A System of Operative Surgery, Volume 4 (of 4)

by Unknown

(iii) In chronic stenosis, intubation is now extensively employed. Fibrous contraction such as follows some cases of thyrotomy, or syphilis and other inflammatory diseases, can be treated successfully by this method. Short light tubes, of vulcanite or similar material, are inserted and retained in position for long periods, three months or longer; with the pressure so exerted the amount of fibrous tissue appears to be diminished, and the lumen of the larynx is dilated.

Operation (in diphtheria). The apparatus required consists of a gag for opening the mouth, a set of tubes with a gauge showing the size for each age, an instrument for intubation and extubation, and equipment for tracheotomy.

Fig. 276. Instruments for Intubation of the Larynx. A, Gag (O’Dwyer’s); B, Forceps for intubation and extubation (Thorner’s); C, Gauge; D, Tubes: 1, O’Dwyer’s; 2, Thorner’s.

The tubes recommended by O’Dwyer are of gilded bronze, but other materials such as vulcanite or hard rubber are sometimes used. The tubes have undergone frequent modifications and those designed by Bayeux are shorter, lighter, and a great improvement (Goodall). In Thorner’s type (Fig. 276) the lower end has been cut off at an angle, so that it may pass more easily between the vocal cords; the intubator and extubator have been replaced by a single pair of beaked forceps with a ratchet attached to the handles, so that, when the beaks are separated, the tube is gripped firmly and cannot be disengaged until the trigger of the ratchet has been pulled; with these forceps the tube is not obstructed while it is being taken in and out of the larynx, and there is less need for hurry; further, the top of the tube has a funnel-shaped opening ‘which greatly facilitates the introduction of the beaks when the tube is in the larynx, inasmuch as it allows the beak to glide from any point of the rim almost automatically into the opening, and what this means can be appreciated by those who have had experience with the old extractor’ (Kyle).[42]

No preparation of the patient is required, but a blanket must be wrapped round the arms, body, and legs to control the struggling. Two assistants are required, one to hold the patient, the other to steady his head and manipulate a gag. The upright position is preferred by many surgeons because the patient is less frightened, and the breathing is easier; but the child may be laid upon a table, with the head slightly extended and exactly in the middle line of the body, or the head may be allowed to hang over the end of the table and the tube passed from behind, in a manner similar to that used for direct laryngoscopy. No anæsthetic is necessary. The first assistant or nurse should sit on a low chair with the child on his knee, holding him so that he directly faces the surgeon; a second assistant stands behind with a gag in his hand. A tube of suitable size, with a thread attached, and mounted on the introducer, is taken in the right hand; the assistant introduces the gag, opens the mouth to the fullest extent, and steadies the head with his two hands; the surgeon now passes the left index-finger over the back of the tongue, so that the tip of it passes behind and below the epiglottis until the cricoid is felt; this is the most important landmark, and as soon as it is located the finger is drawn upwards and forwards in order to hook up the epiglottis, and the introducer and tube are rapidly passed over it; the method of introduction being that used for all laryngeal instruments. As soon as the end of the tube is level with the end of the finger, the handle of the introducer is raised so as to throw the point as far forward as possible; the instrument is then bodily lowered, so as to drive the tube downwards through the larynx until it rests firmly and securely against the ventricular bands, which prevent further passage of the collar; the tube is now held in place with the left index-finger until the introducer is removed. The whole operation in experienced hands should take from three to five seconds only, and must be performed without force.

If the tube has been properly introduced, it is usual for the child to begin coughing, and this may continue for a short time, accompanied by noisy and rattling inspiration; the cough gradually disappears and breathing becomes easy. The tube causes temporary aphonia, which may persist for a few days after its removal, but is otherwise well tolerated; the patient is not conscious of the presence of the canula unless it becomes blocked.

The operation is simple in the hands of those who are accustomed to the use of laryngeal instruments; in a normal larynx there is no difficulty in introducing a tube, but in diphtheria the parts are inflamed and obstruction is present. Children are often intolerant or frightened; they are liable to retch or choke during introduction, but the latter can sometimes be accomplished by waiting for an inspiratory effort; if the struggling is very troublesome a small quantity of chloroform (cocaine in adults) may be given with safety.

Difficulties of the operation. The difficulty of passing the tube over the base of the tongue can be avoided by pulling the tongue downwards and forwards and passing the introducer through the mouth with the hand to the left of the patient’s face and rotating downwards when the point is in the pharynx. Failure to find the opening of the larynx is often due to not keeping the instrument exactly in the middle line. The tube may be too large (even when it corresponds to the age of the child) owing to swelling either in the larynx or in the subglottic region; in such a case a smaller tube must be tried, and it is essential that no force should be used to drive the tube into place, or dangerous complications may arise. Even a smaller tube may not be passed on the first occasion, and the surgeon has to decide whether he will try the same tube again or one that is smaller; the latter may not be suitable for the age. The tube may be too small, and this may be recognized by the ease with which it passes; as a result, the first strong cough expels it out of the larynx, and another must be introduced. A tube of correct size may be in the larynx without relieving the dyspnœa; this may be due to one of the following causes: (a) some membrane may have been pushed in front of the tube, an event which is evidenced by the noisy and difficult respiration, and which requires that the tube shall be withdrawn with the thread and again introduced, after an interval; (b) the tube itself may become blocked with membrane, with the result that it is at once coughed out; or (c) the child may be asphyxiated so that tracheotomy becomes a necessity. This last is a point that must always be remembered: intubation should never be performed unless everything has been prepared for opening the trachea. The tube may pass into the œsophagus in spite of all care, and this may increase the dyspnœa by pressing upon the posterior part of the larynx, in which case it must be withdrawn by the thread and a further attempt made. It has frequently happened that the tube with its thread has passed down the œsophagus into the stomach, an accident which ought to be avoided. No serious consequences are likely to occur, as the tube will be passed per rectum, or in rare instances vomited.

The question arises as to how many attempts should be made before intubation is abandoned. This varies in each case and depends upon the amount of distress caused by the previous attempts. With each further trial the child becomes more and more restless, and if the third attempt fails, it is better to desist, or to allow at least an interval of half an hour. When the dyspnœa becomes urgent there must be no hesitation, and either the tube must be reintroduced or tracheotomy performed; both operations are difficult under these circumstances, and the surgeon should choose the method of which he has the greater experience.