The Many Uses of Pulse Oximeter

After having been successfully uses in intensive care, the recovery, and during anesthesia, the pulse oximeter has been also introduced in other areas of medicine such as in general wards. The technique of pulse oximetry does have limitations and it is possible that patient safety may be compromised with untrained staff.

An oximeter can measure the arterial oxygen saturation of hemoglobin. The technology involved herein is quite complicated. These involve two basic physical principles. First, the absorption of light at two different wavelengths by hemoglobin varies depending on the degree of oxygenation of hemoglobin. Second, the light signal following transmission through the tissues has a pulsatile element. These results a changing volume of arterial blood with each pulse beat. This can be distinguished by a microprocessor from the non-pulsatile component resulting from capillary, venous, and tissue light absorption.


Though oximeter has different functions, it can also be affected by many variables. These variables include ambient light; shivering; abnormal hemoglobins; pulse rate and rhythm; vasoconstriction and cardiac function.

An oximeter can only measure oxygenation, but cannot give indication of a patient’s ventilation. Thus, a false sense of security may occur if supplemental oxygen is being given. In addition, there may be an interruption between the occurrence of a potentially hypoxic event such as respiratory obstruction and a pulse oximeter detecting low oxygen saturation.

But what does an oximeter really measures? It measures the oxygen saturation of hemoglobin in arterial blood. It is a measure of the average amount of oxygen that bounds to each hemoglobin molecule. The percentage saturation is assumed as a digital readout. The pulse rate, however, averaged over 5 to 20 seconds in beats per minute.

A pulse oximeter gives no information on variables such as the oxygen content of the blood, the amount of oxygen dissolved in the blood, the respiratory rate or tidal volume, and the cardiac output or blood pressure.

Nevertheless, an oximeter is indeed a useful non-invasive monitor of a patient's cardio-respiratory system. It has undoubtedly improved patient’s safety in many circumstances. There are advisable reminders to be considered by patients to achieve the desired accurate measurements. Few of the tips include plugging oximeter in to an electrical socket, or if available to recharge the batteries; turning the fingertip pulse oximeter on and wait for it to go through its calibration and check tests; and selecting the probe you require with particular attention to correct sizing and where it is going to go.