Acute Respiratory Failure & ARDS Flashcards
when oxygenation, ventilation, or both are inadequate
Acute respiratory failure
Impaired gas exchange
Hypoxemic respiratory failure (failure of
oxygenation)
Impaired ventilation
Hypercapnic respiratory failure (failure of
ventilation)
Combined failures (failures of oxygenation & ventilation)
Hypoxemic and Hypercapnic
Oxygenation failure
PaO2 <= 60 mmHg on >= 60% oxygen
hypoxemic
Ventilatory Failure
PaCO2 > 50mmHg and pH <7.35
hypercapnic
Ph: 7.37
PacO2: 60
Pao2: 85
Hco3: 24
hypoxemia or hypercapnic
hypercapnic
Ph: 7.35
PacO2: 55
Pao2: 40
Hco3: 24
Hypoxemia or hypercapnic
Both/ hypercapnic and hypoxic
Hypercapnic clinical manifestations. Early signs
- Sudden or gradual onset
- Change in mental status – first sign resp failure
- Early signs – tachycardia, tachypnea, mild hypertension
- Dyspnea
- Other respiratory findings: prolonged expiration, nasal flaring,
retractions, use accessory muscles, SpO2 <80% - Skin cool/clammy, diaphoretic
- Anxiety
- Fatigue, inability to speak in complete sentences without pausing to
Breathe - Decreasing LOC - Lethargy
Hypercapnic clinical manifestations late signs
hypotension, dysrhythmias, cyanosis ( PaO2 45 mmHg or less), paradoxical breathing or abdominal wall movement, coma
How to diagnosis hypercapnic respiratory failure
(1) Chest xray
(2) ABGs
(3) Oxygen saturation
(4) CBC, BMP, urinalysis
(5) Sputum, blood cultures
(6) CT or V/Q (specific to perfusion, can spot PE so can CT) lung scan
If a person has unilateral lung disease how do you lay them?
position the good lung down. Them laying on the side of the good lung
Acute onset (less than 7 days) of refractory hypoxemia and bilateral infiltrates
Adult respiratory distress syndrome (ARDS)
How is ARDS caused
- Caused by direct or indirect injury to lungs – Sepsis most common
- Direct injury
a) Aspiration, pneumonia, sepsis
b) Other causes: chest trauma, embolism,
inhalation injury, near-drowning, O2 toxicity - Indirect injury
a) Sepsis, massive trauma, severe TBI, shock
b) Other: pancreatitis, cardiopulmonary bypass, DIC, opioid
overdose, multiple blood transfusions (TRALI)
ARDS Criteria
- Refractory hypoxemia (intubated pt, p/f ratio less than 300, Fi02 of 100% SpO2 of 88) <- example
- P/F ratio < 300 mmHg
- Bilateral infiltrates on chest x-ray
Ards Severity:
PaO2/FiO2 of 200-300
Mild
Ards Severity:
PaO2/FiO2 of 100-200
Moderate
Ards Severity:
PaO2/FiO2 of < 100
Severe
Diagnosis of ARDS
a) Chest x-ray - Serial
b) ABGs
c) Laboratory testing – CBC, CMP, coagulation studies,
liver and renal function tests, serum lactate (of anaerobic metabolism)
d) Sputum, blood, urine cultures
e) pulmonary function studies
Management for ARDS
d) Identify and treat underlying cause
e) Oxygen administration
Correct hypoxemia – high-flow O2 delivery, BiPAP
f) Mechanical ventilation – Goal – SaO2 > 90% with FiO2 < 60%
(1) Pressure A/C
(2) Low tidal volume ventilation (4-6 mL/kg) predicted body
weight
(3) Permissive hypercapnia (PaCO2 60 acceptable (not used TBI or increased ICP)
(4) PEEP
g) Prone Positioning
(1) Recruit collapsed alveoli in posterior part lungs,
helps mobilize secretions
(2) Dependent areas of lungs are more heavily damaged
than nondependent areas
Adequate hydration (IV fluids - crystalloids, colloids)
(1) Adequate blood volume to maintain organ perfusion
(2) Avoid thick, dry secretion, mucous plugs
l) Improve O2 carrying capacity of blood
(1) Administer packed RBCs (keep Hgb 7g/dL)
m) Nutrition
(1) Enteral or parenteral feedings – initiate in 48 – 72 hours of
initiation of mechanical ventilation
