Pulse Oximeter’s Uses In Managing Hypoxemic Patient

This innovative machine provides information that is essential in determining the proper management of a patient’s needs. This also helps the homebound patients to monitor their blood oxygens.

A Pulse Oximeter is necessary in monitoring a patient’s blood oxygen saturation. This is not the same as getting the oxygen level from a blood sample. This machine is also utilized for getting the changes in blood volume in the skin, which later on produces a “Photoplethysmograph”. This is always attached to a monitor, mostly related to the heart rate. Thus, so that health professionals are able to see the level of oxygenation of an individual. If ever an in-home patient is present, you can always have a battery operated machine.

A brief history of when and who invented the Pulse Oximeter will give you an idea on the concept behind this wonderful invention. Milliken, in the 1940’s, made the first ever original Pulse Oximeter. In the 1970’s, designs were based on the ability to relate arterial haemoglobin saturation to vessel bed pulsation. This is by Aoyagi’s. It was Dr. William New who was the inventor of the prototype Pulse Oximeter in the year 1978. The United States of America until in the 1980’s did not adapt this device.

The medical application of this monitoring machine is that it displays the percentage of arterial haemoglobin in the Oxyhemoglobin composition. Normal ranges that are acceptable are from 95 up to 100%. If a patient is breathing in room air that is not far over sea level, where in an estimated arterial pO2 can be derived from the actual blood. This is along with a so-called assigned oxygen monitor for SpO2 reading. This instrument is non–invasive and it has a pair of small light emitting diodes (LEDs) in front of a photodiode. This is through a translucent part of the patient’s body and usually used is the fingertip or the earlobe.

If the LED is red, this has a wavelength of 660 nanometers. The other one can have the infrared 905, 910 or 940 nanometers. These lights are essential in determining the ratio of absorption of the red and infrared light, from which, the oxygenated blood or Oxyhemoglobin and the un-oxygenated blood or deoxyhemoglobin ratio can be calculated.

Absorption values are also significantly different between oxyhemoglobin and deoxygenated blood form. The absorbance value of oxyhemoglobin and deoxyhemoglobin is the same for the wavelengths of 590 and 805 nanometers and can be called the Isosbestic point. This point is usually the basis of early oximeters for correction of haemoglobin concentration.

Detecting a pulse in a patient is vital in the operation of a Pulse Oximeter because it will not function if it cannot detect one. The monitored pulse signal bounces in time, along with the heartbeat. This is due to the arterial blood vessels that get bigger and contract with each heartbeat. The recent use of pulse oximeters is to determine the amount of blood loss, especially in trauma patients or the ones who went through a tragic accident.

Hence, a Yale University anaesthesiologist developed an algorithm that can determine the accurate estimate of blood loss through the use of the absorption changes in pulse oximeters.

There are certain advantages of this instrument like simplicity and the rapidness of giving information. For example, if the patient has respiratory or cardiac problems, the oxygen level could be displayed in a matter of seconds. Certain professions needs this machine like that of a pilot who is 10,000 feet above the ground, where in, if a non-pressurized aircraft is used, it will really require supplemental oxygen. On this case a battery operated Oximeter can be used. Portable Oximeters are also important to mountain climbers and athletes, especially for those whose oxygen levels can be affected if they ascend in high altitudes or with prolonged exercises.

Just like anything else, this machine has its disadvantages or drawbacks. This would include not having a complete measure of respiratory sufficiency. This would lead to some patients who are suffering from hypoventilation. This means that there are poor gas exchange happenings in the lungs. For this, the patient may be given 100% oxygen but still respiratory acidosis occurs due to high amount of carbon dioxide in the blood.

Pulse Oximeters do not have a complete measure of circulatory adequacy. If there is not enough blood flow or there is low haemoglobin which is termed as Anaemia. Thus, tissues can suffer from hypoxia even though the body is supplied with a high oxygen support. If the individual has Methemoglobin or a substance that is poisonous in the blood, there is a tendency to cause a reading of 85%. This is regardless of the true level of oxygen saturation.

Just in 2005 a corporation introduced the first FDA. It is an approved pulse oximeter to that can monitor carbon dioxide levels non–invasively. The latest machine even uses a digital processing device in order to make out the accurate measurements of clinical conditions that were, on the other hand, impossible to get.

Examples are when the patient is in motion, low perfusion, bright lights, and sometimes electrical interferences. They are commonly used in plastic surgery, especially on severe burn patients in whom there is no possible way to touch the skin because they have been burnt or they have poor peripheral perfusion. Afterwards, the LEDs in front of the forehead are then assigned so as to get the oxygen levels. Thus, pulse oximeters also outweigh the drawbacks that are being compared to the advantages brought up by health professionals.