Chapter 29-ARDS Flashcards
What causes pulmonary edema
When the rate of leakage into the lungs exceeds the lungs capacity to remove fluid
How do the lungs clear fluid
Lymphatic drainage
Net exchange of fluid between intravascular space and lung interstitum is controlled by
Hydrostatic and osmotic pressure within the blood and interstitum
Capillary hydrostatic and interstitial osmotic forces are normally (more/less) than the capillary osmotic and interstitial hydrostatic forces opposing
More
This encourages a small fraction of cardiac output from the capillaries into the interstitial space
What is seen on a chest X-ray with pulmonary edema
Kerley b lines
Large increases in interstitial hydrostatic pressure are caused by
Small increases in lung fluid content
Hydrostatic pulmonary edema occurs when?
The pressure or volume of water exceeds the lungs ability to remove fluid and the alveoli flood
Non hydrostatic pulmonary edema occurs when?
There is a hole in the interstitum which fluid leaks through
What are common cardiac causes of hydrostatic pulmonary edema
Left ventricular failure
Valve disease
What are volume related causes of hydrostatic pulmonary edema
Excessive fluids
Renal or liver failure
Hypoalbuminemia
Hydrostatic pulmonary edema causes what type of pleural fluid
Transudate fluid
Non hydrostatic pulmonary edema causes what type of pleural fluid
Exudate
Ards is caused by
Non hydrostatic pulmonary edema
Congestive heart failure is caused by
Hydrostatic pulmonary edema
Symptoms that present in both ards and chf
Anxiety
Dyspnea
Tachypnea
Hypoxemia
Features favouring chf
Diffuse, bilateral infiltrates
Elevated pcwp
Response to diuretics
Transudate fluid
Features favouring ards
Asymmetric infiltrates on cxr
Little to no improvement with diuretics in first 24 hrs
Exudate fluid
Risk factors of ards
Pneumonia Aspiration Near drowning Sepsis Trauma Burns Pancreatis
Chf typically presents with
Caridomegaly
Perihilar infiltrates
Pleural effusions
Ards typically presents with
Air bronchgrams
Alveolar infiltrates
Normal cardiac size
When is the educative phase
Day 1-7
When is the fibroproliferative phase
3 days- weeks
What happens in the exudaitive phase
Damage to alveoli and blood vessels
Influx of fluid and cells into interstitial space and alveoli
Fully reversible if the cause is found and treated early
What causes barotrauma
High pressures rupturing alveoli
