week 9-2 Flashcards
ventilation- perfusion ratio
the amount of air getting to the alveoli relative to amount of blood getting there
respiratory system will always match
ventilation and perfusion
obstructive lung disease
- ventilation is obstructed(usually due to increased resistance to airflow)
- asthma
restrictive lung disease
-reduced lung compliance- increase- stiffness- limited expansion
-pulmonary fibrosis
vascular disorder that impairs gas exchange
- pulmonary edema
- pulmonary embolism
increased resistance to airflow due to ???
reduced airways radius
obstructive lung disease volume levels statis
-increase in residual volume and increase in expiratory reserve volume
decrease in inspiratory reserve volume
restrictive lung volume levels
decrease expiratory and inspiratory reserve volume
Dynamic force vital capacity (FVC) Obstructive
- blowing out is harder
- takes a lot longer to get the air out
-FEV1 is lower (<0.7)
Dynamic force vital capacity (FVC) restrictive
-can’t get as much air exchange in the lung
-FEV1 is higher (0.75-0.9)
-shorter breaths
FEVi/FVC = (normal)
0.8
Flow-Volume Loops in Obstructive
All flow rates diminished, Volumes:
increased RV; Decreased VC, IRV, ERV
Flow-Volume Loops in restrictive
Flow rates normal, Lung volumes:
Decreased RV, VC
Which of the two lead to an increased residual
volume due to ‘air trapping’?
obstructive
Which of the two display a more normal flow rate
but an inability to fully inflate the lungs?
restrictive
asthma
- bronchial obstruction due to hypersensitive and/or hyperresponsive immune response
-reversible but chronic asthma can cause irreversible damage (COPD)
-Allergic (extrinsic) or Non-Allergic (intrinsic)
asthma universal response
- Inflammation & edema of
mucosa - Bronchoconstriction
- Increased secretion of thick
mucus within airways
asthma symptoms
- Coughing, wheezing,
shortness of breath - Rapid breathing
- Rapid heart rate
- Cough up thick mucus
Allergic (Extrinsic)
- more commonly manifests in childhood
- hypersensitivity reaction triggers an immune response
- triggered by inhaled allergens such as dust mite allergens
reduced alveolar elastic recoil (emphysema)
airways are tethered to surrounding alveoli. when alveoli inflate airways are forced to dilate also
(radial traction)
nonallergic (intrinsic)
- More commonly manifests in
adulthood - Hyperresponsive reaction to
certain stimuli - Triggered by factors such as
anxiety, stress, exercise, cold air,
dry air, hyperventilation, viruses,
smoke, other irritants.
the first stage of asthma
-sensitized mast cells within the respiratory mucosa regonize antigen
- release of chemical mediators
- inflammation bronchoconstriction,
edema, increased mucus secretions
- also stimulates vagus nerve- reflex bronchoconstriction
The second stage (within a few hours)
- Increased leukocyte infiltration
Increased release of chemical mediators
Prolonged inflammation, epithelial
damage bronchoconstriction, and
airway obstruction (partial or total)
Partial Obstruction
- some air passes through the obstruction
- less ability to move air out resulting in air trapping. attempting to forcefully expire can lead to collapse of the bronchial wall
- Residual Volume Increases Less fresh air
inspired, harder to cough out mucus - Air trapping & hyperinflation over time can
stretch out alveoli and cause loss of elasticity
Total Obstruction
Mucus plugs completely block airflow through
the narrowed airway
* Air distal to the block diffuses out but is not
replaced Non-aeration and atelectasis of the
whole section distal to the block
* Hypoxemia causes local vasoconstriction in
pulmonary blood vessels (pulmonary
hypertension) increased work load of right
side of the heart
Asthma Treatment
-Determine triggers and avoid them if possible
* Good ventilation is key
* Keep healthy to avoid illness
* Swimming is a great sport, walking
* Inhaler if needed or prophylactically
* E.g. Salbutamol a Beta-2 adrenergic agonist Bronchodilation
* Other meds: anti-inflammatories (corticosteroids), inhibitors of chemical
mediator release, long-acting bronchodilators
Asthma is considered an Obstructive Pulmonary
Disease. Which of the following functional
measures would you expect to see?
Lower FEV1 (forced expiratory volume in the first second of expiration)
the end goal of asthma
MINIMIZE THE NUMBER AND SEVERITY OF ACUTE ATTACKS
chronic obstructive pulmonary disease
-a group of chronic respiratory disorders that causes airways obstruction and progressive tissue degeneration
-irreversible and progressive damage to the lungs
-develops over time and usually in people over 40
-causes by smoking
emphysema
- the destruction of alveolar walls
due to smoking or genetics
- breakdown of alveolar walls
decrease SA for gas exchange
- loss of pulmonary capillaries alongside the alveolar wall breakdown
- altered ventilation perfusions ratio
- loss of elastic fibers– decreased elastance/ increased compliance
- decreased radial traction- collapse of small airways
- increases mucus production
- due to chronic inflammation and infection
leads to thickening and fibrosis of the bronchial walls
- progressive difficulty with expiration
- air trapping and increased residual volume
-overinflation of lungs
-ribs remain in inspiratory position and increased anterior-posterior diameter
Consequences of Advanced Emphysema
- chronic hypercapnia (high CO2 levels in the blood) Results in more Hypoxic drive
- frequent and more sever infection because secretion are more difficult to remove
-pulmonary hypertension and cor pulmonale in later stages
Emphysema symptoms
Subtle at first, but permanent damage is being done
- Dyspnea upon exertion at first then at also rest
- Hyperventilation with a prolonged expiratory phase
- Hyperinflation leading to barrel chest
-
Emphysema - Diagnosis
Diagnosis is based on chest x-rays and pulmonary function tests
- Increased residual volume and TLC, decreased vital capacity,
and inspiratory & expiratory reserve volume
- FEV1 and FVC reduced
emphysema Treatment
- Avoid irritants and infection
- Immunizations (flu and pneumonia)
- Pulmonary rehab and breathing techniques
- Bronchodilators, antibiotics, O2 therapy
Chronic Bronchitis
- Chronic irritation of the bronchi due to exposure to inhaled irritants
- Cigarette smoke
- Industrial or environmental pollution
- Exposure leads to inflammation and frequent infections
- Result is swollen airways with increased mucus production
Chronic Bronchitis – Treatment
- Reduce exposure to irritants, treat infections promptly
- Vaccination – flu, pneumonia
- Expectorants & chest therapy to help with expelling mucus
- Bronchodilators
- Low-flow forced O2
Chronic Bronchitis – Diagnosis
Diagnosis
* Symptoms
* Chest X rays
* Blood gases
chronic symptoms of bronchitis
- Chronic ‘productive’ cough
- Secretions are thick and purulent
- Most severe in the morning
- Dyspnea
- Hypoxia, hypercapnia
