The main objection to any of the forms of tube just described exists in the nature and shape of their curve, which not infrequently causes the lower or tracheal end to lie in contact with the anterior tracheal wall, or its convexity with the posterior, and irritate, even ulcerate, them. This misfortune is entirely obviated by the canula of Durham, the second of the two forms to which I have called special attention, and which is essentially a right-angled tube, made of four sizes, with a long horizontal portion, varying from 7 to 4 centimeters, and short vertical portion, of from ½ to ¾ of an inch in length and slanting slightly backward. The former portion is capable of being lengthened or shortened in any sized tube by means of a screw arrangement attached to it as it passes through the usual neck-collar or shield; and the vertical tube can thus be correctly adapted to the particular depth at which the trachea naturally lies in a given case from the surface; and not alone this, but also to the condition of the overlying parts, whether thin or fat, swollen or otherwise. Once in position, the vertical portion of the tube remains in the long axis of the trachea, and does not touch its walls to any injurious degree. Owing to its right-angled shape, the angular and descending portions of the inner tube of this canula are necessarily made upon the lobster-tail principle, with joints—a possible disadvantage, as they can become clogged with mucus and may become detached. Other modifications and improvements exist in this Durham canula over the older one first described, which add to its utility, but need not here be dwelt upon. Suffice it to say that the tube is an excellent one for its purpose, and is deservedly highly spoken of and recommended by those who have had experience in its use. Its cost is an objection.
The other forms of tracheal tube need but passing mention. The bivalve canula of Fuller is made in two lateral segments, fastened to a collar and tapering when closed to a point, so that introduction of the apparatus through the tracheal wound is made easy. Once introduced, an inner complete canula is slid into its place, thus separating the two outer halves and rendering the whole round and compact. It has been criticised unfavorably on account of the danger of hemorrhage that it is likely to cause through pressure on the tracheal walls by the sharp edges of the outer canula. In Gendron's canula the same lateral blades are separated after introduction by means of a screw fastened on a transverse bar.
Soft-rubber canulas were introduced to the profession not long since by Morrant Baker for subsequent use after the operation of tracheotomy, the usual tube having been worn meanwhile for a few days. Being soft and flexible, they are certainly safe and comfortable for the patient, but their thickness and the absence of any inner tube are, especially the latter, serious disadvantages. They are not, I believe, generally used. Finally, the long, flexible tracheal tube of König was devised by its author to meet the indications in cases where the trachea is compressed from without by tumors, and where a long canula that is flexible, but at the same time rigid enough to resist pressure, becomes a necessity. It is made in the form of the ordinary tracheal canula, only larger, some three or more inches of the centre of the descending portion of the tube being constructed of spirally-twisted silver wire.
It may not be out of place to remind at this point that a tracheotomy is not infrequently performed, of necessity, very hastily, and in the absence not only of a tracheal tube, but likewise of other and even more essential instruments. The lack of the former need never be a barrier to the prompt performance of the operation, for the ready wit of the true surgeon will show him various ways out of his temporary difficulty. A thick goosequill fastened by threads passed through its outer end makes an efficient improvised canula. A bit of elastic catheter answers the same purpose. Retractors for the edges of the tracheal wound, made of wire—silver if it be at hand, a couple of hairpins if it be not—and connected together by an elastic tape which passes around the neck, will not only answer a good temporary purpose in holding the tracheal wound dilated, but have been recommended by Martin—in a more elegant form, it is true—as a proper method of treatment after opening the trachea. Finally, one or more stitches passed through the cartilaginous edges of the wound, and attached to the soft parts beyond it, will serve to secure its patency, at least temporarily.
If a patient be doomed to wear a tube constantly in his trachea, the instrument described above can be removed at a suitable interval after the operation and its place supplied by a single tube of the same size and form as has been found adapted in the case. In the convexity of this permanent tube an ovoid opening should be made to allow of the passage to the larynx of the respiratory current, in part at least, and to its mouth a pea-valve may be fitted which shall admit air on inspiration, and not allow it to escape on expiration, thus doing away with the necessity of the patient's closing the opening of his tube with his finger each time that he requires to speak. Several forms of these valves have been devised, but practically they are of little use, are annoying to the patients, and, as a rule, not tolerated by them.
How shall the operation of tracheotomy be performed? An answer to this question necessitates a short description of the operative steps of the different procedures that is given in the order in which, I believe, the operations are, as a matter of experience, found to occur in practice—viz. 1st, superior tracheotomy, combined or not with cricotomy; 2d, thyro-cricotomy and, 3d, inferior tracheotomy. Certain preliminaries are common to all.
The patient should be extended upon a table covered with one or two thicknesses of blanket and of suitable height, which has been placed sideways in front of a window if the operation is done by daylight. (At night several candles tied together afford a better and safer light than a kerosene or oil lamp.) The surgeon stands at the right side of his patient and facing the window. Of his two assistants—and the value of trained assistance in this operation is inestimable—one faces him, without obscuring the light, and is prepared to use the sponges, hand the instruments, manipulate the retractors, and render such direct assistance as may be required. The second sits at the head of the table and holds the head of the patient steadily, the neck being well extended and thrown backward over a small round pillow (or, better, a wine-bottle wrapped in a towel) which has been placed beneath it. The head must be held directly in the median line of the patient's body, and even in that of the operating-table. The assistant's attention must never waver from this important duty. In certain cases too great inclination of the head backward serves to increase the urgent dyspnoea, or even to check respiratory efforts. This effect he must watch for, and be prepared to relieve instantly by raising the head. His duties also include the preliminary administration of an anæsthetic, and its use during the operation if required. That such use is safe in this class of operations is now generally admitted, but it is not always necessary. The operation is not an exceedingly painful one, and I have often performed it, with the adult patient's consent, without using any anæsthetic (sometimes freezing the skin over the site of the incision before making it), he submitting rather than undergo any addition to the sense of urgent dyspnoea from which he is already suffering. In children anæsthetics—ether being more commonly employed, although chloroform is often used—are much more necessary, often indispensable. Their effects are speedily manifested when asphyxia is present in any marked degree, and but little of the vapor need be inhaled. The administration, always to be carefully watched and profound anæsthesia avoided, renders breathing easier in many instances, certainly lessens laryngeal spasm, and may be discontinued early in the operation when the air-tube is or has been nearly reached by dissection. Any slight risk attending their use is more than outweighed by the safety and precision which they ensure in the more difficult and delicate steps of the operation (Sands). If the patient be already insensible or if death be imminent, their use, of course, is contraindicated.
The operator having previously decided which operation he will perform, and after carefully identifying the position of the various parts, the larynx especially, marking them with ink upon the skin if he chooses, now steadies the loose skin over the site of his intended incision, and then makes it, freely, firmly, cleanly, and exactly in the median line. If it be for a superior tracheotomy, combined or not with cricotomy, the operation I shall first describe, it must extend from just at the notch of the thyroid cartilage downward for about four inches. A free external incision is very desirable in all cases. The subcutaneous tissue now rapidly dissected through by the careful use of the knife, the veins as met with either being pushed to one side or, if they cross the line of incision, cut if small, then twisted or immediately ligated, or if large doubly ligated and then cut between the ligatures, the interval between the sterno-hyoid muscles is sought for and found, then separated by the blade or handle of the knife and held apart by retractors at the side of the wound. It is important that the faint whitish line of connective tissue which marks the interval between the muscles be recognized, otherwise it happens that the operator passes through the body of one of them, deviates at once from the median line, and approaches the side of the trachea instead of the front. The ring of the cricoid cartilage above and the upper edge of the isthmus of the thyroid gland below can now be either seen or felt by the finger in the wound between them; and about the latter lies more or less connective tissue and numerous small veins. As a rule, careful touches of the point of the knife, or, as some operators prefer at this stage, its handle or the use of a blunt director, serves to dissect up piecemeal or tear through and clear this away, the veins again being pushed out of the way, or if necessary cut and tied, and all parts held aside by removing and replacing freshly the retractors from time to time as the dissection proceeds, until the ring of the cricoid and the upper rings of the trachea come plainly into view; that is, are seen, not alone felt. During this dissection, especially if the handle of the scalpel be used, too much pressure must not be made upon the trachea. More than once I have known it to cause sudden suspension of the respiration, probably by exciting reflex spasm of the larynx. If the isthmus of the thyroid gland extend far upward, it must be pressed downward, its facial attachments to the cricoid and trachea cut or torn through, and may require to be held downward in the lower angle of the wound by an additional retractor. The upper rings of the trachea having been thus well cleared of their overlying parts, the next step of the operation follows. I am in the habit of now removing the retractors and allowing the trachea, which may have become displaced by them, to resume its normal position, the head of the patient being meanwhile readjusted. All this takes but a few seconds. A tenaculum is then implanted in the median line, either just below the edge of the thyroid or the cricoid cartilage, if the latter is not to be severed, and held firmly by the assistant at the head of the table, thus steadying and elevating slightly the trachea and rendering the incision into it certain. The retractors are now reintroduced at the sides of the wound, and the operative field is clear and steady. A glance having shown that all bleeding has ceased, another that the tracheal dilator and tracheotomy-tube lie ready at hand, the operator plunges a straight-pointed bistoury through the tracheal wall at the level of the third or fourth ring in the median line, and cuts quickly upward until the cricoid cartilage is reached, if he proposes, as in the adult can usually be done, to limit his operation to a superior tracheotomy. If not, as in the child, and the cricoid cartilage must be cut through to gain sufficient space for the introduction of the tube, it also is severed by prolonging the incision upward to the thyro-cricoid membrane. A hissing of escaping air, with the bubbling of a little blood and paroxysms of cough, follows the incision and shows that the trachea has been fairly opened. The tracheal dilator is now introduced, the lips of the tracheal wound separated, and the canula slipped neatly into the windpipe (unless in the case of a foreign body), and secured a moment or two later, when respiration is fairly established, by tapes passing around the neck. The tenaculum and retractors are removed at the same moment that the tube is slipped into place.
Many different methods have been recommended for the dilatation of the tracheal wound and to assist the introduction of the canula. The dilator (Trousseau) which has been mentioned surely answers all purposes, and is simple and easily used. An ordinary dressing forceps will likewise do the work if introduced closed and afterward opened. More complicated procedures are unnecessary.
Thyro-cricotomy requires that the superficial incision be so made over the larynx that the thyro-cricoid space shall lie in the centre of one, about two inches long, made in the median line. Following now the dissection just described, the thyro-cricoid membrane is easily reached and quickly seen as soon as the sterno-hyoid muscles are retracted. It should then be divided transversely close below the lower edge of the thyroid cartilage, the wound dilated, and the tracheotomy-tube slipped into place.