Pre-operative Assessment of the Patient – General Anesthesia

00:06 Hello ladies and gentlemen. Welcome back to our ongoing series of lectures on Anesthesiology. In this lecture we're going to talk about General Anesthesia.

00:18 And we're going to review many of the devices that we talked about in the last lecture. So you'll get to see some of the devices and how they are used. We're going to start with our agenda for the talk and it will include Pre-Operative Assessment of the patient, which is a very important aspect of the anesthesiologist's care of the patient. We're going to talk about Evaluation of the Airway.

00:42 Induction of general anesthesia. Securing the airway. Maintenance of general anesthesia.

00:48 Reversal of muscle relaxation if necessary. Recovery from general anesthesia.

00:54 Management of pain. And Recovery room care of the patient.

01:00 So, immediately before surgery, or days before surgery, patients undergoing any form of anesthesia require an Anesthetic Assessment. This could be immediately before surgery, if the surgery is a fairly straightforward simple procedure, and the patient is known to be healthy before you go ahead with the surgery. Surgery will be canceled at this point, if the anesthesiologist is dissatisfied that the patient is safely prepared for surgery.

01:30 So there is an incentive for surgeons to make sure that their patients are seen by anesthesiology in advance of their admission to hospital. In many hospitals, including my own, patients are seen days to weeks before surgery, so that the anesthesiologist can assure that the patient is fully prepared for surgery. So what do we ask about? What do we do when we see these patients prior to the surgery? Well, we get a full history of previous anesthetics, we get a family history of anesthetic problems, particularly if there's any history of Malignant hyperthermia or Pseudocholinesterase deficiency.

02:06 We examine the airway, lungs and heart, and we do a general history and physical for other potential medical conditions such as diabetes, heart disease, asthma, rheumatoid arthritis, etc.

02:18 Almost any medical disease has some anesthetic implications.

02:24 We're the airway experts, so it's really important that we maintain an open airway during surgery. One way of doing this is using a Guedel airway, which is the little hooked airway most of you have seen, goes in the mouth and holds the tongue forward.

02:42 This is often useful in preparing the patient position for intubation. So after they're induced, but before intubation, you can use the Guedel airway. We're going to talk about the laryngeal mask airway, which is very useful for maintaining an airway during surgery, particularly in patients who are maintaining spontaneous ventilation. This device is also useful for maintaining oxygenation in a difficult airway situation. Additional helpers include the stylet, which I described earlier, and the bougie, which is basically a long, very thin device that can go through the endotracheal tube, and can act as a guide for the endotracheal tube, through the cords and into the trachea.

03:24 And then a number of devices for visualizing the airway, including the standard laryngoscope, a device known as a Glidescope, a Storz Videoscope, and the fiber optic bronchoscope. So part of the airway assessment is to do a Mallampati Score.

03:42 And a Mallampati Score is extremely easy to do and everybody gets it done. Basically, the patient should be sitting between 30 and 45 degrees, open the mouth as wide as possible and extend the tongue as far as possible. They should not say, “Aahh.” If it's a Mallampati I, you can see all the teeth, you can see the hard palate, the soft palate, the uvula, you can see right into the oropharynx.

04:06 Mallampati II, the uvula, the tip of the uvula gets cut off, it's a little harder to see the oropharynx, but you can still get a pretty good view. Mallampati III, you've lost the uvula, and you can only see perhaps just a tiny bit of the oropharynx. In Mallampati IV, you basically see tongue and very little else. It's an incredibly easy test to perform and everybody gets it done. Problem is, it isn't very sensitive and it doesn't really tell us very often that we're going to have problems.