How SpO2 Sensors Work: Understand How Oxygen Levels Are Measured in Real Time

As part of modern healthcare practices, the continuous measurement of the patient’s oxygen level is among the most important considerations. Starting from intensive care units, through emergency rooms and up to operating theaters, doctors use a tiny yet highly important apparatus called SpO2 sensor for measuring how oxygen circulates in the bloodstream.

Despite being a compact piece of technology, the measurement process is actually quite accurate. It takes place in real time, non-invasively, and gives immediate feedback that enables doctors to take appropriate actions.

The purpose of this article is to explore how SpO2 sensors operate and how oxygen levels are measured in real time.

What is SpO2 Sensor?

SpO2 sensor is a device that measures the oxygen saturation level in the blood without being invasive. SpO2 means peripheral capillary oxygen saturation, which is a measurement of the proportion of hemoglobin in blood that is bound to oxygen. Put simply, it indicates the amount of oxygen in a person’s body.

The use of SpO2 sensors includes the following areas:

• Intensive Care Units (ICU)
• Surgical theaters
• Emergencies
• Mobile emergency transportation systems
• General hospital wards

It is typically mounted on the fingertip, toes, or earlobes of a patient.

How SpO2 Sensors Measure Oxygen Levels in Real Time

The principle of a SpO2 sensor works based on the mechanism of light absorption using pulse oximetry.

There are two types of light sources in the sensor:

• Red light
• Infrared light

These two types of light penetrate the skin tissue and blood vessel areas, after which the amount of absorption of light by the tissues as well as the transmission is measured by the detector at the other end.

The science is very easy but effective:

• Blood that contains oxygen will absorb more amounts of infrared light
• Blood that does not contain oxygen will absorb more red light

From this data, the oxygen concentration levels are determined by calculating the SpO2%.

Importance of Real-Time Monitoring

The real-time monitoring of SpO2 levels is essential in the process of making medical decisions. The oxygen level of the patient with either respiratory disease or heart problem could fall fast, and this could create problems if there were any delays in detecting them.

The use of SpO2 sensors enables physicians to:

• Detect early signs of hypoxia
• Monitor patients under anesthesia
• Make adjustments of the oxygen level immediately
• Calculate respiratory stability of patients in ICUs
• Take prompt action in emergencies

Real-time SpO2 monitoring is an integral part of contemporary medical practice.

Kinds of SpO2 Sensors Used in Hospitals

There are various kinds of SpO2 sensors that can be utilized depending on the clinical setting.

Reusuable SpO2 Sensors: They are made for multiple use. These are used in hospitals for long term patient monitoring and are very economical and durable.

Disposable SpO2 Sensors: These are single use SpO2 sensors used where infections are a risk factor, like in emergency room settings.

Pediactric/Neonatal SpO2 Sensors: This is a smaller type of sensor meant for babies and children.

Compatibility with Patient Monitoring System

Not all SpO2 sensors have the same compatibility with the patient monitoring systems. They need to be compatible with the monitoring systems installed in the hospitals.

Some of the common systems are:

• Philips patient monitors
• Mindray monitoring systems
• GE healthcare monitors
• Dräger patient monitors

The sensors that are OEM compatible with the patient monitoring system will function properly along with the systems.

Incompatibility between any patient monitor and its corresponding sensor will produce incorrect results.

Role of SpO2 Sensors in Contemporary Medical Monitoring

SpO2 sensors belong to a bigger family of patient monitors that includes:

• Patient monitor cables
• EtCO2 sensors
• Capnography accessories
• Extension cables

These monitors help detect all vitals of patients, such as oxygenation, heart rate, and breathing.

In highly-developed medical facilities, SpO2 sensors are usually paired with EtCO2 sensors.

Choosing the Correct SpO2 Sensor

Medical practitioners choose SpO2 sensors considering many critical elements such as:

• Patient Type (adult, children, neonate)
• Compatibility with monitor brand
• Reusability or disposability
• Site of use (ICU, Emergency, Transportation)
• Conduit connection

Using the right sensor leads to proper measurement of SpO2 levels.

SpO2 Monitoring Technology in the Future

The technology used in SpO2 monitoring is continually developing. Today’s sensors are becoming increasingly miniaturized, accurate, and incorporated into sophisticated monitoring systems for patients.

Additionally, wearable SpO2 monitors are becoming increasingly popular, enabling monitoring even when patients are outside hospitals.

Although technology changes, the method by which oxygen levels are determined by light remains consistent.

FAQs

Q1. What does a SpO2 sensor do?

It calculates the levels of oxygenation in the blood through noninvasive optical means.

Q2. How do SpO2 sensors detect oxygen levels?

They make use of the different ways red and infrared lights are absorbed by oxygenated and deoxygenated hemoglobin.

Q3. Is a SpO2 sensor accurate for all patients?

The answer is yes, except when it comes to proper placement, health status, and monitor compatibility.

Q4. What is the difference between reusable and disposable SpO2 sensors?

A reusable sensor can be used with multiple patients, whereas the latter will be used for one specific patient at a time.

Q5. In what areas are SpO2 sensors widely used?

They are used in ICU, ORs, emergency units, ambulances, and general wards.

Q6. Can SpO2 sensors be used with EtCO2 monitoring systems?

SpO2 sensors can be used with EtCO2 monitors.

Q7. What would happen when the incorrect sensor was used in a monitor?

Incorrect sensor-compatibility may result in inaccurate readings.