Factors That Affects The Accuracy Of Pulse Oximeter
A pulse oximeter is a device that measures the saturation of the oxygen in the
patient's blood without the need to draw blood samples and carry out batteries of test. The process creates a photoplethysmograph which provides a volumetric measurement of the body part being tested optically. A medical monitor attached to the device shows the oxygenation level of the patient's blood as well as his or her heartbeat rate. This displays the percentage of the arterial hemoglobin in the oxyhemoglobin configuration. Acceptable levels of blood oxygenation ranges from ninety five to ninety nine percent, but reading below ninety percent are common as well.
The pulse oximeter is attached to a translucent part of the body, which can be a fingertip, a toe or even an earlobe. The light source and the sensor on each side of the probe's clip read the saturation of oxygen in the blood. The red and infrared light pass through the skin and is absorbed by the sensor on the other side of the clip. The data is then passed through the computer attached to the device. The computer will then collate the data, and interpret it into understandable numerical values that can be used by the doctors to determine the saturation of oxygen in the patient's blood.
Even though it is a medical device designed for convenience of use, a pulse oximeter's accuracy can still be altered by several factors. For instance, a patient afflicted with hyperventilation who receives a hundred percent oxygenation may reveal normal levels although he or she may be suffering from respiratory acidosis.
Inadequate blood flow can cause body tissues to read high levels of oxygen saturation even though the patient is having a case of hypoxia. High levels of methemoglobin can also cause pulse oximeters to have readings closer to eighty five percent, regardless of the actual oxygen saturation in the blood.
A patient who shivers a lot or is suffering from recurring seizures or tremors can also affect the reading of a pulse oximeter. Also, if the sensor is too loose or too tight, the readings of the device can be altered significantly.