What is hypoxia and hypoxemia (low blood oxygen)?
Hypoxia is a condition or state in which the supply of oxygen in the arteries is insufficient for normal life functions. Hypoxemia is a condition or state in which there is a low arterial oxygen supply. Hypoxia is sometimes used to describe both states (hypoxia and hypoxemia).
Within the body, hypoxemia can lead to hypoxia (tissue hypoxia) in various tissues and organs with the most severe being cerebral hypoxia which can rapidly result in brain damage or death.
Conversely, if a person experiences environmental hypoxia (low or absent oxygen in the environment from high altitudes or drowning, for example), the person can develop hypoxemia.
What are the types of hypoxia and hypoxemia?
- Hypoxic hypoxia (arterial hypoxia or generalized hypoxia):
- Anemic hypoxia:
- Decreased hemoglobin levels in the blood, hence there is decreased oxygen capacity of the blood. Hemoglobin is a protein in red blood cells (RBC) that binds to oxygen and supplies oxygen to the entire body. It also gives blood its characteristic red color.
- Anemic hypoxia can be caused by heavy blood loss, decreased RBCs, or decreased hemoglobin levels due to severe iron deficiency or hemoglobin deformity.
- Ischemic/Stagnant hypoxia:
- Inadequate blood flow to the body tissues because the velocity of blood flow decreases.
- This could be due to heart failure, severe blood loss, or clots in a blood vessel.
- Dysoxic/Histotoxic/Tissue hypoxia:
- The oxygen delivered to the tissues is normal, but the cells are unable to use the oxygen. For example, cyanide poisoning.
- Cyanide binds to the oxygen-binding proteins and other parts of the cells in the tissue, preventing the interaction and consumption of oxygen in the tissues.
What causes hypoxia and hypoxemia?
The causes of both environmental and tissue hypoxia often result in the intermediate state of hypoxemia; thus, the causes of any type of hypoxia are also potential causes of hypoxemia.
Some of the many causes of hypoxia include:
- Chemical or gas poisoning (for example cyanide, carbon monoxide)
- The low or absent concentration of oxygen (for example, high altitudes reached without supplemental oxygen as seen in mountain climbing, aviation, drowning, or fires)
- Lung problems, for example:
- Any medications that reduce or stop the effort for breathing (for example, fentanyl and other narcotics, or general anesthetic medications)
- Heart problems (for example, severe bradycardia, and ventricular fibrillation)
- Anemia and/or conditions that destroy red blood cells
- Reducing or stopping arterial blood flow to any tissue for an organ (for example, arterial blockage by a clot or by injury such as a gunshot)
- After Salmonella Cases Double in a Week, Cantaloupe Recall Expanded
- Soccer 'Heading' Tied to Declines in Brain Function
- Smoking Tobacco Plus Weed Greatly Raises Odds for Emphysema
- COVID Vaccines Curbed Pandemic-Linked Surge in Preemie Births
- Could a 'Brain Coach' Help Folks at Higher Risk for Alzheimer's?
- More Health News »
What are the symptoms of hypoxia and hypoxemia?
The symptoms of hypoxia and/or hypoxemia may be acute or chronic.
Acute symptoms can come on rapidly and usually consist of:
- Shortness of breath
- Rapid breathing
- A fast heart rate
Other associated symptoms that can occur in both acute and chronic hypoxia and hypoxemia include:
The affected individual may be mildly confused initially and appear weak or may experience rapid changes in skin color ranging from blue to cherry red (depending on the causes).
Severe symptoms seen with cerebral hypoxia include:
- Inability to communicate
- Coma, which can lead to death
The symptoms of cerebral hypoxia in pediatric patients can be similar to the above and may include:
- Sitting up and leaning forward to improve diaphragmatic breathing
- Children with epiglottitis and airway restriction may drool and mainly breathe by mouth
How are hypoxia and hypoxemia diagnosed?
In general, an individual patient’s hypoxemia is usually diagnosed by oxygen monitors placed on fingers or ears (pulse oximeter) and/or by determining the oxygen level in a blood gas sample (a sample of blood taken from an artery). Normal readings are about 95% to 100% oxygen saturation levels; generally, oxygen is supplied if the level is about 92% or below.
|Normal||95% to 100%|
|Brain Gets Affected||80% to 85%|
Other tests may be ordered to determine if other potential problems such as carbon monoxide poisoning are responsible for the hypoxia.
Pulmonary function tests may also be ordered along with other studies to help determine the cause of unexplained low oxygen saturation.
What is the treatment for hypoxia and hypoxemia?
The treatment for hypoxia and/or hypoxemia is to give additional oxygen to the patient and into the body (blood) as quickly as possible, especially if cerebral hypoxia is suspected, or to treat the underlying cause of the hypoxia.
Many patients will respond to additional oxygen supplied by a nasal cannula. The quicker the oxygen level reaches normal, the better the prognosis is for the patient. However, timing is very important, because cerebral hypoxia can occur within a few minutes and, in many patients, may not be reversible.
Some patients may be treated in a hyperbaric chamber that increases oxygen concentrations in the blood (used in carbon monoxide poisoning), while others may require mechanical ventilation (intubation) with oxygen supplied at higher than normal atmospheric concentrations.
Others, such as mountain climbers or airline passengers, may need only additional oxygen provided by oxygen masks until they reach lower levels where oxygen concentrations are closer to the normal levels (about 21%) in the atmosphere.
Care must be used when giving oxygen, as it can be toxic to tissues if it is used excessively (hyperoxia). Hyperoxia may cause:
- Behavior changes
- Other central nervous system changes such as seizures and/or tissue damage, may result in:
Hyperoxia may occur in patients undergoing hyperbaric therapy or in long-term ICU patients.
What are complications of hypoxia?
Hypoxia causes decreased oxygenation of multiple organs such as the brain, liver, kidneys, etc., damaging them, and ultimately leading to organ failure. It can potentially lead to death. Hypoxia during pregnancy may also result in fetal death. Hypoxia in newborns is associated with a high mortality rate.
If hypoxia is identified and treated early, patients can recover without any complications.
Can hypoxia and hypoxemia be prevented?
Hypoxia and hypoxemia may be prevented in some individuals by avoiding circumstances that reduce the oxygen concentration in the environment or by providing oxygen via nasal cannula or oxygen masks before hypoxia and/or hypoxemia develop.
This can be done by recognizing individuals who tend to develop hypoxia and/or hypoxemia and providing them oxygen if they develop any early symptoms.
Health Solutions From Our Sponsors
Medscape. Pediatric Respiratory Failure.
Patel, N. D. "Oxygen Toxicity." JIACM 2003; 4(3): 234-7.
Top Hypoxia and Hypoxemia Related Articles
AnemiaAnemia is the condition of having less than the normal number of red blood cells or less than the normal quantity of hemoglobin in the blood. The oxygen-carrying capacity of the blood is, therefore, decreased. There are several types of anemia such as iron deficiency anemia (the most common type), sickle cell anemia, vitamin B12 anemia, pernicious anemia, and aplastic anemia. Symptoms of anemia may include fatigue, malaise, hair loss, palpitations, menstruation, and medications. Treatment for anemia includes treating the underlying cause for the condition. Iron supplements, vitamin B12 injections, and certain medications may also be necessary.
What Is Asthma? Symptoms, Causes, and TreatmentsWhat is asthma? What is the main cause of asthma? Learn information about asthma, a chronic disease of the bronchiole tubes. Discover information about asthma attacks, complications of asthma, and how to control an asthma attack.
Asthma QuizAsthma is a chronic disease of the airways of the lungs, which can be managed with proper treatment. Triggered by two main causes, asthma symptoms can be brought on by environmental factors and surprising allergens.
Acute BronchitisBronchitis is inflammation of the airways in the lung. Acute bronchitis is short in duration (10-20 days) in comparison with chronic bronchitis, which lasts for months to years. Causes of acute bronchitis include viruses and bacteria, which means it can be contagious. Acute bronchitis caused by environmental factors such as pollution or cigarette smoke is not contagious. Common symptoms for acute bronchitis include nasal congestion, cough, headache, sore throat, muscle aches, and fatigue. Acute bronchitis in children also my include runny nose, fever, and chest pain. Treatment for acute bronchitis are OTC pain relievers, cough suppressants (although not recommended in children), and rest. Infrequently antibiotics may be prescribed to treat acute bronchitis.
COPD QuizCOPD is a combination of three conditions? Take this quiz to learn the three conditions that make up the pulmonary disease called chronic obstructive pulmonary disease (COPD).
COPD Lung SymptomsCOPD is a pulmonary disorder caused by obstructions in the airways of the lungs leading to breathing problems. Learn about COPD symptoms, diagnosis, and treatment options.
Lung CancerLung cancer kills more men and women than any other form of cancer. Eight out of 10 lung cancers are due to tobacco smoke. Lung cancers are classified as either small-cell or non-small-cell lung cancers.
Lung Cancer SlideshowLearn about lung cancer early warning signs, symptoms and treatments. What causes stage IV lung cancer? Get more information on small cell lung cancer, non-small cell lung cancer, and the diagnosis of lung cancer stages.
Lungs PictureThe lungs are a pair of spongy, air-filled organs located on either side of the chest (thorax). See a picture of the Lungs and learn more about the health topic.
OximetryOximetry is a procedure used to measure the concentration of oxygen in the blood. Oximetry is used in the evaluation of various medical conditions that affect the function of the heart and lungs. Pulse oximeters are the most common oximeter used because they respond only to pulsations. Oximetry can also be done on blood within the heart, or on whole blood that has been removed from the body. Similar technology to oximetry is currently used to measure carbon dioxide levels at the skin.
PneumoniaPneumonia is inflammation of the lungs caused by fungi, bacteria, or viruses. Symptoms and signs include cough, fever, shortness of breath, and chills. Antibiotics treat pneumonia, and the choice of the antibiotic depends upon the cause of the infection.
High Red Blood Cell Count (Polycythemia)Polycythemia (elevated red blood cell count) is a rare blood disease in which the body produces too many red blood cells. Causes of polycythemia are either primary (acquired or genetic mutations) or secondary (diseases, conditions, high altitude).
Pulmonary EdemaPulmonary edema, or fluid in the lungs, can cause symptoms such as shortness of breath. Learn about causes, diagnosis complications, treatment, and prevention.
Sleep ApneaSleep apnea is defined as a reduction or cessation of breathing during sleep. The three types of sleep apnea are central apnea, obstructive apnea (OSA), and a mixture of central and obstructive apnea. Central sleep apnea is caused by a failure of the brain to activate the muscles of breathing during sleep. OSA is caused by the collapse of the airway during sleep. OSA is diagnosed and evaluated through patient history, physical examination and polysomnography. There are many complications related to obstructive sleep apnea. Treatments are surgical and non-surgical.
Sleep Disorders: Insomnia, Sleep Apnea, and MoreLearn about the different types of sleep/wake disorders such as insomnia, narcolepsy, and sleep apnea. Explore the symptoms, causes, tests and treatments of sleep disorders.
Sleep QuizTake our Sleeping Quiz to learn which sleep disorders, causes, and symptoms rule the night. Trouble falling or staying asleep? Find out which medical treatments fight sleep deprivation, apnea, insomnia, and more!
What Are Blood Oxygen Levels?Blood oxygen levels (arterial oxygen) indicate the oxygen levels present in the blood that flows through the arteries of the body. Normal arterial oxygen pressure (PaO2) measured using the arterial blood gas (ABG) test is approximately 75 to 100 millimeters of mercury (75-100 mmHg).
What Are the Three Types of Asthma?Asthma is a long-term medical condition that causes breathing difficulties due to airway narrowing, airway swelling, and excessive mucus production in the airway. The common types of asthma include nocturnal asthma, exercise-induced asthma or exercise-induced bronchoconstriction, allergic asthma/seasonal asthma, as well as occupational asthma and cough variant asthma.