airway management Flashcards

Question

Blood supply and size of larynx

Answer 1

Blood supply: - external carotids (superior laryngeal artery) - subclavians (inferior laryngeal artery) In children younger than 10 years, the narrowest segment lies just below the cords at the level of the cricoid ring

Answer 2

innervation: branches of the vagus nerve superior laryngeal nerve: - sensation of the glottis and supraglottis - motor fibers to the cricothyroid muscle, which tenses the vocal folds - this nerve leaves the vagus high in the neck - innervation: * sensory-internal branch of superior laryngeal *including surface of larynx facing pharynx (on tracheal side- recurrent laryngeal) * motor- external branch of superior layngeal (motor to cricothyroid muscle) recurrent laryngeal nerve: - sensation of the subglottis, and motor fibers to intrinsic muscles of the larynx - this nerve branches from the vagus in the mediastinum, then turns back up into the neck - on the right, it travels inferior to the subclavian artery and on the left, the aorta. - innervation: * all intrinsic muscles of the larynx innervated by the recurrent laryngeal nerve EXCEPT for the cricothyroid * *cricothyroid is an adductor innervated by the external branch of the SUPERIOR LARYNGEAL NERVE

Answer 3

thyrohyoid: - function: * depresses the larynx * modifies the thyrohyoid and arrepiglottic folds - innervation: * cervical plexus * hypoglossal nerve * C1, C2 Sternohyoid: - function: indirect depressor of the larynx - innervation: * cervical plexus * ansa hypoglossi * C1, C2, C3 sternothyroid: - function: * depresses the larynx * modifies the thyrohyoid and arrepiglottic folds - innervation: * cervical plexus * ansa hypoglossi * C1, C2, C3 thyroepiglottic: - function: * mucosal inversion of aryepiglottic fold - innervation: * recurrent laryngeal nerve ``` stylopharyngeus: -function: *assists folding of thyroid cartilage -innervation: glossopharyngeal ``` ``` inferior pharyngeal constrictor: -function: *assists in swallowing -innervation: vagus, pharngeal plexus ```

Answer 4

is a reflex closure of the true cords (and sometimes the false cords too) because of stimulation of intrinsic laryngeal muscles - muscles: * cricothyroids (adducts and tense true cords) - innervation: * sensory- internal branch of superior laryngeal and surface of larynx facing pharynx (on tracheal side- recurrent laryngeal) * motor- external branch of superior laryngeal (motor to cricothyroid muscle)

Answer 5

- immediate hypoxemia - delayed-negatie pressure pulmonary edema * *forceful inspiratory effort in presence of closed glottis

Answer 6

- central or peripheral, unilateral, or bilateral - central-posterior fossa surgery, brainstem infarctions - peripheral- usually neck or cardiothoracic surgery - unilateral superior laryngeal nerve palsy: * *inability to sound a high- pitched "C" - unilateral recurrent nerve palsy: * *hoarseness - bilateral (incomplete): * *recurrent nerve (adductors) palsy may leave a glottic opening so small that an emergency airway will be needed - bilateral (complete): * *cords neither adduct or abduct * *severe harseness, but an adequate glottic opening may remain

Answer 7

* Trigeminal (5): * *anterior 2/3 of the tongue * Glossopharyngeal (9): * * posterior 1/3 of tongue to epiglottis * *afferent limb of gag reflex *internal branch of superior laryngeal nerve Vagus (10): **epiglottis to vocal cords * recurrent laryngeal nerve (vagus) * *trachea below vocal cords

Answer 8

- total or partial - total obstruction: * lack of any air movement or breath sounds - actual air movement: * must be perceived by feeling with the hand or placing the ear over the mouth * recognition of obstruction depends on close observation and a high index of suspicion - partial obstruction: * exhibits diminished air exchange that is associated with retraction of the upper chest and accompanied by a snoring sound if the obstruction is NASOPHARYNGEAL or by INSPIRATORY STRIDOR if obstruction is near the area of the larynx - if inspiratory efforts are severe, the upper airway may undergo a dynamic inspiratory compression because of the marked pressure gradient in the upper airway

Answer 9

-depends on whether it is caused by soft tissue obstruction, tumor, foreign body, or laryngospasm - most often, upper airway obstruction is caused by a reduction of the space between the pharyngeal wall and the base of the tongue by relaxation of the tongue and jaw. - the same obstruction may occur with foreign bodies or dentures - in the absence of a foreign body airflow may be restored by: * *pulling the mandible forward * *slightly extending pt's neck * *the extention of the neck and anterior displacement of the mandible moves the hyoid bone anteriorly and lifts the epiglottis to provide clear access to the laryngeal inlet * *if the occiput is elevated toward a sniffing position, less extention is required to achieve airway patency -oropharyngeal obstruction (soft palate to tip of epiglottis) can also be overcome by positive pressure from manual inflations with a breathing bag - gastric inflation rarely occurrs when pressures les than 15-20 cm h20 were used * *In general, such pressures were associated with TV well in excess of 1L

Answer 10

- once the skin over the mandible and upper neck is removed, you can identify the submandibular triangle and its boundaries - boundaries: * *mastoid and mandible * *anterior belly of digastric anteriorly (abd) * **1 of the extrinic laryngeal muscles in the suprahyoid group * *posterior belly of digastric (pbd) [suprahyoid group] * *stylohyoid posteriorly (sh) [suprahyoid group] - tongue displaced into submental space during intubation - look at the large number of very important structures in the anterior neck...edema, bleeding or infection in the neck can rapidly displace important airway structures * ***please note position of cricothyroid membrane in anterior neck slide * *********IT IS B/W THE THYROID CARTILAGE AND THE CRICOID CARTILAGE

Answer 11

- C6-T5 - it is flattened posteriorly and supported along its 10-15cm lenghth by 16-20 horseshoe-shaped cartilaginous rings until bifurcating into right and left main stem bronchi at the level of T5 vertebra aka carina or angle of louis; can be localized approximately at the same level as the sternal notch - the cross-sectional area of the trachea is considerable larger than that of the glottis

Answer 12

- in adults, the trachea ranges 12-15cm in length - terminating distally at the carina - maximum transverse diameter of 15-17mm in women and up to 22mm in males; sagittally the trachea is narrower, having a maximal diameter of 12-14mm - On CT, the carina visually appears as a vertical cleft, representing the junction of the superomedial surfaces of the 2 mainstem bronchi - LMSB: 4. 5-5cm in length - RMSB: 2. 5cm in length

Answer 13

``` RIght bronchus: -wider -shorter -steeper -2cm Left bronchus: -narrower -longer -more horizontal -5cm ```

Answer 14

-Located at T4

Answer 15

QUIET BREATHING: - the predominant muscles of respiration is the diaphragm - as it contracts, pleural pressure drops, which lowers the alveolar pressure - draws air in down the pressure gradient from mouth to alveoli - expiration during quiet breathing is predominantly a passive phenomenon, as the respiratory muscles are relaxed and the elastic lung and chest wall return passively to their resting volume, the functional residual capacity-elastic recoil EXCERCISE: - many other muscles become important to respiration - during inspiration, the external intercostals raise the lower ribs up and out, increasing the lateral and anteroposterior dimensions of the thorax - the scalene muscles and sternomastoids also become involved, serving to raise and push out the upper ribs and the sternum ACTIVE EXPIRATION: the most important muscles are those of the abdominal wall (including the rectus abdominus, internal and external obliques, and transverse abdominus), which drive intra-abdominal pressure up when they contract, and thus push up the diaphragm, raising pleural pressure, which raises alveolar pressure, which in turn drives air out INTERNAL INTERCOSTALS: assist with active expiration by pulling the ribs down and in, thus decreasing thoracic volume

Answer 16

- an indispensable mechanism for expelling secretions and foreign bodies from the lower respiratory tract - First event: * there is a deep inspiration to attain a high lung volume, which allows attainment of maximum expiratory flow rates - Second event: * a tight closure of glottis occurs along with contraction of the expiratory muscles - Third event: * intrapleural pressure rises to above 100cm H20 such that during the third (expiratory) phase, a sudden expulsion of air occurs as the glottis opens * glottic opening at the onset of the phase is associated with oscillation of tissue and gas that results in the characteristic noise of a cough

Answer 17

- Glottic closure is the one phase of cough that differentiates it from other forced expiratory maneuvers and that allows for greater development of pressure - Closure of the glottis is not crucial, however, to the development of high pressures and flow rates of a normal cough - Well illustrated in trached and intubated patients - tubes prevent normal glottic closure and allows flow to begin as soon as pressure begins to increase...allows flow to continue b/w cough burst - the normal timing of pressure and flow is altered such that cough resembles a normal forced expiration. - b/c the tube is noncollapsible, it does not permit the high velocities through the tracheal segment that it occupies - secretions therfore are likely to accumulate in the area at the end of the tube unless subsequent coughs are begun from high lung volumes to allow high flow rates to be acheived

Answer 18

C1: - The atlas is a ring that interacts with the skull base above and C2 - the articulation of C1 with the occiput is very tight, providing little of the flexion of the cervical spine and only about 20 degrees of extension C2: - the axis has an unusual thumb-like extension of its vertebral body that passes through the arch of C1. - this process is called the dens or odontoid - the odontoid process is normally held very tightly against the anterior arch of C1 by the transverse ligament - the spinal cord travels behind the odontoid within the arch of C1 - The ATLANTO-AXIAL JOINT: * provides the majority of the rotational motion of the cervical spine * flexion and extension are primarily accomplished at C2 and below, and particularly b/w C4 and C6 - ATLANTO-OCCIPITAL JOINT (occiput-C1): * the sniffing postion involves neck flexion in the lower cervical spine with extension superiorly. * during laryngoscopy, as the laryngoscope is lifted upward, the occiput is extended primarily at the ATLANTO-OCCIPITAL JOINT (occiput-C1), while flexion occurs at C2-3 and below - Flexion and extension problems will make visualization of the glottis more difficult - Always assess pt history of neck problems or cervical spine disease and observe for symptoms on maximal flexion and extension. - RA and Down's affect the cervical spine

Answer 19

The thyroid cartilage is more prominent and superior to the cricoid cartilage.

Answer 20

Move hyoid cartilage and epiglottis anteriorly

airway management Flashcards

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