Table of ContentsView AllTable of ContentsSymptomsCausesDiagnosisTreatment
Table of ContentsView All
View All
Table of Contents
Symptoms
Causes
Diagnosis
Treatment
Acidic blood can lead to increasingly serious symptoms, starting with sleepiness and progressing to coma. Respiratory acidosis is a medical emergency that requires prompt diagnosis and treatment.
This article looks at the symptoms and causes of respiratory acidosis plus how it’s diagnosed and treated.
Acidosis: Understanding the Imbalance of Acids and Bases
Symptoms of Respiratory Acidosis
As carbon dioxide levels in your blood rise, blood flow to your brain increases.That leads to specific impairments, each tied to certain symptoms.
Because respiratory acidosis puts the body under stress, it generally releases stress hormones (catecholamines).These may lead to further symptoms.
Madelyn Goodnight / Verywell
The most common symptoms of respiratory acidosis include:
Less common symptoms may be:
Some of these symptoms may occur early on. Others may develop later. For example, someone may at first be fatigued, become more lethargic, and eventually grow unresponsive and slip into a coma.
Call 911Severe respiratory acidosis is a medical emergency and requires immediate medical attention. If you suspect symptoms are developing, call 911 or get to an emergency room. If left untreated, it can lead to organ failure, shock, and even death.
Call 911
Severe respiratory acidosis is a medical emergency and requires immediate medical attention. If you suspect symptoms are developing, call 911 or get to an emergency room. If left untreated, it can lead to organ failure, shock, and even death.
Causes of Respiratory Acidosis
When your breathing becomes too impaired to clear carbon dioxide out of your blood, it’s calledhypoventilation. Hypoventilation makes blood carbon dioxide levels rise, which makes your blood more acidic.
These changes may be acute (from sudden illness) or chronic (from long-term diseases).
In acute respiratory acidosis, carbon dioxide levels may build up very quickly due to an acute medical condition that disrupts the acid-base balance. These illnesses include:
Chronic respiratory acidosis is the result of long-term illnesses including:
Shifting Acid-Base Balance
The pH scale is used to measure acidity or alkalinity. Higher numbers mean it’s more alkaline and lower numbers mean it’s more acidic.
The body’sacid-base balanceis usually a pH level between 7.35 and 7.45. When it falls below 7.35, it’s called acidosis. If it goes above 7.45, it’s called alkalosis.
Conditions that cause or contribute to respiratory acidosis include:
Brainstem Impairment
Yourbrainstemcontrols respiration (breathing). To do so, it sends signals to the respiratory muscles (especially the diaphragm) that make the lungs inflate (as you inhale) and deflate (when you exhale).
As the diaphragm contracts, it’s drawn down and allows the lungs to fill with air. As it relaxes, the lungs passively empty.
These abnormalities typically cause other symptoms, often affecting consciousness and contributing to unresponsiveness and, in severe cases, coma.
Airway Blockage
Air can be blocked at various points before reaching your lungs. The windpipe (trachea) can be obstructed. Small grape-like sacs within the lungs—calledalveoli—may become stiff or filled with mucus.
A blocked airway may gradually lead to respiratory failure and acidosis. Causal factors can include:
These conditions may be associated with wheezing, shortness of breath, coughing, and other signs of breathing problems.
Inadequate Lung Tissue Ventilation and Perfusion
To rid the body of carbon dioxide, the blood must deliver it to functioning alveoli that are well ventilated (able to move air in and out properly). Compromised blood flow, or lung tissue that cannot be adequately filled with air, both affect function.
When there’s a mismatch between airflow (ventilation) and blood flow (perfusion), this leads to a condition called dead space ventilation.This loss of function can contribute to respiratory acidosis and may be due to:
Many of these problems lead to breathing difficulties that may become evident due to decreased oxygen levels.
Musculoskeletal Failure
Thediaphragmis primarily responsible for expanding and filling your lungs. If this muscle fails, it can compromise your breathing.
Disorders that restrict lung expansion or weaken the muscles that aid breathing may gradually cause respiratory acidosis. Potential causes include:
Your healthcare provider may order tests to gauge the impact of these conditions on respiratory acidosis.
Diagnosis of Respiratory Acidosis
Respiratory acidosis typically gets noticed when someone shows signs of difficulty breathing or has a change in consciousness (being disoriented or passing out).
Sudden symptoms need emergency treatment. Gradual symptoms aren’t usually as urgent but you should call your healthcare provider or get checked out soon.
Your healthcare provider has many tools available to help them identify respiratory acidosis.
Physical Exam
During a physical examination, they’ll generally:
If your provider determines your condition is unstable, they’ll move on to blood tests.
Initial Blood Tests
Blood tests for respiratory acidosis reveal thecarbon dioxideand pH levels of your blood.
In chronic respiratory acidosis, the PaC02 may be elevated with a normal or near-normal acidity level. This occurs when the kidneys compensate for acidosis.
Further Testing and Imaging
To identify the causes of respiratory acidosis, your healthcare provider may order:
More tests may be necessary depending on the suspected cause, especially if it may be due to an abnormality of the brain or musculoskeletal system.
Treatment of Respiratory Acidosis
However, it may not be enough to bring your acidity level back to normal, meaning you need treatment. The standard treatment is to improve your breathing and address the underlying cause of respiratory acidosis.
Noninvasive Positive-Pressure Ventilation
Your breathing may be improved with acontinuous positive airway pressure (CPAP)orbilevel (BiPAP)machine. These devices are typically used to treat obstructive sleep apnea (OSA), but they can be used for acute cases of respiratory acidosis.
CPAP and BiPAP deliver pressurized air through aface maskover your nose and sometimes your mouth. That helps your lungs expel carbon dioxide.
Oxygen Supplementation
If your blood oxygen level is low, you may be given additional oxygen.
However,oxygen therapyalone isn’t an effective treatment—it may actually suppress breathing in some cases, pushing the acidity even further.
Intubation
If breathing difficulties progress, it may be necessary to put a breathing tube in your airway, where it can directly ventilate the lungs.This means you’ll need to be in an intensive care unit.
If you need this treatment, you’ll be sedated and restrained so you don’t accidentally rip out the tube. The tube is then connected to a ventilator, which helps your lungs breathe in oxygen and breathe out carbon dioxide.
Cause-Depended Treatments
Other treatments depend on the causes and contributing factors of your respiratory acidosis. These may include:
Summary
Respiratory acidosis is a potentially life-threatening condition in which your blood becomes too acidic. This is usually due to a breathing problem.
Diagnosis involves a physical exam, blood tests for carbon dioxide and acid levels, lung function tests, and imaging.
Treatment involves breathing assistance and resolving or managing the underlying cause(s).
A Word From Verywell
If you think you have respiratory acidosis, don’t hesitate—call 911 or get to an emergency room right away.
Once you get a proper diagnosis and treatment, you can get better and hopefully prevent future recurrences. Be sure you follow your healthcare provider’s directions for treating both respiratory acidosis and any conditions that may have caused it.
18 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.MedlinePlus.Respiratory acidosis.Palmer BF, Clegg DJ.Respiratory acidosis and respiratory alkalosis: core curriculum 2023[published correction appears in Am J Kidney Dis. 2024 Jan;83(1):126. doi:10.1053/j.ajkd.2023.10.005].Am J Kidney Dis. 2023;82(3):347-359. doi:10.1053/j.ajkd.2023.02.004Robba C, Siwicka-Gieroba D, Sikter A, et al.Pathophysiology and clinical consequences of arterial blood gases and pH after cardiac arrest.Intensive Care Med Exp. 2020;8(Suppl 1):19. Published 2020 Dec 18. doi:10.1186/s40635-020-00307-1MedlinePlus.Hypoventilation.Seifter JL, Chang HY.Disorders of acid-base balance: new perspectives.Kidney Dis (Basel). 2017;2(4):170-186. doi:10.1159/000453028Alon MH, Saint-Fleur MO.Synthetic cannabinoid induced acute respiratory depression: case series and literature review.Respir Med Case Rep. 2017;22:137-141. doi:10.1016/j.rmcr.2017.07.011Csoma B, Vulpi MR, Dragonieri S, et al.Hypercapnia in COPD: Causes, consequences, and therapy.J Clin Med. 2022;11(11):3180. Published 2022 Jun 2. doi:10.3390/jcm11113180Shaw I, Gregory K.Acid-base balance: a review of normal physiology[published correction appears in BJA Educ. 2023 Jan;23(1):39. doi: 10.1016/j.bjae.2022.11.004].BJA Educ. 2022;22(10):396-401. doi:10.1016/j.bjae.2022.06.003Imenez Silva PH, Mohebbi N.Kidney metabolism and acid-base control: back to the basics.Pflugers Arch. 2022;474(8):919-934. doi:10.1007/s00424-022-02696-6Benghanem S, Mazeraud A, Azabou E, et al.Brainstem dysfunction in critically ill patients.Crit Care. 2020;24(1):5. Published 2020 Jan 6. doi:10.1186/s13054-019-2718-9Fayssoil A, Mansencal N, Nguyen LS, et al.Diaphragm ultrasound in cardiac surgery: state of the art.Medicines (Basel). 2022;9(1):5. doi:10.3390/medicines9010005Claytor B, Cho SM, Li Y.Myasthenic crisis.Muscle Nerve. 2023;68(1):8-19. doi:10.1002/mus.27832Valsamis EM, Smith I, De Sousa A.An unusual cause of ventilatory failure in motor neurone disease.Respir Med Case Rep. 2017;21:59-61. doi:10.1016/j.rmcr.2017.03.013Pippalapalli J, Lumb AB.The respiratory system and acid-base disorders.BJA Educ. 2023;23(6):221-228. doi:10.1016/j.bjae.2023.03.002Wasilewska E, Małgorzewicz S, Sobierajska-Rek A, et al.Transition from childhood to adulthood in patients with Duchenne muscular dystrophy.Medicina (Kaunas). 2020;56(9):426. doi:10.3390/medicina56090426Mani S, Rutecki GW.A patient with altered mental status and an acid-base disturbance.Cleve Clin J Med. 2017;84(1):27-34. doi:10.3949/ccjm.84a.16042Brown LK.Obesity hypoventilation syndrome.Curr Sleep Medicine Rep.2015;1:241–250. doi:10.1007/s40675-015-0026-8Ogino H, Nishimura N, Yamano Y, et al.Analysis of the clinical backgrounds of patients who developed respiratory acidosis under high-flow oxygen therapy during emergency transport.Acute Med Surg. 2015;3(1):26-31. doi:10.1002/ams2.138
18 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.MedlinePlus.Respiratory acidosis.Palmer BF, Clegg DJ.Respiratory acidosis and respiratory alkalosis: core curriculum 2023[published correction appears in Am J Kidney Dis. 2024 Jan;83(1):126. doi:10.1053/j.ajkd.2023.10.005].Am J Kidney Dis. 2023;82(3):347-359. doi:10.1053/j.ajkd.2023.02.004Robba C, Siwicka-Gieroba D, Sikter A, et al.Pathophysiology and clinical consequences of arterial blood gases and pH after cardiac arrest.Intensive Care Med Exp. 2020;8(Suppl 1):19. Published 2020 Dec 18. doi:10.1186/s40635-020-00307-1MedlinePlus.Hypoventilation.Seifter JL, Chang HY.Disorders of acid-base balance: new perspectives.Kidney Dis (Basel). 2017;2(4):170-186. doi:10.1159/000453028Alon MH, Saint-Fleur MO.Synthetic cannabinoid induced acute respiratory depression: case series and literature review.Respir Med Case Rep. 2017;22:137-141. doi:10.1016/j.rmcr.2017.07.011Csoma B, Vulpi MR, Dragonieri S, et al.Hypercapnia in COPD: Causes, consequences, and therapy.J Clin Med. 2022;11(11):3180. Published 2022 Jun 2. doi:10.3390/jcm11113180Shaw I, Gregory K.Acid-base balance: a review of normal physiology[published correction appears in BJA Educ. 2023 Jan;23(1):39. doi: 10.1016/j.bjae.2022.11.004].BJA Educ. 2022;22(10):396-401. doi:10.1016/j.bjae.2022.06.003Imenez Silva PH, Mohebbi N.Kidney metabolism and acid-base control: back to the basics.Pflugers Arch. 2022;474(8):919-934. doi:10.1007/s00424-022-02696-6Benghanem S, Mazeraud A, Azabou E, et al.Brainstem dysfunction in critically ill patients.Crit Care. 2020;24(1):5. Published 2020 Jan 6. doi:10.1186/s13054-019-2718-9Fayssoil A, Mansencal N, Nguyen LS, et al.Diaphragm ultrasound in cardiac surgery: state of the art.Medicines (Basel). 2022;9(1):5. doi:10.3390/medicines9010005Claytor B, Cho SM, Li Y.Myasthenic crisis.Muscle Nerve. 2023;68(1):8-19. doi:10.1002/mus.27832Valsamis EM, Smith I, De Sousa A.An unusual cause of ventilatory failure in motor neurone disease.Respir Med Case Rep. 2017;21:59-61. doi:10.1016/j.rmcr.2017.03.013Pippalapalli J, Lumb AB.The respiratory system and acid-base disorders.BJA Educ. 2023;23(6):221-228. doi:10.1016/j.bjae.2023.03.002Wasilewska E, Małgorzewicz S, Sobierajska-Rek A, et al.Transition from childhood to adulthood in patients with Duchenne muscular dystrophy.Medicina (Kaunas). 2020;56(9):426. doi:10.3390/medicina56090426Mani S, Rutecki GW.A patient with altered mental status and an acid-base disturbance.Cleve Clin J Med. 2017;84(1):27-34. doi:10.3949/ccjm.84a.16042Brown LK.Obesity hypoventilation syndrome.Curr Sleep Medicine Rep.2015;1:241–250. doi:10.1007/s40675-015-0026-8Ogino H, Nishimura N, Yamano Y, et al.Analysis of the clinical backgrounds of patients who developed respiratory acidosis under high-flow oxygen therapy during emergency transport.Acute Med Surg. 2015;3(1):26-31. doi:10.1002/ams2.138
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
MedlinePlus.Respiratory acidosis.Palmer BF, Clegg DJ.Respiratory acidosis and respiratory alkalosis: core curriculum 2023[published correction appears in Am J Kidney Dis. 2024 Jan;83(1):126. doi:10.1053/j.ajkd.2023.10.005].Am J Kidney Dis. 2023;82(3):347-359. doi:10.1053/j.ajkd.2023.02.004Robba C, Siwicka-Gieroba D, Sikter A, et al.Pathophysiology and clinical consequences of arterial blood gases and pH after cardiac arrest.Intensive Care Med Exp. 2020;8(Suppl 1):19. Published 2020 Dec 18. doi:10.1186/s40635-020-00307-1MedlinePlus.Hypoventilation.Seifter JL, Chang HY.Disorders of acid-base balance: new perspectives.Kidney Dis (Basel). 2017;2(4):170-186. doi:10.1159/000453028Alon MH, Saint-Fleur MO.Synthetic cannabinoid induced acute respiratory depression: case series and literature review.Respir Med Case Rep. 2017;22:137-141. doi:10.1016/j.rmcr.2017.07.011Csoma B, Vulpi MR, Dragonieri S, et al.Hypercapnia in COPD: Causes, consequences, and therapy.J Clin Med. 2022;11(11):3180. Published 2022 Jun 2. doi:10.3390/jcm11113180Shaw I, Gregory K.Acid-base balance: a review of normal physiology[published correction appears in BJA Educ. 2023 Jan;23(1):39. doi: 10.1016/j.bjae.2022.11.004].BJA Educ. 2022;22(10):396-401. doi:10.1016/j.bjae.2022.06.003Imenez Silva PH, Mohebbi N.Kidney metabolism and acid-base control: back to the basics.Pflugers Arch. 2022;474(8):919-934. doi:10.1007/s00424-022-02696-6Benghanem S, Mazeraud A, Azabou E, et al.Brainstem dysfunction in critically ill patients.Crit Care. 2020;24(1):5. Published 2020 Jan 6. doi:10.1186/s13054-019-2718-9Fayssoil A, Mansencal N, Nguyen LS, et al.Diaphragm ultrasound in cardiac surgery: state of the art.Medicines (Basel). 2022;9(1):5. doi:10.3390/medicines9010005Claytor B, Cho SM, Li Y.Myasthenic crisis.Muscle Nerve. 2023;68(1):8-19. doi:10.1002/mus.27832Valsamis EM, Smith I, De Sousa A.An unusual cause of ventilatory failure in motor neurone disease.Respir Med Case Rep. 2017;21:59-61. doi:10.1016/j.rmcr.2017.03.013Pippalapalli J, Lumb AB.The respiratory system and acid-base disorders.BJA Educ. 2023;23(6):221-228. doi:10.1016/j.bjae.2023.03.002Wasilewska E, Małgorzewicz S, Sobierajska-Rek A, et al.Transition from childhood to adulthood in patients with Duchenne muscular dystrophy.Medicina (Kaunas). 2020;56(9):426. doi:10.3390/medicina56090426Mani S, Rutecki GW.A patient with altered mental status and an acid-base disturbance.Cleve Clin J Med. 2017;84(1):27-34. doi:10.3949/ccjm.84a.16042Brown LK.Obesity hypoventilation syndrome.Curr Sleep Medicine Rep.2015;1:241–250. doi:10.1007/s40675-015-0026-8Ogino H, Nishimura N, Yamano Y, et al.Analysis of the clinical backgrounds of patients who developed respiratory acidosis under high-flow oxygen therapy during emergency transport.Acute Med Surg. 2015;3(1):26-31. doi:10.1002/ams2.138
MedlinePlus.Respiratory acidosis.
Palmer BF, Clegg DJ.Respiratory acidosis and respiratory alkalosis: core curriculum 2023[published correction appears in Am J Kidney Dis. 2024 Jan;83(1):126. doi:10.1053/j.ajkd.2023.10.005].Am J Kidney Dis. 2023;82(3):347-359. doi:10.1053/j.ajkd.2023.02.004
Robba C, Siwicka-Gieroba D, Sikter A, et al.Pathophysiology and clinical consequences of arterial blood gases and pH after cardiac arrest.Intensive Care Med Exp. 2020;8(Suppl 1):19. Published 2020 Dec 18. doi:10.1186/s40635-020-00307-1
MedlinePlus.Hypoventilation.
Seifter JL, Chang HY.Disorders of acid-base balance: new perspectives.Kidney Dis (Basel). 2017;2(4):170-186. doi:10.1159/000453028
Alon MH, Saint-Fleur MO.Synthetic cannabinoid induced acute respiratory depression: case series and literature review.Respir Med Case Rep. 2017;22:137-141. doi:10.1016/j.rmcr.2017.07.011
Csoma B, Vulpi MR, Dragonieri S, et al.Hypercapnia in COPD: Causes, consequences, and therapy.J Clin Med. 2022;11(11):3180. Published 2022 Jun 2. doi:10.3390/jcm11113180
Shaw I, Gregory K.Acid-base balance: a review of normal physiology[published correction appears in BJA Educ. 2023 Jan;23(1):39. doi: 10.1016/j.bjae.2022.11.004].BJA Educ. 2022;22(10):396-401. doi:10.1016/j.bjae.2022.06.003
Imenez Silva PH, Mohebbi N.Kidney metabolism and acid-base control: back to the basics.Pflugers Arch. 2022;474(8):919-934. doi:10.1007/s00424-022-02696-6
Benghanem S, Mazeraud A, Azabou E, et al.Brainstem dysfunction in critically ill patients.Crit Care. 2020;24(1):5. Published 2020 Jan 6. doi:10.1186/s13054-019-2718-9
Fayssoil A, Mansencal N, Nguyen LS, et al.Diaphragm ultrasound in cardiac surgery: state of the art.Medicines (Basel). 2022;9(1):5. doi:10.3390/medicines9010005
Claytor B, Cho SM, Li Y.Myasthenic crisis.Muscle Nerve. 2023;68(1):8-19. doi:10.1002/mus.27832
Valsamis EM, Smith I, De Sousa A.An unusual cause of ventilatory failure in motor neurone disease.Respir Med Case Rep. 2017;21:59-61. doi:10.1016/j.rmcr.2017.03.013
Pippalapalli J, Lumb AB.The respiratory system and acid-base disorders.BJA Educ. 2023;23(6):221-228. doi:10.1016/j.bjae.2023.03.002
Wasilewska E, Małgorzewicz S, Sobierajska-Rek A, et al.Transition from childhood to adulthood in patients with Duchenne muscular dystrophy.Medicina (Kaunas). 2020;56(9):426. doi:10.3390/medicina56090426
Mani S, Rutecki GW.A patient with altered mental status and an acid-base disturbance.Cleve Clin J Med. 2017;84(1):27-34. doi:10.3949/ccjm.84a.16042
Brown LK.Obesity hypoventilation syndrome.Curr Sleep Medicine Rep.2015;1:241–250. doi:10.1007/s40675-015-0026-8
Ogino H, Nishimura N, Yamano Y, et al.Analysis of the clinical backgrounds of patients who developed respiratory acidosis under high-flow oxygen therapy during emergency transport.Acute Med Surg. 2015;3(1):26-31. doi:10.1002/ams2.138
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