subject: Modern Oximetry and ABG [print this page] The fields of Medicine and Technology are perhaps two of the most utilized branches of Science today. Constantly these two fields intertwine and collaborate to give us breakthrough methods and devices that provide convenience on top of medical benefits.
Recently, the same fields gave birth to another child that, like its many siblings, spell benefit. Before the pulse oximeter was invented, the only way to check a person's arterial oxygen level was by drawing blood from an artery and having it analyzed. Although this procedure is still used and is quite indispensable during emergencies, critical and even acute care when a patient is in distress, it is rather time-consuming and potentially dangerous especially if done improperly.
With the invention of the oximeter, oximetry or the measurement of a person's oxygen saturation became fast and safe for patients. Though the traditional method can provide more information because of the arterial blood gases (AGB), oximetry can give reading of a patient's saturation of oxygen (SaO2) in a short span of time. Plus, patients do not have to suffer from the pain of blood drawing.
However, it is important to remember that while oximeters do provide by-the-second information and are quite indispensable during emergencies, there are cases when the said method is not applicable. Some chronic conditions like the Chronic Obstructive Pulmonary Disease (COPD) make oximetry readings unreliable due to the nature and treatment of the disease. With COPD the body struggles to ventilate and therefore becomes less sensitive to the rising CO2, despite the presence of oxygen sensors (baroreceptors) that detect low oxygen levels in the arterial blood - which also triggers the medulla oblongata to increase the rate and depth of breathing.
Other issues that make oximetry readings false include a person being exposed to carbon monoxide, which gives the apparatus a false high reading because hemoglobin is saturated with CO. The same is true if a person has too few or too many red blood cells. Fewer RBCs mean less oxygen available to tissues, but will show a normal reading with a pulse oximeter. Polycythemia (too many RBCs) would show a low reading with the pulse ox, but still have a respectable amount of oxygen available to the tissues. In the strictest sense of the above examples, oximeters, though very efficient and fast, strictly provide reading of the amount of oxygen in the blood under normal circumstances.
One great thing about oximeters is virtually anyone can use it. Little to no training is needed to perform pulse oximetry. Most oximeters have only one button and as long as the probe is placed properly, almost anyone can use it. In their infancy, oximeters were the size of old cassette recorders and just as cumbersome. The newest generation of oximeters is streamlined, rugged and even easier to use. Furthermore, they are now available for home use.
ABG measurements, though exact, require blood drawn from an artery, which can lead to complications ranging from hematoma to laceration of the artery. Pulse oximetry is performed on a fingertip and measures through the nail bed. As long as the oximeter is used properly and is calibrated regularly, it is easy to use and usually reliable. Good peripheral circulation in the patient's extremities is critical to obtaining accurate readings, and most oximeters on the market incorporate a perfusion gauge, usually in LED bar lights, that shows the strength of the patient's peripheral circulation. When a strong pulse is not present in the hands or feet, readings can be made with a special adhesive probe placed on the patient's earlobe or even the bridge of the nose.
Yes, ABG measurements are exact even though it requires blood drained from an artery, yet this can actually lead to complications like hematoma or artery laceration. With oximeters, the measurement can be done perfectly without the dangers of invasive blood collecting that can further distress a patient's condition. Concord Health Supply, Inc. provides this state-of-the-art device that can aid people who want to keep their oxygen in blood on track. Visit their website today to have one for yourself and for loved ones.
