ARDS Flashcards
4 criteria for ARDS
- acute onset w/i 7 days
- bilateral opacities
- respiratory failure NOT from cardiogenic or fluid overload source
- low oxygenation (PaO2/FiO2 ratio)
division of ARDS into mild, moderate, severe
depends on oxygenation ratio:
mild- 200-300
moderate- 100-200
severe- less than 100
2 broad categories of ARDS causes
direct lung injury and indirect injury (via blood stream, etc)
2 most common direct lung injury causes of ARDS
pneumonia, aspiration
also include fat emboli, inhalation injury, near drowning, pulm contusion
main cause of indirect ARDS lung injury
sepsis
trauma and other shock also possible
define sepsis
organ dysfn caused by dysregulated response to infection
qSOFA criteria for sepsis
hypotension (systolic below 100)
altered mentation
tachypnea
septic shock
subset of sepsis, w/ circulatory or metabolisms abnormalities that raise mortatlity
how to identify septic shock
hypotension that requires vasopressors to keep MAP above 65
lacatate above 2mmol/L despite volume therapy
7 pathophys factors that cause respiratory failure in ARDS
- inflammation
- ^vascular permeability=edema
- fluid overwhelms surfactant=atelectasis
- increased deadspace
- lower lung compliance
- higher work of breathing
3 phases of ARDS
exudative phase, fibroproliferative phase, organizing phase
ARDS resolution
type II pneumoncyte hyperplasia, resorption of edema fluid and protein, gradual resolution of fibrosis
ARDS managment
- Tx underlying process (early antibiotics for sepsis)
- support w/ ventilation
- dont kill w/ first two esp ventilation
what is ventilator induced lung injury
ventilator can cause overdistension of alveoli, making initial insult worse
causes endo/epithelial disruption, inflammation, more vascular permeability, edema
ways to prevent VILI
reduce tidal volumes
prone ventilation also reduces mortality
