We are concerned here mainly with the technic of the insertion of the intratracheal tube. The larynx should be examined with the mirror, preferably before the day of operation, for evidence of disease, and incidentally to determine the size of the catheter to be introduced, though the latter can be determined after the larynx is laryngoscopically exposed. The following list of rules for the introduction of the catheter will be of service (see Fig. 59).
RULES FOR INSERTION OF THE CATHETER FOR INSUFFLATION ANESTHESIA
1. The patient should be fully under the anesthetic by the open method so as to get full relaxation of the muscles of the neck. 2. The patient's head must be in full extension with the vertex firmly pushed down toward the feet of the patient, so as to throw the neck upward and bring the occiput down as close as possible beneath the cervical vertebrae. 3. No gag should be used, because the patient should be sufficiently anesthetized not to need a gag, and because wide gagging defeats the exposure of the larynx by jamming down the mandible. 4. The epiglottis must be identified before it is passed. 5. The speculum must pass sufficiently far below the tip of the epiglottis so that the latter will not slip. 6. Too deep insertion must be avoided, as in this case the speculum goes posterior to the cricoid, and the cricoid is lifted, exposing the mouth of the esophagus, which is bewildering until sufficient education of the eye enables the operator to recognize the landmarks. 7. The patient's head is lifted off the table by the spatular tip of the laryngoscope. Actual lifting of the head will not be necessary if the patient is fully relaxed; but the idea of lifting conveys the proper conception of laryngeal exposure (Fig. 55).
[71] CHAPTER V—BRONCHOSCOPIC OXYGEN INSUFFLATION
Bronchoscopic oxygen insufflation is a life-saving measure equalled by no other method known to the science of medicine, in all cases of asphyxia, or apnea, present or impending. Its especial sphere of usefulness is in severe cases of electric shock, hanging, smoke asphyxia, strangulation, suffocation, thoracic or abdominal pressure, apnea, acute traumatic pneumothorax, respiratory arrest from absence of sufficient oxygen, or apnea from the presence of quantities of irrespirable or irritant gases. Combined with bronchoscopic aspiration of secretions it is the best method of treatment for poisoning by chlorine gas, asphyxiating, and other war gases.
Bronchoscopic oxygen insufflation should be taught to every interne in every hospital. The emergency or accident ward of every hospital should have the necessary equipment and an interne familiar with its use. The method is simple, once the knack is acquired. The patient being limp and recumbent on a table, the larynx is exposed with the laryngoscope, and the bronchoscope is inserted as hereinafter described. The oxygen is turned on at the tank and the flow regulated before the rubber tube from the wash-bottle of tank is attached to the side-outlet of the bronchoscope. It is necessary to be certain that the flow is gentle, so that, with a free return flow the introduced pressure does not exceed the capillary pressure; otherwise the blood will be forced out of the capillaries and the ischemia of the lungs will be fatal. Another danger is that overdistension causes inhibition of inspiration resulting in apnea continuing as long as the distension is maintained, if not longer. The return flow from the bronchoscope should be interrupted for 2 or 3 seconds several times a minute to inflate the lungs, but the flow must not be occluded longer than 3 seconds, because the intrapulmonary pressure would rise. A pearl of amyl nitrite may be broken in the wash bottle. Slow rhythmic artificial respiratory movements are a useful adjunct, and unless the operator is very skillful in gauging the alternate pressures and releases with the thumb according to the oxygen pressure, it is vitally necessary to fill and deflate the lungs rhythmically by one of the well known methods of artificial respiration. Anyone skilled in the introduction of the bronchoscope can do bronchoscopy in a few seconds, and it is especially easy in cases of respiratory arrest, because of the limp condition of the patient.
The foregoing applies to cases in which a pulmotor would be used, such as apnea from electric shocks, etc. For obstructive dyspnea and asphyxia, tracheotomy is the procedure of choice, and the skillful tracheotomist would be justified in preferring tracheotomy for the other class of cases, insufflating the oxygen and amyl nitrite through the tracheotomic wound. The pulmotor and similar mechanisms are, perhaps, the best things the use of which can be taught to laymen; but as compared to bronchoscopic oxygen insufflation they are woefully inefficient, because the intraoral pressure forces the tongue back over the laryngeal orifice, obstructing the airway in this "death zone." By the introduction of the bronchoscope this death zone is entirely eliminated, and a free airway established for piping the oxygen directly into the lungs.
[73] CHAPTER VI—POSITION OF THE PATIENT FOR PERORAL ENDOSCOPY
It is the author's invariable practice to place the patient in the dorsally recumbent position. The sitting position is less favorable. While lying on a well-padded, flat table the patient is readily controlled, the head is freely movable, secretions can be easily removed, the view obtained by the endoscopist is truly direct (without reversal of sides), and, most important, the employment of one position only favors smoother and more efficient team work, and a better endoscopic technic.
General Principles of Position.—As will be seen in Fig. 47 the trachea and esophagus are not horizontal in the thorax, but their long axes follow the curves of the cervical and dorsal spine. Therefore, if we are to bring the buccal cavity and pharynx in a straight line with the trachea and esophagus it will be found necessary to elevate the whole head above the plane of the table, and at the same time make extension at the occipito-atloid joint. By this maneuver the cervical spine is brought in line with the upper portion of the dorsal spine as shown in Fig. 55. It was formerly taught, and often in spite of my better knowledge I am still unconsciously prone to allow the head and cervical spine to assume a lower position than the plane of the table, the so-called Rose position. With the head so placed, it is impossible to enter the lower air or food passages with a rigid tube, as will be shown by a study of the radiograph shown in Fig. 49. Extension of the head on the occipito-atloid joint is for the purpose of freeing the tube from the teeth, and the amount required will vary with the degree to which the mouth can be opened. Whether the head be extended, flexed, or kept mid-way, the fundamental principle in the introduction of all endoscopic tubes is the anterior placing of the cervical spine and the high elevation of the head. The esophagus, just behind the heart, turns ventrally and to the left. In order to pass a rigid tube through this ventral curve the dorsal spine is now extended by lowering the head and shoulders below the plane of the table. This will be further explained in the chapter on esophagoscopy. In all of these procedures, the nose of the patient should be directed toward the zenith, and the assistant should prevent rotation of the head as well as prevent lowering of the head. The patient should be urged as follows: "Don't hold yourself so rigid." "Let your head and neck go loose." "Let your head rest in my hand." "Don't try to hold it." "Let me hold it." "Relax." "Don't raise your chest."