What is Oxygenation in Nursing / Medical ? [Definition]

As a nursing student, you understand that oxygenation is critical to patient care, and even the slightest blip can have serious repercussions. Although learning and comprehending all the nuances involved in successful oxygenation management is intimidating, nurses can confidently develop their skill set with some practice and understanding.

In this blog post, we’ll be breaking down various concepts related to oxygen therapy and oxygenation definition so newbies and veterans alike can gain valuable insight into the world of improving one’s respiratory health as quickly and efficiently as possible.

Let’s first review some essential medical terms related to oxygenation fundamentals. These are oxygenation, ventilation, diffusion, and perfusion. So let’s get started.

What is Oxygenation?

Oxygenation delivers oxygen to the body’s cells, tissues, and organs. It is an essential function of the respiratory and circulatory systems vital for sustaining life.

The respiratory system takes in air through the nose and mouth, which is filtered, warmed, and humidified before entering the lungs. The lungs then extract oxygen from the air and release carbon dioxide, which the circulatory system carries to the heart.

The heart pumps the oxygen-rich blood to all body parts, where it is used to fuel metabolism and generate energy.

Without proper oxygenation, cells can’t perform their functions optimally, which can lead to a range of health problems. Understanding the importance of oxygenation is crucial for promoting overall wellness and maintaining good health.

  • The Oxygenated Blood – Oxygenated blood is the term used to describe blood saturated with oxygen throughout its circulation in the body. Oxygenated blood is bright red and carries oxygen to cells and organs throughout the body.
  • Deoxygenated Blood -Deoxygenated blood is the term used to describe blood depleted of oxygen during its circulation in the body. Deoxygenated blood is dark red or purple and carries carbon dioxide away from cells and organs throughout the body. It does not contain oxygen, so it relies on external sources such as oxygen tanks or respirators to replenish the oxygen supply.

The term arterial oxygen saturation (SaO2) describes the amount of oxygen dissolved in the blood. A healthy oxygen saturation level is usually between 95% and 100%, while a range of 90-95% is considered low, and less than 90% is considered critically low. Nurses are trained to monitor SaO2 levels and intervene with oxygen therapy when levels drop too low.

Some Other Oxygen Transportation Methods

What is Ventilation?

Ventilation is breathing air in and out of the lungs to supply oxygen to the body’s tissues. It also involves exchanging carbon dioxide for fresh oxygen. Without proper ventilation, our cells cannot receive the oxygen they need to perform their daily functions. Nurses must be able to assess a patient’s respiratory rate and volume to monitor their ventilation needs appropriately.

What is Diffusion?

Diffusion is the process by which oxygen molecules move from an area of higher concentration (in the alveoli) to a place of lower concentration (in the blood). The diffusion capacity of a person’s lungs can be measured to assess their overall oxygenation levels. Nurses must understand the monitoring process and adequately treat patients with inadequate oxygenation levels.

What is Perfusion?

Perfusion is blood movement through the body’s capillaries, carrying oxygen and other metabolic substances. Poor perfusion can result in inadequate oxygenation levels, and nurses must be able to assess a patient’s perfusion status to monitor and treat the patient properly.

By understanding these critical concepts related to oxygenation, nurses can develop their skillset and provide better care for patients suffering from respiratory problems. With practice and dedication, nurses can become experts in oxygenation management. As always, stay safe and keep learning.

Assessing Oxygenation Status As Nurse

Pulse Oximetry Reading

Pulse oximetry, or SpO2, is a commonly used method to assess the oxygenation status of patients. This measure reflects the percentage of hemoglobin saturated with oxygen in the blood, as this molecule carries the most oxygen within red blood cells. A pulse oximeter can be utilized to estimate SpO2 levels accurately. The information obtained through such assessment helps healthcare providers evaluate and monitor patient health.

The typically accepted SpO2 level for an adult is 94-98%. However, those with chronic respiratory disorders such as COPD may have a target range of 88% to 92%. While SpO2 is a simple and noninvasive way to measure oxygen levels in the body, it may be misleading. Anemic patients tend to have lower hemoglobin levels, affecting readings, while low peripheral circulation can also cause inaccurate readings.

(ABG) Reading

An arterial blood gas (ABG) test provides a more precise measure of oxygen and carbon dioxide levels in the bloodstream. It is commonly used to assess respiratory status in patients with deteriorating or unstable conditions requiring urgent medical attention. The ABG sample is usually taken from the radial artery by a respiratory therapist, emergency or critical care nurse, or other healthcare professional. It evaluates oxygen, carbon dioxide, pH, and bicarbonate levels. Usually, adults have a normal partial pressure of oxygen level (PaO2) range of 80-100 mmHg.

The PaO2 is more precise than a SpO2 reading, as hemoglobin levels do not impact it. The standard PaCO2 level of a healthy adult is 35-45 mmHg, while the normal pH range for arterial blood is 7.35-7.45, and the bicarbonate (HCO3) level should be 22-26. The SaO2 level is also presented, representing the calculated arterial oxygen saturation level (see the following Table for a summary of ABG values). These are the usual ranges of readings from a healthy individual.

Value Description Normal Range
pH The acid-base balance of blood 7.35-7.45
PaO2 The partial pressure of oxygen 80-100 mmHg
PaCO2 The partial pressure of carbon dioxide 35-45 mmHg
HCO3 Bicarbonate level 22-26 mEq/L
SaO2 Calculated oxygen saturation 95-100%


It is important to note that patients with underlying respiratory or cardiac conditions, such as asthma and congestive heart failure, may have different levels of ABGs. Similarly, people at higher altitudes may also have slightly altered readings due to the thin air of these regions. Thus, healthcare providers must be aware of potential effects on oxygen levels and adjust their care accordingly.

Hypoxia vs. Hypoxemia: Compare causes, symptoms, treatments & more

What is Hypoxia?

Hypoxia, a term that describes a shortage of oxygen in the body’s tissues, can be life-threatening if left untreated. This lack of oxygen can occur in various settings, including high altitudes, underwater environments, and even within the body.

External forces, such as a lack of oxygen in the environment, or internal factors, like airway obstruction, certain medications, and diseases, can cause hypoxia.

What are the symptoms of Hypoxia?

Symptoms of hypoxia can range from mild to severe and depend on the severity and duration of oxygen deprivation. Some common signs and symptoms include:

• Shortness of breath

• Confusion

• Dizziness

• Headache

• Muscle weakness

• Chest pain

• Rapid heart rate

• Reduced alertness

• Blue skin, lips, and nails (cyanosis)

Hypoxia diagnosis

Your healthcare provider will perform a physical examination to check for abnormalities in the heart and lungs and look for signs of low oxygen levels, such as blue-tinged skin, lips, or fingernails. Your doctor may use several tests to measure your oxygen levels to confirm the diagnosis. These include:

  • Pulse oximetry – a non-invasive and painless procedure that uses a unique sensor to measure the amount of oxygen in your blood.
  • Arterial blood gas test – taking a sample of your blood from the wrist, arm, or groin to assess oxygen levels.
  • Six-minute walk test (6MWT) – this evaluates both heart and lung function while you move around and measures oxygen levels with exertion.

These tests will help your healthcare provider diagnose hypoxemia accurately and provide appropriate treatment.

What Is Hypoxemia?

Hypoxemia is a condition related to hypoxia but distinct from it. It refers specifically to low levels of oxygen in the blood rather than the body’s tissues as a whole. Causes of hypoxemia may include disorders such as COPD, pulmonary edema, or asthma; diseases like COVID-19 that cause respiratory distress; and external factors such as smoke inhalation or high altitudes.

What are the symptoms of hypoxemia?

Hypoxemia symptoms vary depending on the severity and underlying cause. Some hypoxemia symptoms include:

  • shortness of breath
  • rapid breathing
  • confusion or difficulty concentrating
  • dizziness, lightheadedness, or fainting
  • cyanosis (blue discoloration of the skin)
  • fatigue and weakness.
Hypoxemia diagnosis

Your doctor will likely use the same tests as they do for hypoxia, such as pulse oximetry and a blood gas test, to diagnose hypoxemia. Your healthcare provider may also order additional tests depending on your circumstances. Treatment of hypoxemia depends on its cause but may include oxygen supplementation, medications to reduce inflammation or open airways, and lifestyle modifications.

Differences between Hypoxia And Hypoxemia

The main difference between hypoxia and hypoxemia is the location of oxygen deficiency. Hypoxia refers to a lack of oxygen in the body’s tissues, while hypoxemia refers specifically to low oxygen levels in the blood. However, the symptoms and treatments for both conditions may overlap, as an insufficient oxygen supply to the body causes both.

Treating Hypoxia and Hypoxemia

The treatment for both conditions may include supplemental oxygen, mechanical ventilation, or medications such as bronchodilators and corticosteroids. In severe cases, a patient may need to be intubated to ensure adequate oxygen levels. It is important to note that each patient’s treatment plan may vary and should be tailored to their needs.

Preventing Hypoxia and Hypoxemia

To prevent hypoxia and hypoxemia, nurses must be able to assess a patient’s respiratory status accurately. This includes monitoring oxygen saturation levels, studying pulse oximetry readings, and evaluating a patient’s overall ventilation needs. Nurses must also recognize the signs and symptoms of both hypoxia and hypoxemia, so they can intervene early if needed.

Let’s Examine Some Case Studies to Determine the Course of Action

Case Study: 1

Alex, who suffers from COPD, has arrived at the emergency room with difficulty breathing. His skin feels warm, and he is coughing up thick, yellow-green mucus. To understand his condition better, it’s essential to record two vital signs:

  1. Oxygen saturation (SpO2)
  2. Respiratory rate

Alex likely suffers from pneumonia; therefore, a complete set of vitals should be monitored and a focused respiratory assessment conducted. Tests such as WBC count, sputum culture, and chest X-rays may also be necessary.

The issue appears to be related to inadequate gas exchange due to fluid-filled alveoli, so supplemental oxygen may need to be supplied in addition to prescribed medications such as antibiotics or corticosteroids.

Case Study: 2

Samantha is a 35-year-old woman with a history of asthma who presents to the emergency room with shortness of breath. She has audible wheezes when she exhales, and her oxygen saturation on the finger oximeter is 94%. What two vital signs do you want the most?

  • Respiratory rate
  • Peak Expiratory Flow Rate (PEFR)

In this case, respiratory and peak expiratory flow rates are both crucial indicators to get an accurate picture of Samantha’s level of airway obstruction. You would also perform a physical assessment focusing on Samantha’s respiratory system and anticipate MD orders for medications such as bronchodilators, steroids, or antibiotics if other factors suggest an infection.

So is Samantha’s problem ventilation or oxygenation? The narrowed airways are causing an obstruction and preventing sufficient air flow, so her problem is ventilation. You would anticipate supplying supplemental oxygen to support her breathing and administering ordered medications such as bronchodilators, steroids, or antibiotics if other factors suggest an infection.

Case Study: 3

Chris was brought in by a brother who found her unresponsive on the bathroom floor. However, the reason for not calling an ambulance is unclear. Upon examination, it was observed that Sally’s breathing rate is only 7 times per minute. What additional information do you need to obtain?

  • SpO2
  • Glasgow Coma Scale score (GCS)
  • Other vital signs
  • Focused respiratory assessment

In Chris’s case, her low respiratory rate indicates a potential problem with oxygenation. Conducting a complete set of vitals and a focused respiratory system assessment is essential to get an accurate picture of her condition. Tests such as WBC count, sputum culture, and chest X-rays may also be necessary. She may require supplemental oxygen or prescribed medications such as antibiotics or corticosteroids, depending on the results.

Additionally, it would be essential to assess for other conditions that could have caused her unresponsiveness by setting her GCS score. Thus, when presented with any patient in the emergency room that has difficulty breathing, it is essential to evaluate two critical vital signs—oxygen saturation and respiratory rate— as well as to address any underlying conditions that may be contributing. With the right tools, you can accurately assess patients and provide them with the best care.

Related & Useful Questions About Oxygenation

1. A nurse is caring for a patient with COPD. What would be an expected finding upon assessment of this patient?

A. Dyspnea

B. Hypotension

C. Decreased respiratory rate

D. Decreased pulse rate

Answer: A. Dyspnea. Patients with COPD typically experience shortness of breath (dyspnea) and decreased respiratory rate and oxygen saturation due to difficulty exchanging oxygen in the lungs. Hypotension and reduced pulse rate may also be present but are not necessarily expected findings.

2. A nurse is suctioning the nasopharyngeal airway of a patient to maintain a patent airway. For which condition would the nurse anticipate the need for a nasal trumpet?

A. The patient vomits during suctioning.

B. The secretions appear to be stomach contents.

C. The catheter touches an unsterile surface.

D. A nosebleed is noted with continued suctioning.

Answer: D. A nosebleed is noted with continued suctioning. When suctioning the nasopharyngeal airway, a nasal trumpet can help manage a nosebleed due to trauma. It should not be used if vomiting occurs during suctioning, secretions that appear to be stomach contents are present, or if the catheter touches an unsterile surface.

3. A nurse is assessing a patient with COPD for signs of respiratory distress. What would the nurse expect to find in this patient?

A. Decreased oxygen saturation

B. Increased pulse rate

C. Normal breath sounds

D. Increased tidal volume

Answer: A. Decreased oxygen saturation. Patients with COPD often experience decreased oxygen saturation due to difficulty exchanging oxygen in the lungs. Other expected findings include dyspnea, wheezing or crackles on auscultation, increased respiratory rate and effort, and an increased pulse rate. Tidal volume may be average or reduced.

Final Words

Oxygenation medical definition, is the process of taking in oxygen from the environment and delivering it to the body’s cells for use in metabolic processes. This process is essential for maintaining life, supplying oxygen for energy production and other metabolic processes.

To assess a patient’s oxygenation status, medical professionals must measure vital signs such as respiratory rate, oxygen saturation, and pulse oximetry. Additionally, tests such as WBC count, sputum culture, and chest x-rays may be necessary to assess for any underlying conditions contributing to the patient’s unresponsiveness. Medical professionals can provide the best possible care by accurately evaluating a patient’s respiratory status with these tools.

The importance of oxygenation is evident: life cannot be sustained without it. Therefore, medical practitioners must understand how to accurately assess patients’ oxygenation status and address any underlying conditions contributing to their unresponsiveness. With the right tools and knowledge, medical professionals can accurately evaluate a patient’s respiratory status to provide the best possible care.


  • https://en.wikipedia.org/wiki/Oxygen_saturation_(medicine)
  • https://www.ncbi.nlm.nih.gov/books/NBK482316/
  • https://wtcs.pressbooks.pub/nursingskills/chapter/11-2-basic-concepts-of-oxygenation

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