Pulmonary Flashcards
(120 cards)
Basic COPD pathology
Something is obstructing airflow. This obstruction is caused by either chronic bronchitis or emphysema.
Overall, this obstruction is progressive, but may be partially reversible. May be associated with hyper-reactivity
Basic gas problems with COPD
High CO2 levels and difficulty maintaining sats
The ventilatory center is in the _____ and works by monitoring _____
Brainstem
CO2
In COPD, airway obstruction is worse on (expiration/inspiration)
Expiration
I:E consideration for COPD
Increase expiration time. Remember that expiration time is passive (there is a limit to how fast you can expire).
Common s/s for someone with COPD
Dyspnea and wheezing
What is dyspnea?
The subjective sensation of not being able to get enough air. Often described as breathlessness, air hunger, SOB, labored breathing, and preoccupation with breathing.
Lung volume changes with COPD
Increased TLC, VC, FRC, and RV. Decreased TV and IC.
Basically, FRC is falsely increased because the lung tissue has lost it’s elasticity (less elastic recoil).
For someone with COPD, CO2 levels are usually worse at (day/night) because _____
Night. Because they are unconscious and unaware that they need to compensate by increasing their RR, etc.
Common obstructive disorders
Asthma, emphysema, chronic bronchitis
Patho of air trapping
People with COPD have mucus plugs on the bronchial walls. During inspiration, the airways are pulled open, allowing gas to flow past the obstruction. During expiration,decreased elastic recoil of the walls causes them to collapse onto the mucus and cause air trapping.
The trapped air in air trapping is useless volume because ventilation is not occurring. Air gets in, but is not coming out.
What is asthma?
A chronic inflammatory disorder of the airways associated with airway obstruction and bronchial hyperresponsiveness.
This airway obstruction is widespread but often reversible either spontaneously or with treatment.
Inflammation associated with asthma causes
1) Recurrent episodes of wheezing
2) Breathlessness
3) Chest tightness and cough (particularly at night and early in the morning)
4) Hyperresponsiveness to stimuli
What is atopy?
A genetic predisposition to developing an IgE-mediated hypersensitivity response to common allergens.
This is the strongest predisposing factor to the development of asthma.
What do we give asthmatics before surgery?
2 puffs of their inhaler and an anticholinergic
Patho of the asthmatic response to an allergen
1) The allergen binds to pre-formed IgE on a mast cell in the airway
2) The mast cell degranulate, releasing mediators such as histamine, leukotrienes, prostaglandins, etc. The effect is the opening of intercellular tight junctions
3) With cell junctions open, the antigen penetrates the junctions and activates submucosal mast cells.
4) Submucosal mast cells degranulate, causing bronchospasm, edema, and mucus secretion. The inflammatory response is initiated by chemotactic factors from mast cells.
5) In the late asthmatic response, epithelial cells are damaged due to products of eosinophils (which arrived as part of the inflammatory response)
Why is there V:Q mismatch in asthma?
Ait trapping and alveolar hyperinflation create areas of the lung that are being perfused but not ventilated
Risk factors for COPD
Cigarette smoking***** Passive smoking Air pollution Hyperresponsive airways Occupational factors Alpha1- antitrypsin gene mutation (results in early COPD development even in non-smokers)-rare-<1% of cases
Definition of chronic bronchitis
Hypersecretion of mucus and chronic productive cough that last for 3 months out of the year for at least 2 years.
Those with chronic bronchitis have mucus that is thicker than normal. Inspired irritants increase mucus production and increase the size and number of mucus glands.
This thick mucus makes it easier for bacteria to adhere as well. Repeated infections are common.
What are the acini?
Gas-exchanging airways
What is emphysema?
Destruction of the alveolar walls causes enlargement of the gas-exchange airways (mostly the alveoli) and decreased elastic recoil. There is no obvious fibrosis in this disease process.
Two types of emphysema
Centiacinar- damage and overinflation occurs in the respiratory bronchioles (middle of the acina)
Panacinar- Damage to the entire acina, but more focused on the alveoli (starts in the alveoli and will eventually progress to the bronchioles)
Patho of emphysema due to smoking
1) Toxins in smoke lead to endothelial damage, causing inflammation and infiltration of cells (neutrophils, macrophages, etc).
2) ROS and inflammatory cytokines inhibit antiproteases (alpha1-AT).
3) Imbalance between proteases and antiproteases causes breakdown of elastin in the alveolar septa. 4) Destruction septa and elastin reduces elastic recoil, which reduces the volume of air expelled during exhalation.
Function of alpha1 antitryspin
Inhibits a wide variety of proteases