is referred to as balanced anesthesia. Some of the agents used include inhalational agents, induction and

[11:40] intravenous amnestic agents, neuromuscular blocking agents, opioids, reversal agents and antagonists, inotropes, vasoconstrictors, vasodilators, and more.

[12:00] In addition to using various drugs for these objectives, we also often use various techniques in combination to achieve optimal outcomes. For example, in addition to general anesthesia

[12:20] we may administer a regional anaesthetic for pain relief post-operation. Another example would be the use of sedative drugs with regional anaesthetics to make the patient feel drowsy and more relaxed during the procedure.

[12:40] In summary, surgery without anesthesia is not possible today. Great advances in the field of anesthesia have occurred in the past 75 years. Anesthesia as a medical specialty is very broad-based, encompassing many

[13:00] roles. Anesthesia can be categorized into local, regional, and general. There are four main goals of general anesthesia, amnesia, analgesia, achinesia, and homeostasis.

[13:20] No one agent can achieve all of the use objectives safely. Therefore, a combination of drugs and techniques are used. This is referred to as balanced anesthesia.

[13:40] Thanks, Danica, for such an excellent introduction to the topic of anaesthesiology. You’ve got me going now, so I’m here looking forward to the rest of the episode, which will be coming out in the following weeks. Please remember to check out our shining new web

[14:00] website. Thesurgery101.org is completely redesigned and much easier to use. You can find all of the episodes organised by topic there. We think it’s really fantastic. You can also find links there to the Surgery 101 app and the Surgery 101 notes. We’re also on Twitter and Facebook as well. And you may not know, we’re also on Reddit and

[14:20] Instagram to check us out on those services as well. I should take a moment here because it’s a Danagas episode to promote our Surgery 101 surgical education electives programme. We get students from all across Canada and further afield as well applying to work with us, to come and play with us on Surgery 101 basically to make

[14:40] virtual patients or to make audio podcasts or to make videos or other things to do with surgical education. So if you’re interested in coming to work with us at Surgery 101, even for just a few weeks, please just get in touch through the website. It’s under the About menu at the top and Surgical Education elective. That’s all we have for you this week, so we’ll see you back next week for the next

[15:00] episode of Anesthesiology here on Surgery 101.

[15:20] you