In 1854, the Spanish singer Garcia (son) Manuel Patricio Rodriguez (1805-1906) invented a laryngoscope for indirect laryngoscopy. For this invention in 1855, he was awarded the degree of Doctor of Medicine. It should be noted, however, that the method of indirect laryngoscopy was known from earlier publications, beginning in 1743 (the Levert obstetrician glotoscope). Then Dozzini (Frankfurt, 1807), Sem (Geneva, 1827), Vabingston (London, 1829) reported similar devices operating on the periscope principle and allowing to examine in the mirror image the inner space of the larynx. In 1836 and in 1838 the Lyons surgeon Baums demonstrated a guttural mirror, which exactly corresponds to the modern one. Then in 1840, Liston used a mirror similar to the dental one, which he applied when examining the larynx in a disease that caused her swelling. A wide introduction to the medical practice of the laryngoscope Garcia is due to the neurologist of the Vienna Hospital L.Turck (1856). In 1858, the professor of physiology from Pest, Hungary, Schrotter first used for artificial laryngoscopy artificial lighting and a round concave mirror with a hole in the middle (a reflector of the Schreter) with a rigid vertical headband of Cramer adapted to it. Previously, for the illumination of the larynx and pharynx, the sunlight reflected by the mirror was used.
The modern technique of indirect laryngoscopy does not differ from that used 150 years ago.
Use flat larynx mirrors of different diameters attached to a narrow stem inserted into a special handle with a screw stopper. To avoid fogging the mirror, it is usually heated on a spirit lamp with a mirror surface to a flame or in hot water. Before the introduction of the mirror into the oral cavity, check its temperature by touching the rear metal surface to the skin of the back surface of the hand. Indirect laryngoscopy is usually carried out in a sitting position with a slightly deflected forward torso of the subject and slightly deflected behind the head. With removable dentures, they are removed. The technique of indirect laryngoscopy requires certain skills and appropriate training. The essence of the methodology is as follows. The doctor with his right hand takes the handle with the mirror fixed in it, like a writing pen, so that the mirror surface is directed at an angle downward. The examinee opens his mouth wide and maximizes his tongue. The doctor I and III with fingers of the left hand grasps the tongue wrapped in a gauze and keeps it in the protruding state, at the same time the finger of the same brush lifts the upper lip for a better view of the zona area, directs a ray of light into the oral cavity and introduces into it a heated mirror . The rear surface of the mirror is pressed against the soft sky, pushing it backward and upward. To avoid reflection of the soft-sky tab in the mirror, which is a barrier to the larynx, it must be completely covered with a mirror. At the time of insertion of the mirror into the oral cavity, one should not touch the root of the tongue and the posterior pharyngeal wall so as not to cause a pharyngeal reflex. The rod and handle of the mirror rest on the left corner of the mouth, and its surface should be oriented so that it forms an angle of 45 ° with the axis of the mouth. The luminous flux directed to the mirror and reflected from it into the larynx cavity, illuminates it and the corresponding anatomical formations. For inspection of all structures of the larynx, the angle of the mirror is changed by manipulating the handle so as to consistently inspect the inter-head space, scoop, folds of the vestibule, vocal folds, pear-shaped sinuses, etc. Sometimes it is possible to examine the lining space and the back surface of two or three rings of the trachea. The larynx is examined with a calm and forced breathing of the subject, then with the phonation of the sound "and" and "e". When these sounds are spoken, the muscles of the soft palate contract, and the protruding of the tongue helps lift the epiglottis and opens the epiglottis space for viewing. At the same time there is a phantom clamping of the vocal folds. Inspection of the larynx should not last more than 5-10 seconds, a second inspection is carried out after a short pause.
Sometimes an examination of the larynx with indirect laryngoscopy causes significant difficulties. The hindering factors include the infantile sedentary epiglottis, which obscures the entrance to the larynx; a pronounced (indomitable) gag reflex, observed most often in smokers, alcoholics, neuropaths; a thick "disobedient" tongue and a short bridle; comatose or co-morbid condition of the subject and a number of other reasons. An obstruction to the examination of the larynx is the contraction of the temporomandibular joint, which occurs with a paratonsillar abscess or its arthrosoarthritis, as well as with parotitis, phlegmon of the oral cavity, fracture of the lower jaw, or in trism caused by certain CNS diseases. The most frequent obstacle to indirect laryngoscopy is the expressed pharyngeal reflex. There are some tricks for its suppression. For example, the subject is offered, as a distraction, to draw in the mind the inverse account of two-digit numbers, or by clasping his hands with bent fingers, pulling them with all his might, or offering the subject to hold his tongue. This technique is also necessary when the doctor must have both hands free to perform certain manipulations inside the larynx, for example, removal of the fibroid on the vocal fold.
With indomitable gag reflex, resort to anaesthesia of the root of the tongue, soft palate and posterior pharyngeal wall. Preference should be given to lubrication, rather than aerosol spraying of anesthetic, since anesthesia develops in the latter, spreading to the mucous membrane of the oral cavity and the larynx, which can cause spasm of the latter. In young children, indirect laryngoscopy is almost impossible, therefore, if necessary, mandatory examination of the larynx (for example, with its papillomatosis) resort to direct laryngoscopy under anesthesia.
The picture of the larynx with indirect laryngoscopy
The picture of the larynx with indirect laryngoscopy is very characteristic, and since it is the result of a mirror image of the true picture, and the mirror is positioned at an angle of 45 ° to the horizontal plane (periscope principle), the displayed is located in the vertical plane. With this arrangement of the displayed endoscopic picture, the anterior part of the larynx is visible in the upper part of the mirror, often covered by the epiglottis in the commissure; The rear departments, including scoop and inter-head space, are displayed in the lower part of the mirror.
Since in the case of indirect laryngoscopy, only one left eye can examine the larynx, ie monocularly (as is easily seen when it is closed), all the larynx elements are seen in the same plane, although the vocal folds are 3-4 cm below the edge of the epiglottis. The lateral walls of the larynx are visualized sharply truncated and, as it were, in the profile. Above, in fact, in front, a part of the root of the tongue with the lingual amygdala is visible, then a pale pink epiglottis, the free edge of which rises when the sound of the sound "u" rises, releasing the cavity of the larynx for viewing. Immediately under the epiglottis in the center of its edge, one can sometimes see a small tuberculum cpiglotticum, formed by the leg of the epiglottis. Below and behind the epiglottis, apart from the angle of the thyroid cartilage and commissure to the arytenoid cartilages, there are vocal folds of whitish-pearly color, easily identifiable by characteristic trembling movements, sensitive to even a slight attempt at phonation. During quiet breathing, the laryngeal lumen has the appearance of an isosceles triangle, the lateral sides of which are represented by vocal folds; the apex, as it were, rests against the epiglottis and is often covered by it. The epiglottis is an obstacle to the examination of the anterior wall of the larynx. To overcome this obstacle, the position of the Türk is applied, in which the examinee throws back his head, and the doctor conducts an indirect laryngoscopy while standing, as if from above downwards. For a better view of the posterior parts of the larynx, Killian's position is used, in which the doctor examines the larynx from below (standing on one knee in front of the patient), and the patient tilts his head downwards.
Normally, the edges of the vocal folds are even, smooth; when they inhale, they diverge somewhat, during a deep breath, the vocal folds diverge to the maximum distance and the upper tracheal rings, and sometimes even the tracheal keel, become visible. In some cases, the vocal folds have a dull reddish hue with a shallow vascular network. In the face of a thin, asthenic warehouse with a pronounced Adam's apple, all the internal elements of the larynx are more distinctly distinguished, and the boundaries between the fibrous and cartilaginous tissues are well differentiated.
In the upper-lateral regions of the laryngeal cavity above the vocal folds, folds of the vestibule are visible, pink and more massive. They are separated from the vocal folds by spaces that are better seen from thin people. These spaces are the entrances to the ventricles of the larynx. The mezhcherpalovodnoe space, which is like the base of the triangular slit of the larynx, is limited by arytenoid cartilages, which are visible in the form of two clavate thickenings, covered with pink mucosa. During phonation, one can see how they rotate towards each other with their front parts and pull together the attached vocal folds. The mucous membrane covering the posterior wall of the larynx becomes smooth when the arytenoid cartilages divergent on inhalation; when pharyngeal, when the arytenoid cartilages approach, it gathers into small folds. In some individuals, the arytenoid cartilages touch so closely that they seem to go for each other. From the arytenoid cartilages are directed upward and forward scoop-epiglottis folds that reach the lateral margins of the epiglottis and along with it serve as the upper boundary of the entrance to the larynx. Sometimes, with the subatrophic mucous membrane, in the thickness of cherpal-nasal folds one can see small elevations above the arytenoid cartilages; it is carobs cartilage; lateral from them are located wedge-shaped cartilages. For inspection of the posterior wall of the larynx, Killian's position is used, in which the examined person tilts the head to the chest, and the doctor examines the larynx from below upwards or becomes in front of the patient on one knee or the patient assumes standing position.
With indirect laryngoscopy, you can see some other anatomical formations. So, above the epiglottis, in fact in front of it, the pits of the epiglottis are formed, formed by the lateral lingual-epiglottis fold and separated by a medial lingual-epiglottis fold. The lateral parts of the epiglottis connect to the walls of the pharynx with the help of pharyngeal-epiglotti folds that cover the entrance to the pear-shaped sinuses of the throat part of the pharynx. During the expansion of the glottis, a decrease in the volume of these sinuses occurs, during the narrowing of the glottis, their volume increases. This phenomenon arises due to the reduction of inter-capillar and cherpalodnagortan muscles. He is given a great diagnostic significance, since his absence, especially on one side, is the earliest sign of tumor infiltration of these muscles or the onset of neurogenic damage to them.
The color of the mucous membrane of the larynx should be assessed in accordance with the history of the disease and other clinical signs, as in the norm it is not constant and often depends on smoking, alcohol intake, occupational exposure. In hypotrophic (asthenic) persons of asthenic physique, the color of the mucous membrane of the larynx is usually pale pink; in normostenics - pink; in persons of fat, full-blooded (hypersthenic) or smokers, the color of the mucous membrane of the larynx can be from red to bluish without any significant signs of the disease of this organ.
Direct laryngoscopy allows you to examine the internal structure in a direct image and to perform a variety of manipulations on its structures (removal of polyps, fibroids, papillomas by usual, cryo-or laser-surgical methods) and also to perform emergency or planned intubation. The method was put into practice by M. Kirshtein in 1895 and was subsequently improved several times. It is based on the use of a rigid directory, the introduction of which into the laryngopharynx through the oral cavity becomes possible due to the elasticity and compliance of surrounding tissues.
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Indications for direct laryngoscopy
Indications for direct laryngoscopy are numerous, and their number is continuously growing. This method is widely used in pediatric otorhinolaryngology, because the indirect laryngoscopy in children is almost impossible. For infants, a single laryngoscope with a fixed handle and a fixed spatula is used. For adolescents and adults, laryngoscopes are used with a detachable handle and a pull-out spatula plate. Direct laryngoscopy is used when it is necessary to examine the laryngoscopy sections of the larynx, which are difficult to access for observation, with its ventricles, commissure, the front wall of the larynx between the commissure and the epiglottis, and the lining space. Direct laryngoscopy allows for various endolaryngeal diagnostic manipulations, as well as for insertion into the larynx and trachea of the endotracheal tube during anesthesia or intubation with emergency ventilation.
Direct laryngoscopy is contraindicated in severe stenotic breathing, severe changes in the cardiovascular system (decompensated heart defects, severe hypertension and angina pectoris), epilepsy with a low threshold of convulsive readiness, with lesions of the cervical vertebrae that do not allow the head to roll back, with aortic aneurysm. Temporary or relative contraindications are acute inflammatory diseases of the mucous membrane of the oral cavity, pharynx, larynx, bleeding from the pharynx and larynx.
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Direct laryngoscopy technique
The individual selection of the appropriate model of a laryngoscope (Jackson, Udritz, Brunings Mezrin, Zimont, etc.) is of great importance for effective direct laryngoscopy, which is determined by many criteria - the goal of interventions: (diagnostic or surgical), the position of the patient in which it is supposed to be performed laryngoscopy, his age, anatomical features of the maxillofacial and cervical areas and the nature of the disease. The study is performed on an empty stomach, except in case of emergency. In young children, direct laryngoscopy is performed without anesthesia, in young children - under anesthesia, older - either under anesthesia, or under local anesthesia with appropriate premedication, as in adults. For local anesthesia, various anesthetics of the application can be used in combination with sedatives and anticonvulsants. To reduce the overall sensitivity, muscle tension and salivation, one tablet of phenobarbital (0.1 g) and one sibazone tablet (0.005 g) is given 1 hour before the procedure. For 30-40 minutes, 0.5-1.0 ml of a 1% solution of promedol and 0.5-1 ml of a 0.1% solution of atropine sulfate are injected subcutaneously. For 10-15 minutes before the procedure, applicative anesthesia (2 ml of a 2% solution of dicaine or 1 ml of a 10% solution of cocaine) is performed. For 30 minutes before this premedication, to avoid anaphylactic shock, intramuscular injection of 1-5 ml of a 1% solution of dimedrum or 1-2 ml of a 2.5% solution of diprazine (pipolpene) is recommended.
The position of the subject may be different and is determined mainly by the patient's condition. It can be held in a sitting position, lying on the back, less often in a position on the side or on the stomach. The most convenient position for the patient and the doctor is the lying position. It is less tiring for the patient, prevents saliva from flowing into the trachea and bronchi, and in the presence of a foreign body prevents its penetration into the deeper parts of the lower respiratory tract. Direct laryngoscopy is carried out in accordance with the rules of asepsis.
The procedure consists of three stages:
- advance of the spatula to the epiglottis;
- carrying it across the edge of the epiglottis toward the entrance to the larynx;
- advance it on the back of the epiglottis to the vocal folds.
The first stage can be carried out in three versions:
- with the tongue sticking out, which is held by means of a gauze pad or by an assistant doctor, or by the examining person;
- at the usual position of the tongue in the oral cavity;
- when inserting a spatula from the angle of the mouth.
With all variants of direct laryngoscopy, the upper lip is moved upward. The first stage is completed by squeezing the root of the tongue downwards and holding a spatula to the edge of the epiglottis.
At the second stage, the end of the spatula is slightly raised, leads it to the edge of the epiglottis and promotes it by 1 cm; After this, the end of the spatula is lowered down, covering the epiglottis. In this case, the spatula presses on the upper incisors (this pressure should not be excessive). The correct direction of the spatula advancement is confirmed by the appearance in the friction field backward from the arytenoid cartilages of the whitish vocal folds leaving them at an angle.
At the approach to the third stage the head of the patient is rejected backwards even more. Language, if it was held outside, released. The examiner increases the pressure of the spatula on the root of the tongue and the epiglottis (see the third position - the direction of the arrows) and, holding the midline, disposes the spatula plumbly (at the position of the patient being seated) along the longitudinal axis of the larynx in the position of the patient lying down, respectively). And in that, and in the other case, the end of the spatula is directed along the middle part of the respiratory slit. At the same time, the back wall of the larynx, first the vestibular and vocal folds, the ventricles of the larynx enter the field of vision. For a better view of the anterior larynx, you have to squeeze the root of the tongue somewhat downwards.
To the special types of direct laryngoscopy is the so-called pendulous laryngoscopy, proposed by Killian, an example of which is the Seifert method. At present, the Seifert principle is applied when the pressure on the root of the tongue (the main condition for holding the spatula into the larynx) is provided by the counterpressure of the lever resting on a special metal stand or on the breast of the examinee.
The main advantage of Seifert's method is the release of both hands of the doctor, which is especially important for long and complex endolaryngeal surgical interventions.
Modern foreign laryngoscopes for hanging and supporting laryngoscopy are complex complexes, including spatulas of various sizes and sets of various surgical instruments specially adapted for endolaryngeal intervention. These complexes are equipped with technical means for infectious ventilation, injection anesthesia and special video equipment that allows performing surgical procedures using an operating microscope and a television screen.
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