Respiratory Flashcards
Describe the pathophysiology of asthma
Reversible increased resistance to airflow due to airway narrowing during attack. Patients have normal physiology between the attacks. Caused by bronchospasm or inflammation.
Airway narrowing in asthma is caused by?
- bronchospasm
- inflammation
What are the triggering factors for Asthma
- Airway irritants
- Exercise, cold air, dry air
- Resp infection; upper/lower
- ASA from overproduction of leukotriens
- Beta blockers
- GERD
Identify the clinical features of asthma
- SOB Cough,
- chest tightness
- Wheezing
- Dyspnea
- Worst at night
What are the physical exam findings of Asthma between attacks
- Normal physical examination
- Abnormal PFT
What are the physical exam findings of Asthma during attacks
- Tachypnea
- Inspiratory and expiratory wheezing
- Use of accessory muscles
- pulsus paradoxus
- Paradoxical movement of abdomen
Identify the diagnosis criteria for asthma
Decreased Peak flow expiratory rate
FVC, FEV1 and FEV1/FVC decreases
- Increased RV
- Normal diffusion capacity
- Improvement of flow rate with bronchodilators
- Bronchial hyperesponsiveness to histamine
- Eosinophilia
- CXR: hypeinflation; flatening of diaphragm; mucus plug; atelectasis
- ABG: Hypocapnia; Mild hypoxemia; Hypocarbia is common
What are CXR diagnostic findings for asthma
- Hypeinflation
- Flatening of diaphragm
- Mucus plug .
- Atelectasis
What are the ABG diagnostic findings for asthma
Hypocapnia
Mild hypoxemia
Hypocarbia is common
Tachypnea in presence of normal or high CO2 (40@40) = Respiratory Emergency, respiratory failure will occur. Intubation is indicated.
Describe the treatment of asthma
Anti-inflamatory drugs
Bronchodilators
Anti-leukotrienes- Zileuton(Zyflo)
Montelukast (Singulair) and Zafirlukast
Anti-IgE monoclonal therapy
Describe the use of Anti-inflamatory drugs for treatment of Asthma
- Inhaled Steroids
- Systemic Steroids
- Cromolyn to prevent mast cell degranulation
This drug is used only for prophylaxis and not acute asthma attacks. It can also be used to prevent exercise induced asthma
Cromolyn
Describe the use of bronchodilators for treatment of Asthma
- Beta 2 agonists
- Anticholinergics
- Aminophyline preparations
- theophyline: PDE inhibitor with narrow therapeutic index
This drug is a PDE inhibitor with a narrow therapeutic index, used as a bronchodilator
theophyline
Describe the use of Anti-leukotrienes- Zileuton(Zyflo) for treatment of Asthma
- 5-lipoxigenase inhibitor
- Blocks conversion of arachidonic acid to leukotriene
- Adverse effects; Dyspnea, arthralgia, chest pain, fever
This drug can cause Dyspnea, arthralgia, chest pain, and fever
Anti-leukotrienes- Zileuton(Zyflo)
Describe the use of Montelukast (Singulair) and Zafirlukast for treatment of Asthma
- Competitive antagonist of leukotriene on cysteinyl-leukotriene1 receptor.
- Prevent bronchospasm, vasoconstriction and eosinophil recruitment.
- Good for aspirin induced asthma
Blocks the conversion of arachidonic acid to leukotriene
Zileuton (zyflo): 5-lipoxygenase inhibitor
Competitive antagonist of leukotriene on cysteinyl-leukotriene1 receptor
Montelukast (singulair) and Zafirlukast
Describe the use of Anti-IgE monoclonal therapy for treatment of Asthma
Use Omalizumab which binds free IgE
This drug binds free IgE
Omalizumab
Describe the management of acute asthma attack
- Beta agonist + steroid + ipatropium
- Systemic steroids IV
- Aminophyline not effective in severe acute attack
Describe the management of chronic asthma
Inhaled steroids as maintenance + beta 2 agonist for symptomatic control
Add ipatropium
Consider aminophyline
Short course steroids
3 messenger systems for bronchial smooth muscle tone are?
Beta 2 stimulant via Gs Protein
Nitric oxide via cGMP
Cholinergic muscarinic via IP3
Destruction of alveolar walls and abnormal enlargement of air spaces distal to terminal bronchiole
Chronic pulmonary emphysema
Chronic pulmonary emphysema is defined as?
Destruction of alveolar walls and abnormal enlargement of air spaces distal to terminal bronchiole
Most common cause of Chronic pulmonary emphysema is?
Smoking
Features of Chronic pulmonary emphysema
Chronic infection
Chronic obstruction
Co2 retention due to decreased diffusion capacity
Hypoxia and hypercapnia due to V/Q mismatch
Cor pulmonale due to pulmonary hypertension
What is the pathogenesis of emphysema
Inflamatory cells are recruited to the lungs due to long term exposure to smoking.
They release proteinases in excess of inhibitors
If repair is abnormal, airspace destruction and enlargement results (Emphysema).
Features of COPD
Fourth leading cause of death in US
Emphysema
Chronic bronchitis
Both characterized by chronic airway obstruction, dyspnea, caugh, sputum production
MCC is smoking -> PMNs (polumorphonucleus cells) and macrophages -> increased free radicals
Other causes apha1 antitrypsin deficiency- antiprotease, second hand smoking, chronic asthma
This drug has no receptor, it crosses the cell membrane and its action results in bronchodilation
Nitric oxide via cGMP
Patient has a teardrop shaped heart on CXR. What is his most likely diagnosis
COPD
This is the 4th leading cause of death in USA
COPD
Airway inflammation lasting >2years
Chronic bronchitis
Pathophysiology of smoking in the lungs
increases PMNs (polumorphonucleus cells) and macrophages leading to increased free radicals
In COPD diagnosis FE, FEV1 and FEV1/FVC ratio is increased or decreased?
FEV1 and FEV1/FVC ratio is decreased
Prolonged FE>6 seconds
In COPD diagnosis CXR findings would show?
Hyperinflated lungs
Bullae
Flattening diaphragm
Decreased vascular markings
Decreased lung markings
In COPD diagnosis ABG findings would show?
Compensated respiratory acidosis
CO2 retention that worsens with supplemental oxygen
Residual volume and Total lung capacity in COPD
Residual volume and Total lung capacity are increased due to air trapping
Diagnostic signs and symptoms of COPD are?
Chronic dyspnea cough
Wheezing
sputum production
airflow obstruction of PFTs
Diminished breathing sounds, wheezing
JVD, peripheral edema and hepatomegaly due to Cor pulmonale
DLCO in COPD is increased/decreased?
decreased due to emphysema
Hematologic finding in COPD
Polycythemia
Treatment of COPD
Smoking cessation
ABX for H.influenzae, S.pneumoniae
Bronchodilators
Steroid- demonstrate effectiveness with PFT
Supplemental O2 with PO2<55 -improves survival
Complications of COPD
Acute exacerbation after infection
Polycythemia
Pulmonary HTN
Cor pulmonale
Anesthetic considerations for COPD
VA anesthetics are potent bronchodilators except for des
Protect against reflex bronchoconstriction during intubation/suction in COPD and Asthma
Propofol agent of choice
This drug can cause pulmonary fibrosis
Bleomycin
Pulmonary fibrosis pathophysiology
Is a restrictive disease with decreased lung compliance in which inspiration is impaired due to scarring of lungs with increased collagen
Decreased lung volumes
Increased or normal FEV1/FVC ratio because FEV1 is only slightly low whereas FVCis significantly low
This drug can cause Rales,cough, infiltration and fetal fibrosis
Bleomycin
Patient has significantly low FEV1 and FV1/FVC and slightly low FVC with High FRC. What is the possible diagnosis
COPD or Asthma (Obstructive condition)
Patient has a normal to slightly increased FV1/FVC ratio slightly low FEV1, significantly decrease FVC and low FRC. What is the possible diagnosis
Fibrosis (Restrictive condition)
Infection of the alveoli is
Pneumonia
Most common cause of pneumonia is?
Gram+ Diplococci in pairs
Features of pneumonia
Consolidation; alveoli filled with fluid and cellular debris
Impaired gas exchange
Low V/Q ratio
Hypoxia and hypercapnia
Pathophysiology of TB
- Mycobacterium tuberculosis (Acid fast) enters the respiratory tract in small aerosolized droplets
- Macrophages accumulate in the lung forming a tubercle that harbors M. Tuberculosis
- Bacteria spread throughout body when tubercle breaks apart
Signs and symptoms of clinical TB
Fever
Night sweats
Weight loss
Hemoptysis
Latent TB may reactivate within_____ months and be transmitted to others
3 months
Development of active tubercles throughout the body is referred to as
Miliary TB
Positive montoux test shows
Recent immunization
Previous tuberculin test
Past exposure to M. tuberculosis
Need further tests
Multidrug resistance M. tuberculosis is affecting with antibiotics that are used for TB
INH
pyrazinamide
Rifampin
Used in TB immunization
Attenuated M. Bovis
Explain why M. Tuberculosis are Apical lessions
They are obligate aerobes that preffer apex of the lung due to its high PO2 and V/Q.
Forms cavities- Caseating (cheesy) Granuloma
Collapse of alveoli is
Atelectasis
Features of Atelectasis
Collapse of alveoli
Fever in first 48 hrs post op (95%) Pathogenesis of fever is unknown
Minimum decrease in %Sat
Atelectasis Can be prevented by
Early mobilization
Breathing exercises
Incentive spirometry
Most common causes of Atelectasis are
- Airways obstruction due to mucous plug or tumor
- Lack of surfactant (RDS)
Normal pulmonary artery pressure is?
10-14 mmHg
Pulmonary hypertension is pressure
≥25 mmHg or ≥35 mmHg during exercise
Causes of Pulmonary hypertension are
Atherosclerosis
Medial hypertrophy
Intimal fibrosis of pulmonary arteries
Primary pulmonary hypertension is due to
an inactivating mutation in the BMPR2 gene (normally functions to inhibit vascular smooth muscle proliferation)
Secondary pulmonary hypertension is due to
Due to COPD (destruction of lung parenchyma)
Mitral stenosis (Increased resistance leading to high pressure)
Recurrent thromboemboli (reduced cross-sectional area of pulmonary vascular bed)
Autoimmune disease (e.g. systemic sclerosis ; inflammation leading to intimal fibrosis hence medial hypertrophy )
Left-to-right shunt (High shear stress leading to endothelial injury )
Sleep apnea or living at high altitude (hypoxic vasoconstriction)
What is the course of pulmonary hypertension
Severe respiratory distress -> cyanosis and RVH -> DEATH from decompensated cor pulmonale
Most PE (95%) originate from?
DVT from leg
Non-thrombotic pulmonary emboli are
Septic: endocarditis in IV drug abusers; infected catheters
Fat: after long bone fractures
Amniotic fluid: During childbirth
What are the pathological consequences
Increased PVR
Increased PAP
Increased Afterload
Risk factors for PE
- Immobilization (esp. post op)
- Pelvic/leg surgery or trauma
- Malignancy
- Obesity
- CHF ( predisposes to vascular stasis)
- OCPs ( Oral contraceptives)
- Hypercoagulability
- Endothelial damage
PE FAT BAT
FAT BAT: Fat, air, thrombus, bacteria, amniotic fluid and tumor
Clinical features of PE
Dyspnea
Pleuritic chest pain
SOB
Signs of RV overload (loud P2 , RV heave)
Look for signs of DVT
What are the signs of a DVT
- Leg pain
- Tenderness
- warmth
- redness
- swelling
- Homan’s sign: dorsiflexion of foot cause tender calf muscle
25% of patients with PE have no suggestive physical findings, making a difficult diagnosis. T/F?
False
50% have no suggestive physical findings, making a difficult diagnosis
CXR finding of PE are
Normal
Regional oligemia
Pleural infarct
Pleural effusion
Diagnosis of PE is based on
- H&P
- CXR
- ABG
- Elevated D- dimer
- V/Q Scan- replaced by CT
- CT arteriography
- Pulmonary angiography- rarely needed
- Lower extremities duplex US for DVT
ABG diagnostic findings of PE include
Respiratory alkalosis
Low PCO2 – pt. is hyperventilating
Hypoxemia
Increased O2 A-a gradient
What causes Elevated D-dimer in PE
Byproduct of intrinsic fibrinolysis
The most sensitive and specific test for PE is?
CT arteriography
PE treatment
- Heparin– follow PTT(1.5-2.5 X, normal = 30 sec)
- Warfarin, coumadin– follow PT (=12 sec)
- Inferior vena cava filter
- Thrombolytic therapy—streptokinase, tPA Risk of bleeding is very high. Use only with life-threatening PE
PEEP Indications
PO2 < 60 mmHg
Widespread alveolar collapse- Atelactasis
ARDS
Pulmonary edema
Dose of PEEP is
5-10 cmH2O
What are the benefits of PEEP
- Prevent collapse of alveoli
- Helps to maintain patency of alveoli
- Helps to recruit more alveoli
- Increases FRC by expanding previously collapsed alveoli
- Decreases intrapulmonary shunting
- Improves V/Q ratio => increased PO2
Complication of PEEP
- Decreased Cardiac Output due to interference with Venous return
- Barotrauma e.g. pneumothorax, air in mediastinum, and subcutaneous emphysema
- Fluid retention due to obstruction of lymph flow and capillary damage
- Redistribution of pulmonary blood flow leading to decrease V/Q resulting in decrease PO2
Positive pressure is maintained during both inspiration and expiration
CPAP
What is the risk associated with CPAP
Risks of gastric distension and regurgitation
CPAP level
< 14-15 cm H2O (lower than LES pressure)
What is the effect of air flow on airway pressure
- Increased flow causes decreased pressure
- If intrapleural pressure > air ways pressure, the air ways closes
- Intrapleural pressure increases in force expiration or Valsalva maneuver
At some point during a force expiration, airways begin to close. The volume that can subsequently be exhaled is
the closing volume.
Closing capacity=
Closing volume + Residual Volume
What factors increase closing volume
Age
COPD
Airways secretion
Anesthesia
Lateral Decubitus- Unanesthetized patient
V/Q distribution to dependent and nondependent lung are similar to those found in the upright position
Blood flow and ventilation to dependent lung are greater than nondependent lung
Thus the dependent lung is similar to the dependent areas of the upright lung (near the diaphragm) under normal conditions
Lateral Decubitus - Anesthetized and Paralyzed patient
Dependent lung is “compressed” by the weight of abdominal contents
The nondependent lung is well ventilated but poorly perfused (dead spacing)
Depending lung is poorly ventilated and well perfused (shunting) Greatest degree of V/Q mismatch occurs
Hypoxemia, hypoxia and ischemia leads to
Oxygen deprivation
Causes of Hypoxemia
High altitude (normal A-a gradient)
Hypoventilation (normal A-a gradient)
V/Q mismatch (high A-a gradient)
Diffusion limitation (high A-a gradient)
Right-to-left shunt (high A-a gradient)
What would be the causes of low PaO2 in a patient with normal A-a gradient
High altitude (normal A-a gradient)
Hypoventilation (normal A-a gradient)
What are the causes of hypoxia (low O2 delivery to tissue)
Low Cardiac output
Hypoxemia
Anemia
Cyanide poisoning
CO (Carbon monoxide) poisoning
What are the causes of Ischemia (loss of blood flow)
Impeded blood flow
Reduced venous drainage
Patient has Chronic necrotizing infection of bronchi resulting in dilatation and destruction of airways, purulent sputum, recurrent infections, hemoptysis. What is the diagnosis
Bronchiectasis
Bronchiectasis is associated with what causes?
Bronchial obstruction
Cystic fibrosis
Poor ciliary motility ( Kartagener’s Syndrome)
What are the symptoms of Bronchiectasis
Chronic purulent cough with large amount of sputum
Clubbing
Air fluid levels on chest X-ray
What is the Treatment of Bronchiectasis
Treat the infection
Bronchodilators
Supplemental O2
Postural drainage
Surgical resection of localized region of bronchiectasis
Non- cardiogenic pulmonary edema; due to damage to alveolar-capillary membrane leading to stiff lungs
ARDS
What are the features of ARDS
Severe hypoxemia PO2 < 60 , FIO2 ≥60,
large A-a gradient
Bilateral pulmonary infiltrates on CXR
Normal or low PA pressure
Mortality 50% !!
What are the causes of ARDS
Sepsis syndrome
Overwhelming pneumonia
DIC
Major trauma
Multiple transfusion
Pancreatitis
Drowning or near drowning
What is the treatment of ARDS
Treat underlying cause
Correct hypoxemia but intrapulmonary shunting limits effectiveness of supplemental Oxygen
PEEP
A collection of air in pleural space leading to lung collapse
Pneumothorax
What are the causes of Secondary pneumothorax
COPD
TB
Trauma
PCP
Thoracocentesis
Central line placement
PPV or bronchoscopy
pneumothorax caused by Rupture of subpleural belbs
Spontaneous (primary) pneumothorax
pneumothorax where a one way valve-like hole develops creating a Life threatening condition
Tension pneumothorax
Pneumothorax caused by COPD, TB ,trauma, PCP, thoracocentesis, central line placement , PPV or bronchoscopy
Secondary pneumothorax
What are the physical examination findings in a pneumothorax
Tachypnea,
Diminished/absent breath sound
Hyperresonance
Falling O2 sat
Hypotension
Distended neck vein
Tracheal deviation
What is the treatment of Pneumothorax
Chest tube, needle decompression
Identify A

COPD
Identify B

RLD= restrictive lung disease
What abnormality is represented

Extrathoracic obstruction
Inspiration is impaired
Identify the abnormality represented

tracheal obstruction
Both inspiration and expiration are impaired
Identify the abnormality represented

Intrathoracic obstruction
Expiration is impaired
What does the curve represent

Maximum expiratory flow
Be able to label

Closing volume
closing capacity
Residual volume
Airway closure begins
FRC
TLC