Pulse Oximeters
An oximeter is a device with which the concentration of oxygen in the blood and the pulse rate can be measured. The results of this device help in the detection and diagnosis of various ailments affecting the lungs and the heart. It is also used by sportsmen as well as pilots to monitor the oxygen level in the body. A pulse oximeter is the most common type of oximeter in use these days. It is portable device and is easy to use.
Functions of a pulse oximeter
Apulse oximeter responds to pulsations only; mostly to the pulsating capillaries of the area being tested. A clip is used to attach the device to the translucent (semi transparent) part of the body such as a finger or an ear lobe. The pulse oximeter works by emitting light of two different wavelengths; one red and the other infrared. The light is absorbed by the hemoglobin or the oxygen carriers present in the blood. The absorption of light by the oxygenated blood and the deoxygenated blood is quite different; the oxygenated blood has a brighter red shade while the deoxygenated blood is bluish purple. The ratio between the oxygenated blood and the deoxygenated blood can be calculated by the absorption of red and infrared light. The final reading appears as a percentage on the screen. The device also detects the pulse and gives its reading. The device considers the absorption of light over a number of pulses and the final reading is the average of these readings.
Types of Pulse Oximeter
There are different types of pulse oximeters such as the finger oximeter, handheld oximeter, tabletop oximeter and wrist oximeter. They work on the same principle; the emission of red and infra red light and their absorption by the blood.
The Finger Pulse Oximeter: This type of device is attached to the index finger through a clip and features a mini computer and a screen. The light is emitted from one end of the device and measured at the other. This device is light weight and portable and as it is easy to operate, it is mostly used in homes.
Limitations: Although the finger pulse oximeter gives fairly accurate readings, it has certain limitations. It does not work accurately if the hand of the user is injured. This is because the injury or sometimes a clot of blood slows down the blood flow resulting in inaccurate readings. Also do not expect accurate results if you are wearing nail polish especially black nail polish. The readings also get compromised if the hands are very cold.
The Handheld Pulse Oximeter: This type of pulse oximeter is quite sensitive and is mostly used in hospitals. It has a clip which can be attached to the patient's ear lobe or finger and a cord connects the clip to a computer. Sometimes due to accidents or any other medical condition, the flow of blood in the body gets affected and it is not possible to get an accurate reading by attaching the device to the finger tip. For this reason, the handheld oximeter is clipped to the ear lobe. This device can also be attached to the toe of the patient.
The Tabletop Pulse Oximeter: The tabletop oximeter is a sophisticated device used in hospitals only. It has more sensors and is capable of monitoring the blood continuously. Besides oxygen saturation and pulse rate, it also shows the blood pressure.
The Wrist Pulse Oximeter: As the name implies, this type of device is worn around the wrist (just like a wrist watch) and a sensor is attached to the finger; a wire connects the two units. This device is also capable of continuous monitoring and for this reason is used in sleeps centers to monitor patients suffering from sleep apnea; a sleep disorder in which the patient usually suffers from pause/s in breathing.
Uses and Benefits of Pulse Oximeters
Pulse oximeter is used in hospitals and clinics and at home to monitor the oxygen saturation and pulse rate. It can also be used at homes for the same purpose. Athletes use it during training and pilots find it very helpful in determining their blood pressure at heights.
Over the years the oximeter has proved to be a very vital device in the operation theater and during emergencies where time is extremely important. This is because it gives precise readings within seconds. The affordable price is another benefit of this device.
Patients suffering from respiratory diseases such as emphysema, asthma, COPD (chronic obstructive pulmonary disease) and COAD (chronic obstructive airway disease) need pulse oximeter to regularly monitor their oxygen saturation level.
Mountaineers, pilots and people at high altitudes also carry this device to avoid hypoxia a condition in which the oxygen content in the body is lowered because of the difference in the demand and supply of oxygen at high altitudes.