105. Thoracic Cavity Flashcards
Reported outcomes of nonsx tx for chylothorax
Pleural evacuation–26%Rutin–67%(cats)Octreotide–40%Low fat diets
Octreotide to tx chylothorax
Octreotide = somatostatin analogue (also used to treat insulinoma)Decreases chyle flowVariable success 40%
Rutin for tx of chylothorax
Rutin= benzopyrene from Brazilian fava d’anta treeMx suspected to decrease lymphatic leakage, increase protein removal/increased proteolysis, increase macrophagic numbers and phagocytic function
TDL alone success for chylothorax
Dog 50-59%Cat 14.3-53%not much better than 50:50 when alone
TDL + subtotal pericardiectomy success for chylothorax
Dogs 60-100%Cats 80%
TDL+ CCA success rates for chylothorax
Dogs 83-87.5% (>80%)Cats not reported
TDL+ subtotal pericardiectomy + thoracic omentalization success rates for chylothorax
Dogs 72.7%Dogs and cats 57%not much benefit than TDL and pericardectomy combo
Thorascopic TDL w pericardiectomy success rates for chylothorax
Dogs 85.7%
Consider CCA with recurrence of chyle flow for treatment of recurrent chylothorax
Lymphatic hypertension leads to formation of secondary lymphatics following TDLRecurrent chylothorax may be seen–consider CCA Reported in dogs 83-87.5% success
Fossum et al in 2004 Success rates for subtotal pericardiectomy for chylothorax
TDL+ SP100% (10/10) dogs80% (8/10) cats
Thoracic omentalization for chylothorax treatment
Pass mall amount of omentum through the pars costalis of the diaphragm or through SQ tunnelShould help w absorption however some speculate that lymph from omentum will drain into TD anyways
Pleurodesis
Creation of adhesion between parietal and visceral pleuraMechanical (gauze)Chemical (tetracycline)autologous blood has also been reported
most complication of chylothorax surgery
Persistent effusion ( most common )– chylothorax or nonchylous40% occur even despite diagnostic imaging confirmation of occlusionDue to failure to locate branches at time of surgery, new branches forming, or previously non patent branches now open 1-50 days post op
TD Embolization for chylothorax treatment
Cyanoacrylate glue- inject from catheterization of mesenteric lymph vessel. Eliminates need for thoracotomy 1989 Pardo et al success8/8 healthy dogs 2/6 33% in natural dz dogs
DeSilva and Monnet in 2011 stated what about long term outcome of dogs tx w TDL, thoracic omentalization and subtotal pericardiectomy for chylothorax treatment
w TDL thoracic omentalization and subtotal pericardiectomy 73% (8/11) were free of clinical signs up to 5 years post opnot much benefit than TDL and pericardectomy combo
Dog vs cat anatomy of TD
begins sublumbar region (btwn diaphragmatic crura) as an extension of the cisterna chyli (retroperitoneal lymph channel sits on floor of 1-4 lumbar vertebra)Dog right in caudal thorax then crosses to left at 5th-6th thoracic vertebra Cat leftterminates in the left external jugular vein or jugulosubclavian anglePRIMARY CHANNEL FOR THE RETURN OF LYMPH FROM MOST OF THE BODY EXCEPT RIGHT thoracic limb, shoulder and cervical region
Location of cisterna chili and surgical approach
The cisterna chyli is a bipartate, dilated, retroperitoneal lymph channel that lies ventral to the first through fourth lumbar vertebrae along the cranial abdominal aortaMEDIAL to left kidney hilusapproach: ventral midline or LEFT paracostalcan use intestinal lymphangiography or methylene blue injection to visualize
normal pleural fluid
cell < 500protein < 1.5
exudate pleural fluid
cell >5000-7000protein > 3.0SG >1.025
transudate vs modified transudate pleural fluid
TRANSUDATEcell < 1500protein < 2.5SG < 1.015MODIFIED TRANSUDATEcell 1500-7000protein 2.5-5SG 1.015-1.025
origin of thymus
3rd pharyngeal pouchgrows until 45 days of age and then involutescranial to heartHassal bodies (seen on cytology)fx Cell mediated immunity (T cells–maturation and enhancement)
volume of air remaining in the lung at the end of normal exhalation
45 ml/kgfunctional residual capacity
minute ventilation
= tidal volume (volume taken in with each breath) x RRestimated tidal volume is usually 10-15 ml/kg
based on the summation of starling forces how is net absorption and fluid production achieved
fluid production: parietal pleura produces fluid into parietal spacefluid absorption: visceral pleural absorbs fluid via lymphatics/capillariesabsorption is encouraged by movement
4 mechanisms of fluid production within the thoracic cavity
- incr hydrostatic pressure (R-CHF)2. decr colloid oncotic pressure (hypoalbuminemia)3. incr vascular permeability (inflm conditions)4. decrease lymphatic drainage (vascular/lymphatic obstruction)
clinically useful classification (not laboratory classification) of thoracic pleural effusion
- pure transudate2. hemorrhagic/serosanguineous 3. inflammatory4. chylous5. neoplastic
chylous effusion characteristics
—white/pink white opaque–modified transudate with cell counts < 7000 but higher protein 2.5-4–SMALL LYMPHOCYTES PREDOMINATE , but can have mixed inflammation
4 methods to confirm effusion is chyle
–Sudan black test–ether clearance test–detect chylomicrons in fluid–effusion: high TG and low cholesterol
causes of chylothorax
anything that increases hydrostatic P in the cranial cavaor leakage of lymphatics1. trauma (penetrating/blunt)–may resolve on own 1 wk2. iatrogenic (surgery–ie. post op PDA)3. idiopathic****4. R CHF5. Heartworms6. obstructive disease–pericardial effusion7. neoplasia (heart base, mediastinal)8. lymphangectasia9. congenital malformations of thoracic duct10. diaphragmatic hernias11. jugular vein thrombosis
septic effusion with pyothorax microorganisms cultured
usually poly microbial (aerobes and anaerobes)also culture for actinomyces and nocardia ( gm positive acid fast filamentous rods—sulfur granules)
diagnostic tests for pleural effusion
- rads 3 view thoracic2. diagnostic/therapeutic thoracocentesis3. cytology, culture, cell counts, biochem analysis4. US +/- FNA, trucut5. CT +/- FNA, trucut6. echocardiogram is suspect cardiac disease7. CBC/Chem/UA8. arterial blood gas
radiographs as a sensitive indicator of pleural effusion
SNcan detect small volumes 100 ml in dogs 50 ml in cats
continuous suction pressure recommendations for evacuation of fluid/air from thoracic cavity
5-10 cm H20
what is the complication rate for maintaining a thoracostomy tube and list possible complications
22%–discharge at insertion site–accidental removal/premature removal–kinking/obstruction–tube/adapter leakage –>pneumothorax–sub cutaneous emphysema
descrube a three bottle suction system
- suction control 2. water seal chamber 3. collection reservoir (collects fluid from patient: quantify and visualize color, clarity characteristic)
goal of thoracostomy tube production prior to removal
< 2 ml/kg/daysome studies showed average of 3-5 ml/kg/d at tube removal with no significant difference in time to discharge from hospital so 2 ml/kg/day is a guidelinealso do cytology and cell counts +/- culture if indicated to note progress
recommended intercostal thoracotomy site for thoracic duct ligation in dog vs cat
dog RIGHT 8-11 ICcat LEFT 8-11 IC+/- addition of a paracostal abdominal approach for lymphangiography and/or CC ablation
common complications after thoracotomy
–wound complications up to 70%–thoracostomy tube complications 22%–death or euthanasia up to 20%–painpatients w chylothorax and pyothorax had longer duration of tube placement and more complications
most common cause of pneumothorax in small animals
leakage from thoracic wall penetration (dog bites, gunshots, stab wounds)other causes leakage from airway (blunt trauma, bullae/blebs, spontaneous) or esophagus (trauma, FB, neoplasia, fistula, diverticulum)
treatment for spontaneous pneumothorax
siberian huskies over representedbilateral and bled/bullae presentCT to look for underlying parenchymal disease and to look for location of lung lobectomy.+/- pleurodesis (autologous blood, mechanical)continuous vs intermittent suction post op
recurrence rate and mortality for surgical and medical therapies for spontaneous pneumothorax
WITH SURGERY recur 3% mortality 12%WITHOUT SURGERY recur/mortality 50%
breeds predisposed to chylothorax
Afghan hounds (also 133 x risk of lung lobe torsion)siamese cats
sequele of chronic chylothorax
fibrosing pleuritisdesquamated mesothelial cells increase production of type 3 collagen and promote fibrosismay restrict pulmonary expansion
list diagnostic (pre and intraoperative) methods to determine thoracic duct location and branches
preop: lymphangiography with CT, MRI, or rads following iohexol injection of a popliteal LNintraop: inject <0.2 ml and dilute methylene blue into popliteal or mesenteric LN, canalization of an intestinal lymphatic efferent with injection of methylene blue/iohexol (intestinal lymphangiography) OR feed patient heavy whipping cream 3-4 hours before surgery
list surgical options for treatment for chylothorax
- pericardectomy2. TD ligation3. CC ablation4. omentalization5. pleurodesis6. MI thorascopic TD ligation7. embolization of TD8. pleuro-peritoneal shunting9. VAP placement for palliative removal of fluidANY COMBINATION OF THE ABOVE
dose of iohexol for popliteal lymphangiography, how long will it take to appear in TD
iohexol 60 mg of iodine/kg (can dilute 1:1)contrast appears in TB in 2-13 minutesrads, CT, MRI
dose of methylene blue for intraop intestinal lymphangiography, how long will it take to appear in TD
0.2 ml methylene blue dilute with salineseen within 10 min and persists for 60 minscomplications: heinz body anemia and renal failure
methods of TD ligation
as far caudally in the chest as possible (area of the fewest branches)–hemoclips–individual ligation with non absorbable suture–enbloc (all tissue above aorta, ventral to sympathetic trunk, may or may not need to ligate azygous vein)
which branches of the TD are most commonly missed
left sided branches!bc approach is right sided in dogs may need to repeat postligation lymphangiography
other than recurrent chylous or nonchylous effusion what are other complications with surgery for chylothorax
–lung lobe torsion–pneumothorax–recurrent effusion
management for recurrent effusion
—percutaneous drainage system (indwelling SQ vascular access ports or JP drain)–pleuroperitoneal shunting (50% short term comp/75% long term comp)–Denver catheter
T/Fmedical therapy has been associated with success in more feline than canine patients
TRUEmedical management in canines was 5.4 times more likely to fail than surgical management
thoracic lavage with chest tube for pyothorax cases
10-20 ml/kg sterile crystalloidsencouraged to move30 minutes then aspirate
pyothorax DFI with surgery vs med mgmt
DFI with pyothoraxat 6 months 85% sx vs 30% without sxat 12 months 75% sx vs 25% without sx
most common neoplasia causing malignant effusion
–mesothelioma–carcinoma(less frequently thymoma and lymphoma)
T/FNeoplastic conditions associated with pleural effusion have a significantly shorter survival time than those associated with inflammatory effusions
TRUEneoplastic effusion–15 daysinflammatory effusion– >785 days
most common thymic mass in dogs vs cats
dogs–thymomacats–thymic lymphoma (usually FeLV +)US/CT to look for invasivenessgood prognosis if noninvasive and surgical excision achievedlymphoma suspect on cytology/biopsy (flow cytometry to ddx and thymoma has more epithelial cells) is a contraindication to surgery!
MST of surgically excised thymoma
dogs 800 dayscats 1800 days
paraneoplastic syndromes seen with thymoma
myasthenia gravis (50% dogs with thymoma +/- megaesophagus)hypercalcemia
name possible causes for spontaneous pneumothorax
–bullae–blebs–heartworm–eosinophilic bronchitis–chronic pneumonia–abscessation–asthma–neoplasia–emphysema–migrating plant material
