The Pleural Cavity Flashcards
1
Q
What pre-operative stabilization is recommended for pleural surgery?
A
- shock therapy
- arterial blood gas
- oxygen
- monitor/treat arryhthmias
- effusion/pneumothorax treatment
- thoracocentesis/thoracostomy tube
2
Q
Where are thoracostomy tube initially placed? How are they placed?
A
dorsal 1/3rd of 10th or 11th ICS
tunnel through SQ and enter the body wall at the 7th or 8th ICS, then secure with purse string and fingertrap
3
Q
What anesthetic considerations are used for the pleural cavity? What premeds should be avoided?
A
- lesions impair normal lung expansion
- ventilation/perfusion disturbances
- intermittent positive pressure ventilation and PEEP
- ETCO 35-45 mmHg, avoid high ventilation pressures >25 cm H2O
drugs that cause hypoventilation
4
Q
What is the purpose of positive end expiratory pressure (PEEP)? What effect does it have on the heart?
A
helps maintain open alveolis between breaths to improve oxygenation and limit alveolar cycling
decreases cardiac output
5
Q
What 2 anesthetic complications are associated with pulmonary contusions?
A
- may delay anesthesia and surgery for repair of other injuries (fractures)
- may have to anesthetize despite pulmonary contusions for emergency procedures
6
Q
What is reexpansion pulmonary edema?
A
rapid and forceful expansion of collapse lungs causes damage to pulmonary microvasculature and increased vascular permeability
- may not become apparent until several hours later
7
Q
What 2 things should be avoided to prevent reexpansion pulmonary edema? How is this done?
A
- hyperinflation during positive pressure ventilation
- rapid, full reexpansion of chronically atelectic lobes during surgery
gradual reinflation of lung lobes via chest tube
8
Q
What premedications and induction agents are recommended for pleural cavity surgery?
A
PREMEDS: opioids, ketamine, acepromazine, benzodiazepines, anticholinergics
INDUCTION: propofol, alfaxalone, ketamine + BZD
9
Q
How is anesthesia maintained during pleural cavity surgery? What medications are recommended post-operative?
A
inhalant anesthetics, local anesthetics (Bupivacaine instilled into intrapleural space or intercostally)
opioids, sedation, tranquilizers
10
Q
What 3 complications are seen following thoracotomies?
A
- hypoxemia - low PaO2 caused by decreased fraction of inspired oxygen, reduced ventilation, diffusion impairment, V/Q mismatch, and shunt
- hypoventilation - hurts to breath
- atelectasis
11
Q
What 2 antibiotics are recommended for pleural cavity surgery?
A
- Cefazolin IV
- Amoxicillin/Sulbactam IV
(at induction and every 90 mins to 2 hours)
12
Q
What is the normal anatomy of the lungs?
A
RIGHT = cranial, middle, caudal, accessory
LEFT = cranial, caudal
13
Q
What approach gives the most access to cardiovascular and pulmonary structures?
A
LEFT
14
Q
What is the most common approach to thoracotomies?
A
intercostal —> avoid cartilage where nerves are present
15
Q
What is the median sternotomy a good approach for?
A
gives good access to the pericardial sac and allows for visualization to both sides of the chest
16
Q
What is pneumothorax? What is the most dangerous type?
A
accumulation of air or gas in the pleural space
TENSION - rapidly fatal by impairing venous return and respiratory system
17
Q
How is a closed pneumothorax treated?
A
CONSERVATIVELY - cage rest +/- thoracocentesis (less likely to develop infection)
- thoracotomy only recommended if conservative treatment fails
18
Q
What are traumatic bullae (pulmonary pseudocyst)? Why are they so significant?
A
coalescence of ruptured air spaces within pulmonary parenchyma that become lined with fibrous CT within 3-5 days
can rupture, resulting in pneumothorax
19
Q
How are traumatic bulla (pulmonary pseudocyst) treated?
A
partial lobectomy
20
Q
What is a tension pneumothorax?
A
a flap lesion in the parenchyma of lung acts as a one-way valve, allowing air to enter the pleural space on inspiration, but prevents evacuation on expiration = intrapleural pressure rises rapidly and collapses the lung
21
Q
What is seen on physical examination in tension pneumothorax? What treatment is recommended?
A
severe dyspnea with marked respiratory effort and expanded chest
- place a 16 or 18g needle or thoracostomy tube(s) through the thoracic wall to reduce pressure and allo air evacuation and lung expansion
- oxygen supplementation
22
Q
What causes open pneumothorax?
A
penetration or rupture of chest wall from bite/stab wounds, gunshots, impalement, or inadequate thoracotomy closure
- more likely contamination or lung trauma
23
Q
What emergency management is recommended for open pneumothorax?
A
- cover wound with sterile non-occlusive dressing
- insert thoracostomy tube
- repair definitively or place sterile occlusive dressing over wound until closure
24
Q
What should be done if a penetrating object is present in the chest?
A
DON’T pull out, can lacerate or cause hemorrhage
- radiograph chest to determine intrathoracic location of the object
- perform a thoracotomy at the location to allow removal under direct visualization
25
What are the possible routes of infection that lead to pyothroax?
- hematogenous
- migrating FB
- penetration or bite wounds
- extension of pneumonia
- esophageal perforation
- neoplasia/abscess
26
What is used to determine medical management for pyothorax? What is the recommended treatment?
perform a Gram stain and culture/sensitivity of fluid and initiate broad-spectrum antibiotic therapy
- thoracostomy tube placement
- lavage thoracic cavity with 20 ml/kg of warmed, isotonic fluid with heparin
- alter antibiotic therapy based on culture and sensitivity and continue for 4-6 weeks and 2 weeks beyond clinical resolution
27
What are 5 indications for surgical treatment of pyothorax?
1. lung abscess
2. lung lobe torsion
3. FB
4. esophageal perforation
5. no response to medical management in 3-4 days
28
What causes chylothorax? What is a long-term consequence?
chylous fluid drains into the thoracic cavity secondary to impaired or disrupted lymphatic drainage ---> usually idiopathic
fibrosing pleuritis where surface of lung lobes get scar tissue and are unable to expand normally
29
What are 3 aspects of pleural effusion that are present in chylothorax?
1. triglycerides in fluid > serum
2. cholesterol in fluid < serum
3. cytologic evaluation = modified lymphocytic transudate
30
What is the treatment option preferred for idiopathic chylothorax?
surgical management
- thoracic duct ligation
- cysterna chyli ablation
- subtotal pericardectomy
- omentalization
- pleural port placement
31
What helps for diagnosis and surgical treatment of chylothorax?
lymphangiography or injection of methylene blue into mesenteric LN
32
What approaches are recommended for dog and cat thoracic duct ligation? What approach allows access to abdomen and thorax?
- DOG: R 10th ICS
- CAT: L 10th ICS
transdiaphragmatic
33
What 3 surgical techniques are recommended for proper thoracic duct ligation?
1. dorsal to aorta and central to sympathetic trunk
2. ligate/clip individual branches or perform an en bloc ligatino
3. ligate/clip as close to diaphragm as possible
34
When is a subtotal pericardectomy recommended for chylothorax? What approaches are used? What portions are excised?
restrictive pericarditis as a result
intercostal, median sternotomy, transdiaphragmatic
ventral to the phrenic nerve
35
What does cisterna chyli ablation lead to?
re-routing of abdominal lymphatic drainage to major abdominal vessels
36
What 2 post-op considerations are necessary following surgical treatment of chylothorax? What are 3 possible complications?
thoracic drainage (thoracostomy tube, pleural port) and analgesia
1. persistent chylous or non-chylous effusion
2. lung lobe torsion
3. pneumothorax
(dogs have a better prognosis compared to cats)
37
What is the most common cause of thoracic wall trauma? What do injuries most commonly involve?
hit by car ---> most do NOT require surgical intervention
- thoracic cage
- respiratory tract
- cardiovascular system
- pleural space
38
How are penetrating chest wounds treated?
- stabilize patient
- cover wound with sterile permeable dressing until patient is stable for surgical repair
- thoracocentesis as needed
39
What are the 5 most common results from blunt force trauma?
1. pneumothorax
2. pulmonary contusion (traumatic bullae)
3. trauma to thoracic cage
4. diaphragmatic hernia
5. myocardial contusion
40
What are the 4 most common results from penetrating trauma?
1. pulmonary laceration
2. open pneumothorax
3. hemothorax
4. diaphragmatic hernia
41
What is flail chest? What 3 things are most commonly present?
proximal and distal fractures of 3 or more consecutive ribs (associated with pulmonary contusions or edema)
1. pain with respiration
2. V/Q mismatch
3. hypoxemia and respiratory acidosis
42
How is flail chest treated?
CONSERVATIVE - ventilatory support and analgesics
- simple rib fractures may require splint stabilization to improve comfort
- comminuted or widely displaces rib fractures may require thoracotomy and internal fixation
43
What is the pathophysiology of flail chest? What cause this cause?
flail segment moves independently of chest wall - in with inspiration and out with expiration
respiratory insufficiency - lung trauma, hypoventilation due to pain
44
What is the most common hernia in dogs and cats?
diaphragmatic hernia ---> most commonly traumatic
45
What is the most common congenital diaphragmatic hernia?
peritoneopericardial
(+ pleuroperitoneal, hiatal)
46
What is a congenital pleuroperitoneal diaphragmatic hernia?
rare defect in dorsolateral diaphragm that may involve one or both crura and central tendon - large defects are rapidly fatal periparturient
47
What is a congenital peritoneopericardial diaphragmatic hernia?
abnormal development of the septum transversum or pleuroperitoneal folds, where GI contents are commonly found within the pericardium
- predominantly cardiac signs
- GI and respiratory signs possible
48
What is heard on auscultation in patients with peritoneopericardial diaphragmatic hernias? What else is seen on physical exam?
muffles heart sounds***
pectus excavatum - sternum and ribs grow inward
49
What imagining is preferred for diagnosis of peritoneopericardial diaphragmatic hernias?
- plain and contrast radiographs
- ultrasonography
50
What surgical management is recommended for peritoneopericardial diaphragmatic hernias?
carefully detach adhesions and move entrapped organs back into place before reconstructing the division between the pericardium and diaphragm (herniorrhaphy)
51
Where are congenital cranial abdominal wall and diaphragmatic hernias found? What pentology of defects is associated? What animals are most affected?
abdominal wall defect cranial to the umbilicus
1. cranial abdominal wall defect
2. caudal sternal fusion defect
3. pericardial defect
4. diaphragmatic defect
5. intracardiac defect (VSD)
Cocker Spaniels, Weimeraners, Dachshunds, Collies, kittens
52
In what animals are hiatal hernias most common?What clinical signs are associated?
Shar Peis and brachycephalics, like English Bulldogs
- gastric reflux
- esophagitis
- altered esophageal motility
53
What are the 3 types of hiatal hernias? What surgical treatments are recommended?
1. axial
2. paraesophageal
3. combines
- reconstruct esophageal hiatus
- esophagopexy
- gastropexy on LEFT side +/- right side
54
What is commonly confused with hiatal hernias? What clinical signs are associated?
gastroesophageal intussusception ---> more common in large breed dogs, like GSDs
acute onset:
- regurgitation, vomiting
- hematemesis
- dyspnea
- rapid deterioration with collapse and death
55
How are gastroesophageal intussusceptions treated?
- reduce intussusception and assess viability of stomach
- bilateral incisional gastropexy with caudal traction on the left side
- decrease size of esophageal hiatus
56
What are the most common causes of traumatic diaphragmatic hernias?
indirect injuries - motor vehicles, kicks, falls
(direct injuries = bite wounds, gunshot, sharp objects, kicked by horse)
57
What are traumatic diaphragmatic hernias associated with?
polytrauma and shock ---> thoracic cavity and organ commonly injured
58
What are the 3 most common diaphragmatic hernial contents?
1. liver
2. small intestine
3. stomach
59
What clinical signs are associated with acute diaphragmatic hernias? How is it diagnosed on physical exam?
- respiratory embarrassment (dyspnea, tachypnea)
- shock, trauma
- GI signs
AUSCULTATION - muffles heart and lung sounds, intense heart sounds on contralateral side, borborygmi, arrhythmias associated with traumatic myocarditis
60
What clinical signs are associated with chronic diaphragmatic hernias?
- respiratory embarrassment (dyspnea, tachypnea)
- GI signs
- exercise intolerance
- weight loss
- ascites/pleural effusion associated with malposition of liver lobe(s)
61
Why is the timing of surgery for diaphragmatic hernias important?
loss of integrity or function of diaphragm alone is seldom life-threatening ---> concurrent life-threatening injuries MUST be dealt with first
...however, unnecessary delay can increase risk of complications
62
Diaphragmatic hernia:
stomach in chest, heart pushed cranially
63
What is the general plan for treating diaphragmatic hernias?
- ventral midline celiotomy +/- sternotomy
- place thoracostomy tube
- reduce hernial contents and explore abdomen
- herniorrhaphy
64
What muscles of the diaphragm are most common involved in herniation? What are the 3 types of tears seen?
pars costalis and sternalis > central tendon, pars lumbalis, crura
1. circumferential - vertical
2. radial - horizontal
3. combination
65
How are circumferential diaphragmatic tears stabilized after closure?
suture avulsion around rib
66
How are the lungs maintained while treating diaphragmatic hernias? When is this avoided?
inflate lungs with PPV while typing last suture, but not too much
chronic cases with atelectasis
67
What are 3 ways of evacuating the chest following diaphragmatic hernia repair?
1. transdiaphragmatic thoracocentesis
2. transdiaphragmatic thoracostomy tube - perioperative usually, but can insert through body wall if needed postop
3. intercostal thoracostomy tube - chronic atelectasis, pleural effusion
68
What are 4 herniorrhaphy considerations with chronic hernias?
1. may need to enlarge hernia to reduce contents
2. adhesions/compromised tissues may require median sternotomy approach
3. chronic atelectasis/consolidation = avoid rapid reinflation of lungs with high pressure
4. excessive tension can cause inability to suture hernia
69
How are strangulated viscera in hernias approached? What organ most commonly is associated with this?
resected in situ without re-establishing circulation - repositioning can cause release of toxins and/or vasoactive substances
liver
70
What is loss of domain? Why is it significant?
a result of chronic hernias, where abdominal viscera reside outside the abdominal cavity which leads to contracture of abdominal musculature
potential to cause compartment syndrome during closure
71
What are some diaphragm augmentation devices?
- diaphragmatic advancement
- abdominal wall muscle flap
- synthetic meshes (Marlex polypropylene)
- omentum
seldom necessary even with chronic hernias
72
What are some acute and chronic poor prognostic factors associated with diaphragmatic hernia repair?
ACUTE - concurrent injuries
CHRONIC - reperfusion injury, reexpansion pulmonary edema, complications of adhesiolysis
73
What are peritoneopericardial diaphragmatic hernias? What 3 other congenital defects are associated?
defect in embryogenesis that causes congenital communications between pericardium and peritoneal cavity
1. polycystic kidneys (cats)
2. VSD
3. sternal deformities*
74
What is the most common signalment associated with peritoneopericardial diaphragmatic hernias?
middle-aged Weimeraners, Cocker Spaniels, DLHs, and Minalayans presenting with respiratory, GI, cardiac, or neurologic signs
75
What are the most common exam findings in patient with peritoneopericardial diaphragmatic hernias? How are they diagnosed?
- muffled heart sounds
- ascites
- heart murmur
- concurrent ventral abdominal wall defects
radiographs or ultrasounds - contrasts cosidered only if diagnosis cannot be made with plain films
76
What 7 radiographic findings can be seen in patients with peritoneopericardial diaphragmatic hernias?
1. enlarged cardiac silhouette
2. dorsal elevation of trachea
3. overlap of heart and diaphragmatic borders
4. discontinuity of diaphragm
5. gas-filled structures in pericardial sac (intestines!)
6. sternal defects
7. dorsal peritoneopericardial mesothelial remnant
77
When should peritoneopericardial diaphragmatic hernias be surgically repaired? What approach is most commonly done?
ASAP when the patient is stable - between 8-16 weeks when adhesions are less likely and the thoracic wall is more pliable
ventral abdominal midline
78
What are 3 important considerations for reparing peritoneopericardial diaphragmatic hernias?
1. antibiotics may be necessary due to hepatic compromise releasing toxins
2. may need to enlarge defect to permit relocation of abdominal organs
3. close defect in a simple continuous pattern - no need to close pericardium separately
79
When are chest wall reconstructions indicated?
following en bloc resection of 3 or more consecutive ribs mostly associated with neoplasia, trauma, and infection
80
What are 4 benefits to using polypropylene mesh following chest wall reconstruction?
1. resistant to infection
2. high tensile strength
3. acts as scaffolding for fibrous tissue formation
4. can be autoclaved
81
How are omental pedicle flaps used following chest wall reconstruction? What does it provide? What does it lack?
omental flap is brought through paracostal incision and tunneled subcutaneously to chest wall defect
vascular support
mechanical support
82
How are diaphragmatic advancement flaps placed following chest wall reconstruction?
diaphragm is sutured to the rib more cranial to the defect
83
How are muscle pedicle flaps placed following chest wall reconstruction? What does it provide?
flap is developed from abdominal muscle or latissiumus dorsi and rotated to the defect in the chest wall
vascular and some mechanical support
