JMIR Publications

ABSTRACT

Background:

Respiratory rate is a crucial indicator of disease severity yet is the most neglected vital sign. Subtle changes in respiratory rate may be the first sign of clinical deterioration. Current methods of respiratory rate monitoring are labor intensive and sensitive to motion artifact, which often leads to inaccurate readings or underreporting. The P440 radar module is a contactless sensor that uses radar to detect respiratory rate and may be a useful alternative for clinical settings.

Objective:

This goal of this study was to 1) compare the P440 radar module to gold standard manual respiratory rate monitoring and standard of care telemetry respiratory rate counting and 2) compare P440 radar to gold standard respiratory rate in subgroups based on sex and disease state.

Methods:

This was a pilot study of adults 18 years of age or older being monitored in the Emergency Department. Participants were monitored with the P440 radar module for 2 hours and had gold standard (manual) and standard of care (telemetry) respiratory rates recorded at 15-minute intervals during that time. Respiratory rates between the P440, gold standard, and standard telemetry were compared using Bland-Altman plots and intraclass correlation coefficients (ICC).

Results:

Fourteen participants were enrolled in the study. The P440 and gold standard Bland-Altman analysis showed a bias of -0.76 (-11.16-9.65) and an ICC of 0.38 (95% CI 0.06-0.60). The P440 and gold standard had the best agreement at normal physiologic respiratory rates. There was no change in agreement between the P440 and gold standard when grouped by admitting diagnosis or sex.

Conclusions:

Although the P440 did not have statistically significant agreement with gold standard respiratory rate monitoring, it did show a trend of increased agreement in the normal physiologic range, overestimating at low respiratory rates, and underestimating at high respiratory rates. This trend is important for adjusting future models to be able to accurately detect respiratory rates. Once validated, the contactless respiratory monitor provides a unique solution to monitoring patients in a variety of settings.