The Pleura

  Parietal and Visceral pleura 
  Potential space 
  Histology 
  Arterial supply 

   Parietal 
   Visceral

  Lymphatic drainage 
  Innervation

  Obstruction or injury of thoracic duct
  Anatomy of the duct - main and right 
  Mechanics of lymph flow 
  Chyle 

   1500 - 2400 cc/day 
   Triglyceride 0.4-0.6 g/dl 
   AG ratio 3:1 
   WBC 2,000-20,000 cells/ml (90% T)

  Congenital, traumatic, non-traumatic 

10.  Diagnosis 

   R > L 
   Pleural effusion analysis 
   Pseudochyle

  Management 

Non-operative: Drainage, dietary management 
Non-traumatic 
Traumatic 

Surgery if  > 1,000 cc/day X 7 days or leak > 2 weeks 
Esophageal resection or pneumonectomy 
Lung trapped, nutritional complications 
Direct ligation of fistula, duct ligation

EXTENDED OUTLINE

Usual causes: 

 -contamination of pleural space 
 -imbalance in the dynamic equilibrium with fluid accumulation 
 -mesothelioma 

ANATOMY 

 -mesothelial cells 
 -parietal/visceral components

Blood supply 

 -parietal—systemic>>intercostal, bronchial, and subclavian arteries 

  -venous drainage into the peribronchial veins

 -visceral—systemic and pulmonary circulations 

  -venous drainage into the pulmonary venous system

Lymphatic system—two systems 

 -visceral—pulmonary system (lower lobes) 
 -parietal—direct communications with the pleural space—stomata 

PHYSIOLOGY 

 -pleural pressure is essentially negative during the breathing cycle—at FRC, pressure is –2 to –5 cm H2O; full inspiration –25 to –35 cm H2O 
 -more negative at the apex than the base

Fluid—200cc to 1L absorbed Q24 hours 

 -Composition

MANAGEMENT OF PLEURAL DISEASES 
Spontaneous pneumothorax 

 -Peripheral lung bleb is the usual cause

-usually seen in tall thin individuals 

 -pathogenesis of lung blebs is unknown 

  ? rapid lung growth relative to the pulmonary vasculature 
  ?higher transpulmonary pressure at apex—increased alveolar pressure

 -acute pleuritic chest pain common symptom 
 -physical exertion is unrelated to occurrence

Management 

 -observation if small –air resorbed at 50-75ml/day 
 -supplemental oxygen 
 -tube thorocostomy for 

moderate sized or tension PTX 
disease in the contralateral lung 
persisting symptoms 
progression of size 
Hemothorax quite uncommon—torn adhesion usual cause 
Indications for surgery for first episode PTX: 

Risk factors for recurrence: 
-about 20% recur 

 -75% recur on the same side within 2 years of the first episode 
 -when a surgical procedure is required, two principals are important: 

removal of the offending blebs 
production of pleural symphysis 

 -axillary thoracotomy (3rd interspace) or VAT 
 -pleurodesis achieved via talc or doxycycline—do not use talc in young patients or those with CF because the adhesions formed preclude lung transplantation

Secondary spontaneous pneumothorax 

 -seen mostly in older people with documented lung disease 
 -predominant symptom is severe SOB—not chest pain 
 -initial tx—tube thorocostomy 
 -prolonged air leak common 
 -recurrence rate—50% after one episode; therefore people with a reasonable operative risk should have definitive treatment

Empyema 

 -purulent pleural effusion with (+) bacteriologic cultures

Post traumatic empyemas 

 -penetration of the chest wall—foreign material carried into the pleural space 
 -presence of a hemothorax—becomes secondarily infected from a chest tube

Stage I-parapneumonic effusion 
Stage II-fibrinopurulent phase; (+) bacterial invasion 
Stage III-chronic phase; ingrowth of fibroblasts and capillaries; thick peel 

 Complications most likely, e.g., empyema necessitatis-dissection of pus through the soft tissues of the chest wall and eroding through the skin 

Diagnosis—fever, tenderness 

 -posterior and lateral—extend to the diaphragm 
 -CXR: inverted D-shaped density on the lateral chest film 
 -most common organisms: S. aureus, G(-) bacteria, and anaerobes; almost 50% are polymicrobial 
 -effusions with pH <7, glucose <50, LDH >1000, should be drained 

Management 

 Complete drainage of the collection 
 Obliteration of the empyema space 
 Investigation and treatment of the underlying infection 
 Management of associated conditions

Decortication-goal is full lung expansion—via extensive debridement 

 -early aggressive approach—as soon as tube thorocostomy is ineffective

Eloesser Flap—long term drainage of empyema 

 Removal of chest tube tract and carrying the incision down to the ribs 
 Two ribs and the intervening intercostal muscles are removed 
 Skin sutured to the pleura—dependant drainage insured

Clagett procedure—open window thorocostomy 
 excision of the sinus tract 
instillation of antibiotics in the pleural cavity, 
closure of the chest wall 
described for post-pneumonectomy empyema 
best results (25-60%) when no bronchopleural fistula present 
Streptokinase 
Persistence of empyema usually is secondary to 
inadequate drainage 
chronic pulmonary disease (TB, Fungus, Neoplasm) 
immune suppression 
foreign body 
In summation for chronic empyema: 

 -Tube thorocostomy 
 -thorocoscopy/open decortication 
 -Eloesser flap 
 -Thoracoplasty/Muscle transposition 

Malignant pleural effusions 

 -due to a disturbance in the equilibrium of production and absorption of fluid 
 -lymphatic obstruction esp. with paraneoplastic effusions

Management—palliation/relief of symptoms (usually dyspnea) is the goal—removal of effusion 

 -options—pleurectomy; mechanical pleurodesis; talc poudrage; pleuroperitoneal shunt; tube thorocostomy and sclerosis 

Mesothelioma 
Benign localized 
unassociated with asbestos exposure 
asymptomatic--detected on routine CXR 
paraneoplastic syndromes common 

  well-encapsulated visceral pleural masses 

Malignant localized 
20% 
symptomatic 
wide enbloc excision 
adjuvant therapy of little value 

 Malignant diffuse

asbestos exposure with latency period of 20 years 
intensity of exposure more important than duration. 
usual patient is middle aged male with pleuritic chest pain/SOB 
CXR shows pleural calcifications 

  three main types—epithelial (confused with adenocarcinoma), mesenchymal, and mixed 
  median survival 6 to 14 months--most die of local complications 
  subtotal pleurectomy—1 year survival—60% 
  radical extrapleural pneumonectomy 

adjuvant chemotherapy 

Chylothorax—results from thoracic duct obstruction 
Anatomy of thoracic duct--50% of the population 
originates form the cisterna chyli—T12-L2 

 Right posterior mediastinum between azygous, esophagus, and aorta 
 Tracheal bifurcation, crosses to left chest

Neck-anterior to scalene muscle and enters venous system at jugular/subclavian junction 
Physiology—upward flow secondary to pressure gradient, fat intake, contraction of the duct, and the presence of  valves 

 -1.5-2.5 L/day 
 -odorless with high triglyceride count, total protein, WBC (T-Cell)

Etiology 

Diagnosis—chylomicrons 

 Pseudochyle

Management--Non-operative (tube thorocostomy/thoracentesis) for non traumatic 

 Diet—medium chain triglycerides—reduce lymph flow 
 -Traumatic—operate if >1L/day for 7 days or leak > 2 weeks 
            children >100ml/day per year of age for 2-3 weeks 
 Operate if lung entrapped or nutritional complications

Technique-direct ligation of the fistula [heavy cream] 

 Subdiaphragmatic duct ligation—right thoracotomy; mass ligature of the tissue between the azygous and aorta 

THORACOPLASTY 

Thoracoplasty for TB-historic approaches attempted to copy nature’s intentions, i.e., resection of the chest wall to collapse the underlying diseased lung. 
Most successful was 3 stage approach by Alexander 
75% sputum conversion 
 multiple pulmonary complications 
“frozen shoulder” 
cosmetically unacceptable results 

Schede 

Plombage-introduced in the 1950’s 

 Various materials placed extrapleurally between the lung and ribs or extraperiostally

did not interfere with cough or chest wall movement 
complicated by infection 
60% conversion rate. 

Osteoplastic thoracoplasty 
posterior ends of the upper ribs are resected in increasing lengths back to the tip of the transverse processes which are left intact 
ribs are reflected down 
posterior ends are wired to the uppermost intact rib 
chest wall stability. 

Muscle transposition into chronic empyema cavity 
 Can also be done as a free flap