ARDS Flashcards
What is ARDS?
It is a type of respiratory failure that occurs when the capillary membrane the surrounds the alveoli sac becomes damaged and starts to leak fluid into the alveolar sac.
This impairs gas exchange, leads to the collapse of the sac, and hypoxemia (low O2 in blood)
Is the onset of ARDS slow or fast?
Is the mortality rate high or low?
FAST. The patient is usually already hospitalized with another condition. It develops due to systemic inflammation.
Direct or indirect injuries can cause ARDS
HIGH mortality rate
Any event that leads to major systemic _________ in the body can cause ARDS.
inflammation. Usually this is from indirect sources (not in the lungs)
Indirect conditions that can cause ARDS
Sepsis (poor prognosis with gram negative bacteria) Burns Blood transfusion (multiple) Drug overdose Pancreatitis
Direct conditions that can cause ARDS (source is coming from the lungs, which has been directly damaged)
Pneumonia Aspiration Inhalation Injury Drowning- near Embolism
What are the 3 phases of ARDS ?
Exudative
Proliferative
Fibrotic
The _______ phase of ARDS happens 24 hours after injury. What happens in this phase ?
exudative
There is damage to the capillary membrane- it leaks protein rich fluid that enters the interstitium then the alveolar sac and leads to pulmonary edema and damaged surfactant cells (helps sac stays stable so it doesn’t collapse whenever person exhales)
decreased amount of surfactant equals
unstable alveolar sac that leads to Collapse - this is called
ATELECTASIS
With Atelectasis, the person is not going to be able to
move that oxygen in because that sac is collapsed so our oxygen level will fall (hypoxemia)
When atelectasis occurs, fresh air is unable to reach the tiny structures of lungs, called the alveoli, where oxygen and carbon dioxide are exchanged. This results in decreased levels of oxygen being delivered to the organs and tissues of the body (hypoxia).
What is a hyaline membrane?
Composed of dead cells and proteins, this membrane will affect how the lungs work- it makes them less elastic and more stiff, reduce lung compliance (stretch)
This leads to a VQ mismatch (ventilation ability does not match body’s ability to perfuse)
What is a hallmark sign of ARDS?
Refractory hypoxemia
the lung is stiff, sacs are collapsed, oxygen cannot flow down to that sac to go into that capillary and replenish the body. There is no way you can get the oxygen back up because of what is going on in ARDS
What happens in the proliferative phase of ARDS ?
Occurs about 14 days after injury
the body is trying to grow and reproduce cells quickly to repair structures. There is also reabsorption of fluid that was in that sac.
However, lung tissue becomes very dense and fibrous, which further leads to decreased lung compliance and worsening hypoxemia
What happens in the fibrotic phase bf ARDS?
Occurs about 3 weeks after injury. There is fibrosis of lung tissue and major lung damage. There is dead space in the lungs that doesn’t work and you don’t have gas exchange.
A R D S mnemonic
Atelectasis
Refractory hypoxemia
Decreased Lung Compliance (ability of lungs to stretch and fill with air) - lungs are getting stiff and hard
Surfactant + lung damage
S/S of ARDS
Early on it is barely noticeable. Normal to random crackles. But as fluid moves into sac, that is when problems start to arise
increased RR, low O2, Respiratory alkalosis
As it progresses, pulmonary edema gets worse and compliance gets worse. This leads to Full respiratory failure, refractory hypoxemia, cyanosis, mental status changes, increased HR, retractions, crackles throughout
Chest X-ray will have white out appearance, where patient will have bilateral infiltrates throughout the lungs
