Wearable Technology in Pulmonary Medicine – What Every RT Should Know

By Sara Zaib Khan, MD, Sameer Verma, MD, Rammohan Gumpeni, MD, Arunabh Talwar, MD, F.C.C.P

In recent years, the role of wearable technology has been expanding in healthcare. Wearable technology are devices that a consumer can wear on their clothing or on the body without interfering with daily activities.¹ In regard to pulmonary medicine, these devices are providing opportunities for evaluating and monitoring respiratory function in patients in real-time. Research suggests that wearable devices aimed at monitoring patient behaviors and physiological parameters can help healthcare providers be informed of patient conditions outside of the acute care hospital.²

Generally, in healthcare, most of the diagnostic tools provide information about the patient that is essentially a ‘snapshot in time ‘.¹ The availability of wearable technology devices provides us with an opportunity to monitor our patient’s cardiorespiratory status in real-time, under natural physiological conditions and in any environment. These can help with the purpose of monitoring in both acute and chronic settings. Such technology helps the healthcare provider to monitor, track conditions of the patient in their home setting thereby reducing the workload of healthcare providers, increase efficiency, reducing the cost of healthcare and improving patient comfort.1

In this article, we will discuss a few common types of wearable technologies and their ability to assist in assessing patients with respiratory problems. Respiratory therapy practitioners need to understand and adjust to these changes in healthcare delivery methods to help their patients.

Pulse Oximetry
Pulse oximetry is widely used in pulmonary medicine as a means to check the oxygenation level of the patient and measures the amount of oxygen bound to hemoglobin referred to as oxygen saturation (SP02). It is a small noninvasive device most commonly placed on the fingertip. It uses two wavelengths of light 660 nm(red) and 940 nm (infrared) to measure oxygen saturation.¹ In a healthy population normal SPO2 is >90% and SP02 <90% is referred to as hypoxemia.³ In patients with pulmonary disorders like COPD and interstitial lung disease (ILD), pulse oximetry can be used as a screening tool for oxygen therapy.

Pulse oximetry is used to check hypoxemia urgently. In the critical care setting in the presence of hypoxemia, physicians can get quicker diagnosis and treatment to avoid any serious adverse events of hypoxia. Many anesthesiologists commonly use pulse oximetry to monitor oxygen saturation during a procedure and based on pulse oximetry, change their medical management.⁴

Ochroch and colleagues did a randomized nonblinded study on the effect of pulse oximetry on the transfer of ICU patients from the post-surgical floor.⁵ One group were continuously monitored while the other was the control group. The result was that using an oximeter was cost-effective. These patients had fewer pulmonary complications and a lower chance of being transferred to the ICU due to early acknowledgment of low oxygen levels. As beneficial as pulse oximetry is in pulmonary medicine there are many drawbacks such as error reading, etc. (Table 1). The overall advantages far outweigh the disadvantages, therefore; continuation of regular monitoring of pulse oximetry is strongly recommended.

Table 1

Technology has advanced over the years, where clinicians can now record continuous pulse oximetry reading to assess a patient’s oxygenation and respiratory function. Overnight pulse oximetry is continuous oximetry done overnight when the patient is sleeping. The main parameters recorded during overnight pulse oximetry include mean overnight saturation (mean SaO2) and lowest SaO2. Normal mean Sa02 is generally is greater >96% in healthy populations.⁸ When the value is low, there is suspicion of an underlying cardiorespiratory problem.

In the field of sleep medicine, overnight pulse oximetry is classified as a Type IV monitoring device with good sensitivity, specificity, accuracy and limitations.^9,10 Since this device is easily available and low cost, clinicians can use this device as a tool for screening obstructive sleep apnea for patients who have high probability.

Wrist Actigraphs
Wrist actigraphs are devices that use an accelerometer to measure movements during wakefulness and sleep. Wakefulness is considered as periods of high movement while absent or no movement is interpreted as sleep.¹¹ Insomnia is major sleep problem in our society. Actigraphy can give the clinician an idea about the sleep-wake cycles as well. Actigraphy devices record data from weeks to months to help monitor daily sleep-wake cycle data, which can help diagnose sleep disorders particularly insomnia.

Another advantage of actigraphs is that patients did not have to leave their home and data was collected in the natural sleep environment. The ergonomics of this device make it very convenient for patients because it is very lightweight and small.¹²

The drawbacks of the actigraph that it can overestimate sleep duration in comparison to polysomnography.¹³ It also overestimated results in patient populations with sleep disorders. These devices also have limited battery life and have the potential of misplacement before or after the onset of sleep.¹⁴ Patients who are awake and lying still can be categorized as being asleep. This can reduce the estimation of the severity of the sleep disorder and can lead to false-positive results.¹²

Glucometer
Diabetes is a metabolic disorder characterized by chronic hyperglycemia due to insulin insufficiency. Diabetes causes microvascular changes leading to complications in gas exchange and abnormal pulmonary function testing.¹⁵ Therefore, controlling diabetes can lead to better control of underlying pulmonary complications. A glucometer detects the level of glucose in a person’s blood. An individual uses a lancet to prick the skin and obtain a small drop of blood. The sample is placed on a test strip and then the device gives the glucose reading.

Common ways of management of diabetes include continuous glucose monitoring (CGM) and self-monitoring of blood glucose (SMBG). Continuous glucose monitoring is a wearable body sensor that measures glucose at regular intervals (every 5-15 minutes) and there can be as many as 288 measurements a day.¹⁶ CGM can calculate trend information about the rate of change of glucose. In an event of hypoglycemia, the device sends off an alarm making the patient aware. Figure 2 shows the difference between CGM and SMBG.

Some of the negatives of CGM is that the device occasionally fails by giving false positive and false negative values, therefore decisions about treatment cannot be based on CGM alone. The accuracy of CGM can be difficult to ascertain in certain situations. For example, in hospitalized patients who have skin edema can have diluted interstitial fluid glucose following insertion of CGM.¹⁶

Table 2¹⁶

Accelerometer
An accelerometer is a device that measures acceleration of an object in motion.¹⁷ It captures the intensity of physical activity which is defined as “bodily movement produced by skeletal muscle that requires energy expenditure”.¹⁸ The measure of the physical activity is step count, which correlates well with health outcomes. It has a linear correlation with physical activity and mortality. For example, patients with respiratory diseases who engage in physical activity have a lower risk of hospital admission and mortality.

There are 2 types of accelerometers which include uniaxial or multiaxial. Uniaxial devices detect motion in only one body dimension while multiaxial detects motion in more than one plane of movement. Uniaxial devices are compared similarly to pedometers but have inaccurate reading in activities such as cycling and rowing. Multiaxial accelerometers give more detailed information about the variety of different physical activities.¹⁸

Accelerometers process data by differentiating between activity intensity, body position, activity type and detect heart vibrations as well as respiration rate in an individual.¹⁹ Also, accelerometers which are worn on the torso can give a measurement of the individual’s respiratory rate by measuring movements of the chest wall.²⁰ Respiratory rate is often not recorded in primary care even when the patient’s primary problem is respiratory. High respiratory rate greater than 27 breaths per minute is associated with serious events such as cardiac arrest and unplanned admission to intensive care unit.⁷

Clinicians can get a continuous recording of respiratory rate using an accelerometer. They can also use an accelerometer to identify arrhythmia or respiratory problems related to sleep apnea. These devices can also be used for patients in pulmonary rehabilitation programs. Therefore, it’ll help the clinicians to measure long term activities in their patient which in turn gives them a better idea about the patient’s physical activity.

In conclusion, wearable technology in respiratory medicine is advancing as healthcare providers and patients are using these devices in many ways. Wearable technology can provide unique opportunities in diagnosis and treatment which is cost-effective and personalized for every patient. Healthcare providers must adjust and adapt to this change in healthcare delivery models to provide optimum care for their patients.

 

Authors
Sara Zaib Khan, M.D., American University of Antigua, School of Medicine Jabberwock Road, Antigua and Barbuda

Sameer Verma, M.D., Northwell Health Department of Pulmonary, Critical Care and Sleep Medicine

Rammohan Gumpeni, M.D., New York Hospital of Queens Department of Pulmonary Medicine

Arunabh Talwar, M.D, F.C.C.P, Northwell Health Department of Pulmonary, Critical Care and Sleep Medicine

 

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