ARDS Flashcards
What is the definition of ARDS?
A sudden, progressive form of acute respiratory failure where alveolar capillary membranes become damaged and permeable to intravascular fluid.
What happens with ARDS?
The alveoli fill with fluid (pulmonary congestion) and gas exchange cant occur.
What can ARDS develop from?
A variety of direct or indirect lung injuries, sepsis being the most common cause.
What is the end result of ARDS?
Lung tissue damage, due to inflammatory and immune responses.
What happens to the vessels during the injury phase of ARDS?
Neutrophils adhere to pulmonary microcirculation, and then platelets stick to them and cause pavementing so blood cannot flow. The vessels become damages and increases vessel permeability from the release of mediators.
What do the mediators cause in the injury phase of ARDS?
Increased capillary permeability, microemboli, and pulmonary artery vasoconstriction.
How is an intrapulmonary shunt formed in the injury phase of ARDS?
As the condition progresses, peribronchial and perivascular interstitial space becomes engorged and fluid crosses into the alveolar space, but blood cannot get to the alveoli so it cannot be oxygenated.
What happens overall during the injury phase of ARDS?
Alveolar cells type 1 and 2 are damaged, alveoli are filled with fluid and collapsing, there is a VQ mismatch, and surfactant dysfunction
What are manifestations of the injury phase of ARDS?
Increased work of breathing, increased RR, decreased tidal volume, respiratory alkalosis, decreased CO2, and decreased tissue perfusion
What is being influxed during the Reparative phase of ARDS?
Neutrophils, monocytes, and lymphocytes.
What is fibroblast proliferation and why is it bad?
It secretes collagen and helps heal wounds, but when it proliferates, it makes the lungs dense and fibrous and scar tissue forms in the alveolar membrane.
What are some manifestations in the reparative phase of ARDS?
Decreased lung compliance, worsening hypoxemia, shunting
In the reparative phase, what will happen if the condition worsens?
Widespread fibrosis and significant damage.
In the reparative phase, what will happen if the condition gets better?
Lesions resolve and the patient recovers.
What happens during the fibrotic/chronic late phase?
The lungs become completely remodeled by fibrous and collagenous tissues, there is a decreased lung compliance, pulmonary hypertension, and poor chance of survival.
