Hypoventilation

Not to be confused with hypopnea or hyperventilation.
Hypoventilation
Classification and external resources
ICD-10 R06.8
ICD-9-CM 786.09
DiseasesDB 29214
MedlinePlus 002377
eMedicine med/3470
MeSH D007040

In medicine, hypoventilation (also known as respiratory depression) occurs when ventilation is inadequate (hypo meaning "below") to perform needed gas exchange.[1] By definition it causes an increased concentration of carbon dioxide (hypercapnia) and respiratory acidosis.

Causes

Hypoventilation can be caused by medical conditions, such as stroke affecting the brainstem, by holding one's breath, like during hypoventilation training,[2] or by drugs, typically when taken in overdose. Opioids in particular cause respiratory depression. Hypocapnia stimulates hypoventilation. Hypoventilation may also occur in chronic mountain sickness to conserve energy.[3]

Effects

As a side effect of medicines or recreational drugs, hypoventilation may become potentially life-threatening. Many different central nervous system (CNS) depressant drugs such as ethanol, benzodiazepines, barbiturates, GHB, sedatives and opioids produce respiratory depression when taken in large or excessive doses, or mixed with other depressants. Strong opiates (such as fentanyl, heroin, or morphine), barbiturates, and certain benzodiazepines (short acting ones and alprazolam) are known for depressing respiration. In an overdose, an individual may cease breathing entirely (go into respiratory arrest) which is rapidly fatal without treatment. Opioids, in overdose or combined with other depressants, are notorious for such fatalities.

Treatment

Respiratory stimulants such as nikethamide were traditionally used to counteract respiratory depression from CNS depressant overdose, but offered limited effectiveness. A new respiratory stimulant drug called BIMU8 is being investigated which seems to be significantly more effective and may be useful for counteracting the respiratory depression produced by opiates and similar drugs without offsetting their therapeutic effects.

If the respiratory depression occurs from opioid overdose, usually an opioid antagonist, most likely naloxone, will be administered. This will rapidly reverse the respiratory depression unless complicated by other depressants. However an opioid antagonist may also precipitate an opioid withdrawal syndrome in chronic users.

Associated conditions

Disorders like Congenital Central Hypoventilation Syndrome (CCHS) and Rapid-Onset Obesity, Hypothalamic Dysfunction, Hypoventilation, with Autonomic Dysregulation (ROHHAD) are recognized as conditions that are associated with hypoventilation. CCHS may be a significant factor in some cases of sudden infant death syndrome (SIDS), often termed "cot death" or "crib death".

The opposite condition is hyperventilation (too much ventilation), resulting in low carbon dioxide levels (hypocapnia), rather than hypercapnia.

See also

References

  1. ↑ "hypoventilation" at Dorland's Medical Dictionary
  2. ↑ Woorons, Xavier, Hypoventilation training, push your limits! Arpeh, 2014, 164p. (ISBN 978-2-9546040-1-5)
  3. ↑ Zubieta-Calleja, GR; Paulev, PE; Zubieta-Calleja, L; Zubieta-Calleja, N; Zubieta-Castillo, G (September 2006). "Hypoventilation in chronic mountain sickness: a mechanism to preserve energy.". Journal of Physiology and Pharmacology: An Official Journal of the Polish Physiological Society. 57 Suppl 4: 425–30. PMID 17072073.
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