Pathophysiology Flashcards
First changes to lung
destruction of the alveoli
Breathing movements Air in
- Ribcage moves up and out
- Diaphragm contracts and moves down
- Lung expands, pressure decreases as air comes in
Compliance
- Ability of lunge tissue to expand with ventilation
Hypoxemia
- Low blood oxygen level
Hypercapnea
- High blood carbon dioxide level
Diffusion
- Ability of gas to cross alveolar capillary membrane
PFT’s
- Pulmonary Function Tests
- Measurement of volume and air flow in and out of the lung
- Deep Breath in, and exhale as fast as you can
Tidal Volume
- Amount of air in and out each breath under normal resting conditions
Inspiratory reserve volume (IRV)
- Air forcefully inhaled after a normal tidal breathing
Expiratory reserve volume (ERV)
- Air forcefully exhaled after a normal tidal breathing
Residual Volume (RV)
- Air left in the lung after a forceful exhalation
Total lung capacity
- Maximum amount of air contained in the lungs after a maximum inspiratory effort
- TV + IRV + ERV +RV
Vital capacity (VC)
- Maximum amount of air that can be expired after a maximum inspiratory effort
- TV + IRV + ERV (Should be 80% of TLC)
Inspiratory Capacity (IC)
- Maximum amount of air that can be inspired after a normal expiration
- TV + IRV
Functional Residual capacity (FRC)
- Volume of air remaining in the lungs after a normal tidal volume expiration
- ERV + RV
Causes of Hypoxia
- Hypoventilation
- Diffusion impairment
- Shunt
- Ventilation - Perfusion Inequality
- Altitude or reduction in PO2
- May present without symptoms of dyspnea
Causes of Hypoxia: Hypoventilation
- Increased blood CO2 level
- Decreased blood O2 level
Causes of Hypoxia: Diffusion Impairment
- Gas exchange at the alveolar-capillary border
- Blood and Gas reaching target areas but not able to cross barrier
- Impairment created by increased collagen / tissue at this barrier (Pulmonary fibrosis)
Causes of Hypoxia: Shunt
- Pulmonary blood flow is altered and bypasses aerated areas of the lungs
Causes of Hypoxia: Ventilation - Perfusion Inequality
- unequal ration between blood and air
Causes of Hypoxia: Altitude or Reduction in PO2
- PaO2 is reduced with a decrease in PO2
- Higher altitude destinations
- Airplane travel
Additional Causes of Hypoxia
- Decreased hematocrit
- Decreased Hgb
- SpO2 reading remains normal
Normal hematocrit level
Women: 38 - 46%
Men: 42 - 54%
Normal Hgb level
Women: 12-16 gm/dL
Men: 14 - 18 gm/dL
What causes Dyspnea
- Hypoxia
- Chronic and acute illness
- Anxiety (Hyperventilation)
- Exercise / exertion
- Deconditioning
Difference between Obstructive and Restrictive
- Total lung capacity increased for Obstructive Pulmonary Disease
Chronic Obstructive Pulmonary Disease (COPD)
- Airflow limitation on expiration
- not fully reversible
- Chronic respiratory symptoms, structural pulmonary abnormalities, lung function impairment
- 3rd Leading Cause of Death Worldwide
- COPD related to smoking is associated with more severe emphysema
COPD exacerbation
- an increase in dyspnea, cough, or sputum purulence with or without symptoms of upper respiratory infection
Asthma: Inflammation to Bronchoconstriction
- Irritation (Trigger)
- T cell release
- Mast cell release
- Antibodies
- Inflammation
- Airway constriction
Emphysema
- Abnormally expanded air spaces
- Destruction of the walls of the involved air spaces
- Impaired expiratory airflow
Emphysema: Pathophysiology
- Inflammatory cells reduce the effect of Alpha 1 antitrypsin and increase the effect of proteolytic enzymes
- Proteolytic enzymes leads to erosion of the alveolar septa / lung parenchyma
- Decrease in Radial traction
- Hyperinflation
Centriacinar
- Emphysema
- Bronchioles destroyed with sparing of alveoli
Panacinar
- Both Bronchioles and alveoli are destroyed
Paraseptal
- Along periphery at septum
Alpha 1 Antitrypsin Deficiency Emphysema
- A Genetically linked type of Emphysema
- 5-13% of all emphysema is a1ATD
- Develops between 30 - 40 years of age
a1 AT normal & Deficiency
- Normal: 104 - 276 mg/dL
- Deficiency: less than 50 mg/dL
Emphysema: Patient Presentation
- Irreversible enlargement of terminal bronchioles
- Flattened diaphragm / Increased A-P diameter
- 1:4 Insp & Exp ratio
4 characteristics of Emphysema
- Hyperinflation
- Trapped Air
- Prolonged Expiratoration
- Decreased elastic Recoil
FVC
- Forced (Functional) vital capacity
- Maximum amount of air that can be expired forcefully
FEV1
- Forced expiratory volume / time
- Amount expired over given time interval - 1st second
Chronic Bronchitis
- Wet cough
- Excess mucous production
- 3 consecutive moths of a productive cough for two consecutive years
- Primary cause is tobacco smoke
Bronchiectasis
- Permanent abnormal dilation or widening of one or more large bronchi
- Large quantities purulent sputum and permanently dilated airways
- Bronchial wall thickened by and inflammatory infiltrate of lymphocytes and macrophages
- Purulent sputum
Clinical Findings of Bronchiectasis
- Respiratory failure / RH failure
- Hypoxia → Pulmonary HTN → Right Heart failure
- Osteoporosis and Muscle Atrophy
- Chronic infections
GOLD Classification
- using FEV1 to classify COPD Severity
mMRC
COPD Dyspnea Scale
CAT
- COPD Assessment Test
- Threshold score of 10 for severity
GOLD ABE Assessment Tool
Cystic Fibrosis
- Genetic
- Blocked chloride channels → higher levels of NaCl on the skin and lack of NaCl in the lungs
- Excessive production of thick and purulent mucus in the lung
- No sodium chloride → no water → thicker mucus
Cystic fibrosis: Presentation
- Thin
- Osteoporosis - Malabsorption
- Muscle weakness
- GERD - Reflux
- GI obstruction
- Recurrent pneumonia → airway destruction → bronchiectasis and pneumothoracis
- Chronic Hypoxia (digital clubbing)
COPOD Patients are at Increased Risk for
- Osteoporosis
Risk Factors in patients with COPD
- Tobacco use
- Sedentary lifestyle
- Family history of osteoporosis
- Advanced Age
- Poor nutrition
- Chronic use of drugs known to reduce bone mass
COPD Patients are at Increased Risk for Myopathy
- Decreased activity secondary to DOE
- Side effects of steroids
- Effects both Type I and Type II muscle fibers
