Failure
Acute Respiratory Failure
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Acute Respiratory Failure
, Respiratory Failure
See Also
Dyspnea
Dyspnea Causes
Acute Dyspnea
Tachypnea Causes
Types
Hypoventilatory Respiratory Failure or Hypercapnic Respiratory Failure (Bellows Failure)
Defining features
High
PaCO2
>50 mmHg (not due to respiratory compensation for
Metabolic Alkalosis
)
Normal
A-a Gradient
Causes: Compromised lung mechanics
Upper airway obstruction
Infection (
Epiglottitis
,
Bacterial Tracheitis
, croup)
Adenotonsillar Hypertrophy
Neck Mass
Thyroid
Goiter
Obstructive Sleep Apnea
Vocal Cord Paralysis
(bilateral)
Laryngeal Foreign Body
Pulmonary muscle
Fatigue
(Skeletal muscle
Fatigue
s at >40% of maximum load)
Obesity
Ascites
Pleural Effusion
Supine position
Kyphoscoliosis
Ankylosing Spondylitis
Hypercarbia (fever,
Sepsis
, burns)
Inefficient breathing (flat diaphragm, high
Residual Volume
)
Asthma
Emphysema
Unstable chest wall
Pneumothorax
Flail Chest
or multiple
Rib Fracture
s
Diaphragmatic Rupture
Causes: Neuromuscular
Drug
Overdose
or depressant drugs
Opioid
s
Benzodiazepine
s
Barbiturates
Procedural Anesthesia
(e.g.
Propofol
)
Phencyclidine
(PCP)
Toxins (or other medication adverse effects)
Aminoglycoside
s
Arsenic
Strychnine
Botulism
Electrolyte
and endocrine abnormalities
Hyponatremia
Hypocalcemia
Hypokalemia
Hyperkalemia
Hypomagnesemia
Severe
Hypophosphatemia
Hypothyoidism
Brainstem
injury
Severe global CNS injury
Head Trauma
Intracranial Hemorrhage
CNS Infection
(
Meningitis
,
Encephalitis
,
Brain Abscess
,
West Nile Encephalitis
,
Poliomyelitis
)
Central Sleep Apnea
Central Alveolar Hypoventilation Syndrome (CHS)
Nerve dysfunction
Spinal cord injury
Polyneuritis (e.g.
Guillain-Barre Syndrome
)
Amyotrophic Lateral Sclerosis
Multiple Sclerosis
Nerve Agent Exposure
(e.g.
Organophosphate
s)
Phrenic nerve injury
Example:
Phrenic Nerve Injury from Birth Trauma
Muscular dysfunction
Muscular Dystrophy
Myasthenia Gravis
Polymyositis
Tetanus
Types
Ventilation-perfusion mismatch (venous admixture)
Defining features
High
PaCO2
Increased
A-a Gradient
Often improves with
Supplemental Oxygen
Causes
Asthma
Chronic Obstructive Pulmonary Disease
(
COPD
)
Pneumonia
Pneumothorax
Pulmonary Embolism
Interstitial Lung Disease
Types
Hypoxemic Respiratory Failure (or physiologic right to left shunting)
Defining features
Low
PaCO2
Low
PaO2
<50-60 mmHg on room air
A-a Gradient
may be increased
May not improve with
Supplemental Oxygen
Causes
Cardiac
Pulmonary Edema
(high pressure edema)
Left Ventricular Failure
Acute
Myocardial Ischemia
(left ventricle)
Malignant Hypertension
Mitral Regurgitation
or stenosis
Lung
Conditions
Lobar
Pneumonia
Atelectasis
Pulmonary Contusion
Alveolar
Hemorrhage
Bronchospasm
Cystic Fibrosis
Acute Respiratory Distress Syndrome
(
ARDS
)
Increased permeability (low pressure edema)
Signs
Gene
ral appearance
Altered Mental Status
Diaphoresis
Increased work of breathing
Accessory muscle use
Intercostal retractions
Tachypnea
Paradoxical breathing patterns
Abdominal wall moves inward with inspiration as respiratory
Fatigue
occurs
Cardiovascular changes
Mucous membrane and nail bed
Cyanosis
Tachycardia
Hypertension
Differential Diagnosis
See Causes above
See
Dyspnea Causes
See
Tachypnea Causes
See
Hypoxia
Management
Gene
ral
See
Emergency Breathing Management
See
Advanced Airway
See
Non-Invasive Positive Pressure Ventilation
Specific Approaches
Emergency Management of Asthma Exacerbation
(or
Status Asthmaticus
)
Emergency Management of COPD Exacerbation
Congestive Heart Failure Exacerbation Management
Acute Respiratory Distress Syndrome
Management
Approach to
Non-Invasive Positive Pressure Ventilation
Selection
Hypoxemic Respiratory Failure (Inadequate oxygenation)
Reflected by
Arterial Blood Gas
PaO2
and
Oxygen Saturation
Concepts
Increase oxygen delivered to the lung (esp. FIO2) or
Increase mean airway pressure (or
Positive End-Expiratory Pressure
)
Interventions
Continuous Positive Airways Pressure
(
CPAP
)
Hypercarbic Respiratory Failure (Inadequate ventilation)
Reflected by
Arterial Blood Gas
PaCO2
and pH
Concepts (increase minute ventilation)
Increase
Tidal Volume
(TV) or
Increase
Respiratory Rate
(RR)
Interventions
Bilevel Positive Airway Pressure
(
BiPap
)
References
Mallemat and Runde in Herbert (2015) EM:Rap 15(2): 7-8
References
(2016) Fundamental
Critical Care
Support, p. 46-60
Davies (1986) Acute Respiratory Failure, Cyberlog
Presberg in Noble (2001) Primary Care, p. 705-16
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