Pulmonary- Restrictive disease

Question 1

What are the differences between obstructive and restrictive diseases regarding the FEV₁ and FEV₁/FVC?

(chart)

Answer 1

Question 2

Restrictive lung disease is a reduction in:

No change in:

Answer 2

• Reduction in:
  
  • TLC
  • FRC
  • RV
  • VC (nml >70 ml/kg)
  • FEV1
  • FVC
  • Total volume exhaled
• No change in:
  
  • Expiratory flow rates
  • FEV1/FVC ratio

Question 3

What are the components of restrictive lung disease?

Answer 3

• Inspiration is limited due to reduced compliance or the lung or chest wall (“stiff lungs”)
• Reduction in lung compliance leads to increased work of breathing and dyspnea
• Rapid, shallow breathing pattern
  
  • increased dead space ventilation
• Normal gas exchange
  
  • advanced disease will have increased PaCO2 and decreased PaO2 with pulmonary HTN and cor pulmonale

Question 4

What are the different classifications of RLD?

Answer 4

• Acute Intrinsic- pulmonary edema
• Chronic intrinsic- diseased lung parenchyma
• Chronic extrinsic- chest wall, intra-abdominal and neuromuscular diseases
• Disorders of the pleura and mediastinum

Question 5

What is Pulmonary edema?

What will a CXR show?

Answer 5

• Fluid leakage from the intravascular space into the lung interstitium and alveoli
• Caused by
  
  • increased capillary/hydrostatic pressure (Cardiogenic)
  • increased capillary permeability (inflammatory process)
• CXR will show bilateral symmetrical opacities

Question 6

What is acute respiratory distress syndrome?

Answer 6

• Diffuse pulmonary endothelial injury
  
  • H2O, solutes, and macromolecules diffuse from intravascular space/capillaries into lung parenchyma and alveoli
• Sepsis often co-exists producing further inflammatory mediators and lung injury
• Often ARDS signals the beginning of multiple organ system failure

Question 7

What is aspiration pneumonitis?

What will patient demonstrate clinically?

Answer 7

• Acidic gastric secretions destroy surfactant producing cells and damage the pulmonary capillary endothelium
  
  • Causes increased permeability and pulmonary edema with atelectasis (similar to ARDS)
• Clinically:
  
  • hypoxia
  • tachypnea
  • bronchospasm
  • pulmonary vascular constriction (HPV) can develop into pulmonary HTN
  • CXR changes 6-12 hours later, usually in RLL

Question 8

How is aspiration pneumonitis treated?

Answer 8

• # 1 treatment is delivery of increased FiO2
• PEEP- may need to reintubate
• B2 agonist for bronchospasm
• +/- lavage with 5 ml NS
• fiberoptic bronchoscopy- if solid material aspiration is suspected
• ABX, steroids- some use them, some dont

Question 9

What is cardiogenic pulmonary edema?

symptoms?

Answer 9

• Left ventricular failure with increased pulmonary vascular hydrostatic pressures
• SNS activation more dramatic than with increased capillary permeability edema
• Symptoms
  
  • extreme dyspnea
  • tachypnea
  • hypertension
  • tachycardia
  • diaphoresis

Question 10

What is neurogenic pulmonary edema?

Answer 10

• Occurs minutes to hours following as acute brain injury (especially the medulla)
• Secondary to massive SNS discharge in response to CNS insult
• Generalized vasoconstriction with large shift of blood volume into pulmonary vessels
  
  • causes vessel injury and fluid leaks into lung parenchyma and alveoli
• *similar to cardiogenic

Question 11

What is treatment for Neurogenic (and cardiogenic) pulmonary edema?

Answer 11

• Supportive treatment
• control ICP elevations
• increased FiO2
• positive pressure ventilation, PEEP
• diuretics NOT indicated
• resolution of edema occurs within a few days

Question 12

What drugs cause drug-induced pulmonary edema?

How is it treated?

Answer 12

• Heroin- high permeability type
• Cocaine- pulmonary vasoconsriction or MI can result in edema
• Treatment is supportive

Question 13

What is High altitude pulmonary edema?

Treatment

Answer 13

• Thought to be caused by intense HPV after 48-96 hours at 2,500-5,000 m altitude with rapid ascent
• Increased pulmonary vascular pressures results in high permeability pulmonary edema
• treatment:
  
  • O2
  • prompt descent
  • NO

Question 14

What is re-expansion pulmonary edema?

Treatment?

Answer 14

• Enhanced capillary membrane permeability
• occasionally occurs following evacuation of pneumothorax or pleural effusion
  
  • more common if >1L fluid/air was in the pleural space for >24 hours and if re-expansion occurs rapidly
• Treatment:
  
  • supportive
  • NO diuretics

Question 15

What is negative pressure pulmonary edema?

Answer 15

• Occurs minutes to 3 hours after acute upper airway obstruction in a spontaneously breathing person
• Causes:
  
  • post-extubation laryngospasm
  • OSA
  • epiglottitis
  • tumors
  • obesity
  • hiccups
• Highly negative pressure against the closed upper airway
  
  • decreased interstitial hydrostatic pressure
  • increased venous return
  • increased afterload on left ventricle
  • increased SNS outflow
  • hypoxemia with further SNS activation

Question 16

What are the symptoms of Negative pressure pulmonary edema?

Treatment?

Answer 16

• tachypnea, cough, failure to maintain SaO2 > 95%
• usually self limited: 12-24 hours
• treatment:
  
  • supplemental O2
  • maintain airway
  • mechanical ventilation if necessary

Question 17

What are the key combonents of chronic intrinsic restrictive lung disease?

Answer 17

• Pulmonary HTN and cor pulmonale are likely as progressive fibrosis causes loss of pulmonary vasculature
• pneumothoracies are common with advanced disease
• dyspnea prominent with rapid shallow breathing

Question 18

What is the pathology of pumlonary hypertension?

(chart)

Answer 18

Question 19

What is Sarcoidosis?

Answer 19

• Systemic granulomatous disorder- found in thoracic lymph nodes and lungs
• Often leads to pulm HTN and cor pulmonale
  
  • decreased alveolar diffusion capacity
• Laryngeal sarcoid 1-5% of patients and can interfere with passing ETT
• Myocardial sarcoid is rare
  
  • HB, dysrhythmias, restrictive cardiomyopathy
• Liver, spleen, optic, and facial nerve palsy

Question 20

How is Sarcoidosis diagnosed?

What should you watch for?

Answer 20

• Patients often present for mediastinoscopy for diagnosis
• watch for hypocalcemia (mechanism unknown)
• Pt may need stress dose of steroid

Question 21

What are the key components of chronic Extrinsic restrictive lung disease?

What might thoracic deformity cause?

Answer 21

• Compressed lungs result in increased WOB
  
  • decreased lung volumes with corresponding increase in airway resistance
  • abnormal chest wall mechanics
• Impaired cough leading to chronic infection that can develop into an obstructive component
• Thoracic deformity could cause right ventricular dysfunction d/t chronic compression of pulmonary vasculature

Question 22

How is obesity a restrictive disease?

What class is it?

How is it exacerbated?

Answer 22

• Diaphragm and chest wall movement is restricted by excessive weight and abdominal panniculus.
  
  • Chronic extrinsic RLD
• Dyspnea, especially with exercise
  
  • resistance to breathing and increased work to move excess weight
• FRC decreased with V/Q mismatch
  
  • quick desaturation
• Exacerbated in supine position

Question 23

What are some costovertebral skeletal structure deformities that cause chronic extrinsic RLD?

Answer 23

• Kyphosis
• Scoliosis
  
  • 60 degree angle causes dyspnea with exercise
  • 100 degree angle will cause alveolar hypoventilationd, decreased PaO2, erythrocytosis, pulm HTN, cor pulmonale
  • 110 degree will cause VC <40% and resp failure
• * be careful with CNS depressants d/t increased risk of hypoventilation and PNA

Question 24

What are the deformities of the sternum that cause chronic extrinsic RLD?

Answer 24

• Pectus excavatum
• pectus carinatum- outward protuberance of sternum
• some ppl asymptomatic, some require sugery to reduce restriction

Question 25

What is flail chest?

Answer 25

• Caused by rib fractures or sternotomy dehiscence; paradoxical inward movement of a part of the rib cage during inspiration
• lung will decrease in volume during inhalation and increase in volume during exhalation
• decreased PaO2 and increased PaCO2 secondary to alveolar hypoventilation
• positive pressure ventilation required until thoracic cage can be stabilized

Question 26

How do neuromuscular disorders cause chronic extrinsic RLD?

Answer 26

• person is unable to generate the normal respiratory pressures
• impaired cough
  
  • retained secretions
  • PNA
• Very sensitive to CNS depressants
• Vital capacity useful to measure extent of disease on ventilation

Question 27

What are sme of the examples of neuromuscular diseases that cause RLD?

Answer 27

• Diaphragmatic paralysis
• spinal cord transection C4
• guillian barre syndrome
• myasthenia gravis
• myasthenic syndrome
• muscular dystrophy