Understanding Pulse Oximetry

Pulse oximeters provide physicians with a simple, but highly effective tool for monitoring oxygen levels in the blood, allowing them to screen for several serious conditions and to monitor patients during surgery. Non-invasive and reliable, pulse oximetry devices are widely used in medical facilities around the world, and the yearly market for these devices is around $1 billion.

Pulse Oximetry

Medical facilities considering ordering pulse oximetry devices should research the equipment they are considering purchasing to ensure they get the best quality devices. Physicians aren’t the only ones buying these devices. Pulse oximeters are also sold to patients who are monitoring certain conditions at home. These consumers should also learn more about how these devices operate to make a better informed decision.

A Brief History of Pulse Oximetry

Pulse oximetry devices have their roots in 1930s Germany, where Karl Matthes invented the first O2 saturation meter to gauge oxygenation. In the 1940s, Glenn Allan Millikan developed the original oximeter and continually worked to better the invention. By the 1960s, large pulse oximeters were being sold by Hewlett-Packard, mainly to big facilities and labs, because of the high cost and large size of the early oximeter devices.

Pulse Oximetry

Pulse oximetry was pioneered in Japan in 1972 by a pair of bioengineers. The device was tested on surgical patients and, in time, pulse oximetry became widespread in hospitals as it provided a reliable, non-invasive method of monitoring blood levels in patients under anesthesia. Since the introduction of pulse oximetry to surgical settings, anesthesia has become much safer, as physicians have a better means of monitoring oxygenation to unconscious patients.

How Pulse Oximetry Devices Work

Pulse oximetry devices help determine how well blood is being transported to the areas of the body furthest from the heart, such as the toes or fingers or ear lobes. A pulse oximeter works by sending a beam of red and infrared light all the way through a pulsating capillary bed. The device determines the amount of oxygen saturation of the blood based on the ratio of red to infrared light. Oxygenated blood is a brighter shade of red than deoxygenated blood, which appears as a blue or purple color. The device evaluates the intensity of the shades of red and makes a determination concerning how oxygenated the blood is, displaying that figure on an electronic screen.

Pulse Oximetry

How Pulse Oximetry Devices Are Used

The method for using a pulse oximeter is actually very simple. When doctors use pulse oximetry devices, they attach a clip to the patient’s earlobe, finger, or toe. In some cases, a probe with sticky adhesive may be applied to the patient’s finger or forehead.

During the test, the probe will stay attached to the area it was applied to. When the test is over, physicians or nurses will remove the probe from the patient’s body.

What Pulse Oximeters Test For

Pulse oximeters are used in a variety of scenarios when it becomes necessary to monitor oxygen levels in patients’ blood. Some situations where these devices are commonly used include:

  • During surgery when patients are under anesthesia. When patients are under anesthesia, their brains may begin losing oxygen. Monitoring oxygenation levels helps physicians make anesthesia safer for patients. Since its introduction to surgical practice, pulse oximetry has helped to greatly reduce anesthesia-related deaths.
  • To determine whether a patient has sleep apnea. Sleep apnea is a condition that causes patients to have pauses in breath while they sleep. Because of the pauses, blood may not be oxygenated properly.
  • To monitor the progress of lung medicines. Medication may be used to treat certain lung conditions, and pulse oximetry can help doctors determine whether this treatment is working.
  • To monitor patients’ ability to tolerate higher levels of physical activity. Oximetry devices are frequently used in stress tests to help determine how well oxygen is being transported through the blood.
  • To determine how well a ventilator is working, or to find out whether one is needed.

In addition to these uses, pulse oximetry devices are commonly used to monitor patients with health conditions that impact blood oxygen levels. These conditions include:

  • Heart Attack – During a heart attack, blood flow bringing oxygen to the heart is severely curtailed. Pulse oximetry devices can help determine when a heart attack may be imminent.
Heart Attack

  • Heart Failure –Again, pulse oximetry can be useful for monitoring patients with heart failure, providing a critical warning.
  • Chronic Obstructive Pulmonary Disease – COPD is a disease that causes lung inflammation, making breathing difficult. COPD is a progressive disease, getting worse over time. People with COPD often develop hypoxemia, or low blood oxygen. Pulse oximetry is used to monitor hypoxemia and determine whether patients need to be on oxygen
  • Anemia – This condition is characterized by a lowered ability of the blood to carry oxygen. Pulse oximeters are useful in monitoring this condition
  • Lung Cancer – Cancer of the lungs can impair their ability to deliver oxygen to the blood. Pulse oximetry can help monitor this problem.
  • Asthma – A chronic, inflammatory disease of the airways, asthma can result in reduced blood oxygenation. Pulse oximetry helps to monitor the condition.
  • Pneumonia – Affecting millions of people worldwide each year, pneumonia is an infection affecting tiny air sacs of the respiratory system called alveoli. Pulse oximetry is a tool used to help doctors diagnose this illness.
Risks Associated with Pulse Oximetry

Risks Associated with Pulse Oximetry

Pulse Oximetry is non-invasive and incredibly safe. The worst outcomes patients face when these devices are used is some minor skin irritation or an incorrect reading if the probe falls off the part of the body it is attached to. Some factors that might contribute to incorrect readings include a weak pulse, cardia arrhythmia, or dyes used in other diagnostic tests.

Recent Developments in Pulse Oximetry

In recent years, physicians have proposed new uses for pulse oximetry. For example, in 2011, a panel of experts recommended using pulse oximetry devices to screen newborns for critical congenital heart disease. Critical congenital heart disease (CCHD) is a heart defect that leads to low levels of oxygen in the blood. If it isn’t detected early, this problem can lead to serious complications requiring emergency care and can cause long-term developmental issues. About 7,200 children are born each year with this heart defect , according to the Centers for Disease Control.

Recent Developments in Pulse Oximetry

The workgroup recommending pulse oximetry for screening cited two studies of nearly 60,000 subjects that found pulse oximetry was a highly effective screening tool for CCHD, and reduced the number of false positive tests. Pulse oximetry has been added to the recommended uniform screening panel, and a quickly growing number of medical facilities are using it to screen newborns.

Another recent application discovered for pulse oximetry is the use of high resolution pulse oximetry for in-home testing of sleep apnea and inpatient testing for patients who cannot undergo polysomnography.

Selecting Quality Pulse Oximeters

Medical facilities using pulse oximetry devices need the most reliable, high quality devices on the market. They also need a wide range of pulse oximetry devices to choose from, as several specializations of pulse oximetry devices are available, including tabletop and handheld pulse oximeters, among others.

Hospitals, clinics and other facilities in need of these devices should look no further than Medical Device Depot . Founded by health care professionals who understand the need for knowledgeable and helpful customer service and support in the medical device industry, Medical Device Depot provides health care professionals with state-of-the-art medical equipment sold by trained and experienced employees who can answer questions important to assisting health care professionals in choosing the proper equipment for their practices.

Sources: http://www.cdc.gov/ncbddd/heartdefects/cchd-facts.html