ARDS Flashcards
RF is
a failure in gas exchange (oxygenation or ventilation)
ARDS is
direct or indirect lung injury from progressive hypoxemia, infiltration, and fibrosis of lung tissue
Hypoxemic RF is..
PaO2 less than 60 and normal PaCO2
Hypercapnia RF is..
respiratory acidosis, PacO2 is above 50, and pH less than 7.35
Risk factors for respiratory failure (10)
- Airway obstruction
- chest wall injury
- Opioid excess/OD
- VQ mismatch (COPD, atelectasis, PE, pneumothorax, ARDS, restrictive lung disease/fibrosis)
- Impaired diffusion (pulmonary edema, ARDS)
What are the hypercapnia clinical manifestations?
HA, confusion, decreased LOC, tachycardia, flushed skin
What are the hypoxemia clinical manifestations?
increased HR, RR, BP
What are the early signs of RF?
tachycardia increased BP dyspnea restlessness anxiety fatigue
What are the late signs for RF?
cyanosis
decreased BP
agonal respiration
coma
How do you diagnose RF?
ABG, chemistry, CBC, coats, chest x ray, chest CT, sputum culture, history and physical
What should the pulse ox be kept at for respiratory failure?
above 94
What is the hemoglobin threshold for transfusing RBCs?
7
What is a sudden and progressive form of RF? and how long is the onset?
ARDS
less than 7 days
What are the hallmark signs of ARDS?
- Refractory hypoxemia (hypoxemia that does not improve no matter if you increase the O2)
- Bilateral (must be in both lungs) opacities
- Widespread inflammation
What is ARDS?
diffuse alveolar capillary membrane damage from a direct or indirect injury
What is the most common cause of ARDS?
sepsis
What is a predisposing condition of ARDS?
SIRS: systemic inflammatory response, trauma, gut ischemia, lung injury, consequence of MODS
What is a mild, moderate and severe P/F ratio for ARDS?
Mild: less than 300
Moderate: less than 200
Severe: less than 100
ALL with PEEP or CPAP more than 5 cmH2O
What is the timing of ARDS?
one week of clinical insult or worsening respiratory symptoms
What are direct injury to the lungs that can lead to ARDS? (9)
- Aspiration
- Pneumonia
- Sepsis
- Gastric aspiration, chest trauma, embolism, inhalation injury, near drowning. O2 toxicity
What are indirect injury to the lungs that can lead to ARDS? (11)
- Sepsis: gram -
- Severe trauma
- Acute pancreatitis, cardiopulmonary bypass, shock, DIC, gut ischemia, OD, burns, TBI, TRALI
What are the three phases of ARDS?
- Injury phase or exudative phase
- Proliferation phase
- Fibrotic phase
What is the pathology of alveolar damage in ARDS?
- r/t inflammation and immune systems
- Diffuse membrane damages
- Increased capillary permeability
- destruction of elastin and collagen
- Formation of microemboli
- PA vasoconstriction
When does the exudative phase occur?
24-48 hours after injury
What happens in the exudative phase?
- Damage to the capillary membranes –> protein risk fluid in sac –> intrapulmonary shunt –> draws more fluid in
- Damage to type 1 ad 2 cells (surfactant cells) –> unstable sac that collapses with exhale –> atelectasis –> unable to being in O2 –> decreased O2
- Hyaline membrane –> decreases lung elastic –> stiff non compliant lungs –> VQ mismatch and increases shunting
When does the proliferation phase occur after injury?
1-2 weeks after
What happens in the proliferation phase?
- Inflammation coninues and there is an influx of neutrophils, monocytes, fibroblasts, and lymphocytes that proliferate
- Lung tissue is being reproduced as dense and fibrous –> decreased lung compliance and increased hypoxemia
- If you can stop this process –> lesions will resolve
When does the fibrotic phase occur?
2-3 weeks after injury
What happens in the fibrotic phase?
- lung tissues remodeled–> scarring and fibrous –> decreased lung compliance –> hypoxemia and hypercapnia
- Systemic dysfunction d/t decreased gas exchange
- Pulmonary hypertension
- Prognosis is poor
What are the early clinical manifestations of ARDS?
- SOB, dyspnea, increase RR, cough
- restlessness
- Clear to mild crackles
- Mild infiltrate on chest x ray
- Respiratory alkalosis
how long does it take for chest infiltrates to show up on a chest X-ray?
24 hours, there is a lag
What are the clinical manifestations as ARD progressed? (14)
- Increased WOB, retractions, productive cough
- Course crackle on expiration, rhonchi
- Non-cariogenic pulmonary edema
- Bilateral infiltrates/opacities on cxray
- Respiratory acidosis –> metabolic acidosis
- Refractory hypoxemia
- pleural effusion
- Severe hypoxemia
- Organ dysfunction d/t decreased CO and decreased MAP
- Intrapulmonary shunt
- Extreme V/Q mismatch
- Hemodynamic changes (BP)
Diagnostics for ARD?
- ABG
- increased lactate d/t anaerobic metabolism
- Blood, sputum, and urine cultures
- Coags
- Electrolytes
- Renal/liver function test to determine progression from ARDS –> MODS
Cardiac complications of ARDS
decreased CO, decreased MAP, dysrhythmias
Neuro complications of ARDS
confusion, agitation, delirium, PICS
Infection complications with ARDS
CAUTI, CLABSI, sepsis
Renal complications with ARDS
AKI
Heme complications with ARDS
VTE, anemia, DIC, thrombocytopenia
GI complications with ARDS
stress ulcers, hemorrhage, ileus, pneumonperitoneum
Respiratory complications with ARDS (8)
abnormal lung function, VAP, barotrauma, volutrauma, O2 toxicity, PE, tracheal injury, laryngeal ulcers
Death complications with ARDS
usually d/t MODS with sepsis
Care of patients with ARDS (3 short ones)
- Underlying cause and treat it (sepsis –>antibiotics)
- ECMO or ECCO
- PRBC transfusion if Hbg below 7
Care of patients with ARDS: Maintain adequate oxygenation
- SpO2 > 90, FiO2 < 60, PaO2: 60
- Supplemental oxygen
- Mechanical ventilation with high PEEP, low vT, and permissive hypercapnia
Care of patients with ARDS: maintain perfusion pressure
BP, MAP, CO, SV
Care of patients with ARDS: Monitor fluids
UOP, I&Os, daily weight
Care of patients with ARDS: IV fluids
Maintaining fluid balance is difficult d/t leaky pulmonary capillaries and third spacing
- Crystalloid
- Colloids - controversial d/t leakage into pulmonary interstitium
- Blood products
Care of patients with ARDS: Medication (8)
- Inotropic meds: dopamine, dobutamine, NE, vasopressin, Milrinone
- Corticosteroids –> decrease imflammation
- Vitamin C to decrease oxidative stress
- Nitric oxide
- Surfactant
- Neuromuscular blocking agent (NMDA)
- High does steroid therapy
- Diuretics if needed
Care of patients with ARDS: Nutrition
Start within 24-72 hours of ventilation
maintain protein and energy stores because muscle mass loss can happen when on ventilator with decrease mobility
Enteral or parenteral feedings
Care of patients with ARDS: Positioning
- Proning –> decrease FiO2 needed, increases airflow and move secretions
- Early mobility
Care of patients with ARDS: Mechanical vent
Goal: correct hypoxemia and maintain ventilation with PVV
- Non-invasive PPV (NIVPP) - partial support
- Invasive endotracheal intubation PPV - full support
- High frequency oscillatory vent (HFOV)
Care of patients with ARDS: Prevent DVT, pressure ulcers and stress ulcers
- DVT: compression stockings
- Pressure ulcers: move patient every 2 hours
- Stress ulcers: H2 blocker or PPI
What are the mechanical ventilation indications for ARDS
- Respiratory or ventilation failure
- Increased CO2
- Decreased pH
- Decreased O2
- Increased or decreased RR
- Decreased or absent breath sounds
- Unprotected airway
Pulmonary artery pressure wedge
Measure the pressure in the left pulmonary artery
< 18 –> ARDS
> 18 –> cardiac issue
What is permissive hypercapnia?
retaining CO2
