ARDs Flashcards
PATHOPHYSIOLOGY of ARDS - who gets it? and it triggers what?
ARDS usually occurs in a critically ill patients
ARDS triggers an immune-inflammatory response in the lungs.
Inflammatory mediators play
(alden’s mediators destroy)
a key role in damaging the lung tissue in ARDS
MEDIATORS (Alden mediates with a PLNC)
Neutrophils, Prostaglandin’s, leukotrienes, Complement System
MEDIATORS - TNF - released by what? (tumor nymph)
Released by lymphocytes when cells are injured
Endotoxin - caused by what
Toxic proteins released from bacterial growth
Usually from hypofunctioning gut
Can lead to Sepsis
Clinical Criteria for diagnosing ARDS - onset
ACUTE ONSET
↓ Oxygenation as measure by PaO2/FiO2 ratio - what number
(Alden won’t live to 200)
(ARDS= <200)
FORMULA FOR PaO2/FiO2 ratio
(pa’s artery is first)
PaO/FiO2 ratio (PaO2 ÷ FiO2)
PaO2 = Partial pressure of arterial oxygen (mm Hg) Measured on an ABG
FiO2 = Fraction of inspired oxygen (O2 concentration) Room air = 21%
PaO2/FiO2 -The lower the ratio…
the greater the shunting
PaO2/FiO2 - ranges
(pa starts at 350)
Normal: greater than 350 mm Hg
Acute lung injury: less than 300 mm
ARDS: less than 200 mm Hg
Pulmonary Artery Wedge Pressure (PAWP)
(alden’s wedgy was under 18)
Pulmonary Artery Wedge Pressure (PAWP) (this is measured from a swans catheter) normal or not greater than 18mm Hg (anything greater than 18 is cardiac)
Clinical Criteria for diagnosing ARDS - edema?
Non cardiac bilateral pulmonary edema. (Cardiac pulmonary edema is what is causing the high PAWP > 18)
REVIEW CRITERIA for ARDS: - on TEST (5 things) KNOW THIS
(Alden is fast, dying at 200 and 18 with fat consolidation)
Acute Onset
PaO2/FIO2 ratio < 200
PCWP < 18 mm HG
Non Cardiac Pulmonary edema
CXR: Diffuse bilateral alveolar infiltrates→ consolidation (white-out)
TREATMENT for ARDS (the usual)
Ventilation support
Fluid Management
Nutritional Support
Positioning and other therapies
VENTILATION SUPPORT- high or low?
Pt needs ventilator support
High Vent settings can cause Barotrauma
BAROTRAUMA - what to check for?
Subcutaneous Emphysema
Air noted in subcutaneous tissues upon palpation. (this is bc the vent setting is up too high)
VENTILATOR SUPPORT IN ARDS - to prevent Barotrauma,
(Alden needs a small tide)
smaller tidal volumes can be used.
Unfortunately, smaller tidal volumes cause CO2 retention.
ARDS: MEDICAL AND NURSNG MANAGEMENT - NUTRITIONAL SUPPORT
Early initiation of nutritional support is Vital!
Severe hypermetabolism occurs– equated to running an 8-minute mile, 24 hours per day, 7 days a week.
The enteral route (below pyloris) is preferred to parental to normalize the gut and minimize gut hypoperfusion → ischemia → translocation of endotoxins → sepsis
FLUID SUPPORT in ARDS -
(alden can’t have too much fluid)
Give adequate fluids but keep pt fairly dry
Intravascular fluid ends up leaking out into the lungs due to ↑ capillary membrane permeability.
POSITIONING TREATMENT IN ARDS - prone? and what does it improve?
(alden is prone)
Dependent lung areas are more heavily damaged than non dependent lung areas.
Prone positioning improves V/Q matching
More effective when initiated in the early phases of ARDS.
Prone positioning is labor intensive (may require 7 staff members), can result in accidental extubation, hemodynamic instability, facial edema, ↑ ICP, corneal abrasions.
Prostacycline - what does it do?
(Alden’s prosty dilates)
Selective Pulmonary vasodilator (SPV)
Improves PaO2 / FIO2 ratios
Marked dose related improvement in oxygenation
Review of Treatment for ARDS - is the oxygen high or low?
Intubate
ICU
High peep and low tidal volumes
Prone positioning
Aerosolized Prostacyclin via jet neb
O2 levels - L/min - the numbers
up by 4 starting at 24%
xrays for ARDs will show
Diffuse bilateral alveolar infiltrates→ consolidation (white-out)
what do mediators do?
(alden’s mediators are leaky)
These mediators cause extensive lung damage, ↑ capillary membrane permeability and ‘leaking’ in ARDS
what does the inflammatory response do to the lungs? (what is injured?)
The inflammatory response injures the alveolo-capillary membrane and causes severe pulmonary edema.
what does TNF do during ARDS? (2 things)
(think what mediators do)
In ARDS causes endothelial injury, vasodilation, ↑ capillary permeability
criteria for ARDS - chest xray?
BILATERAL INFILTRATES ON CXR
criteria for ARDS - Pulmonary Artery Wedge Pressure (PAWP)
Pulmonary Artery Wedge Pressure (PAWP) not greater than 18mm Hg (normal 6 – 12)
criteria for ARDS - pulmonary edema?
Non cardiac bilateral pulmonary edema. (Cardiac pulmonary edema causes ↑ PAWP > 18)
criteria for ARDS - oxygenation?
(alden’s 02 won’t last 200 minutes)
↓ Oxygenation as measured by PaO2/FiO2 ratio (less than 200 = ARDS)
PaO2/FiO2 ratio - The lower the ratio…
(low shunts)
the more intrapulmonary shunting.
normal PAWP - number
(pa should be 6 - 12)
(normal 6 – 12)
ventilation support in ARDS - is Hypercapnia ok? And what numbers?
(Alden is hyper at 50)
Permissive Hypercapnia (50 – 70 meq/L) is allowed
Normal 38-42
ventilation support in ARDS - PEEP
(alden is my peep)
PEEP (positive end-expiratory pressure)
Keeps alveoli slightly expanded
Too much PEEP can put pt at risk for Barotrauma
prone position - how often to reposition head?
(alden needs to breathe every hour)
Reposition head every hour, continue enteral tube feeding, turn to supine within 6 hours.
prostacycline - how much?
(prosty in 0 to 50)
Given via aerosolized jet nebulizer at 1 – 50 ng/kg/min
to calculate ARDS
PAO2 = 98% and FiO2 = 50%
98 / .50 = 196 (ARDS)
ARDS - metabolism?
severe hypermetabolism
most sensitive marker for SIRS?
(Alden can’t breathe!)
tachypnea
