Endotracheal anaesthesia: No. 5 (1944)

without a free Airway the administration of a general anesthetic is impossible obstruction may arise at any part of the air passages but the greatest danger and the most difficult to deal with is when obstruction occurs at the larynx itself the popularity of endoral anesthesia is therefore easy to understand because its fundamental principle is absolute Airway control by incubation of the larynx once this control is secured the difficulties and risks of respiratory obstruction no longer arise in operations in the region of the head and neck the tube can be passed through the mouth or through the nose according to the site of the operation obviously when no contraindication exists the oral root is indicated for an operation on the nose and the nasal rout is used when the sight of the operation is the mouth in other operations it is preferable to choose the oral route as this ensures the use of a tube of optimum caliber here is the apparatus you will need first the lingos scope any efficient model will do a wide side slot and illumination from a self-contained battery are advantages this is a U-shaped instrument and this is the modern folding type two types of mouth gags the Moler type and the inzer type angulated forceps these are necessary Ray for packing the throat with gaues and also to assist naso tral incubation they are so constructed that the hand holding them does not obscure the field of vision a spray for applying a surface anesthetic to the patient's throat a drop bottle containing a nephrin paraffin preparation or use before nasal incubation a lubricant for the endot tubes and a roll of gauze impregnated with liquid paraffin you should have handy as well a roll of 1 in a teas of plaster and before beginning incubation prepare a piece for the protection of the teeth during the insertion of the lingos scope cut a strip about 8 in long and fold it over to 1/3 of its length now if the endal tubes these are made from ordinary Commercial Rubber tubing which is stored in coils so that its natural curve is readily adaptable to the course of the air passages this material differs from drainage tubing in being firmer in consistency and less liable to collapse on external pressure to make an endoral tube is a simple matter first cut off the length of the tubing at an angle of about 45° this is how to measure the length of the tube it should be twice the distance between the lobe of the ear and the a of the nose now smooth the beveled edge with an Emory file or a carbonum stone when it is quite smooth it should look like this 13 sizes of endot tube are available they range from o to 10 Mill scale or from 13 to 37 in French catheter gauge lastly a series of metal connections graduated to fit the different sizes of endot tubes there are two types oral and nasal the oral type is a wide angle which fits snugly to the chin and it is long enough to prevent the rubber tube being bitten by the patient's teeth this type should never be used in the nose as it would project too far and tend to cause kinking of the rubber tube when the towels are applied the nasal connection on the other hand is a sharper curve and projects as little as possible from the patient's nostrils as soon as an operation is finished it is important that the endotrail tube is properly prepared for further use first the tube and the connection are taken apart and the tube is then cleaned on the outside with a swab dipped in ether take great care that the inside of the tube is not neglected scrub it with a narrow test tube brush and plenty of hot water then look through to make sure that no mucus has been left inside now place the tube in the sterilizer and boil it for 2 minutes one word of warning however here is a tube that has been boiled with a metal connection attached a thing that should never be allowed to happen you can see that the end of the tube is now permanently stretched it is therefore unsafe to use it when the tubes have been boiled for 2 minutes they are stored in a round box so that the curve is preserved a new C should they be tightly tied in bundles as the constrction will permanently indent them immediately before use the tubes are immersed in a solution of bite of mercury in the proportion of 1 to 1,000 see that the metal connection is properly attached before lubricating the tube it might be disastrous if it came apart during anesthesia Vaseline is a satisfactory lubricant but even better is a lubricating medium which contains a surface anesthetic such as nupercaine because this reduces the tendency to cough when the tube is moved during light anesthesia this is a useful formula lubrication serves two purposes it makes incubation easier and also helps to protect the mucous membranes which may be dry as a result of premedication before or during uction it is a good idea to spray the patient's throat with a surface anesthetic such as 2% aniane this reduces the irritability of the throat reflexes and makes it unnecessary to have a deeper level of anesthesia for intubation than that required by the operation when nasal intubation is indicated a few drops of a parapan Eid drain preparation such as endrin give maximum patency and lubricate the intended course of the tube the correct position of the head is the same for oral and nasal incubation a pillow is placed below the octopot in this way the patient assumes the position of a man sniffing the air these diagrams show the position of the head more clearly the head is slightly extended on the atlas with the cervical vertebrae in normal relationship to the dorsal vertebrae this is the respiratory tract when the head is in the right position the air passage takes a curved course from the nostril to the vocal cords we shall apply this knowledge later to the technique of blind nasal intubation first anesthesia is induced to a depth sufficient to relax the mandible for the beginner it is a good idea to deepen the anesthesia even further and so make sure that the patient will still be deepen enough during the passing of the tube remove the airway and place the folded piece of a tease of plaster over the edge edes of the upper teeth to prevent them from being damaged by the lingos scope the lips and teeth are separated with the fingers and the lingos scope has passed between them along the dorsum of the town from now on the course of the lingos scope must be followed by constantly looking through the instrument first let us see in this diagram which of the landmarks along the course of the lingos scope the first thing to be illuminated is the dorsum of the tongue the lingos scope is Advanced along the tongue and when it is Advanced about half the distance it must eventually travel the uula comes into view when it is reached 2/3 of the full distance the epiglottis is seen when this appears the lingos scope should be gently Advanced and the epiglottis lifted and held by the tip of the instrument finally the glotus and vocal cords come into view so long as the glotus is open the tube can be passed along the Lumen of the lingos scope into the larynx the beginner will have to learn to recognize these landmarks as they appear to the anesthetist we will now see what they look like through the Lingus scope this is the uula silhouetted against the wall of the fings the bulb of the lingos scope can be seen on the left and here is a simplified drawing of this region the epiglottis is the next Landmark to look out for this is the drawing of it and here is the real thing partly masked on the right by a fold of the fenal wall next the aroids and the opening of the esophagus when the epig Lotus has been lifted by the lingos scope the glotus can be seen this is what it looks like when it is closed the cords are in apposition with false cords also coming across on no account should the anus try to incubate when the glotus is closed as attempts to force a passage only lead to spasm besides damaging the mucus membranes when the glotus is open the cords are abducted and the tral Rings can be seen Beyond once this view has been obtained the tube can be slipped through the open GLS into the tra watch for these landmarks closely as you insert the lingos scope once the lingos scope has been successfully guided into possession pass the tube down when it is in the tra and there should be no doubt about this when a lingos scope has been used used the metal connection should be strapped to the patient's face by adhesive plaster the hose from the anesthetic machine is then fixed in position when there is any likelihood of blood reaching the larynx it is necessary to pack the fings carefully packing is deposited in such a way as to hold the soft pallet against the posterior wall of the fings thereby encouraging the soft pallet to fulfill one of its natural functions this method of packing is more satisfactory than putting in packs behind the soft pallet and is less likely to lead to injury no blood can now reach the traa and the packing also makes sure that breathing takes place entirely through the tube an alternative to G packing is the Goodell Waters infatable cuff fitted onto the end of tril tube itself the tube fits quite Loosely into a test tube so long as the cuff is deflated air is pumped into it by syringe attached to the supply tube this is then clamped off as you can see the cuff knife fits firmly against the walls of the test tube and makes a watertight packing the cuff tube is inserted into the traa in the same way as an ordinary endot tube the anesthetic machine is attached and then the cuff is inflated the pilot bulb indicates the state of inflation of the cuff with the tube in anesthesia can now be maintained by ordinary inhalation methods often the anesthetist has to control the administration from a distance any efficient machine will do and the system may be open or closed when no machine is available flag's method of attaching a length of rubber tubing to an ether can is a useful improvisation in emergencies successful blind incubation depends mainly on the correct position of the head as we have already seen the course of the air passage from nostril to glotus is curved when a tube whiches a similar curve as passed through the nose it tends to follow this course and enter the tra after induction of anesthesia the tube is passed along the floor of the nose until the breath sounds are heard at maximum intensity the tube is then Advanced during inspiration its presence in the tracha is indicated by full respiration taking place through the tube now the same process in slow motion photography successful blind incubation depends entirely on the sense of hearing so the anus must listen carefully to every sound that comes through the tube if the ear is kept close to the end the current of air can be felt as well as heard as long as the breast sounds increase in intensity the tube is following the proper course towards the gluts and may be steadily Advanced but if the breath sounds diminish in an intention the tube is no longer advancing towards the glottic opening the tube is then withdrawn a little and rotated slightly during the rotation the distal end of the tube should pass over the glottic opening the breath sounds suddenly increase the rotary movement is arrested and the tube is slipped in here again we repeat the blinding done at normal speed if the tube does not go in readily by the blind method the anesthetist should on no account continue prodding in exert incubation and the use of force instead of skill are likely to result in trauma this this is a potential disadvantage of endot tral anesthesia but it is avoidable in a difficult case the anesthetist should Resort the lingos scope and forceps pass the lingos scope as before and then insert through it the angulated forceps then it is an easy matter to pick up the end of the tube and guide it into the larynx when the tube is in position the metal connection is strapped to the patient's face in the usual way anesthesia can be maintained as before by using an anesthetic machine or by means of an ordinary mask and ether drop bottle when the anesthetist has free access to the patient's face in this case the metal connection may be discarded and the endoral tube is transfixed by a safety pin to prevent its disappearing down the nose a further alter alternative is Flags method used in the same way as with oral incubation the throat can be packed with G as an oral incubation in cases where there is any chance of blood reaching the larynx here we see the end of a nasal operation during the course of the operation the fangel pack has prevented blood from running down towards the gluts when the pack is removed suction is used to clear away any blood which may have trickled down from the nasal fering after this the airway is first inserted and the endot tral tube is then removed it is a good practice where possible to retain the tube in the tra until the cough reflex is active coughing is a safeguard which prevents blood and other foreign fluids from being inhaled the main advantage of endral anesthesia is absolute control of the airway once the tube is in the tra the breathing will remain free and there will be no possible danger of respiratory obstruction this holds true irrespective of the position of the patient's head certain positions on the table make Airway control Difficult by using an endot tral tube this difficulty is overcome once a free Airway is assured the anst and his apparatus can be completely clear of the field of operation by watching the movements of the rebreathing bag he can detect immediately any change in the character of the patient's Breathing by packing the patient's fanks with gwes he can be protected from the entry of blood into the tra here is a patient being placed in the prone position for a craniotomy no notice that the anesthetist does not lose his hold on the tube while the patient is being moved also note that endot tral anesthesia is of the greatest advantage to the surgeon in helping him to maintain strict asepsis not only has the method proved a benefit to the patient and the anesthetist in the protection it affords to the airway it has considerably increased the scope of surgery in the region of the head and neck so