What Is Respiratory Acidosis?

Medically Reviewed by Dan Brennan, MD on June 05, 2021

Respiratory acidosis is your body’s response to having too much carbon dioxide (CO2) in your lungs. The large amount of CO2 makes your body fluids and blood acidic to the point where your blood pH is over 45 mm Hg and then rapidly drops to compensate.

Mm Hg is the way blood pressure is measured and stands for the units of millimeters of mercury. A typical range for your blood pH is 35 mm Hg to 45 mm Hg.

Respiratory acidosis is caused when a disease, another condition, or a physical block limits your ability to breathe. Respiratory acidosis is either chronic and asymptomatic or acute and symptomatic. 


The blood becomes so acidic that the increase of carbon dioxide in your body triggers your kidneys to produce more acidic hydrogen and ammonium to absorb the bicarbonate. While the C02 might cause a disturbance to the body at first, the kidney's response to the disruption in pH creates a surplus of acid in the blood. This response is referred to medically as a “compensation”. 

Depending on whether you have acute, chronic, or acute and chronic respiratory acidosis, the causes of respiratory acidosis will be different. Additionally, the severity and medical situation surrounding the respiratory acidosis will also significantly change the experience of each case. 

Causes of Acute Respiratory Acidosis

Acute respiratory acidosis is defined as a sudden arrival of C02 to the lungs. Due to its sudden nature, the causes of acute respiratory acidosis are more clear-cut and perhaps, shocking. The effects of acute respiratory acidosis are so quick that the kidney’s response to it happens within minutes.

The causes include:

  • Strokes or other cerebrovascular accidents
  • Medications that slow down the nervous system like opioids, benzodiazepines, and pain medication
  • Myasthenia gravis, which is when your voluntary muscles become weak, or you lose control of them.
  • Muscular dystrophy, a group of diseases that interfere with your gene's ability to make muscle and cause you to steadily lose your muscles. 
  • Guillain-Barre Syndrome, a very rare neurological disorder in which the immune system attacks itself. This can cause problems from trouble eating to full body paralysis. 
  • Blocked airways
  • Cardiac arrest (heart attack)

Causes of Chronic Respiratory Acidosis

On the contrary, chronic respiratory acidosis is usually a symptom of a more serious, underlying condition. It usually happens at a lesser degree than acute respiratory acidosis and at a slower rate. People who have chronic respiratory acidosis bodies are often desensitized by certain features of respiratory acidosis. The most common of which would be being accustomed to a lower oxygen rate than is necessary for your tissues to be fully supplied with blood, also known as hypoxemia. They might even regard their symptoms as usual. 

These conditions could be: 

  • Chronic obstructive pulmonary disease (COPD); a group of airflow and breathing diseases that include diseases like emphysema and bronchitis
  • Asthma
  • Diseases that happen in the lung tissue like pulmonary fibrosis
  • Muscular or nerve diseases
  • Obesity
  • Sleep apnea
  • Thoracic skeletal defects that cause your rib cage, pecs, or sternum to be shaped in such a way that it limits your breathing or lung functioning


Symptoms of respiratory acidosis include: 

  • Hyperventilating
  • Shortness of breath
  • Fatigue
  • Chronic exhaustion
  • Headaches
  • Drowsiness
  • Confusion 
  • Sweating 
  • Flushed skin
  • Memory loss
  • Irregular sleep patterns
  • Tremors
  • Trouble walking
  • Slower tendon refluxes
  • Involuntary muscle twitching 
  • Papilledema, the swelling of the eye nerves due to cranial pressure
  • Hypoxia, a lack of oxygen in the blood and tissues

Usually, respiratory acidosis is a symptom of another underlying condition. If untreated, this condition could cause the symptoms of respiratory acidosis to become more severe and noticeable. It can even lead to:

  • Organ failure
  • Shock
  • Coma
  • Severe damage to the kidneys 
  • Seizures
  • Intracranial pressure

Depending on the severity of the respiratory acidosis, its symptoms, and its causes, it can lead to death. When there is a clear cause, it needs to be removed or otherwise dealt with. 

Some of the most common forms of treatment for these underlying illnesses are:

  • Medicines that help widen the bronchi
  • Anti-inflammatory medications to ease any constrictive swelling
  • Breathing machines like a CPAP or BiPAP
  • Oxygen tubes
  • Medication or other treatment to stop smoking
  • Different medications
  • Naloxone (for opioid overdose)

Testing for Respiratory Acidosis

If you think you have respiratory acidosis, you will need to get tested by a healthcare professional to understand how severe it is. This is especially true if you have chronic respiratory acidosis, which can be challenging to detect.

Most likely, these tests will be:

Serum Bicarbonate Testing‌

Possibly the most important test to get for respiratory acidosis, this test will test the level of carbon dioxide in your blood. It is a relatively non-invasive procedure that merely requires a blood sample from the arm with a needle. 

Arterial Blood Glass (ABV) 

These tests show the acidity as well as the balance between oxygen and carbon in your blood. This test is also done by collecting a blood sample with a needle.

In addition to these tests, your healthcare provider might want to do other tests related to your muscles, kidneys, sleep, or breathing. It all depends on your unique medical situation and the cause or possible cause of your respiratory acidosis. 


The best way to prevent getting respiratory acidosis is simply to quit smoking or not to start smoking. Being overweight or obese also dramatically increases your chances of getting respiratory acidosis. Losing weight would help you to avoid getting it.

Additionally, if you are prescribed strong pain medications or opioids, it is imperative that you do not drink alcohol when you take these medications. 

Show Sources


Centers for Disease Control and Prevention: "Alcohol Screening and Brief Intervention For People Who Consume Alcohol and Use Opioids," "Chronic Obstructive Pulmonary Disease (COPD)."

Harvard Health Publishing: Harvard Medical School: "Optic Nerve Swelling (Papilledema)." "What is blood pressure and how is it measured?"

Johns Hopkins Medicine: "Pulmonary Function Test."

Mayo Clinic: "Myasthenia gravis," "Muscular dystrophy," "Hypoxemia."

Medscape: "Respiratory Acidosis."

Merck Manual: “Respiratory Acidosis.”

National Institue of Neurological Disorders and Stroke: "Guillan-Barre Syndrome Fact Sheet."

Patel, S.; Sharma, S. StatPearls: Respiratory Acidosis. StatPearls Publishing, 2021.

Riley's Children's Health: "Thoracic Abnormalities."

University of Rochester Medical Center: “Arterial Blood Gas (ABG),” “Bicarbonate.”

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