Respiratory Flashcards
Surgically speaking, where does the upper airway start and where does it end?
Nares to Larynx
What are the neoplasias of the nasal cavity?
Adenocarcinoma, SCC, lymphoma, MCT
What is the best imaging tool for nasal disease?
CT
T/F: Always perform rhinoscopy and nasopharyngoscopy after imaging the nose.
True
What is the most common nasal neoplasia indicated for surgery?
SCC
What are some complications seen with nasal surgery?
Hemorrhage, flap necrosis, fistula, dehiscence, stenosis
What are the primary disease components of brachycephalic airway syndrome?
Stenotic nares, elongated soft palate, everted laryngeal saccules, hypoplastic trachea
What is the pathophysiology of upper airway obstructive disease?
Higher negative pressures that overcome obstruction, secondary soft tissue changes, decreased air flow with increased obstruction
What is the most common component of BAS, and what does it lead to?
Elongated soft palate - leads to stertor.
How much of the airway resistance in BAS does stenotic nares make up?
77% of the airway obstruction
What are the 3 stages of laryngeal collapse?
Stage 1 - everted laryngeal saccules
Stage 2 - collapse of cuniform cartilage
Stage 3 - collapse of corniculate cartilage
Which dog breed most commonly has hypoplastic tracheas?
English Bulldogs
What are some GI comorbidities that go along with BAS, and what is a potential, more important complication they can lead to?
Regurgitation, vomiting, hiatal hernias, ulceration
These can lead to aspiration pneumonia
How does BAS affect the cardiovascular system?
The chronic decrease in Pa02 from the airway obstruction leads to pulmonary vasoconstriction, V/Q mismatch, and then CV hypertenson
What gender is more commonly affected by BAS?
Males
T/F: Aspiration pneumonia is associated with severe BAS
True
What are some space occupying masses that can occur in the upper airway?
Neoplasia, abscess, granuloma, foreign body, epiglottic retroversion
What are the preferred methods of examining and diagnosing BAS?
Examination of upper airway under light anesthesia, thoracic radiographs
What drug is a general CNS stimulant and used to improve the rate and strength of respiration?
Doxapram
What are the indications for surgery in a case of BAS?
Any presence of the components or clinical signs of BAS, also to prevent secondary changes of BAS
What are the surgical procedures used to treat BAS?
Wedge resection, soft palate resection, excision of everted laryngeal saccules
Spay/neuter
What anti-inflammatory would you give as a pre-op therapy for BAS?
Dexamethasone
What tools are used for soft palate resection?
CO2 laser, bipolar sealing device, sharp dissection with stay sutures on the soft palate
What surgical techniques are performed to treat stenotic nares?
Wedge resection, allapexy, trader’s technique
T/F: Tonsillectomies are not recommended because the swelling will usually resolve after the treatment of other tissues
True
What must you distinguish before performing a unilateral arytenoid lateralization?
The presence of laryngeal paralysis (do procedure) and laryngeal collapse (do not do procedure)
What are some post-op therapies for BAS?
Prolonged intubation, analgesia, NPO, e-collar
What are some post-op complications with BAS?
ASPIRATION PNEUMONIA
rhinitis, swelling, bleeding
What CxS does epiglottic retroversion cause?
Extreme inspiratory effort
How do you treat epiglottic retroversion?
pexy of the ventral epiglottis and dorsal base of tongue
What is the muscle and nerve responsible for the larynx to abduct?
Muscle: crycoarytenoideus dorsalis
Nerve: caudal laryngeal nerve
What are the 3 functions of the larynx?
Swallowing, abduction for breathing, voice production
What are the two big diseases of the larynx?
Paralysis, trauma
What are the CxS seen with laryngeal disease?
Stridor, exercise intolerance, dysphagia, coughing
What is the pathophysiology of laryngeal paralysis?
Dysfunction to the vagus nerve that branches to the recurrent laryngeal and caudal laryngeal nerves
What is the most common cause of laryngeal paralysis?
Idiopathic
How do you surgically treat laryngeal paralysis?
Unilateral arytenoid lateralization (yes, I said it already)
What are some post-op therapies for surgical treatment of laryngeal paralysis?
Keep ET tube in until patient is awake, NPO for 24 hours, avoid heavy sedation, check for aspiration pneumonia
What lobe of the lung is most commonly affected by aspiration pneumonia?
Right middle lung lobe
What are the chances that laryngeal paralysis may reoccur after surgical intervention?
33% due to suture failure, progression of disease, or contralateral issues
When performing a ventriculocordectomy, how much of the ventral cord do you want to leave in tact and why?
1-2 mm to decrease the risk of webbing
Surgically speaking, what part of the trachea becomes apart of the lower respiratory tract?
Cricoid cartilage to the carina
Where does the trachealis muscle connect to on the trachea?
Dorsally
What are the layers of the trachea?
Mucosa, submucosa, mucociliary elevator
What are some surgical approaches to reach the trachea?
Cervical ventral midline, median sternotomy, intercostal thoracotomy
Name some big surgical tracheal diseases
Tracheal collapse, foreign bodies, tracheal rupture (from ET tube), trauma
T/F: Tracheal collapses are reversible degenerations of the upper airway.
False. Progressive, irreversible degeneration of the LOWER airway
What is the cause behind tracheal collapse?
Weakness of the tracheal cartilage from decreased water retention
What are some factors that lead to tracheal collapse?
Obesity, environmental allergens, respiratory irritants, kennel cough
What is the typical signalment for tracheal collapse?
Small/toy breed dogs, middle aged.
What does a tracheal collapse sound like?
Goose honk. waxing and waning
What is the gold standard diagnostic technique for tracheal collapse?
Tracheoscopy
What % of the trachea is affected with Grade I-IV tracheal collapse?
Grade I - 25%
Grade II - 50%
Grade III - 75%
Grade IV - almost 100%
When is surgery indication for tracheal collapse?
When medical management fails
What portion of the trachea are external prosthetic tracheal rings placed on?
Cervical portion
What are some surgical complications that can occur with surgery on the trachea?
Laryngeal paralysis, tracheal necrosis, pneumothorax
What is the surgical method of treating tracheal collapse?
Intraluminal stent
How do you determine the size of the surgical stent for tracheal collapse?
Imaging using an esophageal measurement probe
What are the pros and cons of an intraluminal stent to treat tracheal collapse?
Pro: not invasive, fast procedure, used on all portions of trachea, immediate improvement
Cons: expensive, uses scope, short-lifespan of stent, complications
What are some complications with an intraluminal stent placement?
Stent fracture, stent migration, tracheitis, extended collapse, granulation formation leading to obstruction, tracheal rupture
How can the trachea have internal trauma?
Foreign body, ETT
What is the primary method of treating tracheal trauma?
Medically
When is surgical treatment of tracheal trauma indicated?
When dyspnea persists, pneumothorax, or trauma is severe
What are the ways to surgically treat tracheal trauma?
Primary tear closure, resection & anastomosis
What are some complications of surgical treatment of tracheal trauma?
Stricture, pneuothorax/mediastinum, infection
When would you perform a permanent tracheostomy?
as a salvage procedure when you cannot treat an upper airway obstruction
What are some complications associated with permanent tracheostomies?
Infection, bleeding, stenosis, foreign bodies, pneumonia,
What kinds of dogs are best suited for permanent tracheostomies?
Indoor dogs with diligent owners
T/F: Permanent tracheostomies are also indicated for cats!
False. poor prognosis
What are some key things to do when performing a median sternotomy and opening the thoracic cavity? How do you close it?
Leave the manubrium and xiphoid intact
Close the cavity with a figure of 8 polypropylene suture or orthopedic wire
Besides the median sternotomy, what is another approach to access the thoracic cavity? When is this indicated? How do you perform this approach?
Lateral/intercostal thoracotomy
Used to approach a specific structure in the cavity
Incise layer by layer
Close with circumcostal suture
T/F: Median sternotomy is less painful than lateral thoracotomy
False.
Which is the most minimally invasive technique to access the thoracic cavity?
Thoracoscopy
What approach to the thoracic cavity is used to access the thorax during a celiotomy, and is used to ligate the thoracic duct, caudal esophagus, or intra-operative CPR?
Transdiaphragmatic approach
T/F: Positive pressure ventilation is mandatory when performing thoracic surgery
True
How would you access the thoacic cavity when performing a total or partial lung lobectomy? (2 answers)
Lateral thoracotomy, thoracoscopy
What is the name of the procedure where you remove all lobes of one lung?
Pneumonectomy
What is the maximum lung mass that can be acutely removed without being fatal?
65%
When is a pneumonectomy indicated?
When disease is diffuse through multiple lung lobes
What surgical instrument is used with complete or partial lung lobetomies?
Thoracoabdominal stapler (TA)
T/F: The thoracoabdominal stapler is too large for small patients
True
What can the thoracoabdominal stapler be used to do?
Isolate hilus of lobe or portion of it so it can be excised
T/F: When suturing a partial lobectomy, you want to suture distal to the clamps.
False. Proximal
What type of suture pattern is used for small peripheral masses?
Guillotine.
How do you suture for a complete lobectomy?
Triple ligate the vessels, pre-place horizontal sutures and tie before cutting, close bronchus with sutures
Why should you isolate affected lung tissue with moistened laparotomy sponges when performing pulmonary surgery?
Decreases the risk of contamination
What are some things to check before closing up the surgery?
Hemorrhage, air leaking, chest tube placement
What are some surgical diseases of the lungs?
Cysts, fistulas, abscesses, lacerations, torsions, neoplasia
What is a bleb?
localized collection of air between internal and external layers of the visceral pleura
What is a bullae?
Cavity in the lung not separated by epithelium or viscera
What are some complications that can occur with cysts, bullae, and blebs?
Abscessation, rupture, spontaneous pneumothorax
What is the problem with treating cysts, bullae, and blebs conservatively?
high recurrence rate
What are the surgical methods of treating cysts, bullae, and blebs?
Partial or complete lung lobectomy
What types of dogs are most commonly affected by lung lobe torsion?
Large, deep chested dogs and pugs
What CxS will you find with lung lobe torsion?
Dyspnea, tachycardia, cough, exercise intolerance, hemoptysis
What PE findings are reported with lung lobe torsion?
Pyrexia, pale mucous membranes, decreased ventral lung sounds
How can you diagnose lung lobe torsion?
Thoracocentesis - serosanguinous/chylous effusion
Imaging - rads/CT
What will happen if you untorse a lung lobe torsion?
It will release cytokines and endotoxins - reperfusion injury
What surgical treatment do you use for lung lobe torsion?
Lung lobectomy
What do you want to do to treat lung lobe torsion before performing the lung lobectomy?
patient stabilization - thoracocentesis, O2, fluids
Which dog, large or pug, has a better prognosis with lung lobe torsion?
Pug
What are the two most common types of primary pulmonary neoplasias?
Bronchiolar and alveolar carcinomas
How do you treat primary lung neoplasias?
Lung lobectomy for peripheral tumors not involving the hilus
What is the most common cause of thoracic wall trauma?
Hit by car
T/F: Most thoracic wall traumas do not require surgery
True
How do you treat a patient with a penetrated chest wound?
Stabilize, cover wound with dressing until patient is stable enough for surgery (may not need it if mild wounds)
What should you NOT do with an object that is penetrating the chest wall?
Remove it before fully accessing and preparing the area for removal
What is the most common cause for chylothorax?
Idiopathic
How do you diagnose chylothorax? What will you see?
Cytology of pleural effusion.
Modified transudate, lymphocytic effusion, triglycerides more in fluid, cholesterol less in fluid
How do you surgically treat chylothorax?
Thoracic duct ligation, cysterna chyli ablation, subtotal pericardiectomy
How can you better visualize the lymphatic structures when performing surgery on the chylothorax?
Injection of methlyene blue
Lymphangiography
Where on the dog do you approach the chylothorax surgery? Cat?
Dog: Right 10th IC space
Cat: Left 10th IC space
Where do you ligate and clip the thoracic duct when performing the thoracic duct ligation?
Close to the diaphragm as possible
How can you approach a subtotal pericardectomy?
Intercostal, median sternotomy or transdiaphragmatic approach
Where do you excise the pericardium for a subtotal pericardiectomy with a chylothorax?
Ventral to the phrenic nerve
What does a cisterna chyli ablation do
Re-routes the abdominal lymphatic drainage to major abdominal vessels
Which pet, dog or cat, has a better outcome with thoracic duct surgery?
Dog
What are some complications with thoracic duct ligation surgery?
Persistent chylous/non-chylous effusion, lung lobe torsion, pneumothorax
What is the most common cause of diaphragmatic hernias?
traumatic
What part of the thorax is most susceptible to tears from blunt force?
Muscle
What diagnostic imaging technique is the most accurate for diaphragmatic hernias?
Ultrasound
What CxS are seen with DH?
muffled heart sounds, borborygmi heard in thoracic cavity, tachycardia, tachypnea
What should you do to treat a patient with a diaphragmatic hernia before surgery?
Stabilize, look for other conditions, O2 therapy, prop patient at angle to drop organs down
How do you approach a diaphragmatic herniorrhaphy?
Ventral midline abdominal
What organ is most commonly herniated?
Liver
What suture pattern do you use to repair the hernia? Material?
Simple continuous suture pattern with PDS or Prolene
T/F: Re-expansion pulmonary edemas associated with rapid expansion of previously atelectic lungs are most commonly caused from acute hernias
False. Chronic hernias
What pressure ventilation must you keep at all times during a diaphragmatic herniorrhaphy?
< 15 cm H2O
How do you treat re-expansion pulmonary edema?
You can’t. It’s fatal
What is the prognosis for diaphragmatic hernias?
Good if patient survives 24 hours after surgery. 90%
What are some factors that decrease prognosis with DH?
Chronicity, age, concurrent injuries
T/F: Peritoneopericardial diaphragmatic hernias are congenital
True
What occurs with PPDH?
There is a communication with the pericardium and peritoneal cavity
What other congenital defects are seen with PPDH?
Polycystic kidneys, ventricular septal defects, sternal deformation
What PE findings are noticed with PPDH?
Muffled heart sounds, ascites, murmur
How do you diagnose PPDH?
Rads, U/S
What will you see on rads with PPDH?
Enlarged cardiac silhouette, dorsal elevation of trachea, overlap of heart and diaphragm borders, gas in pericardial sac
How do you treat PPDH?
Surgery with ventral midline abdominal approach asap, antibiotics
How do you suture close the surgery of PPDH?
Simple continuous pattern
What is the most common congenital cardiac defect in dogs?
Patent Ductus Arteriosis
What happens with PDA?
Blood is shunted from left to the right side of the heart causing severe volume overload progressing to heart failure of the left side
What do you see with reverse PDA?
Right to left shunt - severe pulmonary hyppertension
How can you treat PDA?
Coil embolization, ductal occluder
Surgical ligation - indicated with top two don’t work
What are some complications of surgical ligation with PDA?
Severe hemorrhage due to PDA rupture, bradycardia (reflex), recanalization
What is the prognosis for PDA? Reverse PDA?
PDA - excellent if younger.
Reverse PDA - grave
T/F: Mitral regurgitation and myocardial insufficiency from PDA is likely to resolve after surgery.
True
What is the most common cardiac neoplasia in the dog?
Hemangiosarcoma of the right auricle
How do you treat hemangiosarcoma of the right auricle?
Emergency pericardiocentesis due to acute cardiac tamponade.
Chemotherapy
What are the functions of the pericardium?
Prevents over-distension of the heart, a gliding surface, and protection from spread of infection from thoracic cavity
What cardiac signs will you see with cardiac tamponade?
Increase intra-cardiac diastolic pressure, decreased stroke volume, decreased cardiac output, increased systemic venous pressure
List some pericardial diseases.
Rupture, effusion, inflammation, herniation
What CxS will you see in animals with pericardial disease?
Muffled heart sounds, weak femoral pulses, weakness, lethargy, dyspnea, exercise intolerance
What is both therapeutic and diagnostic for pericardial diseases?
Pericardiocentesis
What imaging tool will give you instantaneous information on fluid present in the pericardium?
Ultrasound
What types of surgeries are used to treat pericardial disease? What is the difference?
Total pericardiectomy - phrenic nerves dissected from pericardium
Subtotal pericardiectomy - all pericardium ventral to phrenic nerves are removed
What is the most common cause of vascular ring anomaly?
Persistent right aortic arch
What breed of dog is most commonly reported to have PRAA?
German shepards
What signs are seen with PRAA?
Regurgitation, unthrifty, respiratory signs
How do you treat PRAA?
Surgically via left intercostal thoracotomy (5-7 IC space), isolation of the ligament, double ligate and transect
What is the prognosis for PRAA with surgery?
Good to excellent
