ARDS

diffuse inflammation with severe hypoxia.
crackles 
patchy bilateral airspace disease
PaO2/FiO2 <300 example (60/1 = 60 or 60/.8 = 75)

dx requires r/o CHF
BNP >100 r/o 95% of cases
echo (?r/o dCHF). low PWCP more definitive.
bronch should be done to r/o DAH, aspiration, eosinophils

consider bx COP/BOOB, fungus, ILD, vasculitis, cancer
path is diffuse alveolar damage (DAD) and may suggest worse prognosis

in some pt,  10-14 days later fibroliferative phase with reticular infiltrates
decreasing compliance, increasing dead space, and hypercapnia
pHTN
continued healing for up to 6 months

overall mortality is decreasing for unclear reasons
lung protection. 6-8ml. plateau < 30. (pk prob less than 35)
intensivists decrease death
keeping patient “dry” may help
steroids prior to ARDS, transfusions worse prognosis

post ARDS morbidity is great
40% neurocongnitive deficits
depression, PTSD probably common
66% have some impaired physical function
many patients will regain lung function especially those that dodge the scarring phase
77% return to work
lack of steroids and ICU complications are related to better functional recovery

- protective ventilation (26% reduction in deaths)
http://summaries.cochrane.org/CD003844/ANAESTH_a-gentler-form-of-mechanical-breathing-for-people-affected-by-severe-lung-failure

 - inhaled prostacycline (negative)
http://summaries.cochrane.org/CD007733/ANAESTH_aerosolized-prostacyclin-for-acute-lung-injury-ali-and-acute-respiratory-distress-syndrome-ards

- iNO (negative plus may increase kidney failure)
http://summaries.cochrane.org/CD002787/ANAESTH_use-of-inhaled-nitric-oxide-in-acute-respiratory-failure-patients-with-low-blood-oxygen-does-not-improve-survival

- high vs low PEEP (trend toward benefits but improved oxygenation)
http://summaries.cochrane.org/CD009098/ANAESTH_high-versus-low-levels-of-positive-end-expiratory-pressure-in-patients-with-acute-lung-injury-and-acute-respiratory-distress-syndrome

- Pressure vs Volume (no difference)
http://summaries.cochrane.org/CD008807/ANAESTH_different-methods-of-ventilation-controlling-pressure-vs-volume-for-people-with-acute-respiratory-failure-due-to-lung-injury

- initial HFO - (may reduce death when kid studies included)
http://summaries.cochrane.org/CD004085/ANAESTH_high-frequency-oscillation-for-the-treatment-of-acute-respiratory-distress-syndrome

- recruitment maneuvers (briefly improved oxygenation but no overall benefit)
http://summaries.cochrane.org/CD006667/ANAESTH_recruitment-manoeuvres-compared-to-standard-care-for-treatment-of-acute-lung-injury-or-acute-respiratory-distress-syndrome. 

- partial liquid ventilation (no help, may harm)
http://summaries.cochrane.org/CD003707/ANAESTH_no-evidence-of-benefit-of-partial-liquid-ventilation-in-adults-with-acute-lung-injury-and-some-evidence-of-increased-risk-associated-with-its-use

potentials
 - surfactant
 - antioxidants
 - GM-CSF
 - steroids prior to day 14
-  macrolides
-  stem cells

negatives
 - NAC
 - procysteine, glutamine, antioxidant combos, lisophylline, IV prostaglandin, neutrophil elastase inhibitors, ibuprofen, ketoconazone, statins