acute respiratory failure Flashcards
1
Q
a syndrome presenting with hypoxemia, hypercapnia, OR both
A
acute respiratory failure
2
Q
- Respiratory dysfunction resulting in abnormalities of oxygenation or ventilation (CO2 elimination)
severe enough to threaten the function of vital organs - There are no absolute lab values that meet the criteria for this, and it may be diagnosed clinically without labs, however some rough
lab guidelines: - PO2 <60 mm Hg (SPO2 <91%) in a non-COPDer
(SPO2 <88% in COPD) - PCO2 >50 mm Hg
- Can occur due to a pulmonary or non-pulmonary disorder
A
acute respiratory failure
3
Q
- Arterial hypoxemia caused by inflammatory lung injury or severe hypoventilation
- Escalating need for supplemental oxygen
- Hypoxemia may be acute or chronic
- Acute - sudden drop in arterial oxygen saturation (SaO2) < 90% concurrent with acute illness, such as pneumonia or acute heart failure
- Chronic - routine measurements of SaO2 < 90% even with stable illness, such as COPD and chronic
neuromuscular conditions
A
hypoxemic respiratory failure (type 1)
4
Q
- Imbalance between load on respiratory muscles and muscle pump capacity leading to PaCO2 > 45 mm Hg
and (if acidotic) pH < 7.35 - In other words: the lungs cannot adequately remove CO2
- Hypercapnic ARF may be classified in 3 subtypes
- Acute
- Acute on chronic
- Chronic
A
hypercapnic respiratory failure (type 2)
5
Q
Characterized most often by acute inflammatory lung injury
associated with one of the following:
* Increased pulmonary vascular permeability
* Increased lung weight
* Loss of aerated pulmonary tissue
A
acute hypoxemia
6
Q
5 different mechanisms that cause hypoxemia
A
- Ventilation-perfusion mismatch (such as in pneumonia or pulmonary edema)
- Hypoventilation
- Diffusion impairment
- Right-to-left shunting of blood
- Reduced ambient oxygen content in inspired air
7
Q
- Pneumonia
- COPD exacerbation
- Acute pulmonary edema (due to ACS or HF)
- Pulmonary embolism
- Sepsis
- Acute asthma (asthma exacerbation or critical asthma syndrome)
- Acute respiratory distress syndrome (ARDS)
- Interstitial lung diseases
- Other causes include recent blood transfusion, burns, or working with toxic
chemicals - Trauma (such as pulmonary contusion or spinal cord injury)
A
Causes of acute hypoxemic respiratory failure
8
Q
- Obstructive lung diseases, such as:
- COPD exacerbation
- Acute asthma (asthma exacerbation or critical asthma syndrome)
- Cystic fibrosis
- Non-CF bronchiectasis
- Pulmonary edema
- Obesity hypoventilation syndrome (OHS)
- Drug intoxication or poisoning
- Neuromuscular disorders (myopathies and neuropathies, such as myasthenia gravis and phrenic
nerve injury) - Chest wall disorders like kyphoscoliosis
A
Causes of acute hypercapnic respiratory failure
9
Q
- Dyspnea
- Note if unable to complete sentences
- Tachypnea and/or tachycardia
- Peripheral or central cyanosis
- Restlessness, confusion, change in
mental status - Tripoding
- Inability to lie supine
- Manifestations of stress response
(such as hypertension or diaphoresis) - Use of accessory muscles (check the
abdomen with shirt up/off!)
A
hypoxia PE
10
Q
- Dyspnea + HA
- Peripheral and conjunctival hyperemia
- Hypertension, tachycardia, tachypnea
- Impaired consciousness
- Papilledema
- Myoclonus –involuntary jerking/spasming
- Asterixis
A
hypercapnia PE
11
Q
- Reduced air
movement - Wheezing
- Squeaking
- Rhonchi
A
COPD exacerbation
12
Q
- Wheezing (may
be absent late in
exacerbation—
scary sign) - Retractions
A
acute asthma
13
Q
Crackles
A
pulmonary edema
14
Q
ARF diagnostics
A
ABG
15
Q
ARF treatment
A
- O2 with nasal cannula
- Ventilation (BiPAP or intubation (MUST blow off CO2))
- Treat the underlying cause
16
Q
indications for intubation
A
- hypercapnic encephalopathy
- refractory hypoxemia
- respiratory muscle exhaustion
