Validation of Heart Rate Derived from a Physiological Status Monitor-Embedded Compression Shirt Against Criterion ECG

Abstract

Firefighters are subject to extreme environments and high physical demands when performing duty-related tasks. Recently, physiological status monitors (PSM) have been embedded into a compression shirt to enable firefighters to measure, visualize, log, and transmit vital metrics such as heart rate (HR) to aid in cardiovascular risk identification and mitigation, thereby attempting to improve the health, fitness, and safety of this population. The purpose of this study was to validate HR recorded by the PSM-embedded compression shirt against a criterion standard laboratory ECG-derived HR when worn concurrently with structural firefighting personal protective equipment (PPE) during four simulated firefighting activities. Ten healthy, college-age men (mean ± SD: age: 21 ± 1 yr; body mass: 91 ± 10 kg; body mass index: 26.9 ± 3.1 kg/m(2)) completed four tasks that are routinely performed during firefighting operations: outdoor fast-paced walking (FW), treadmill walking (TW), searching/crawling (SC), and ascending/descending stairs (AD). They wore the PSM-embedded compression shirt under structural firefighting PPE. HR was recorded concurrently by the PSM-embedded compression shirt and a portable metabolic measurement system accompanied with a standard 12-lead electrocardiograph that was used to provide criterion measures of HR. For all four tasks combined there was very high correlation of PSM and ECG HR (r > 0.99; SEE 0.84 /min) with a mean difference (bias) of -0.02 /min and limits of agreement of -0.07 to 0.02 /min. For individual tasks, the correlations were also high (r-values = 0.99; SEE 0.81-0.89). The mean bias (limits of agreement) was: FW 0.03 (-0.09 to 0.14); TW 0.04 (-0.05 to 0.12); SC -0.01 (-0.12 to 0.10); AD -0.13 (-0.21 to -0.04) /min. These findings demonstrate that the PSM-embedded compression shirt provides a valid measure of HR during simulated firefighting activities when compared with a standard 12-lead ECG.

Psychometric properties of the Zephyr bioharness device: a systematic review

“… Dolezal et al (2014). [ 28 ] Ten healthy men, age 21.0 ± 1.0 years, height 184 ± 5 cm and weight 91 ± 10 kg. 10 Criterion validity & agreement.…”

“…[ 27 ] 5 Lead ECG Cycle ergometer Rest 1.00 ≥0.99 12- Stages 0.00 ≥0.99 Recovery 2.00 ≥0.99 Dolezal et al (2014). [ 28 ] 12 Lead ECG Treadmill Walk 0.04 0.99 Search (Crawl) − 0.01 0.99 Stairs −0.13 0.99 Fast walk 0.03 0.99 Smith et al (2014). [ 29 ] 3 Lead ECG Treadmill Walk −0.40 0.99 Search (Crawl) −1.70 0.95 Stairs 0.40 0.99 Gatti et al (2014).…”

“…In regards to ZB vs ECG comparisons, Flanagan et al [ 27 ] study rated at “Very good”, reported (− 2.84–2.42) 95% LoA. Similarly, Dolezal et al [ 28 ] and Smith et al [ 29 ] studies rated at “Good”, reported (− 0.21–0.14) and (− 3.01–0.70) 95% LoA between ZB vs ECG respectively. It is important to note that there are no thresholds to help categorized 95% LoA into excellent or poor, however, narrower 95% LoA between ZB vs ECG, is suggestive of better agreement and possible interchangeable use.…”

Cost-effectiveness of workplace wellness to prevent cardiovascular events among U.S. firefighters

“…Use of real-time physiologic monitors may extend beyond the fireground and aid in early identification of distress occurring hours after a high-stress incident. Unfortunately, research exploring use and utility of continuous physiologic monitoring is incomplete and information on cost limited [11, 12]. This creates a dilemma for fire department administrators and physician medical directors.…”

“…Devices may have built in alarms to warn the firefighter that they have reached some threshold value of physiology or may transmit data in real time to a monitoring station. Multiple studies have attempted to validate the devices within the context of fire suppression and it seems likely this trend in research of device application and functionality will continue [11, 12]. …”