(xi) _Sudden dyspna during surgical operations_, due to--

(_a_) Mechanical obstruction to respiration, such as is caused by impaction of foreign bodies within the larynx (tooth-plates, teeth, blood, pus, vomited food, &c.), by faulty position of the head or falling backwards of the tongue, by a swollen condition of the larynx, by tumours or abscesses (retropharyngeal) which obstruct the air-way, by cicatricial contraction of the pharynx or larynx, by paralysis of the vocal cords, or by spasm of the muscles of the jaws so often a.s.sociated with a similar condition of the glottis and auxiliary muscles of respiration. In a case reported by Boyle, a well-nourished muscular man was anaesthetized for the operation of internal urethrotomy; considerable difficulty was encountered with his breathing, and only towards the end of the operation was it discovered that he had well-marked stenosis of the upper opening of the larynx.

The entrance into the larynx of vomited food or blood is certainly dangerous, and may occur during the simplest operations even when properly performed, as, for instance, during removal of tonsils or adenoids. It is more likely to occur if the patient has not been prepared for an anaesthetic, or if the latter be badly administered, if the laryngeal reflex be lost, if the patient be in a bad position or suddenly moves, or if the surgeon allows too much blood to collect in the pharynx.

(_b_) Failure of respiration from an overdose of chloroform or other anaesthetic. To remedy such conditions it is essential that the air should be expelled from the chest as rapidly as possible. Artificial respiration can only be successful when the air pa.s.ses freely both into and out of the lungs: in rare instances there may be so much difficulty in maintaining a free pa.s.sage that tracheotomy should be performed.

(xii) _Multiple papillomata of the larynx._ Here tracheotomy is required for the relief of dyspna and as a preliminary to other operations. It has also been suggested as a method of curing the papillomata by giving rest to the larynx. After the performance of tracheotomy the congestion is relieved and the growths decrease in size; in some cases they completely disappear, but the treatment is uncertain and not to be recommended (see p. 485).

(xiii) _Malignant disease of the pharynx or larynx which is too advanced for other forms of treatment._ Palliative tracheotomy may be employed in order to relieve dyspna or as a means of giving rest to the larynx. It is most commonly used for cases of extrinsic carcinoma of the larynx: thus C. Jackson reported twenty-nine such cases, in twenty-one of which he advised palliative tracheotomy and in only eight laryngectomy. Of the former, tracheotomy was actually performed in nine, but none of the patients lived for more than thirteen months. It seems doubtful whether tracheotomy has any marked effect in r.e.t.a.r.ding the course of malignant disease, though it sometimes gives relief.

(xiv) _Foreign bodies in the air-pa.s.sages._ It makes no difference what views are held as to the advisability of tracheotomy in the treatment of these cases. The fact remains that the first essential is the safety of the patient, and, if the dyspna is urgent, relief must be afforded.

When a foreign substance has been inhaled the surgeon must always be prepared for tracheotomy, and it is not advisable for him to leave the patient, even for a short interval, without proper supervision. In addition, the operation has been advocated as the proper treatment for all cases of foreign bodies in the lower air-pa.s.sages: nevertheless, removal by Killian's method gives far better results (see p. 559).

(xv) _As a preliminary to operations upon the upper air-pa.s.sages_ tracheotomy is rarely necessary, its place having been taken by infrathyreoid laryngotomy: it is, however, often performed before undertaking the larger operations upon the larynx (see p. 489).

=Anatomy.= The length of the trachea of an adult is about 4-1/2 inches, of which 2-1/2 inches lie above the level of the sternum; the cervical portion, which consists of eight or more rings, extends from the cricoid cartilage above to the suprasternal notch below. In order to determine the upper limit of the trachea it is advisable to palpate the following structures, which lie in the middle line, from above downwards: namely, the hyoid bone with its greater cornua, the thyreoid cartilage which forms the greatest prominence on the front of the neck, and the cricoid cartilage; in this manner it is possible to detect whether there is any deflexion of the trachea from the middle line as the result of a tumour lying in one side of the neck.

The anterior border of the sterno-mastoid muscle on each side is also an important landmark; the two muscles approach each other as they descend to their attachments to the sterno-clavicular joints, thus forming an angle the position of which corresponds to the notch in the manubrium sterni. By drawing a line transversely across the cricoid cartilage to the anterior borders of the sterno-mastoid muscles, a triangular s.p.a.ce is marked off which may be described as the _tracheotomy triangle_ (Fig.

264).

Beneath the skin and superficial fascia lie the two anterior jugular veins; these run from above downwards, to communicate with a branch which crosses the middle line of the neck, commonly in the lower part of the tracheotomy triangle, and there is an interval between them which is, in most cases, sufficiently large to prevent their being injured by a central incision. The pretracheal muscles, namely, the sterno-hyoids and sterno-thyreoids, are closer together; but the interval can be recognized by the greater thickness of the deep fascia which pa.s.ses between them. When the latter is incised, these muscles can be separated, and the trachea is exposed, together with the structures that lie on its anterior aspect. These are the following:--

[Ill.u.s.tration: FIG. 268. ANATOMY OF THE LARYNX AND TRACHEA AND THE POSITION OF INCISIONS FOR THE OPERATIONS IN THIS REGION. A, Subhyoid pharyngotomy; B, Thyrotomy; C, Infrathyreoid laryngotomy; D, 'High'

tracheotomy; E, 'Median' tracheotomy; F, 'Low' tracheotomy; 1, Platysma; 2, Crico-thyreoid muscle; 3, Sterno-hyoid muscle; 4, Isthmus of thyreoid gland; 5, Sterno-thyreoid muscle; 6, Sterno-mastoid muscle; 7, Crico-thyreoid artery; 8, Anterior jugular vein; 9, Inferior thyreoid vein; 10, Innominate artery; 11, Right innominate vein; 12, Left innominate vein.]

(_a_) _The isthmus of the thyreoid gland_, which varies greatly in size.

It may be either a thin band with few vessels of importance, covering the second, third, and fourth tracheal ring; or hypertrophied and vascular, extending higher in the neck even to the front of the cricoid or thyreoid cartilage. This condition also results when a pyramidal lobe is present.

(_b_) _The pretracheal fascia_, which encloses the isthmus of the thyreoid gland and, when traced upwards, finds attachment to the anterior aspect of the cricoid cartilage, thus forming the suspensory ligament of the isthmus. Pa.s.sing downwards it covers the anterior surface of the trachea, and, though somewhat indefinite, can easily be traced behind the sternum as far as the pericardium, with which it blends. This is a point of great practical importance in determining the extension of inflammation into the mediastinum.

(_c_) _Veins._ Small transverse branches of the superior thyreoid veins run upon the upper border of the isthmus between the layers of the fascia which surround this structure. The inferior thyreoid veins, larger in size, run from the lower border of the isthmus vertically downwards in front of the trachea to communicate with the left innominate; in their upper part they may consist of several small veins which join together to form two main branches, of which the left may lie directly in the middle line; small communicating branches of these veins run transversely across the lower border of the isthmus. The left innominate vein crosses the front of the trachea somewhat obliquely, and may lie at least half an inch above the suprasternal notch.

(_d_) _Arteries._ The crico-thyreoid artery runs transversely across the crico-thyreoid s.p.a.ce, being placed in front of the suspensory ligament, and gives off numerous branches, which enter and supply the interior of the larynx, as well as small descending branches which run to the isthmus of the thyreoid gland. A small branch of the inferior thyreoid artery is also constantly found behind the isthmus, and in rare instances a thyreoidea ima branch of the innominate, varying greatly in size, may pa.s.s upwards in front of the trachea.

In young children the same relations are found, but with certain differences. Owing to the larynx being relatively high in the early years of life, the length of the cervical portion of the trachea is almost 2 inches when the head is extended, and the bifurcation is considerably higher than in the adult; further, the trachea is more movable and is smaller in diameter. The laryngeal cartilages are difficult to distinguish, but a ma.s.s composed of the thyreoid and cricoid cartilages can always be felt, and its position determined by careful inspection. It is very important to remember that, even when the head is extended, the cricoid cartilage lies rather less than 2 inches above the upper margin of the sternum. In very young children it is common to find two transverse creases in the skin, of which the upper usually lies over the upper border of the thyreoid and the lower over the cricoid cartilage. The lower crease thus a.s.sists in determining the upper limit of the trachea.

The anterior jugular veins in young children are comparatively large; the infrahyoid muscles are less defined and more difficult to recognize; and the isthmus of the thyreoid gland is very broad, appears to be part of the lateral lobes, and occupies a higher position in the neck, often pa.s.sing in front of the crico-tracheal membrane as well as the first and second tracheal rings. The inferior thyreoid veins are larger, more numerous, and more difficult to separate; the left innominate vein is somewhat higher in the neck; the thymus gland, which gradually decreases in size with the increase of age, may extend into the neck, in front of the trachea, and may even reach as high as the isthmus of the thyreoid; the fasciae are softer and less definite, and the fascia which covers the trachea is easily stripped from its surface.

TRACHEOTOMY IN DIPHTHERIA

=Operation.= As local anaesthetics are of little practical value in the case of children, the surgeon must decide whether a general anaesthetic shall be used; for any nervousness on his part increases the danger of death upon the table. A general anaesthetic is not necessary, but undoubtedly has certain advantages: the operation is easier and can be performed more rapidly; the patient is more likely to fall asleep; and any vomiting that occurs is beneficial rather than harmful. On the other hand, children suffering from diphtheria are apt to die suddenly under chloroform; and it should never be administered when there is any sign of heart failure, when obstruction is very marked, when cyanosis is present, or when the patient is prostrate. The danger has probably been exaggerated, and depends more upon the experience of the anaesthetist than upon the actual disease; in my opinion it is as a rule safer to employ a small quant.i.ty of chloroform, which should be given on the operating table after everything has been prepared. The child should be allowed to choose its own position, generally curled up on one side, and the administration must be slow. By observing these precautions it usually happens that the child becomes quiet, and that with the loss of consciousness the breathing improves; the child can then be placed in the proper position, and the more difficult part of the operation can be completed before restlessness returns.

The instruments required are: a small scalpel, scissors, two dissecting forceps, three or more fine-pointed pressure forceps, two double hook retractors, one blunt hook, an aneurysm needle, and a suitable dilator for the wound; some form of aspiration apparatus may also, in rare instances, be necessary (Fig. 278). Three or four tracheotomy tubes such as described by Parker, and a small tube containing sterilized catgut, which is eminently suitable for the tying of vessels, and for that purpose preferable to silk, should also be in readiness. All the instruments should be kept together in a metal case, as well for private as for hospital practice, so as to be ready in case of emergency. They should be boiled for at least twenty minutes both before and after each operation, and should be laid out separately upon a dry sterilized towel in the position selected by the surgeon.

[Ill.u.s.tration: FIG. 269. TUBES FOR TRACHEOTOMY. A, Parker's; B, Durham's; C, Baker's rubber tube.]

Tracheotomy tubes may be made of silver, rubber, vulcanite, celluloid, or a gum-elastic material, but most surgeons prefer a silver tube in the early stages of treatment. An angular form should be used, for 'with the ordinary quarter circle tube, the lower extremity tends to impinge on the anterior wall of the trachea, and this is attended with many inconveniences and even with grave risks' (Parker[27]). A movable shield is equally important, and this should be flush with the neck in order to avoid the possibility of its being removed by the patient. Further, the tube should consist of two parts--an outer tube to which the shield is attached, and an inner tube which projects slightly beyond the outer and can be removed for purposes of cleaning. To encourage breathing through the larynx, a window may be added in the upper part of the tubes.

Parker's tube, which meets all the above requirements, is the one most commonly used in England. When longer tubes are necessary, either Durham's or Stewart's is recommended: in these, the position of the shield can be altered, and the length of the tube arranged, to suit the patient. In cases of long duration the use of rubber tubes such as Morrant Baker's is indicated. An introducer is rarely necessary except for rubber or long tubes. As taper and bivalve tubes are liable to injure the trachea, their use is not advised. The tube chosen should fit loosely, and should project far enough into the trachea to be secure from slipping out during coughing or struggling. Short tubes are preferable, and the wider the tube the easier the breathing and the better the drainage. The approximate diameter of the trachea varies at different ages, and the size of tube suitable in each case varies chiefly according to the trachea, but partly also according to the fatness of the neck. The accompanying table indicates the appropriate dimensions.

[27] _Tracheotomy in Laryngeal Diphtheria_, 2nd ed., p. 42.

TABLE SHOWING SIZE OF TRACHEA AND OF TUBE REQUIRED AT DIFFERENT AGES

+--------------+------------+------------+---------------------+

_Approximate

_Approximate

_Number of tube._

_Age._

diameter of

diameter of+----------+----------+

trachea._

tube._

_Parker's_

_Durham's_

+--------------+------------+------------+---------------------+

6 months

4 mm.

4 mm.

16

--

1-1/2--2 years

6-8 mm.

7 mm.

20

1

2-4 years

8-10 mm.

8 mm.

24

2

4-10 years

10-12 mm.

9 mm.

28

3

10-20 years

12-19 mm.

10 mm.

30

4

+--------------+------------+------------+----------+----------+

Tracheotomy, even under favourable circ.u.mstances, is attended by _many difficulties_; the urgency of the case, the restlessness of the patient, the movements of the larynx, the frequent absence of a proper operating table and equipment, the importance of a good light, of sensible a.s.sistants, of a trained nurse, and, above all, of a calm disposition, make this one of the most anxious and difficult operations in surgery, yet there is no medical man who may not be called upon to perform it.

It is important to make the best possible preparations. A table of suitable height can usually be improvised and placed in a good light. If the operation be at night, gas lamps or candles can be used, and the illuminant should be placed in a definite position rather than held by the parents. The child should be wrapped in a large towel in order to control the movements of the arms, body, and legs, and should then be placed upon the table; it is advisable to leave him in ignorance of the operation, whatever his age, until the last moment. The skin of the neck should be rapidly washed or sponged with ether, and the head extended over a small pillow or rolled towel. The operation must never be commenced until the proper position is obtained; on the other hand, extension of the head should not be too great for fear of increasing the dyspna. Three a.s.sistants are preferred--one to hold the head firmly in the middle line so that the point of the chin is exactly in line with the suprasternal notch (this is probably the anaesthetist), a second to hold the body at the opposite end of the table, and a third to a.s.sist the surgeon with sponges or retractors. It should be the duty of the last named to prevent any membrane or pus from being coughed over the princ.i.p.als after the trachea has been opened.

There are four varieties of the operation, viz.:

1. _Crico-tracheotomy_ (with division of the cricoid cartilage).

2. _High tracheotomy_ (involving section of the trachea above the isthmus of the thyreoid gland).

3. _Low tracheotomy_ (section of trachea below the isthmus of the thyreoid gland).

4. _Median tracheotomy_ (section of trachea through the isthmus of the thyreoid gland).

=Crico-tracheotomy= is an easy operation owing to the superficial position of this portion of the air-pa.s.sage, but is inadvisable for the following reasons:--

(1) The larynx being narrower than the trachea, a smaller tube is required; (2) the swelling of the mucosa often extends downwards and causes constriction of this region; (3) the tube is not well tolerated; (4) pressure ulcers, necrosis of the cricoid, and granulations are frequent complications; and (5) retained tube is more common than with other operations, this really being the most important consideration.

The comparative value of the remaining operations is largely a matter of opinion.

It is not uncommonly stated that tracheotomy is better done by touch than by sight: the object to be achieved is to find the trachea, and there are two methods of doing this. The first is the _deliberate method_, suitable for patients in good condition when there is no urgent dyspna; it can be performed entirely by sight, and the greater the experience of the surgeon the fewer his difficulties. In such cases skilful technique is of far greater value than haste. The high operation is preferred, because the trachea is more superficial, less movable, and easier to find; it has less complicated relations, the blood-vessels are less numerous, the fasciae are not so loose, the tube is easier to fit and unlikely to slip out, healing of the wound is more rapid, and complications seldom occur. In cases where the isthmus is very broad or highly placed, so that the upper parts of the trachea and cricoid are covered, a median operation is recommended. Low tracheotomy is rarely necessary.

The second is the _rapid method_, to be applied in cases of emergency.

Turner, of the South Eastern Hospital, strongly advocates such an operation without an anaesthetic. The incision made is from 1/2-5/8 of an inch in length, this being repeated without attention to the bleeding until the trachea is reached. The latter is opened in the usual manner.

The tip of the finger is placed in the wound in order to control the haemorrhage, and as a guide to the dilators. When these have been introduced, the child is at once drawn beyond the end of the table so that the head hangs downwards. The bleeding usually ceases in a few moments, though in some cases the tube is inserted to control it. The advantages claimed for this method are that the operation is quicker, and that no distinction between 'high' and 'low' is required. The wound is smaller, there is less danger of sepsis, and the eventual scar is hardly visible; no hooks or retractors are used, so that the trachea cannot be displaced. If the wound be in the middle line it is impossible to miss the trachea. This operation is performed entirely by touch, and the bleeding is not considered. Its adoption may be necessary to save the patient's life, but in the hands of an inexperienced surgeon the operation is attended with great difficulties.

=High tracheotomy.= The incision must be exactly in the middle line; this can be accomplished easily if the surgeon keeps in mind two important landmarks, namely, the point of the chin, and the suprasternal notch. To determine the upper end of the incision, a point is chosen midway between the anterior borders of the sterno-mastoid muscles at the level of the cricoid cartilage. The thyreoid cartilages being steadied between the fingers and thumb of the left hand, a bold incision is made from the upper point, 1-1/2 inches in length, extending in a young child almost to the suprasternal notch. A long incision is generally preferable, and, when the neck is fat, should commence over the middle of the thyreoid cartilage. The skin and superficial fascia are divided between the two anterior jugular veins, and any bleeding is controlled.

The incision is repeated so as to divide the deep fascia lying between the sterno-hyoid muscles, close to one another in the upper part of the incision, and these are separated with the knife. It is now advisable to pause and to seize the bleeding points, allowing the pressure forceps to fall on both sides of the wound to act as retractors. The infrahyoid muscles are separated by at least an inch, and, if retractors are necessary, care must be taken that the muscles alone are included and that the retraction is equal on the two sides. If there has been no 'tailing' of the wound the following structures are then exposed from above downwards: the lower border of the thyreoid cartilage, and the front of the cricoid, both easily seen or felt; and a vascular ma.s.s, namely, the isthmus of the thyreoid gland, covered by fascia and completely concealing the trachea. The landmark that is required at this stage is the cricoid arch; this should be found, and a small transverse incision should be made along its lower border to divide the suspensory ligament; the handle of the scalpel or a blunt hook is introduced beneath the pretracheal fascia, and the isthmus dragged downwards into the lower portion of the wound, an operation which can be accomplished easily if done without hesitation. The upper rings of the trachea are now exposed; and, unless the superficial veins have been divided, there should be no bleeding. The trachea should not be opened until it has been exposed completely and all bleeding has been arrested. It is unnecessary to ligature the vessels at this stage unless the forceps have been so placed as to interfere with the part of the trachea chosen for section, or an artery of considerable size is encountered; in the latter instance there is a danger of subsequent haemorrhage if the ligature is applied close to the tube. While the trachea is being opened, it is necessary to overcome the movements of the larynx by grasping the cricoid with the finger and thumb of the left hand. The scalpel should be gently stabbed into the middle of the trachea to ensure puncturing the mucous membrane as well as the outer wall, and the opening should be quickly enlarged in an upward direction until three rings have been divided, preferably the first, second, and third. It is imperative that this incision should be in the middle line, should not be too small, and should only pa.s.s through the anterior tracheal wall; if force be used there is danger of puncturing the sophagus, or even of striking the bodies of the vertebrae.

At the moment when the trachea is opened there is a sudden rush of air out of the lungs. This is rea.s.suring to the surgeon, and at this point the dilator should be introduced and the anaesthetic abandoned. Temporary cessation of breathing is common after the first inspiration, but the great improvement in colour shows that there is no cause for alarm; with the return of consciousness the child begins to cough, and this has two results, partly clearing the tubes of mucus, pus, or membrane, and partly promoting deeper inspiration and better expansion of the lungs.

Cyanosis is thus speedily removed, unless membrane is abundant; and even where this is the case, it is advisable to encourage coughing in order to dislodge the membrane, which can be grasped with forceps or caught with a sponge as it appears in the wound. The use of a feather or a soft rubber catheter for irritation of the trachea to promote coughing should be abandoned, as such instruments often displace the membrane downwards.

As soon as breathing is regular and the cough allayed, the vessels can be ligatured.

A tube of suitable size having next been selected, the opening in the trachea is widely dilated and the point of the canula quickly inserted into position, the outer tube alone being used, with tapes for tying attached. Unless the tube 'sits' well without tilting, different sizes should be tried until the breathing becomes easy, a sure sign that the lower opening of the canula is pointing in the right direction. The tapes are tied firmly on the right side of the neck, after which the inner tube is introduced and fixed in position.

The wound remains to be treated. Various methods have been recommended to guard against infection: the use of antiseptic watery solutions, such as perchloride of mercury, chloride of zinc, carbolic acid, and perchloride of iron, is dangerous; insufflation of powders, on the other hand, such as orthoform, aristol, and the like, is certainly effective in keeping the wound clean, and is better than the employment of an oil emulsion; suturing the wound is unnecessary and is not recommended. A dry antiseptic gauze is applied to the wound and kept in position by the pressure of the shield. Lastly, a thin covering of gauze is placed over the front of the neck, and the patient returned to bed.

=Low tracheotomy.= The incision should be rather longer than in the 'high' operation and should reach almost to the suprasternal notch. The fasciae, anterior jugular veins, and infrahyoid muscles are treated as before, and there must be no 'tailing' of the wound. The landmark required is the isthmus of the thyreoid gland, and its lower border must be determined and dragged upwards by a blunt hook. It is important to remember that the lower part of the trachea lies deeper in the neck and is more difficult to expose owing to the blood-vessels that lie anterior to it; the thymus gland, also, may extend upwards and require to be retracted. Whereas in high tracheotomy practically the whole operation is best done by clean cutting, in the lower operation this is more dangerous, and the deep dissection must be performed partly with forceps or blunt director; if an artery be divided or venous bleeding occurs, it should be controlled immediately. No attempt should be made to perform this operation rapidly owing to the relations of the parts; nor should the trachea be opened before its rings are exposed thoroughly, as complications may arise after imperfect division of the pretracheal fascia. In the opening of the trachea and the further stages, the operation is similar to high tracheotomy.

=Median tracheotomy.= The child being placed in the required position as before, an incision is made, from the lower border of the thyreoid cartilage almost to the sternum, through the skin and superficial fascia. With a series of cuts, exactly in the line of the original incision, the fascia lying between the pretracheal muscles is divided; the bleeding points are seized with pressure forceps, and retractors are introduced to expose the isthmus. The isthmus itself is treated in one of two ways: in urgent cases it is boldly divided by one or two cuts of the knife; but if time can be spared, a threaded aneurysm needle may be pa.s.sed under it, first on one side and then on the other, after which the needle is withdrawn, and the two ligatures can be tied so as to leave between them a s.p.a.ce of one-third of an inch in which a cut can be made without haemorrhage. The tracheal rings are thus exposed and can be divided as before.

=Accidents.= The accidents that occur are less numerous than might be expected when it is considered how often this operation is performed by those who are quite unpractised in surgery; many of them are the direct result of inexperience or arise because the operator becomes confused.

If the patient be in a bad position, or if a wrong incision be made, the trachea is difficult to find, and it is better to expose the thyreoid cartilage and prolong the incision downwards until the windpipe has been discovered.