Pulse Oximeters for Monitoring Asthma

Every day, millions of people around the globe are battling with asthma, a chronic respiratory condition characterized by inflamed and swollen air passages that result into sudden shortness of breath and chest tightness. The narrowed airways make it difficult for air to pass through and subsequently causing lowered oxygenation. Asthma could be extremely fatal when left unmanaged, however, with proper treatment; the prognosis of asthma is good.

Monitoring Asthma

Any disease involving the airways must be assessed with utmost accuracy because of the involvement of a person’s oxygenation. Hence, doctors use a pulse oximeter to find out how well a patient is doing.

The pulse oximeter is a device that shows how much oxygen is present in a subject’s blood. In medicine, they call this the saturation of peripheral oxygen or SpO₂. Ideally, the SpO₂ reading should be between 95 to 100%. Any value below 95% would mean that the person is receiving less oxygen into his body due to a variety of reasons. In the case of asthma, airway obstruction secondary to the inflammation of the air passages is the most probable cause of desaturation.

Pulse oximeters are highly effective instruments for diagnosing and monitoring asthma. They are the first tools used for the assessment of the severity of the condition because they are portable, non-invasive, and can yield immediate results. The physician will simply slip on a probe to the patient’s finger or earlobe. A light-emitting diode (LED) will transmit light through the body part where the probe is clipped. The device will then read how much light is absorbed and reveal the value of the quantity of oxygen saturation in the blood.

Accuracy

Patients presenting with breathing difficulty and/or has a medical history of asthma are often hooked to a pulse oximeter immediately upon arrival for initial assessment. However, many are still quite doubtful on how reliable a small device can be, especially when the pulse oximeter reveals results that are not congruent to the symptoms of the patient.

There might be some instances that a person with asthma may appear “normal” or asymptomatic, and yet the oxygen saturation is quite low. There are a lot of reasons behind this. Nevertheless, a low reading indicates the possibility of desaturation. It will be the physician’s prerogative to perform more tests and physical assessment to aid to his diagnosis.

Traditionally, vital signs include the pulse and breathing rate, as well as one’s body temperature and blood pressure. But because of the increasing needs of ill patients and the rapid change in medical technology, health professionals now consider the oxygen saturation of a person to be the fifth vital sign.  Hence, nowadays, many health care units require the use of pulse oximeters to assess and diagnose various conditions. Several studies have been performed to test the accuracy and sensitivity of pulse oximetry to patients with acute asthma. Most of the time, pulse oximeters are reasonably accurate, but not absolutely as certain factors such as nail polish, movement, anemia and some medical conditions may interfere in getting a good reading. Thus, it is also important to choose a pulse oximeter wisely.

Home Application

Today, manufacturers have found a way in making the pulse oximeter more convenient to use, especially for those who require constant monitoring outside health care facilities. Handheld devices have started to replace the traditional bulky units found in hospitals. Recently, pulse oximeters that only consist of a probe with a tiny colored display have come out to the market. This allows for people to be able determine the presence of hypoxemia brought about by acute asthma exacerbations. In addition, measuring the percentage of hemoglobin that is carrying oxygen within the blood can also be a great way in identifying how well the person is responding to treatment, or when the person needs to rest.

A pulse oximeter can also show the heart rate. Usually, during an asthma attack, the heart rate also rises due to anxiety and in response to the decreasing amount of oxygen entering the respiratory tract. The heart will be the one to compensate for the decreased amount of oxygen distributed throughout the body. This indicates a need for immediate intervention.

With the pulse oximeter, errors in the diagnosis and evaluation of patients with asthma are minimized. Moreover, many are even spared from unnecessary invasive procedures like blood tests in order to determine their state of oxygenation. But as a rule, when in doubt, a battery of tests may also be performed to confirm the presence of a medical condition.