Week 6 - ARDS Flashcards
Most common cause of ARDS
Sepsis
ARDS criteria
Within 1 week of known clinical risk; new or worsening symptoms
Key symptom of ARDS
Refractory hypoxia (unresponsive hypoxia)
Phases of ARDS
- Exudative phase
- Fibroporliferative phase
- Resolution phase
Endothelial injury to alverolar capillary membrane causes… (2)
- Damaged type 2 alveolar cell (decreased production of surfactant –> atelactasis)
- Release of inflammatory mediators (leakage, vascular narrowing and obstruction, pulmonary edema, bronchoconstriction)
Nursing diagnosis with ARDS patho
Impaired gas exchange
Neutrophils are attracted and release mediators producing 4 changes in the lungs
- Increased pulmonary capillary membrane permeability (leak)
- destruction of elastin and collagen (decreased integrity)
- formation of pulmonary microemboli
- pulmonary artery vasoconstriction
Exudative phase
- 1-7 days after injury
- neutrophils adhere
- engorgement of peribronchial and perivascular interstitial space
- intrapulmonary shunt
- damage to alveolar cells
- hyaline membranes
Fibroproliferative phase
- 1-2 weeks after lung injury
- influx of neutrophils, monocytes, lymphocytes
- fibroblast proliferation
- dense and fibrous lung
- worsening of hypoxemia
Fibrotic/Chronic late phase
- 2-3 weeks after injury
- lung is remodeled by collagenous and fibrous tissues
- decreased lung compliance
- low survival chance
- need long term mechanical ventilation
Exudative phase s/s
- tachypnea
- restlessness
- apprehension
- moderate accessory muscle use
Fibroproliferative phase s/s
- agitation
- dyspnea
- fatigue
- excessive accessory muscle use
- fine crackles
ABGs
- refractory hypoxia (low PaO2 despite increase in O2 therapy)
- PaO2/FiO2 ratio < 200 mm/Hg
Diagnostics
- opacities on x ray (atelactasis)
Low tidal volume
- 6 ml/kg
Permissive hypercapnia
want Co2 because its a vasodilator
Pressure control ventilation
prevents damage to tissue
Inverse ratio ventilation
I > E to promote gas exchange
High Frequency Oscillatory Ventilation
seen in NICU
- low tidal volumes at super high rates
Risk for O2 toxicity
FiO2 > 60% for more than 48 hrs
O2 therapy goal
lowest concentration that results in PaO2 60 mmHg or greater
PEEP
positive end expiratory pressure
- high levels to allow alveolar capillaries to take up more O2
- also decreases preload, CO, and BP
Positioning
- prone
- continuous lateral rotation
Risk with prone
aspiration
