A Detailed Comparison Among SpO2, Sao2, PaO2, FiO2, Vo2 Max, Pulse Ox, etc.

In this post, we are going to figure out different types of terms related to blood oxygen saturation levels.

Let’s dive into the comparison among SpO2, SaO2, PaO2, and so on.

What Is Spo2 Monitoring?

If you are using a smartwatch you most suggestively have seen a feature called SpO2 monitoring in your smartwatch and fitness tracking App. The term SpO2 means Peripheral Oxygen saturation level. Using this method, we can measure the oxygen saturation level in the arterial blood.

It is the comparison of Oxygenated hemoglobin and the Total amount of hemoglobin in percentage. If you are a medical student you can solve any question with the previous equation. To check SpO2 we use 2 types of tracking devices. Either we can use Pulse OX or Spo2 monitoring smartwatch Like Garmin Forerunner 245, or Apple Watch Series 4.

Let’s zoom in on the micro level of oxygen saturation. Our blood has main 3 types of cells in terms of chemical composition.

  • RBC
  • WBC
  • platelets

RBC refers to Red Blood Cells, WBC: White Blood Cells and platelet is generally used in their full form. Among them, RBC consists of a unique type of chemical composition, called Hemoglobin(hgb).

During oxygen saturation or O2 sat oxygen molecules combine with hemoglobin bindings. If the hemoglobin(hgb) is totally saturated it can be combined with 4 Oxygen molecules.

Oxygen Saturation is referred to by SpO2. 100% oxygen saturation means all Hemobins bindings are combined with Oxygen.

After covid-19 we have become more aware of the Blood Oxygen levels? But what would happen if you have a low(less than 93%) or high(99%-100%) oxygen saturation level. Low oxygen saturation level causes such as diseases like hypoxemia. When Oxygen saturation levels affect tissues it is called hypoxia.

SpO2 is one of the clarified concepts to represent blood oxygen saturation level. Now, you can check the Saturation level of your blood. If you have low SpO2, you can increase your oxygen saturation level by following these steps.

There are multiple ways: Exercise, and medicine to increase SpO2 levels. Dive into the article to increase the oxygen saturation level naturally.

Related: Comparison between SpO2 vs SaO2

What Is SaO2?

In medical or clinical terms, Arterial Blood Saturation Level means SaO2. Oxygen molecules binding with the hemoglobin in the arteries. The calculation of SaO2 is complex and only available to medical experts. Point to be noted that we talk about arterial Blood that included oxygen in hemoglobin.

Measurement of SaO2 is measured by the Blood Gas Analyzer machine that is generally found in Hospitals or clinical labs. It is an Invasive Way of tracking Blood Oxygen Saturation. Therefore, Oximeters and Smartwatches are not capable of measuring SaO2.

During the test of Sao2, doctors do not only measure Oxygen saturation level. There are other parameters of tracking available too. To know more check the above article: SpO2 Vs SaO2.

Due to low SaO2 (<60%) one can have hypoxemia. Doctors check SaO2 levels for surgery units, Post-anesthesia, patient care of Anemia, and so on.

SaO2 is represented in percentage.

What Is PaO2?

This is not a saturation-level representator. PaO2 indicated the Partial Pressure of Oxygen in Arterial Blood. During respiration, gas is dissolved in the blood.

When gas is dissolved with Liquid it creates pressure in the container walls naturally. Here Oxygen is the gas that is dissolving in the blood. And it creates pressure on the wall of arteries.

In the theory of Oxy-hemoglobin Dissolution, we would see some relation between Oxygen saturation as well as PaO2. It says when oxygen is present in the air space such as lung and dissolved in liquid like blood both equalize their partial pressure.

Here is an Oxygen-Hemoglobin Dissociation Curve that shows the relation between PaO2 and Oxygen Saturation(SpO2)

What Are Some Examples OF Respiratory Distress?

Cyanosis, Agitation, Tachypnea, etc.

What is PaCO2?

Partial Pressure Of Carbon dioxide.

Note: If the Oxygen saturation level is under 92%-90% the PaO2 level will decrease below 60 mm Hg. This is a hypoxic situation. The patient must be given external oxygen delivery to increase the SpO2 level.

What Is FiO2?

FiO2 is a short form of Fraction Of Inspired Oxygen. It represents the concentration level of Oxygen in the air. Let me simplify it. If you are in a room and somebody says the Fio2 is 40% here. That means the total room air is filled with 40% Oxygen and 60% other gases.

Here ‘I’ in FiO2 refers volumetric fraction of oxygen. The unit of the volume is ‘molar’ (mol).

During respiratory issues, doctors used to give external oxygen delivery. That air is enriched with higher FiO2 than the normal atmosphere.

What Is In The FiO2 Ventilator?

Hospitalized patients are given Oxygen supply. FiO2 ventilator maintains the oxygen supply such as compliance, and flow. It delivers the required unit of oxygen delivery per minute in terms of volume and speed.

What is FiO2 of Nasal Cannula?

Nasal Cannel is a device to provide supplemental oxygen to a patient. It can regulate about 4 to 6 liters of Oxygen per minute.

What Is The Normal Level Of FiO2?

Generally, Ventilators maintain FiO2 less than 0.5 to avoid the toxicity of Oxygen. However, there are some cases where chemists or doctors use 100% FiO2.

What Is VO2 Max?

VO2 Max is the Maximum amount of Oxygen a body can utilize during exercise. Here ‘V’ means Volume, ‘O’ means Oxygen. This measurement is crucial to understanding the body of functions such as the activeness of tissues and the overall metabolism and Respiration. Users can measure it using Smartwatches.

A good VO2 Max score is 52-60 at the age of 18-25. Above 66 users could stay at 33-37.

What Is SvO2?

The full form of SvO2 resents Venous Oxygen Saturation of Level in our Blood. It is found in the returning blood of the heart’s right side after traveling through the entire body.

The level of SvO2 states how much oxygen is in sufficient to perform well and good metabolism in the tissues.

What Is The Normal Range Of SvO2?


How to measure SvO2 Online?

You can use a SvO2 calculator to measure Venous Oxygen Saturation. But you need several data such as blood volume, hemoglobin unit, etc.

What Is StO2?

StO2 means Skeletal Muscle Oxygen Saturation Level. It states the content of tissue oxygen saturation. It is one of the most important oxygen saturation detection.

Oxygen levels in tissues protect your body in terms of proper metabolism. If your tissue is healthy you would surely feel lively and energetic.

How To Measure StO2?

To measure StO2, a Regional Monitoring circulation is used called Near-infrared Spectroscopy.

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