What you need to know about low blood oxygen levels (Hypoxemia)!

Do you sometimes feel short of breath, your chest feels tight, or you feel dizzy even after walking a short distance? Or do you often get headaches? One reason behind this could be a decrease in the oxygen level in your blood. In medical terms, we call this hypoxemia . Since this can be a serious condition, let's get to the bottom of it simply and clearly.

Okay, what is this Hypoxemia?

Simply put, Hypoxemia is a condition where your blood has less than the normal amount of oxygen. Oxygen is essential for every cell and organ in our body to function properly, just like a car needs gasoline to run.

Think of it this way. When we breathe, the oxygen in the air goes into our lungs. Inside the lungs are a network of tiny air sacs called alveoli. These air sacs are surrounded by very fine blood vessels (capillaries). When we breathe, the oxygen that enters the lungs is absorbed through these air sacs into the blood vessels. The blood then picks up this oxygen and distributes it to the tissues throughout the body.

Hypoxemia occurs when something goes wrong with this process. Either you can't breathe in enough oxygen , or the oxygen you breathe in can't be absorbed into your blood properly . This is why people with lung disease and heart disease are at higher risk for this condition.

Are Hypoxemia and Hypoxia two different things?

Yes, although many people confuse these two words, there is a slight difference. It's important to know that.

• Hypoxemia is a decrease in oxygen levels in the blood .
• Hypoxia is a decrease in the amount of oxygen reaching the body's tissues .

Think of blood as a 'delivery truck' carrying oxygen. Tissues are 'customers' waiting for oxygen. Hypoxemia is when the truck's cargo (oxygen) is low. Therefore, Hypoxia is when the customer does not receive the cargo. Often, when oxygen in the blood is low (Hypoxemia), the tissues also lack oxygen (Hypoxia). But that does not always happen.

What are the symptoms of this condition?

Symptoms of hypoxemia can vary depending on its severity and cause. Some common symptoms are listed in the table below.

Why does this happen? What are the causes of hypoxemia?

There can be many reasons for this. The main reason is an underlying medical condition that affects the breathing process or blood circulation. For example, when you go to a high altitude, such as a mountainous area, this condition can temporarily occur due to the lack of oxygen in the environment.

Below are some of the main medical conditions that can cause hypoxemia.

• Asthma
• Pneumonia
• COPD (Chronic Obstructive Pulmonary Disease)
• Congestive Heart Failure
• Pulmonary Embolism
• Pulmonary Edema
• Sleep apnea
• Anemia
• Congenital Heart Defects
• Severe respiratory infections like COVID-19

5 main mechanisms that contribute to oxygen depletion

From a medical perspective, there are 5 main mechanisms that contribute to the lack of oxygen in the blood. These are a bit complicated, but let's keep it simple.

1. Ventilation-Perfusion (V/Q) Mismatch: Think of the lungs as a bus stand. Air (oxygen) is the passengers. Blood is the bus. Sometimes the stand is full of passengers, but there are no buses (low blood flow). Or there are many buses, but no passengers (low ventilation). This mismatch between the flow of air and the flow of blood is called V/Q mismatch.

2. Diffusion Impairment: Now imagine that the passengers (oxygen) are at the stand, and the bus (blood) is moving. But there is an obstacle for the passengers to board the bus. This is the obstacle to the oxygen from the lungs to the blood . This can happen due to things like thickening of the walls of the lungs.

3. Hypoventilation: Simply put , breathing slowly or not breathing deeply , which results in insufficient oxygen reaching the lungs.

4. Low Environmental Oxygen: This one is obvious. If the environment we are in is low in oxygen , for example, when we go to the top of a mountain, we will not be able to take in enough oxygen.

5. Right-to-Left Shunting: Our heart has low-oxygen blood (blue blood) on the right side and high-oxygen blood (red blood) on the left side. These two do not mix. But in some heart diseases, instead of going to the lungs to get oxygen, some of the low-oxygen blood jumps directly to the left side and goes to the body . This is also a cause of Hypoxemia.

How does a doctor find this?

After listening to your symptoms, the doctor will examine you. This includes listening to your heart and lungs, checking your skin color, and performing several tests to determine your oxygen levels.

• Pulse Oximetry: You may have seen this. It's a device that clips onto your finger and measures your oxygen levels. It's painless and very easy. A healthy person's pulse should be 95% or higher.
• Arterial Blood Gas (ABG) Test: This is the most accurate test. A small sample of blood is taken from an artery in the wrist, the crook of the elbow, or the groin, and the levels of oxygen, carbon dioxide, and the acidity (pH) of the blood are measured.
• Six-Minute Walk Test (6MWT): A test that measures how far you can walk on level ground in 6 minutes, and how your oxygen levels change with exercise.

How is it treated?

The main thing when treating hypoxemia is to treat the underlying cause . In addition, treatment is also used to quickly restore blood oxygen levels to normal.

Several treatment methods:

• Oxygen: Oxygen is given through a nasal cannula or a mask. Some people are prescribed oxygen concentrators that can be used at home.
• Inhalers: People with conditions like asthma or COPD are given inhalers that widen the airways (bronchodilators) or reduce swelling (steroids).
• CPAP machines: This machine is provided to people who suffer from sleep apnea to use at night.
• Ventilator: If the patient's condition is very severe, meaning they have difficulty breathing on their own, they are connected to an artificial respiration machine (ventilator) in the hospital's intensive care unit.
• Other medications: If the lungs are filled with fluid, medications (diuretics) are given to remove the extra fluid.

What should we do to maintain good oxygen levels?

If you have heart disease or lung disease, these things are important to reduce the risk of hypoxemia.

• Manage your condition properly: Use the medication and inhaler prescribed by your doctor on time. Be sure to attend clinics.
• Avoid smoking completely: Smoking is very harmful to the lungs. Quitting smoking will help increase oxygen levels.
• Do breathing exercises: Ask your doctor about things like deep breathing and using devices like an Incentive Spirometer.
• Be aware of new symptoms: If you have new shortness of breath or chest pain, don't ignore it.
• Be careful when traveling to high altitudes: If you have a heart or lung condition, talk to your doctor and get the necessary advice before traveling to a mountainous area.

When should we see a doctor as soon as possible? (When to go to the ETU)

Hypoxemia is a life-threatening condition. If you have any of the following symptoms, go to a hospital's Emergency Department (ETU) immediately.

• Sudden severe shortness of breath.
• Blue discoloration of the lips, fingernails, or skin (Cyanosis).
• Severe chest pain.
• Confusion, agitation, or loss of consciousness.
• If you already have an illness, its common symptoms may suddenly worsen.

Hypoxemia, oxygen, shortness of breath, blood oxygen, cyanosis, pulse oximeter, COPD