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composed of cartilaginous and membranousportions, beginning with the cricoidcartilage, the first complete cartilaginous

ring of the airway and consists of an anteriorarch and a posterior broad-based plate

arytenoid cartilages - articulate with the

posterior cricoid plate

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vocal cords - originate from the arytenoidcartilages and then attach to the thyroidcartilage

subglottic space - the narrowest part of thetrachea internal diameter: approximately 2 cm

begins at the inferior surface of the vocal cords and

extends to the first tracheal ring

The remainder of the distal trachea is 10.0 to13.0 cm long, consists of 18 to 22 rings, and has

an internal diameter of 2.3 cm.

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enters the airway near the junction of themembranous and cartilaginous portions of theairway

It is segmental each entering small branch supplies a segment of 1.0

to 2.0 cm, which limits circumferential mobilizationto that same distance.

The vessels are interconnected along thelateral surface of the trachea by an importantlongitudinal vascular anastomosis that feedstransverse segmental vessels to the soft tissuesbetween the cartilages.

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The arteriessupplying thetrachea

inferior thyroid Subclavian

supreme intercostal

internal thoracic

innominate, and

superior and middlebronchial arteries

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postintubation injuries Collectively termed tracheal injuries

Injury secondary to endotracheal intubation is most

commonly the result of overinflation of the cuff Although high-volume/low-pressure cuffs are now

ubiquitous, they can easily be overinflated, and pressurescan be generated that are high enough to cause ischemia ofthe contiguous airway wall.

In some patients, periods of ischemia as short as 4 hoursmay be all that is required to induce an ischemic eventsignificant enough to lead to scarring and stricture.

With prolonged overinflation and consequent full-thicknessdestruction of the airway, fistula development between theinnominate artery and esophagus may ensue.

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Tracheal stenosis is nearly always iatrogenic.

secondary to either endotracheal intubation ortracheostomy due to scarring and local injury

Factors associated with an increased risk oftracheal stenosis

incorrect placement of the tracheostomy throughthe first tracheal ring or the cricothyroid membranewhere the airway is narrowest

use of a large tracheostomy tube, and

transverse incision on the trachea

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even a properly placed tracheostomy can leadto tracheal stenosis secondary to scarring andlocal injury

mild ulceration and stenosis frequently areseen after tracheostomy removal.

The rate of stomal stenosis can be minimizedby using the smallest tracheostomy tube

possible and downsizing as soon as the patientwill tolerate it, and by using a vertical trachealincision without removing cartilage.

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primary symptoms of tracheal stenosis:

stridor

dyspnea on exertion

The length of time to onset of symptoms afterextubation or after tracheostomy decannulationvaries, usually ranging from 2 to 12 weeks;

however, symptoms can appear immediately oras long as 1 to 2 years later.

Frequently, patients are misdiagnosed as havingasthma or bronchitis, and treatment for such illnessescan persist for some time before the correct diagnosis

is discovered.

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In nearly all postintubation injuries theinjury is transmural, and significant portionsof the cartilaginous structural support are

destroyed

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treatment of tracheal stenosis: resection andprimary anastomosis

laser ablation temporizing

dilation using a rigid bronchoscope - useful togain immediate relief of dyspnea and to allowfull assessment of the lesion in the early phaseof evaluating patients

Rarely, if ever, is a tracheostomy necessary.

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internal stents, typically silicone T tubes -useful for patients who are not operativecandidates due to associated comorbidities

Wire mesh stents - should not be used, giventheir known propensity to erode through thewall of the airway

use of balloon dilation and tracheoplasty alsohas been described, although their efficacy ismarginal

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Most intubation injuries are located in the upper third ofthe trachea, so tracheal resection usually is donethrough a collar incision.

Resection typically involves 2 to 4 cm of trachea for

benign stenosis. However, a primary anastomosis canstill be performed without undue tension, even if up toone half of the trachea needs to be resected.

When resection for a postintubation injury is performed,it is critical to fully resect all inflamed and scarredtissue.

Tracheostomies and stents are not requiredpostoperatively, and the patient often is extubated inthe operating room or shortly thereafter.

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TRACHEOINNOMINATE ARTERY FISTULA two causes

1. too low a placement of the tracheostomy

Tracheostomies should be placed through the secondto fourth tracheal rings without reference to thelocation of the sternal notch.

When they are placed below the fourth trachealring, the inner curve of the tracheostomy cannulawill be positioned to exert pressure on the uppersurface of the innominate artery, which will lead toarterial erosion.

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2. hyperinflation of the tracheal cuff

the tracheal cuff, when hyperinflated, will causeischemic injury to the airway and subsequenterosion into the artery and fistula development.Most cuff-induced fistulas develop within 2weeks after placement of the tracheostomy.

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present with bleeding, although it usually is notmassive, it must not be ignored or simply attributedto general airway irritation or wound bleeding

With significant bleeding, the tracheostomy cuff canbe hyperinflated to temporarily occlude the arterialinjury.

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If such an effort is unsuccessful, the tracheostomy

incision should immediately be opened widelyand a finger inserted to compress the arteryagainst the manubrium.

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The patient can then be orally intubated, and theairway suctioned free of blood. Emergent surgicalresection of the involved segment of artery isperformed, usually without reconstruction.

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occur primarily in patients with an indwellingnasogastric tube who are also receivingprolonged mechanical ventilatory support.

Cuff compression of the membranous tracheaagainst the nasogastric tube leads to airway andesophageal injury and fistula development.

Clinically, saliva, gastric contents, or tubefeeding contents are noted in the materialsuctioned from the airway. Distention of thestomach secondary to positive pressureventilation can occur.

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Diagnosis of a suspected TEF is bybronchoscopy.

Withdrawal of the endotracheal tube withthe bronchoscope inserted allows the fistulaat the cuff site to be seen. Alternatively,esophagoscopy will enable visualization of

the cuff of the endotracheal tube in theesophagus.

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TREATMENT: requires weaning the patient from the ventilator

and then extubating as soon as possible. Duringthe weaning period, the nasogastric tube shouldbe removed, with attention given to ensuringthat the cuff of the endotracheal tube is placedbelow the fistula and that it is not overinflated.

Then a gastrostomy tube should be placed foraspiration (to prevent reflux) and a jejunostomytube for feeding. If aspiration is relentless and isnot managed by the aforementioned steps,esophageal diversion with esophagostomy can beperformed.

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Once the patient is weaned from theventilator, a single-stage operation should bedone, consisting of:

tracheal resection and primary anastomosis

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repair of the esophageal defect, and

interposition of a muscle flap between thetrachea and esophagus

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The most common primary trachealneoplasms (approximately 65%):

squamous cell carcinomas (related tosmoking) and,

adenoid cystic carcinomas

The remaining 35%

small cell carcinomas, mucoepidermoid carcinomas,

adenocarcinomas,

lymphomas, and others

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Primary tracheal neoplasms are exceedinglyrare

diagnosis frequently is delayed

present with cough, dyspnea, hemoptysis,stridor, or symptoms of invasion of

contiguous structures (such as the recurrentlaryngeal nerve or the esophagus)

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tracheal stenosis: most common radiologicfinding of tracheal malignancy is, but it isseen in only 50% of cases

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Squamous cell carcinomas

often present with regional lymph nodemetastases

frequently not resectable at the time ofpresentation

biologic behavior is similar to that of squamouscell carcinomas of the lung

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Adenoid cystic carcinomas

a type of salivary gland tumor

generally slow growing, spread submucosally,

and tend to infiltrate along nerve sheaths andwithin the tracheal wall

Spread to regional lymph nodes can occur

Although indolent in nature, they aremalignant and can spread to the lungs andbones

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Evaluation and treatment of patients withtracheal tumors should include

neck and chest computed tomography (CT) and

Bronchoscopy

Rigid bronchoscopy

permits general assessment of the airway and

tumor allows dbridement or laser ablation of the

tumor to provide relief of dyspnea

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If the tumor is judged to be completely resectable,primary resection and anastomosis is the treatmentof choice.

The length limit of tracheal resection is roughly 50%of the trachea.

To prevent tension on the anastomosispostoperatively, specialized maneuvers are necessary

anterolateral tracheal mobilization, suturing of the chin to the sternum with the head

flexed forward for 7 days,

laryngeal release, and

right hilar release

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For most tracheal resections (which involvemuch less than 50% of the airway),anterolateral tracheal mobilization andsuturing of the chin to the sternum for 7 daysare done routinely.

Radiotherapy is frequently givenpostoperatively after resection of both adenoidcystic carcinomas and squamous cell

carcinomas, due to their radiosensitivity.

For recurrent airway compromise, stenting orlaser therapies should be considered part of the

treatment algorithm