Overview of Respiratory Arrest

Obstruction may involve the

Upper airway obstruction may occur in infants < 3 months, who 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 portion of the tongue displaces into the oropharynx. Other causes of upper airway obstruction include

Patients with congenital developmental disorders (eg, Down syndrome Down Syndrome (Trisomy 21) Down syndrome is an anomaly of chromosome 21 that can cause intellectual disability, microcephaly, short stature, and characteristic facies. Diagnosis is suggested by physical anomalies and... read more , laryngeal disorders Overview of Laryngeal Disorders The larynx contains the vocal cords and serves as the opening to the tracheobronchial tree. Laryngeal disorders include Benign laryngeal tumors Contact ulcers Laryngitis Laryngoceles read more , congenital jaw abnormalities Congenital Jaw Abnormalities The jaw can be missing, deformed, or incompletely developed at birth, often in conjunction with other congenital abnormalities and syndromes. (See also Introduction to Congenital Craniofacial... read more ) often have abnormal upper airways that are more easily obstructed.

Lower airway obstruction may result from

Decreased respiratory effort reflects central nervous system (CNS) impairment due to one of the following:

Central nervous system disorders that affect the brain stem (eg, stroke Overview of Stroke Strokes are a heterogeneous group of disorders involving sudden, focal interruption of cerebral blood flow that causes neurologic deficit. Strokes can be Ischemic (80%), typically resulting... read more , infection, tumor) can cause hypoventilation. Disorders that increase intracranial pressure usually cause hyperventilation initially, but hypoventilation may develop if the brain stem is compressed.

Drugs that decrease respiratory effort include opioids and sedative-hypnotics (eg, barbiturates, alcohol; less commonly, benzodiazepines). Combinations of these drugs further increase the risk of respiratory depression (1 Etiology references Respiratory arrest and cardiac arrest are distinct, but inevitably if untreated, one leads to the other. (See also Respiratory Failure, Dyspnea, and Hypoxia.) Interruption of pulmonary gas exchange... read more ). Usually, an overdose (iatrogenic, intentional, or unintentional) is involved, although a lower dose may decrease effort in patients who are more sensitive to the effects of these drugs (eg, older patients, deconditioned patients, patients with chronic respiratory insufficiency or obstructive sleep apnea). Respiratory arrest due to illicit drug use especially use of opioids Opioid Toxicity and Withdrawal Opioids are euphoriants that cause sedation. Respiratory depression may occur with high doses and can be managed with antidotes (eg, naloxone) or endotracheal intubation and mechanical ventilation... read more , including heroin and fentanyl, is a common cause of out-of-hospital respiratory arrest. In hospitalized patients, the risk for opioid-induced respiratory depression (ORID) is most common in the immediate postoperative recovery period but persists throughout a hospital stay and may affect almost 50% of postoperative patients (2 Etiology references Respiratory arrest and cardiac arrest are distinct, but inevitably if untreated, one leads to the other. (See also Respiratory Failure, Dyspnea, and Hypoxia.) Interruption of pulmonary gas exchange... read more ). OIRD can lead to catastrophic outcomes such as severe brain damage or death (3 Etiology references Respiratory arrest and cardiac arrest are distinct, but inevitably if untreated, one leads to the other. (See also Respiratory Failure, Dyspnea, and Hypoxia.) Interruption of pulmonary gas exchange... read more ).

Gabapentinoids (gabapentin, pregabalin) may cause serious breathing difficulties in patients using opioids or other drugs that depress the CNS (eg, sedatives Sedatives Sedatives include benzodiazepines, barbiturates, and related drugs. High doses can cause decreased level of consciousness and respiratory depression, which may require intubation and mechanical... read more ), older patients, or patients who have underlying respiratory impairment such as patients with chronic obstructive pulmonary disease Chronic Obstructive Pulmonary Disease (COPD) Chronic obstructive pulmonary disease (COPD) is airflow limitation caused by an inflammatory response to inhaled toxins, often cigarette smoke. Alpha-1 antitrypsin deficiency and various occupational... read more (COPD).

Metabolic disorders that cause CNS depression due to severe hypoglycemia or hypotension ultimately compromise respiratory effort.

Weakness may be caused by

Respiratory muscle fatigue can occur if patients breathe for extended periods at a minute ventilation exceeding about 70% of their maximum voluntary ventilation (eg, because of severe metabolic acidosis Metabolic Acidosis Metabolic acidosis is primary reduction in bicarbonate (HCO3⁻), typically with compensatory reduction in carbon dioxide partial pressure (Pco2); pH may be markedly low or slightly... read more or hypoxemia).

Neuromuscular causes include spinal cord injury, neuromuscular diseases (eg, myasthenia gravis Myasthenia Gravis Myasthenia gravis is characterized by episodic muscle weakness and easy fatigability caused by autoantibody- and cell-mediated destruction of acetylcholine receptors. It is more common among... read more , botulism Botulism Botulism is poisoning that is due to Clostridium botulinum toxin and that affects the peripheral nerves. Botulism may occur without infection if toxin is ingested, injected, or inhaled... read more , poliomyelitis Poliomyelitis Poliomyelitis is an acute infection caused by a poliovirus (an enterovirus). Manifestations include a nonspecific minor illness (abortive poliomyelitis), sometimes aseptic meningitis without... read more , Guillain-Barré syndrome Guillain-Barré Syndrome (GBS) Guillain-Barré syndrome is an acute, usually rapidly progressive but self-limited inflammatory polyneuropathy characterized by muscular weakness and mild distal sensory loss. Cause is thought... read more ), and neuromuscular blocking drugs (eg. succinylcholine, rocuronium, vecuronium).

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 have feeble, gasping, or irregular respirations and paradoxical breathing movements. Patients with a foreign body in the airway may choke and point to their necks, exhibit inspiratory stridor, or neither.

Monitoring end-tidal carbon dioxide can alert practitioners to impending respiratory arrest in decompensating patients.

Infants, especially if < 3 months, may develop acute apnea without warning, secondary to overwhelming infection, metabolic disorders, or respiratory fatigue.

Patients with asthma Asthma Asthma is a disease of diffuse airway inflammation caused by a variety of triggering stimuli resulting in partially or completely reversible bronchoconstriction. Symptoms and signs include dyspnea... read more or with other chronic lung diseases may become hypercarbic and fatigued after prolonged periods of respiratory distress and suddenly become obtunded and apneic with little warning, despite adequate oxygen saturation.