102.Trachea_bronchi

Question 1

segments of the lower airway

Answer 1

trachea down to the carina then splits to principle main stem bronchi–>lobar bronchi (to each lung lobe respectively–>segmental bronchi (overlapping cartilage plates)–>subsegmental bronchi–>bronchioles (lack cartilage plates)

Question 2

what does the trachea consists of

Answer 2

incomplete hyaline cartilage ringsdorsal muscle attachment==trachealis muscle (smooth muscle)~ 35 ringsbtwn rings = annular ligament (fibroelastic tissue)

Question 3

outter layer of the trachea

Answer 3

cervical trachea = adventitiathoracic trachea = serosa

Question 4

cell types of the trachea

Answer 4

trachea and upper bronchimucosa= pseudo stratified coloumnar epithciliated columnar cells, goblet cells, basal cells with few endocrine cells in the mucosatubuloalveolar glands in the lamina propria (secret 40x goblet cell mucus)further distal: glands decr, then goblet cells, then ciliated cells

Question 5

describe blood supply to trachea

Answer 5

segmentalcranial and caudal thyroid arteriesrich subepithelial mucosal plexusat carina= bronchoesophageal arteries

Question 6

innervation to the trachea

Answer 6

right vagus (left vagus only results in < 30% stimulation compared to right vagus—RIGHT VAGUS IS DOMINANT INNERVATION TO TRACHEA)recurrent laryngeal nerve

Question 7

functions of trachea

Answer 7

1. conduit for inspired gases and gas echange2. condition inspired air (warmth and humidification)3. airway homeostasis with mucociliary apparatus (10-15 mm/minute)

Question 8

tracheal size

Answer 8

tracheal diameter: thoracic inlet< 0.13 in bull dogs< 0.16 abN for non bulldog brachy cephalics< 0.20 abN for nonbrachycephalic dogs

Question 9

diagnostics for diseases of the trachea

Answer 9

compelte PE, ortho, neuroassess airway flow and patentcypalpate larynx and cartilage of trachea to elicit coughT radsfluoroscopyCTtracheobronchoscopy (only way to reliably grade collapse and eval for bronchomalacia)bronchoalveolar lavage (guided sample)transtracheal wash (non guided sample)

Question 10

tube size recommendations for temporary tracheostomy

Answer 10

–tube should be large enough to provide adequate airflow but small enough to allow for airflow around the tube (to help prevent from immediate death due to tube occlusion)–cuff vs noncuff (non cuff or deflated cuff preferred to avoid tracheal necrosis)

Question 11

methods of temporary tracheostomy placement

Answer 11

general anesthesia–transverse incision not more than 50% diameter of trachea–tracheal flap–vertical incision

Question 12

mgmt of tracheostomy tubes

Answer 12

—-STERILE technique—-humidification/coupage to break down mucus—-gentle lavage (0.2 ml/kg saline) and suction of airway (PREOXYGENATE and suction no more than 10 seconds)—-clean tube with 2% chlorohexidine and saline before replacement—-change tube (sterile) q 12 hr ( may need to q 4-6 hrs initially bc mucus production)—-avoid cuff inflation unless PPV given (then change cuff position q4hr)—-gentle cleansing stoma

Question 13

what locations have stenosis been ID’d post temporary tracheostomy tube placement

Answer 13

—at stoma site–at the level of cuff or tube tipusually loss of 25% luminal area

Question 14

immediate temporary tracheostomy complication rate

Answer 14

50% complications plugging (most common 20%)gag.cough/vomitsubcutaneous emphysemapneumomediastinuimpneumothoraxinfectionrespiratory distresspremature tube removal/dislodgementstenosismucosal erosion** cats may produce more mucus and have higher incidence of tracheal mucus plugs

Question 15

recommended cuff for temporary tracheostomy

Answer 15

IF using a cuff (non cuffed are preferred)high volume low pressure cuffs are preferred

Question 16

how long does it take for the trachea to adapt to a permanent tracheostomy

Answer 16

squamous metaplasia occurs 0-4 weeks becoming normal at 16 weeksstricture of stoma is to be expected (in one study up to 60%)

Question 17

how many tracheal rings have been resected in experimental dog studies

Answer 17

15-27 rings have been resected experimentally20-25% in puppies (higher elasticity but fragile bc high water content than collagen)60% in adults

Question 18

how to minimize tension on tracheal R&A site

Answer 18

tension relieving sutures may not be necessary (Behrend et al)–tension relieving sutures proximal and distal to resection site (try to not further impair blood supply)–fixed ventroflexion of neck (may be uncomfortable)–release of annular ligaments with preservation of mucosa

Question 19

suture material preferred for tracheal R&A

Answer 19

monofilament absorbable to avoid complications with granuloma formation and stricture

Question 20

advantages and disadvantage of suture patten on tracheal R& A healing

Answer 20

continuous suture pattern is faster, distributes tension evenly, reduces focal irritation/ischmeia and increases tensile strengthBUTcontinuous suture causes more tracheal stenosis than simple interrupted

Question 21

two techniques for tracheal R& A

Answer 21

1. split cartilage technique (less stenosis, stronger anastomosis)2. annular ligament cartilage technique

Question 22

approach to cervical and thoracic trachea

Answer 22

cervical—ventral midlinethoracic– RIGHT 3-5 IC (ligate and transect azygos, preserve vagus, phrenic, recurrent laryngeal n)

Question 23

complications of tracheal R&A

Answer 23

–infection (impaired MC apparatus decr 3 fold takes 1 month to reestablish)—leakage (SQ emphysema, pneumomediastinum, pneumothorax)–stricture formation (med mgmt, ballon, stent, bougienage, R&A)

Question 24

two reasons why tracheal R&A may fail

Answer 24

—disruption to segmental blood supply–too much tension

Question 25

cause and location commonly associated with tracheal rupture

Answer 25

–cats and recent dental procedure/intubation–occurs at the junction of tracheal is muscle and ring near the end of the cuff or tip of endotracheal tube

Question 26

methods of tracheal FB removal

Answer 26

–tracheobronchoscopy–fluoroscopic guidance–foley catheter technique–thoracotomy/tracheotomy (increased morbidity)most FB are not retrieved

Question 27

biphasic age distribution with tracheal neoplasia

Answer 27

young–benign masses (Granuloma–Onchocerca, Spirocerca lupi, cuterebra; Hematoma; Lithiasis)old–malignant massesrequires 50% of lumen to be obstructed prior to clinical signstx: tracheobronchoscopy (biopsy, debulk), R&A

Question 28

grades of tracheal collapse

Answer 28

1. 25%2. 50%3. 75%4. 100%Tangner and Hobson classificationsurgery for stages 2-4 or if failed medical mgmt

Question 29

pathophysiology of tracheal collapse

Answer 29

laxity trachealis muscledecreased water content/GAG in cartilage of tracheal rings making them more compliant and less rigidperpetual inflammatory cycle; squamous metaplasia, decrease mucociliary apparatus, pulmonary hypertension (cor pulmonale–right heart enlargement)

Question 30

results of tracheal palpation to elicit a cough is how diagnostic for tracheal collapse

Answer 30

palpation is only positive in 40% of tracheal collapse patients

Question 31

diagnostics for patient with tracheal collapse

Answer 31

1. thoracic rads2. fluoroscopy3. tracheobronchoscopy 4.+/- bronchioalvelor lavage (culture and cytology)

Question 32

medical management success in tracheal collapse patient

Answer 32

70% success with rx for longer than 1 yrwt lossGCCcoolcontrolled exerciseharnessavoid smoke, scented candles, airway irritantsnebulize with humidificationbronchodilators

Question 33

surgical tx of tracheal collapse

Answer 33

10% risk of severe life threatening complications 1. extraluminal prosthetic rings(polypropelene rings or syringe cases)–segmental external skeleton for cervical and cranial thoracic trachea2. extraluminal spiral prosthesis–uniform support to the entire trachea; requires lateral thoracotomy for distal placement3. intraluminal stents–thoracic and cervical trachea (across thoracic inlet); nitinol (nickel and titanium allow), self expanding

Question 34

complications with extraluminal tracheal stenting

Answer 34

1. laryngeal paralysis (place rings on MEDIAL aspect of recurrent laryngeal nerve and vessels); 10-30%2. tracheal necrosis (damage to segmental blood supply of trachea); characterized by cough, SQ emphysema, death3. pneumothorax (accidental entrance of thoracic cavity and/or excessive tension on stay sutures)

Question 35

T/Fresponse to surgical intervention of tracheal collapse has not been associated with the grade of collapse before surgery

Answer 35

TRUE

Question 36

avoid damage to blood supply of trachea during extraluminal ring prosthetic placement by skeletonizing what side of the trachea?

Answer 36

recommend skeletonizing the RIGHT pedicle because there is more space between the right recurrent laryngeal nerve and cervical trachea than on the leftalternatively, do not skeletonize either pedicle but rather make a tunnel to pass each ring around

Question 37

advantages of intraluminal tracheal stent prosthesis

Answer 37

Reconstrainable, woven, foreshortening SEMS (nitinol) which resist alterations up to 10% without plastic deformation, have thermal shape memory, super elasticity, and hysteresis propertiesavoids damage to nerves and blood supply; non invasive, quick anesthetic timeexert a radial stress against the tracheal wall (to resist migration)

Question 38

difference of woven vs laser cut stents

Answer 38

woven experience foreshortening (measurable shortening with placement)laser cut do not experience foreshortening (but have a high unacceptable rate of fracture)

Question 39

tracheal stent size recommendations

Answer 39

rads, fluor, trachobronchoscopylength: scope or fluoroscopy for length in an awake patient (fluoro preferred to decrease anesthetic episode)diameter: general anesthesia and PPV at 20 cm H20 to maximize tracheal diameter (fluoro or rads)stent is chosen that exceeds the widest measured tracheal diameter (with PPV) by 10-20%stent length needed to span collapse area/entire length of trachea; expect some foreshortening

Question 40

outcome following intraluminal stent placement for tracheal collapse

Answer 40

SEMS resulted in immediate improvement 96%long term improvement in 83% (longer than a year)

Question 41

complications of intraluminal tracheal stents

Answer 41

–stent fracture (can be removed piecemeal, new stent deployed, extraluminal ring placement, removal via tracheotomy)–stent migration (if inappropriate size used)–tracheitis (60%—treat in order to avoid inflammation and potential granulation tissue buildup)–collapse beyond the stented area–obstruction of lumen with granulation tissue (anti-inflammatories, colchicine therapy)–tracheal rupture–rectal prolapse/perineal hernia (suspect from persistent cough)

Question 42

bronchiectasis

Answer 42

chronic irreversible damage to bronchi most commonly caused by recurrent/chronic pneumoniabronchial lumen dilates from the pull of adjacent pulmonary parenchyma (dilation distally without tapering)3 forms: cylindrical**, cystic, saccularright cranial lung lobe most common

Question 43

ciliary dyskinesis

Answer 43

immotile cilia syndrome(respiratory, sperm, and auditory tube epithelium affected)prone to bronchopneumoniaconcurrent situs inversus (50%)

Question 44

what is Kartagener syndrome

Answer 44

triad situs inversuschronic rhinosinusitisbronchiectasis