So in the last entry, I got into what exactly happens in the time between leaving the preoperative area holding room and the time you go to sleep, with the monitors and oxygen being applied, but usually not remembered by the patient due to the amnesia properties of midazolam...
It is at this point that general anesthesia begins. I get asked all the time, not unreasonably, about what kinds of drugs I will use. Being that most patients don't know or care much about pharmacology, I don't bore the crap out of them with details. Most want to know if I will give them "gas." Most are surprised by my reply, which is that the actual drug that initially puts them to sleep is given through the IV. That drug, which is used in 98 to 99 percent of anesthetics in the United States, is propofol, which has unfortunately gained quite a notorious reputation due to its link to the death of Michael Jackson.
Propofol, in the right hands, i.e. those of a trained and skilled anesthesiologist or nurse anesthetist, is a very safe drug. It has been used millions of times in operating rooms in the last twenty years and has a great track record of success. But it does two important things. It makes the blood pressure go down significantly, and when given in the quantities needed to induce general anesthesia, it slows and even stops breathing. Now these are the qualities that can make it dangerous when not given in the proper setting. That's why the monitors are put on the patient before they go to sleep, so that if the blood pressure goes down and/or the breathing stops, we can do something about it right away.
Fortunately, when I give propofol to a patient to put them to sleep for anesthesia, I'm not walking out of the room or standing in another room while other people give it. I, like every other anesthesiologist who does the same thing, am right there, standing at the head of the patient's bed, waiting for them to fall asleep. Once they are asleep, I use the mask, which is attached to an anesthesia machine, to help them breathe.
Propofol also hurts when it's injected. We try to give a little bit of local anesthetic through the IV with the propofol, to try to diminish that discomfort. Usually it works; sometimes it doesn't. Fortunately, because of the midazolam the patient has received before, they don't remember the displeasure of that experience.
Once the propofol has been given to put the patient initially to sleep, then that is the point where we turn on the anesthetic gas, and that keeps the patient asleep during the duration of the surgery. The problem is that we need a way to give that gas, and if the initial medicine has made the patient stop breathing, then we need to breathe for them. So some sort of tube is inserted into the patient's mouth and is hooked up to a breathing machine from there.
Often, especially in shorter surgeries, the tube that is placed in the patient's mouth is a soft, plastic or rubber tube called a laryngeal mask airway, or LMA. The LMA has a large, teardrop shaped cuff at one end, which when placed correctly, sits on top of the opening to the esophagus and vocal cords. It's usually fairly straightforward to put in; the patient's mouth is opened and the LMA is just gently inserted. It's the other kind of tube that is put in, an endotracheal tube, that is what most people associate when they think of a "breathing tube."
An intubation, as it is called, is the process of placing one of these endotracheal tubes into the patient's mouth and through their vocal cords, where the tip of the tube sits inside the trachea. From this point, the other end of the tube can be attached to an anesthesia machine, and the anesthetic gases that keep the patient asleep can be given.
An intubation, to a layperson who has never seen one before, is kind of a wild procedure. It always amazes me when I'm intubating a patient and can see out of the corner of my eye, some medical student or nursing student and the shocked look on their face. They're fascinated and horrified at the same time.
I remember the first time I saw an intubation as a medical student. The anesthesiologist tilted the patient's head back a little bit, opened the mouth, and stuck this...big, metal thing...into the patient's mouth, and then after some maneuvering, grabbed the breathing tube and shoved it into the patient's mouth for what seemed like forever. I thought he would shove it in so far that it'd get lost. And as he pushed the tube in, I could see the patient's Adam's apple sort of bounce up. I swallowed hard, and I think I felt a little twinge of sympathy pain in my own throat at that point.
I found later on that the big metal thing was a laryngoscope, a metal flashlight of sorts with a straight, dull metal blade attached to it. When held in the right position, a little light shines down the length of the blade. The blade is placed into the patient's mouth to move the tongue out of the way and visualize the epiglottis and vocal cords. Once the vocal cords are in view, it is just a matter of guiding, gently, the tube through them. It's not nearly as violent a procedure as I witnessed that day, but it can be a challenging one that takes some getting used to. But again, as general anesthesia slows or even stops the patient's breathing, it is up to the anesthesiologist to maintain an airway and use that airway to breathe for the patient during the duration of the surgery. That's where the intubation comes in. There is method to the madness...
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