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Interruption of pulmonary gas exchange for > 5 min may irreversibly damage vital organs, especially the brain. Cardiac arrest almost always follows unless respiratory function is immediately restored.
Etiology
Respiratory arrest can be caused by airway obstruction, decreased respiratory effort from neurologic or muscular disorders, or drug overdose.
Airway obstruction may involve the upper or lower airway. Infants < 3 mo are usually nose breathers and thus may have upper airway obstruction secondary to nasal blockage. At all ages, loss of muscular tone with decreased consciousness may cause upper airway obstruction as the posterior tongue displaces into the oropharynx. Other causes of upper airway obstruction include blood, mucus, vomitus, or foreign body; spasm or edema of the vocal cords; and pharyngolaryngeal tracheal inflammation (eg, epiglottitis, croup), tumor, or trauma. Patients with congenital developmental disorders often have abnormal upper airways that are more easily obstructed.
Lower airway obstruction may occur from aspiration, bronchospasm, airspace filling disorders (eg, pneumonia, pulmonary edema, pulmonary hemorrhage), and drowning.
Decreased respiratory effort due to CNS impairment may result from drug overdose, carbon monoxide or cyanide poisoning, CNS infection, brain stem infarct or hemorrhage, and intracranial hypertension (due to mass lesions, hydrocephalus, or brain injury). Respiratory muscle weakness may be secondary to spinal cord injury, neuromuscular diseases (eg, myasthenia gravis, botulism, poliomyelitis, Guillain-Barré syndrome), neuromuscular blocking drugs, and metabolic disturbances.
Symptoms and Signs
With respiratory arrest, the patient is unconscious, or about to become so, and cyanotic (unless markedly anemic). If uncorrected, cardiac arrest follows within minutes from onset of hypoxemia.
Before complete respiratory arrest, patients with intact neurologic function may be agitated, confused, and struggling to breathe. Tachycardia and diaphoresis are present; there may be intercostal or sternoclavicular retractions. Patients with CNS impairment or respiratory muscle weakness exhibit feeble, gasping, or irregular respirations and paradoxical breathing movements. Patients with a foreign body in the airway may choke and point to their necks.
Infants, especially if < 3 mo old, may develop acute apnea without warning, secondary to overwhelming infection, metabolic disorders, or respiratory fatigue.
Diagnosis
and Treatment
Respiratory arrest is usually clinically obvious; treatment begins simultaneously with diagnosis. The first consideration is to identify a foreign body obstructing the airway. If present, there will be marked resistance to ventilation during mouth-to-mouth or bag-valve-mask ventilation. Foreign material may be discovered during laryngoscopy for endotracheal intubation (see Respiratory and Cardiac Arrest: Clearing and Opening the Upper Airway for removal).
Treatment is to clear the airway, establish an alternate airway, and provide mechanical ventilation (see Respiratory Failure and Mechanical Ventilation).
Last full review/revision November 2005
Content last modified November 2005
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