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ICD-10 R06.8
DiseasesDB 29214
MeSH D007040

For patient information, click Hypoventilation

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1],Associate Editor(s)-in-Chief: Amresh Kumar MD [2]

Synonyms and keywords:


In medicine, hypoventilation (also known as respiratory depression) occurs when ventilation is inadequate (hypo means "below") to perform needed gas exchange. It generally causes an increased concentration of carbon dioxide (hypercapnia) and respiratory acidosis. It can be caused by medical conditions, by holding one's breath, or by drugs, typically when taken in overdose. Hypoventilation may be dangerous for those with sleep apnea.



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

Associated Conditions

  • Disorders like (CCHS) and Rapid-Onset Obesity, Hypothalamic Dysfunction, Hypoventilation, with Autonomic Dysregulation are recognized as conditions that are associated with hypoventilation. CCHS may be a significant factor in some cases of (SIDS), often termed "cot death" or "crib death".
  • The opposite condition is (too much ventilation), resulting in low carbon dioxide levels, rather than hypercapnia.


Life Threatening Causes

Common Causes

Causes by Organ System

Cardiovascular No underlying causes
Chemical/Poisoning No underlying causes
Dental No underlying causes
Dermatologic No underlying causes
Drug Side Effect Acetaminophen/Codeine Phosphate, Acetaminophen/Oxycodone Hydrochloride, Alcuronium, Alfentanyl, Alfentanil Hydrochloride, Alprostadil, Amobarbital sodium, Apomorphine, Aspirin/Caffeine/Dihydrocodeine Bitartrate, Aspirin/Codeine Phosphate, Aspirin/Oxycodone Hydrochloride, Atropine Sulfate, Baclofen, Brimonidine, Bupivacaine, Buprenorphine, Buprenorphine Hydrochloride, Buprenorphine/Naloxone, Butalbital/Acetaminophen/Caffeine/Codeine Phosphate, Butalbital/Aspirin/Caffeine/Codeine Phosphate, Butorphanol, Butorphanol Tartrate, Carisoprodol/Aspirin/Codeine Phosphate, Cifenline, Clobazam, Clonazepam, Clonidine, Codeine, Codeine Phosphate/Guaifenesin, Codeine Sulfate, Dantrolene, Desflurane, Dexmedetomidine, Dexmedetomidine Hydrochloride, Diazepam, Diclofenac, Dihydrocodeine, Disulfiram, Droperidol, Enflurane, Ethanol, Fentanyl, Fentanyl Citrate, Fentanyl/Droperidol, Halazepam, Homatropine Methylbromide/Hydrocodone Bitartrate, Hydrocodone, Hydrocodone Bitartrate, Hydrocodone Bitartrate/Acetaminophen, Hydrocodone Bitartrate/Chlorpheniramine Maleate, Hydrocodone Bitartrate/Guaifenesin, Hydrocodone Bitartrate/Ibuprofen, Hydrocodone Bitartrate/Pseudoephedrine Hydrochloride, Hydrocodone Polistirex/Chlorpheniramine Polistirex, Hydrocodone/Chlorpheniramine/Pseudoephedrine, Hydromorphone, Hydromorphone Hydrochloride, Ipratropium, Isoflurane, Ketamine, Ketamine Hydrochloride, Levorphanol, Levorphanol Tartrate, Lidocaine, Lopinavir/Ritonavir, Lorazepam, Magnesium, Meperidine, Meperidine Hydrochloride, Methadone, Methadone Hydrochloride, Methohexital, Methohexital Sodium, Midazolam, Midazolam Hydrochloride, Morphine, Morphine Sulfate, Morphine Sulfate Liposome, Morphine Sulfate/Naltrexone Hydrochloride, Nalbuphine, Nalbuphine Hydrochloride, Nefopam, Neostigmine, Nortriptyline, Onabotulinumtoxina, Opium, Oxaprozin, Oxycodone, Oxycodone Hydrochloride, Oxycodone Hydrochloride/Naloxone Hydrochloride, Oxycodon, Oxycodone Hydrochloride, Oxycodone Hydrochloride/Naloxone Hydrochloride, Oxycodone/Ibuprofen, Oxymorphone, Oxymorphone Hydrochloride, Paregoric, Pancuronium, Pancuronium Bromide, Pentazocine, Pentazocine Hydrochloride/Acetaminophen, Pentazocine Hydrochloride/Naloxone Hydrochloride, Pentazocine Lactate, Pentobarbital, Phenelzine, Polymixinb, Prilocaine, Prilocaine Hydrochloride, Promethazine, Promethazine Hydrochloride, Promethazine Hydrochloride/Codeine Phosphate, Promethazine/Phenylephrine/Codeine Phosphate, Propoxyphene, Propoxyphene Napsylate/Acetaminophen, Quinine, Remifentail, Remifentanil Hydrochloride, Riluzole, Rimabotulinumtoxinb, Secobarbital sodium, Sevoflurane, Sodium Oxybate, Succinylcholine, Succinylcholine Chloride, Sufentanil, Sufentanil Citrate, Tapentadol, Tapentadol Hydrochloride, Thiopental Sodium, Tilidine, Tramadol, Tramadol Hydrochloride, Tromethamine, Zanamivir
Ear Nose Throat No underlying causes
Endocrine No underlying causes
Environmental No underlying causes
Gastroenterologic No underlying causes
Genetic No underlying causes
Hematologic No underlying causes
Iatrogenic No underlying causes
Infectious Disease No underlying causes
Musculoskeletal/Orthopedic No underlying causes
Neurologic No underlying causes
Nutritional/Metabolic No underlying causes
Obstetric/Gynecologic No underlying causes
Oncologic No underlying causes
Ophthalmologic No underlying causes
Overdose/Toxicity No underlying causes
Psychiatric No underlying causes
Pulmonary No underlying causes
Renal/Electrolyte No underlying causes
Rheumatology/Immunology/Allergy No underlying causes
Sexual No underlying causes
Trauma No underlying causes
Urologic No underlying causes
Miscellaneous No underlying causes

Differentiating hypoventilation from other Diseases

Abbreviations: Ab (antibody); ABG (arterial blood gas); BMP (basic metabolic panel); BPS (biophysical profile score); CHS (central hypoventilation syndrome); CBC (complete blood count); CPK (Creatine phosphokinase); CSF (cerebrospinal fluid); CT (computed tomography ); CXR (chest X-ray); DMD (dystrophin gene);  ECG (electrocardiogram); EMG (electromyography); FEF (forced expiratory flow rate); FEV1 (forced expiratory volume); FRC (functional residual capacity); FVC (forced vital capacity); GIT (gastrointestinal tract); JVD (jugular vein distention); MAS (meconium aspiration syndrome); MCV (mean corpuscular volume); MRI (magnetic resonance imaging); NCS (Nerve conduction studies); PEF (pulmonary expiratory flow); RDS (acute respiratory distress syndrome); ROHHAD (rapid-onset obesity with hypothalamic dysfunction, hypoventilation and autonomic dysregulation); RV (residual volume); SIRS (systemic inflammatory response syndrome); SMN1 (survival of motor neuron 1); TLC (total lung capacity) TSH (thyroid stimulating hormone); Vt (tidal volume); WBC (white blood cell);

Diseases Clinical manifestations Diagnosis Associated features
Symptoms Physical exam
Chest pain Dyspnea Orthopnea Fever Palpitations Poor

quality sleep

Cyanosis JVD Peripheral edema Auscultation ABGs Lab findings Imaging Spirometry Gold standard
Central hypoventilation syndrome CHS[1][2][3] - + + - +/- + + +/- +/-
  • Normal
O2, ↑CO2 Normal
Asphyxia[4][5][6] - + +/- - +/- + + +/- +/- O2, ↑CO2 Normal
Chiari II malformation (Arnold-Chiari)[7][8][9] - + + - + + - - - Normal _ _ MRI Brain
Spinal muscular atrophy[10][11][12] - + + - +/- + + - - _ _ _ Molecular genetic testing  by detection of homozygous deletions of exons 7 of the SMN1 gene
Guillain-Barré syndrome[13][14][15] - + +/- - + +/- - - - O2, ↑CO2 FEV1



Phrenic nerve injury ((Cardiothoracic surgery, central venous catheter insertion, critical illness polyneuropathy, paralytic agents, Subacute inflammatory demyelinating polyneuropathy)[16][17][18] +/- + + +/- - +/- - - -
  • Normal
Normal Vt, ↑RV


  • Fluoroscopic "sniff" test (diaphragmatic movement is observed fluoroscopically while the patient sniffs forcefully)
Myasthenia gravis[19][20][21] - + +/- - - + - - - O2, ↑CO2
  • Anti-AChR ab
  • Anti–striated muscle ab
  • Anti-MuSK ab


Muscular dystrophy[22][23] +/- + +/- - +/- +/- - +/- +/- O2, ↑CO2 FVC, ↓PEF
Pneumonia[24][25][26] + + +/- + +/- +/- - - - Normal Lobar consolidation Normal Normal Productive cough
Aspiration[27][28][29] +/- + +/- + +/- +/- + - - Normal Vt, ↑RV Bronchoscopy
Obstructive sleep apnea[30] + + +/- - +/- + +/- +/- +/- O2, ↑CO2 FRC Polysomnography
Pulmonary hypoplasia[31][32][33] - + +/- - +/- +/- + - - O2, ↑CO2 RV _
Metabolic alkalosis[34][35][36][37] - + +/- - +/- +/- - +/- +/- _ O2, ↑CO2 _ _ _
Sepsis[38][39][40] - + - + +/- +/- - - - Normal O2, ↑CO2 Normal Normal SIRS criteria
ROHHAD[41][42][43] - + +/- - +/- + +/- - - O2, ↑CO2 Vt _
Drugs ( e.g. morphine and barbiturates)
Encephalitis[44][45][46][47] - + - + + - + - - O2, ↑CO2
    • CSF PCR:
      • May reveal HSV-1, HSV-2, VZV, Enterovirus, parechovirus
    • Viruses: IgM and IgG in CSF and serum (acute and convalescent), for antibodies against HSV 1 & 2, VZV, CMV, HHV6, HHV7, enteroviruses, RSV, parvovirus B19, adenovirus, influenza A & B
    • If associated with atypical pneumonia, test serum for:
      • Mycoplasma serology and cold agglutinins
      • Chlamydia serology
  • Brain CT scan may show:
    • In case of HSV, subtle swelling of the frontotemporal region with loss of the normal gyral pattern
  • Brain MRI may show:
    • In case of autoimmune encephalitis, unilateral or bilateral medial temporal T2 high signal
    • In case of encephalitis associated with HSV, frontotemporal atrophy may be observed
  • Diagnostic criteria:
    • Major criteria (must be present):
      • Altered mental status (decreased level of consciousness, lethargy) present for greater than equal to 24 hours
    • Minor criteria ( 2 required for possible encephalitis, greater than equal to 3 required for probable or confirmed diagnosis):
      • Fever greater than equal to 24 hours without any other identified cause
      • Seizures without any history of seizure disorders
      • New onset focal neurological deficits
      • EEG changes typical of encephalitis without presence of other causes
      • CSF leukocyte count greater than equal to 5 cells/mm cube
      • Acute brain parenchymal changes of neuroimaging
  • PCR of CSF for viral encephalitis
  • Anti-NMDA-R antibody in the blood or CSF
High cervical dislocation (severe whiplash injury)[48][49][50] - + - - - + + - -
  • Normal breath sounds
O2, ↑CO2 -
  • X-ray:
    • Lateral shows subluxation of vertebral bodies
  • CT scan:
    • Demonstrates bony anatomy of the injury
    • Malalignment or subtle subluxation of facet 
    • Facet fracture associated fractures of the pedicle or lamina
Normal -
  • Traumatic injuries
Brainstem infarction or tumor
Severe upper airway obstruction (tracheal stenosis)

Epidemiology and Demographics

Risk Factors


Natural History, Complications, and Prognosis



  • Respiratory stimulants such as nikethamide were traditionally used to counteract respiratory depression from CNS depressant overdose, but were of only 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 is from opioid overdose, then the overdose itself is usually treated with an inverse agonist, most likely naloxone, which will itself almost instantaneously stop the respiratory depression if caused by an opioid (and also, depending on the dose, plunge the patient into precipitated withdrawal).


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