Chapter 3 Respiratory System

 

   

 3.1 STENOTIC NARES

Etiopath - lack of rigidity in D. parietal Cart.

• - collapse medially on inspiration
• - resultant to selective breedings. Common
• - in brachycephalic skull. Boston Terrier, Peke.
• - May progress to inversion of lat. ventricle
• - collapse of arytenoid carti laryngeal edemaSigns - Collapsed nares act as one way valve
• - Chr. anorexia, stunted growth, unthriftiness Early fatigue, insp. dyspnea. Open mouth breathing, impaired olfactory function

Dx - Physical Exam

Rx - Elliptical incision; tip of nostrils

• - Wedge excision at mucocutaneous jt. with resection of levator nasolabialis M. 

3.2 NASAL CAVITY DISORDERS

• - Facial part of U. resp. T., Ex. nares to nasopharynx
• - Dorsally bounded by nasal bones, lat. by maxillae and floor by hard palate. Post. turbinates
• - Separate it into dorsal, middle, common & vent. meatus - Controls heat, humidity and particle size of insp. air
• - Disorders are wounds, F.B., Neopl. parasites, mycotic,etc. 

3.3 NASAL FOREIGN BODY (F, B)

• ETIOPATH - Grass awns, fox tails, twigs, hay
• Signs - Sneezing, paroxysmal, epistaxis, N. dis.
• Dx - MDB, Rhinoscopy, X-ray
• Rx - Removed by alligator forceps
• - Rhinotomy 

3.4 INTRANASAL NEOPLASIA

Etio - About 1% of total canine tumors

• - Equal set distribution
• - BP medium to large breeds

Signs - Upper resp. system involvement signs e.g. sneezing, epistaxis, discharge, deformity

• Dx MDB, cytology, Biopsy, Endoscopy 67% epitheleoma, carcinoma, adenocarc 33% mesenchymal, chondroma osteocarc.
• Rx - Surgical nasal flap elevation
• - Surgical and radiation. A. total of 1750 rads. given every other day for 3 days
• - Chemotherapy - ? 

3.5 LARYNX

• - Laryngeal skeleton is formed by: paired arytenoid, cuneiform, unpaired - epiglottic, thyroid, cricoid, sesamoid, interarytenoid
• - Sensory innervation - cranial laryngeal motor innervation
• - Recurrent laryngeal
• - Please review Anatomy 

3.6 LARYNGEAL PARALYSIS

Large and giant breeds Mostly Bilateral, rare in cats

• Etio - Trauma, congenital idiopath, neurogenic D.
• Signs - Insp. dyspnea, wheezing, cough on deglution gurgling, cyanosis, etc.
• Dx - Laryngoscopy, absence of movement of larynx,
• Add. V. Cord
• Rx - Venticulocordectomy, lateralization of arytenoids 

3.7 Collapse of Epiglottis

• BP - Toy breeds, fox terrier, poodles, chi., pomer.
• Etio - Trauma
• Signs - Profound resp. distress, epiglottis border rolled in its vent, surface. Looks convex.
• SURGERY - Amputation of Epiglottis
  • - General anesthesia, incubation?
  • - Sternal recumbency. Mouth speculum
  • - Grasp ant. third of epiglottis and amputate b electrosrugery/Scissors Epinephrine infilt. and carmault helpful
  • - Need to suture corniculate P. of arytenoid carti. 

3.8 Collapse of Arytenoid Cartilage

Cuneiform P.

• BP - Toy brachycephalic, Pug, Peke, Boston T., Lhasa A.
• Signs On insp. cuneiform P. drawn inward Generally bilateral, severe insp. distress Edema of the mucosa covering cunei. P.
• Dx Inspec. R/O stenotic nares, Elongated soft P.
• Rx - Surgical amputation
  • - General anesthesia, incubation?
  • - Epinephrine infil. 1:30.000 of mucosa
  • - Incise along a carmalt applied from the lateral junct of cunei P. to corniculate P. of the epigl.
  • - Electrocautery? keep animal sedated. Tracheotomy? 

3.9 Laryngeal Stridor/Roaring

• BP - Large or Giant
• Etio - Unknown. Bilateral vocal folds and L. Ventricles
  • - Vocal folds relax and move medially causing occlusion of laryngeal opening
• Sign - Severe insp. dyspnea, loud roaring sound
• Dx - Inspec. R/O other resp. diseases causing insp. dysp.
• Rx - Excision of lat. vent. lining and ventriculocordectomy
• Surgery G. Anesthesia M. Speculum, stern. Recumb.
  • a. - Evert. the lat. vent. lining by grasping with a forceps and amputate Healing results in lat. abd. of vocal folds
  • b. - Grasp mid section of vocal folds. Severe dorsol. and vent. attachment of the laryngeal wall 

3.10 LARYNGOTOMY

• - General anesth. Dorsal recumb. Neck extended
• - Midline incision through skin, S/Q over larynx
• - Separate sternohyoid M. Continue M. line incision
• - Incision extends from cranial edge of cricoid cart. through body of thyroid cart. larynx is open
• - Larynx closed with 2/0 gut or other absorbable M. Routine S/Q and skin closure 

3.11 VENTRICULOTOMY

• - Eversion of laryngeal ventricles
• - BP Brachycephalic. History of prolonged or repeated airway obstruction
• - Gen. Anesth open mouth sternal recumb.
• - Pull epiglottis forward. Everted vent. visualized Amputate by electro surgery, scissors or wire snares
• - Minimal hemorrh. Stops by compression.
• - Debarking, reduce the volume & pitch of voice
• - Light G. Anesthesia Sternal Recumb. Mouth speculum
• - Depress epiglottis grasp V. fold with carmalt
• - Remove a piece by electro cautery, scissors
• - Replace andotracheal tube 

3.12 CRICOPHARYHGEAL ACHALASIA

• Etiopath - Unknown Glassopharyn H. disorder
  • - Inadequate relaxation of cricopharyn H. dysphagia
• Signs - Difficult swallowing, coughing nasal discharge
• Dx - Radiograph fluroscopy
• Rx - Cricopharyngeal myotomy 

3.13 CRICOPHARYNGEAL MYOTOMY

• - G. Anesthesia, dorsal recumb, neck extended
• - Incubate Esophagus
• - Vent. midline incision over larynx and trachea
• - Separate sternohyoid M.
• - Rotate larynx 90% and visualize cricipharyngeus and thropharyngeus M. on dorsal surfaces
• - Free cricipharyngeus from esophagus
• - Cut in median plane, don’t go in esophagus
• - A portion of thyropharyngeus may also be cut
• - Return larynx to normal position
• - Close strenophyoid M. 3/0 medium chr. gut
• - Routine S/Q and skin closure 

3.14 LARYNGEAL SURGERY POST-OPERATIVE CARE

• - Edema and inflam. always follow surgery
• - Animal may be more obst. than before
• - Inflam. controlled by pre-operative use of dexamethasone or prednisolone
• - For severe post op. resp. emparrasment Tracheotomy and tracheostomy
• - Cool and calm housing, feed soft ration often 

3.15 TRACHEA

• Relatively non collapsible tube
• Extends from cricoid cart. to carina
• Contains approx. 35 "c" shaped carti. rings
• Each ring connected to other by annular lig.
• Dorsally connected by dorsal trachealis M.

3.16 EXAMINATION

• Physical, Ck. for deviations
• Entoscopic exam
• X-ray including contrast studies
• Fluroscopy 

3.17 Tracheal Disorders

• Congenital abnormalities
  • - BP. Toy: Chi, Pomer. T. Poodle, Yorke
  • - All or partial tracheal involvement
  • - Weak and flaccid D. Trachealis M. rusult in Flattening of "C" rings. Lunatic lumen
• Signs - Asymptomatic unless sec. D. occurs
  • - Non responsive chr. harsh dry cough
  • - Insp. stridor, dyspnea cyanosis
  • - Coarse rales in trachea proxysmal cough on exer.
• Dx - GPE, Broncheoscopy, fluoroscopy, Radiography with dorsal flexion of neck on insp. shows R/O T. hypoplasia.. small t. rings; rounded lumen
• Rx - Surgical method
  • - Replacement with prosthesis
  • - Reinforcement with plastic sleeve or rings
  • - Chondrotomy, partial, alternate rings or segments
  • - Plication of D. Trachealis M.
  • - Chondrotomy and plication 

3.18 PLICATION OF D. TRACHEALIS M.

• - Mostly for cervical collapse
• - Anesthetize, intubate, dorsal recum. extend neck
• - Vent, midline incision larynx to thoracic inlet
• - Separate sternohyoid M. sternocephalieus M. in caudal 1/4th
• - Free trachea rotate trachea 1800 to visualize D. trachealis M.
• - Place interrupted horizontal mattress stitch in M. with nylon
• - Return trachea to normal. Routine closure 

3.19 REINFORCEMENT WITH PROSTHETIC PLASTIC RINGS

• - When plication not helpful or cause narrowing
• - Recurrent cases. Prosthetic rings made from syring causing (propylene) Chemical or gas sterilization
• - Isolate trachea after anesthesia and position
• - Segment should not be wider than the plastic rings
• - While placing rings, don’t entrap recurrent laryngeal M.
• - Open end sutured to vent T. surface with 3/) dexam
• - Rotate T. 180. Fix D. trachealis M. to rings by suture
• - Derotate. Routine closure
  • Post-Op. AB. Antitussive. No excitement
  • Prognosis.. Guarded. Patient selection Imp. 

3.20 Chondrotomy for T. Collapse

• Routine exposure
• Segmental cut in every or alternate ring
• Don’t invade a ligament or muxosa
• May lead to lateral form of T. collapse 

3.21 Acquired Lesions of Trachea 

• Wounds - Bite bullet, auto etc
• S/Q or intertitial emphyseme
• Treatment - Surgical or conservative
• Surgical - midline vent, T. wound egges debrided and sutured With 3/0 dexon soft tissue .. treat as open wound or debride and suture with or without drains. Severe cases, teflon mesh, resect and anastomose. Antibiotic treatment. 
• Strictures - - rare, following trauma tracheostomy 
• Surgical - Reaction and anastomosic

Appose T. rings with non absorb structures in simple interrupted fashion

• - Minimize penetration of mucosa
• - Stress relief suture if needed
• - Primary wound closure, drains? AB therapy 

3.22 Tracheotomy/Tracheostomy

• Indications -- Emergency airway
• surgical proc. in larynx, pharynx or nose
• A permanent opening for airway obst.
• Technic - Vent . midline incision at the junction of upper and middle third cervical T.
  • - Incise trachea longitudinal. Transverse window
  • - Transverse incision for temp. access. may cause obst. of lumen by sec. granulation tissue.
  • - metal or plastic tracheostomy tubes. "J & T"
  • - Approximate muscle and skin edge around tubes
  • - Anchor tube to the neck. AB therapy
  • - Clean several times a day. AB dressings
  • - Wound heals by granulation after tube
  • - Disposable cuffed tubes better suited for U. resp. S. 

3.23 PRINCIPLES OF THORACIC SURGERY

• Anesth. Oxy. supplementation. Assisted: control, IPPB.
  • - Lung collapse leads to hypercapnie due to hypoxemia
  • - Smooth anest. induction & recovery, I/V fluid line
  • - Use least depresent drugs. !resp. & cardiac reserve
  • - Closed chest - IPPB 15 to 20 mmHg.
  • - Increased T.V. of lungs on open chest to 10.15 ml/lb
  • - Try to improve patient condition before anesth. e.g reduce penumothorax, hydrothorax, digitalize
  • - Sparing use of dedative tgranqulizer narcotic
  • - Intubate following minimum dose of surgical
  • - Attach to anesthetic machine. Pre.oxygenate?
  • - Keep control over resp. till chest is closed and spontaneous rEsp has ensued.
  • - Post op pain killers, mepridine 2 to 8 mg/lb IM if needed 

3.24 Flail Chest - Uncommon

• - Fr. of two or more ribs dorsally and ventrally
• - Paradoxial movement of the isolated segment
• - Open and closed pneumoth. traumatic L. syndrome. Common
• - Anesthetize and IPP ventilation
• - Dorsoventral incision on flail segment
• - Place large gauge non absorbable suture through Surround skin and flail segment. Don't tie
• - Stabilize the segment with a series of cranial and caudal pericostal gut sutures
• - Close intercostal M. S/Q and skin
• - A maletable splint is attached to chest using nonabsorb. sutures 

3.25 Chest Wall Reconstruction

• - Where radical excision is indicated e.g. neoplasia, chondroma, chondrosarcoma
• - "Emblock" resection of chest wall is necessary
• - Tantalum gauze, fiberglass and polypropylene mesh, plastic spinal plates used as prosthetic materials
• - Poluprepylene least reactive. Granulation tissue can grow through the mesh even in presence of infection
• - Plan surgery before jumping into it. 

3.26 Thoractomy

• - Lateral T. - wideiy used
  • Intercostal T.
  • Rib resection T.
• - Mid ventral T.
• - Trans-sternal T. 

3.27 Technic of Lateral T

• - Routine prep. lateral recumbency
• - Sand bag under the chest
• - Skin incision over selected l/costal space e.g. 4th intercostal space 

3.28 Intercostal Incision

• - Incise skin and cutaneous trunci M.
• - Identify the exact intercostal space
• - Incise the latissimus dorsi M.
• - Extend it vent. by cutting through scalneus M.
• - Divide serratus vent. M. along its fibers
• - Stab intercostal M . with blunt scissors or hemostats
• - Incise carefully during exp. phase
• - Extend incision by scissors
• - Avoid damage to lungs
• - At completion of surgical intervention install a chest drain
• - Individual layer closure of M., S/Q, skin
• - Frequent aspiration with dog in different positions
• - Drain may be removed in 24 hours 

3.29 Rib Resection Technic

• - Select the rib to ~e resected e.g. 5th
• - Incise skin, S/Q, cutaneous T,. over it
• - Incise latissimus D, and scalenus M.
• - Free serratus vent and ext. abd. oblique M.
• - Resect rib, high dorsally and at costerchondral junction ventrally
• - Incise through ventral periosteum and pleura Chest closed with pericostal interrupted sutures of 1 or O monofilament nylon, wire
• - Replace all the stitches and then tie
• - May suture periosternum on either side of incision and reinforce with pericostal sutures
• - Install drain or creat neg. I/pleural P. 

3.30 Lungs

• - Paired organ
• - Left lung-crainal and caudal lobes
• - Right lung-middle acessory in addition
• - Blood supply by bronchial arteries
• - IPPV is a must for surgery 

3.31 Congenital Anomolies of Lungs

• itt e consequence. Either incompatible or totally compatible with life 

3.32 Acquired Lesions of Lung

• Pulmonary Contusion - Hemorrhage in Parenchyma
• Signs - Dyspnea, cyanosis, palor, rales on auscultation
• Dx - X-ray, GPE, percussion, auscult, history of trauma
• Rx - Supportive, IPPV AB, diuretics 

3.33 Lung Tears

Small heal uneventfully - Larger require repair Series of interrupted H. mattress, simple continuous, cross over stitch with 5/0 or B/O C.V. Silk

• - No hyperinflation of lungs
• - Monitor for spontaneous pneumothorax 

3.34 Local/Partial Lobe Incision

• - In benign tumors, solitary lesions
• - A wedge resection of lung tissue
• - Isolate the portion with non-crushing forceps
• - Defect closed with double row of H. mattress simple continuous or combination sutures with 5/0 or 6/0 C.V. silk
• - No hyperinflation, Ck. for pneumothorax, relax the dog. 

3.35 Lobectomy

• Indications - Tumors, F.B. abscess, Torsion
• Technic - Standard thoractomy approach
  • - Identify the lobe to be resected
  • - Isolate, br. A vein, and bronchus
  • - Ligate vessels at 3 places. Incise between the middle and caudal ligature
  • - Pack off the area around bronchus
  • - Place one or two right angle forceps, Doyan’s Intestinal or carmalt around the bronchus nearthe bifurcation
  • - Br. transected 1/2" distal to first forceps 
  • - Br. stump closed with 4/0 silk sutures
  • - 2 rows of H. Mattress. Stump folded on itself and anchored with mattress sutures
  • - Simple cont. suture, stump. fold folded & anchored as above, A parietal pleural cuff, cyanoacrylate polymer may cover the sutured stump
  • - Ck. leaks b -pouring N/S on stump and IPPV of lungs
  • - Any leaks, close by interrupted stitch Routine chest closure
  • - Established Neg Pleural pressure 

3.36 Chest Drain

Indications - constant and rapid accumulation of air or fluid. In less severe cases periodic thoracocentesis, high and low, may suffice

Technic - 10 or 12 Fr. Foley female urethral catheter, Stopcock

• - General, local anesthesia, surgical prep; lat. pos. A metal stylet is passed entire length of catheter
• - An incision just large enough for the tube is made at 9thintercostal space
• - Skin moved up 2 intercostal spaces, i.g. skin incision is now at 7th intercostal space
• - The cath_eter with stylet is passed under skin and thrust through the intercostal space in P. cavity
• - Be sure all holes are in cavity
• - Before completely withdrawing stylet, clamp the catheter to prevent entry of air
• - Catheter anchored to skin entry point by a purse string suture tied in shoe string bow
• - Anchor to skin again a little distal to entry point
• - Ballool in catheter can be inflated with air or N/S. Attach the end to either 3-way stopcock, Heimlich valve, or water trap seal.
• - Put a chest bandage on.