Hypoxemia (Low Blood Oxygen)

Table of Contents
View All
Table of Contents

Hypoxemia is a condition that occurs when you don't have enough oxygen in your blood. Though this can happen for a variety of reasons, hypoxemia appears to be relatively common in people with advanced chronic obstructive pulmonary disease (COPD). It also may result from other conditions, such as asthma, anemia, sleep apnea, and pneumonia.

This article discusses the symptoms, causes, diagnosis, and treatment of hypoxemia.

Health professional administering oxygen
E+ / Sturti / Getty Images 

What Are the Symptoms of Hypoxemia?

Symptoms of hypoxemia include:

  • Confusion
  • Shortness of breath
  • Increases in your heart rate, as your body tries to compensate for the low oxygen in your bloodstream

People with COPD who suffer from hypoxemia when they're at rest are more likely to have trouble concentrating and remembering, and those problems get worse as their hypoxemia does.

Complications

Hypoxemia often leads to hypoxia, a condition in which you don't have enough oxygen getting to your tissues. While many people confuse the two because of their similar names, they are distinct (hypoxemia only involves low oxygen in the blood itself). Hypoxemia may also result in cyanosis.

Hypoxia

In hypoxia, vital organs such as your heart and brain may suffer due to the lack of oxygen, and damage may ensue.

It's possible to have hypoxemia without hypoxia if your body compensates by boosting the amount of oxygen that reaches your tissues (for example, by making your heart beat faster to move oxygen-carrying blood around more quickly).

It's also possible to have hypoxia without hypoxemia if the oxygen delivery to your cells isn't working properly or if your cells aren't able to use oxygen properly.

Cyanosis

In severe hypoxemia, you might start to sweat or wheeze, your skin may get cold and clammy, and you may start to turn blue. The latter, cyanosis, indicates that there's not enough oxygenated blood reaching your cells.

Signs of an Emergency

Hypoxemia and hypoxia may be life-threatening conditions, and cyanosis is also a medical emergency. Seek emergency care by calling 911 if you experience the following.

Symptoms of hypoxemia and hypoxia:

  • Confusion
  • Severe shortness of breath
  • Rapid heart rate

Symptoms of cyanosis:

  • Skin or membranes appearing blue or grayish, especially if you have COPD or another illness that predisposes you to hypoxemia

Causes of Hypoxemia

Any condition that affects the efficient exchange of oxygen and carbon dioxide or the flow of blood in the body could result in hypoxemia.

Some of the most common causes of hypoxemia include:

  • Sleep apnea
  • Asthma
  • Emphysema
  • Bronchitis
  • Anemia
  • Exercising or having an illness at high altitude
  • COPD exacerbation
  • Pneumonia
  • Inflammation or scarring of the lung, such as pulmonary fibrosis
  • Pulmonary embolism
  • Pulmonary edema
  • Interstitial lung disease
  • Congenital heart defects
  • Congenital heart disease
  • Pneumothorax (collapsed lung)
  • Acute respiratory distress syndrome (ARDS)
  • Lung cancer

How Is Hypoxemia Diagnosed?

Hypoxemia is diagnosed by measuring the blood oxygen level via a blood test known as arterial blood gases (ABG) or via pulse oximetry, a noninvasive scanning probe that is usually clipped to a finger or earlobe and uses light to measure the amount of oxygen in your blood.

In an ABG test, the oxygen blood level is measured in millimeters of mercury (mmHg). A normal oxygen level in your arteries is about 80 to 100 mmHg. People with COPD usually have lower levels. If you have a very low level—usually around 60 mmHg—you may need supplemental oxygen.

However, providing too much oxygen can be dangerous, too, so your healthcare provider will need to work with you to get the correct balance.

With pulse oximetry, normal blood oxygen levels are around 95% to 100%; a low level is below 90%. It's possible to use pulse oximetry to measure your blood oxygen level at home. Talk to your healthcare provider about what readings you should expect from pulse oximetry depending on your condition and when to seek medical help for a low reading.

Treatment for Hypoxemia

Hypoxemia is typically the result of another condition that affects how your body processes oxygen. Your healthcare provider will treat your underlying condition in addition to treating symptoms of hypoxemia.

If your medical testing indicates you have chronic hypoxemia, your healthcare provider may recommend you use supplemental oxygen. However, supplemental oxygen may not help everyone, so you'll need to discuss the pros and cons with your healthcare provider.

Other treatment options may include stopping smoking if you're a smoker, avoiding secondhand smoke, and trying to get regular exercise to boost your lung function.

Some people with sleep apnea, COPD, or other lung conditions may experience hypoxemia mostly at night. This occurs because of breathing changes during sleep that decrease the amount of oxygen reaching your bloodstream.

In people without a pre-existing lung or heart condition, these breathing changes may not cause hypoxemia. But in people who have COPD, for example, these breathing changes can cause hypoxemia.

Some patients with mild hypoxemia problems during the day may be more prone to hypoxemia at night.

Talk to your healthcare provider if you're having symptoms of hypoxemia at night, such as shallow breathing, rapid heart rate, not feeling rested upon waking, snoring, mouth breathing, and sweating. Your healthcare provider may recommend a continuous positive airway pressure machine (CPAP) or surgery to remove any potential obstructions.

Summary

Hypoxemia occurs when your blood isn't carrying enough oxygen, which can be a life-threatening condition. Shortness of breath, rapid heart rate, confusion, and cyanosis are symptoms of hypoxemia that require immediate medical attention.

Talk to your healthcare provider if you experience shortness of breath while resting, after exercise or exertion, or during sleep to discuss options for combatting potential hypoxemia.

11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Kent BD, Mitchell PD, Mcnicholas WT. Hypoxemia in patients with COPD: cause, effects, and disease progression. Int J Chron Obstruct Pulmon Dis. 2011;6:199-208. doi:10.2147/COPD.S10611

  2. Cleveland Clinic. Hypoxemia.

  3. Dodd J, Getov S, Jones P. Cognitive function in COPDEuropean Respiratory Journal. 2010;35(4):913-922. doi:10.1183/09031936.00125109

  4. Ebner, F., Ullén, S., Åneman, A. et al. Associations between partial pressure of oxygen and neurological outcome in out-of-hospital cardiac arrest patients: an explorative analysis of a randomized trialCrit Care 2019;23(1):30. doi:10.1186/s13054-019-2322-z

  5. Duke T, Peel D, Graham S, Howie S, Enarson PM, Jacobson R. Oxygen concentrators: a practical guide for clinicians and technicians in developing countries. Ann Trop Paediatr.

  6. Tiep B, Carter R, Zachariah F, et al. Oxygen for end-of-life lung cancer care: managing dyspnea and hypoxemia. Expert Rev Respir Med.

  7. Johns Hopkins Medicine. Pulse oximetry.

  8. Sarkar M, Niranjan N, Banyal PK. Mechanisms of hypoxemia. Lung India. 2017;34(1):47-60. doi:10.4103/0970-2113.197116

  9. Majumdar SR, Eurich DT, Gamble JM, Senthilselvan A, Marrie TJ. Oxygen saturations less than 92% are associated with major adverse events in outpatients with pneumonia: a population-based cohort study. Clin Infect Dis. 2011;52(3):325-31. doi:10.1093/cid/ciq076

  10. Cleveland Clinic. Hypoxemia: prevention.

  11. Dorsch JJ, Wickwire EM. OSA/COPD overlap: convergence on a theme? J Clin Sleep Med. 2019;15(1):9-10. doi:10.5664/jcsm.7556

By Deborah Leader, RN
 Deborah Leader RN, PHN, is a registered nurse and medical writer who focuses on COPD.