Bovine Respiratory Flashcards

1
Q

Sites for scope insertion with thoracoscopy

A

ICS 9 in the middle of the upper 1/3 of the thorax is IDEAL

ICS 7 or 8 in the middle of the middle 1/3 of the thorax may allow better evaluation of the cranioventral structures (pericardium). However, movement of the scope, at this location, is difficult and is painful for the animal.

preferably 57cm-long, 10mm diameter rigid scope with a 30° viewing angle. A shorter scope or a scope with 0° viewing angle limits evaluation

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2
Q

Maximim insufflation pressure with thoracoscopy

A

DO NOT exceed 3mmHg - will cause CV collapse

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3
Q

Sites for sinus trephination in cattle

A

A - frontal sinus

B - Maxillary sinus

C - post orbital diverticulum of frontal sinus (trephine site)

D - anterior turbinate region of frontal sinus (trephine site)

E - turbinate portion of frontal sinus

F - maxillary sinus trephine site

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4
Q

Most common cause of sinusitis in cattle

A

Following dehorning

Dental dz follows

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5
Q

Main cause & management of pharyngeal trauma in cattle

A

Cause - balling/drenching gun

Management - drain abscesses, ideally into the mouth/pharynx. If inaccessible orally need pharyngotomy (ventral midline - thyroid - basihyoid (+/- split) - dissect sternothyroid & hyoepiglotticus mm then sharp oral mucosa).

If cervical cellulitis - create multiple areas of drainage to help prevent mediastinitis.

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6
Q

What dz process may be a cause of pharyngeal swelling/collapse in younger calves?

A

Otitis media - when bilateral can cause signs referable to CN VII & CNVIII. Can also involve CN IX causing pharyngeal collapse, resp obstruction & necessitate temp trach

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7
Q

Recommended sx tx option for permanent DDSP in cattle

A

Not usually tx as rarely clinically sig

If causing dysphagia, can tx with reection of strap mm (sternothyroid & sternohyoid)

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8
Q

Briefly describe the steps for cleft palate repair via mandibular symphysiotomy

A
  1. GA dorsal intubate w trach
  2. Ventral midline incision from basihyoid to lower lips - lips should be spared (will sl ↓exposure)
  3. Split mandibular symphysis w blade or osteotome
  4. Dissect into oral cavity through a place 1.5cm away from one side of the mandible; geniohyoid muscle incised 1cm from its attachment on the mandible. Genioglossus muscle ( & soft tissue, incl mandibular salivary gland, & hypoglossal nerve), are bluntly separated with Metz. Then, oral mucosa incised. The tongue is retracted caudally with a large malleable retractor, and both mandibular rami are gently distracted to gain access to the soft and hard palates
  5. Soft palate first - incise margins to create 2 shelves of tissue. Nasal mucosa closed w simple continuous or a continuous Lembert pattern 2-0. Then muscular layer & oral mucosa closed w an interrupted or continuous horizontal mattress pattern. Finally, everted oral mucosa closed w a simple continuous pattern, w buried knots
  6. Hard palate - incise longitudinally adjacent to the maxillary bone, avoiding palatine artery, from soft palate to 1.5 cm caudal to maxillary pad. Then the hard palate is incised axially from the soft palate to the rostral edge of the defect using a No. 12 Bard-Parker blade. With a blunt periosteal elevator, the flap is detached carefully from the palatine bone, making sure not to lacerate the palatine artery. The flaps created are slid axially and sutured together with interrupted horizontal mattress sutures using 2-0 multifilament absorbable suture material.
  7. Finally, the abaxial portions of the flaps are sutured to the nasal mucosa using a simple continuous pattern with 2-0 multifilament absorbable suture material. The exposed bone will heal by second intention.
  8. Approach incision closed in 4 layers
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9
Q

Common cause of laryngeal dz in calves

What are the surgical tx options?

A

Oral necrobacillosis

Fusobacterium necrophorum and Truperella pyogenes are commonly implicated

Commonly rx in arytenoid chondritis in calves.

Sx tx options incl tracheolaryngostomy, permanent tracheostomy, and arytenoidectomy through a laryngotomy

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10
Q

Main difference in laryngotomy between horses & cattle

A

In horses, incise onlt cricothyroid membrance

Cattle incise membrane and thyroid cartilage

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11
Q

Sites for thoracotomy in cattle

A

Ideally need to have localised lesion so sx can be targeted

Lesions located in the cranial aspects of the thorax are very difficult to access as most cranial thoracotomy can only be done at the level of the fifth rib.

The caudal lung lobes can be reached through a partial rib resection or intercostal approach from ribs 7-9

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12
Q

Considerations for thoracotomy

A

STANDING always preferable - v high mortality rates w GA esp in lateral. GA may be necessary for lesions when extensive pleural debridement near the mediastinum is required, when likelihood of creating potentially fatal bilateral pneumothorax is ↑. DO IN STERNAL

Can be done via an intercostal space or rib resection technique

Cattle usually have imperforate mediastinum so should’t get bilateral pneumothorax

Mostly will be marsupialising abscesses - many walled off enough that if sutured to the skin before opening, drainage occurs outside without causing pleural contamination or significant pneumothorax. Wounds heal by second intention

For non-septic processes, need to try re-establish negative pressure after closure - Drain & Heimlich valve in the dorsal thorax is optional but ↑ comfort by ↓ PO pneumothorax

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13
Q

Briefly describe rib resection and intercostal approaches to thoracotomy in cattle.

A

Thoracotomy through an intercostal space allows limited manipulation but sufficient for simple drainage, lavage, limited debridement of the pleural space, and marsupialisation of an abscess adhered to the parietal pleura if PO access to the thorax is not required

Intercostal approach to thoracotomy - skin incision is centred over the lesion in a proximal to distal direction & the ICS should be incised at the cranial aspect of a rib (to avoid intercostal neurovascular structures immediately caudal to each rib)

Rib resection technique - incision started 20 cm dorsal (or more dorsally if larger lesion) to the CC junction centred over the longitudinal middle of the rib.

DO NOT incise ventral to the CC junction to prevent inadvertent transection of the cranial epigastric vessels.

Dissect through SQ, then the latissimus dorsi mm dorsally & intercostal muscles deep & ventral to latissimus dorsi muscle.

Sharply incise the periosteum, & elevate circumferentially

Transect rib proximally w Gigli wire subperiosteally around the rib, then rib is removed by dislocating at CC junc.

Can also use osteotome/mallet or oscillating bone saw or large rongeur

The axial rib periosteum + parietal pleura is incised to enter thorax

** care re pericardium if performing 5th/6th rib resections

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14
Q

Describe the surgical approach for adult cattle with reticular diaphragmatic hernia

A

Sx approach is 2-fold

  1. Standing left flank rumenotomy - hernia is confirmed through a left-flank laparotomy. A rumenotomy is performed to remove FBs from the reticulum but without dislodging it from the thoracic cavity. Routine closure of the rumen & abdomen, then feed restrict to keep the rumen small for the second surgery, which is planned in 2 to 3 days.
  2. GA cranioventral laparotomy - 30-cm crescent-shaped incision from xyphoid process. The herniated reticulum is carefully freed from adhesions & diaphragmatic hernia sutured

Acquired pneumothorax corrected by inflating the lungs as the last suture knot is tied

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15
Q

Approach to pericardial drainage with TRP/pericarditis

A

Lateral thoracotomy - standing or GA (GA in lateral recumbency w pericarditis is assoc w ↑ mortality, ∴ STERNAL recumbency if GA is absolutely essential (standing preferable))

A reticular FB may enter thorax from either left or right side, ∴ accurate dx essential; Pre-op US

Most common approach to pericardium→ enter thorax at left ribs 5 or 6 or ICS or ribs 6/7

Skin incision at least 20cm long

Pericardium is often adhered to the regional pleura if the disease is advanced. ∴ incising into the pleural cavity must be carefully performed although cattle have separate pleura from the pericardium when no adhesions are present

Find the FB before draining the pericardium, failure to remove will rx in tx failure

Idiopathic septic pericarditis is rare but possible - no rad FB - other than FB removal, management similar

For both - pericardium sutured to the skin at the incision edge w large (#2 or #3), monofilament, absorbable, or nonabsorbable sutures w interrupted or continuous pattern

Pericardium then incised & drained manually. Can be thick/caseous purulent exudates that must be manually removed from the pericardium in longer standing dz.

Lavage w warm isotonic fluid.

Reinflate lungs & use a drain to ↓ pneumothorax & PO pain/morbidity

The pericardial cavity may be left open to drain or be partially closed and managed with drains if this allows appropriate lavage and adequate drainage

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16
Q

List sx tx options for tx of laryngeal disorders in calves

A

1) Laryngotracheostomy
2) Partial (or subtotal) arytenoidectomy
3) Permanant tracheostomy (laryngotracheostomy preferable)

17
Q

Describe procedure for laryngotracheostomy in calves

A
  1. Main indication for this in calves is bilateral arytenoid chondritis 2ry to oral necrobacillosis (Fusobacterium necrophorum)
  2. GA dorsal, intubate by trach tube
  3. Oval or fusiform skin incision on ventral midline, centred over the cricoid cartilage & first 2 tracheal rings
  4. Paired sternohyoideus/sternothyroideus mm split on midline; (in heavily muscled calves, may have to be partially excised to ↓ tension on stoma)
  5. The cricoid cartilage & first 2 tracheal rings are incised on the midline
  6. Wedge of cricoid & 2 tracheal cartilages on each side of the midline incision are removed. Ideally mucosa under the cartilage is saved
  7. Cartilages are attached to the skin w horizontal mattress pattern w USP 0 polypropylene
  8. Then mucosa incised (if still intact) & attached to skin w SI USP 2-0 polypropylene
  9. Cranial and caudal parts of the skin incision are closed
18
Q

Describe procedure for arytenoidectomy in calves

A
  1. GA dorsal, intubate w tract
  2. Ventral midline incision centred on CT space. Dissect sternothyrohyoideus on midline
  3. Laryngotomy performed through CT membrane, thyroid usually also split on midline to improve access
  4. Arytenoids & vocal cords are evaluated. Abscesses are lanced, necrotic vocal cords are excised, and enlarged & deformed arytenoids are removed.
  5. Partial (preserves only the muscular process) or subtotal (preserves corniculte and muscular processes of arytenoid)
  6. Don’t recommend bilateral arytenoidectomy in cattle dt rumination
  7. Partial arytenoidectomy - corniculate process is 1st excised w long curved Mayo scissor (this step is not performed with the subtotal approach). Then ventral & caudal mucosa surrounding the cartilage is incised w. 15 blade. The body of the arytenoid is freed from the thyroid cartilage by lateral blunt dissection. The dorsal mucosa and the muscular process are cut with a curved Mayo scissor allowing excision of the body of the arytenoid. The muscular process is left in place. Redundant mucosa is excised, & defect is left to heal by second intention. (ie similar to horse but no effort at mucosal preservation or closure)
  8. The thyroid cartilage is reattached w SI USP 2-0 PDS. Important to avoid placing the suture through the laryngeal mucosa
  9. Laryngotomy heals by 2nd intention - but this is usually performed in combw w laryngotracheostomy
19
Q

Describe procedure for permanent tracheostomy

A
  1. Simialar as per horses
  2. Tracheolaryngostomy is preferred over permanent tracheostomy in cattle, but permanent trach can be successful. Ideally not performed when there is existing trach tube
  3. Fusiform skin incision ventral midline at junc. of prox & middle 1/3s of the neck
  4. Skin removed, paired sternohyoideus & sternothyroideus mm split. (In beef cattle, part of those muscles can be excised to ↓ tension on stoma)
  5. Select 3-4 tracheal rings & incise on midline & on either side of midline, to allow removal of approx 1/3 circumference of each ring - ideally not penetrating tracheal mucosa at any point
  6. Cartilages carefully detached from mucosa w sharp & blunt dissection.
  7. Suturing cartilage to skin as for laryngotracheostomy is not described for this…
  8. Remaining mucosa is incised in a double Y pattern
  9. Mucosa then sutured to skin w interrupted pattern of nonabsorbable monofilament suture
20
Q

Main cause of tracheal collapse in calves?

How is is treated surgically?

A

Occurs 2ary to rib fx healed w ++callus formation - usually present several wk after birth & cause inspiratory dyspnea, coughing, & poor growth

Tx= Implementation of an extra-tracheal prosthesis +/- unilateral resection of the ribs is the only technique described in cattle. The success rate is around 30%

Prosthesis isfabricated from a 35-60ml syringe barrel. Rings of different length (cut in their middles) or a spiral-shaped prosthesis is made. Holes are predrilled to allow attachment of the prosthesis to the tracheal rings. Edges are smoothed to avoid traumatising soft tissues.

GA dorsal - ventral midline incision from proximal tracheal rings to the manubrium. The paired strap mm are split to expose the trachea Trachea is mobilised on 360° by blunt dissection of the neurovascular bundles.

Thymus is retracted, & if necessary, incision is continued over the 1st rib to allow resection of the bony obstruction.

The prosthesis is positioned and sutured to the trachea w polypropylene suture. If prosthetic rings are used, multiple rings should be used to allow ingrowth of the trachea between the rings. The length of each ring should not be > length of 2-4 tracheal rings.

The sx site is closed in layers (muscle and skin independently).

Ideally, the prosthesis is removed or changed 3 to 4 months after the surgery to avoid obstruction caused by the growth of the trachea within the stiff prosthesis.

21
Q

Describe the surgical management of traumatic reticulopericarditis

A

CSs - congestive heart failure incl. distended jugular, brisket oedema, tachypnea, & tachycardia w muffled heart sounds

Dx w lateral thoracic rad &/or US

  1. Tx - Lateral thoracotomy for drainage & debridement of pericardium, FB removal
  2. STANDING preferable; ↑ mortality rate UGA esp lateral recumbency ∴ STERNAL recumbency if GA is absolutely essential
  3. Enter thorax at left ribs 5 or 6 or ICS or ribs 6/7
  4. Skin incision at least 20cm long
  5. Pericardium often adhered to the regional pleura w advanced dz. ∴ incising into the pleural cavity must be carefully performed although cattle have separate pleura from the pericardium when no adhesions are present
  6. Find the FB before draining the pericardium, failure to remove will rx in tx failure
  7. (Idiopathic septic pericarditis is rare but possible - no rad FB - other than FB removal, management similar)
  8. For both - pericardium sutured to the skin at the incision edge w large (#2 or #3), monofilament, absorbable, or nonabsorbable sutures w interrupted or continuous pattern
  9. Pericardium then incised & drained manually. Can be thick/caseous purulent exudates that must be manually removed from the pericardium in longer standing dz.
  10. Lavage w warm isotonic fluid.
  11. Reinflate lungs & use a drain to ↓ pneumothorax & PO pain/morbidity
  12. The pericardial cavity may be left open to drain or be partially closed and managed with drains if this allows appropriate lavage and adequate drainage
22
Q

Describe at alternative approach to access & drain the pericadium (alternative to lateral thoracotomy via ribs 5/6), suitable for calves <80kg

A

Sternal thoracotomy

  1. Skin/SQ incision over the sternum
  2. A sternal saw used to transect the sternal vertebrae starting on the left or right of the manubrium (manubrium sparing median sternotomy) extending rostrally to the first ICS.
  3. A Finochetto retractor is useful for access.
  4. The pericardium is incised with curved Metz, obv avoiding myocardium
  5. The edge of the pericardium is then sutured to the edge incision to prevent fluid accumulation in the pleural cavity.
  6. The sternum is then reapposed w 8 wires. Deep muscular layers & SQ closed w 0 monofilament SC suture, & skin closed routinely