Monitoring the respiratory rate by miniature motion sensors in premature infants: a comparative study.

Objective: Existing respiratory rate (RR) monitors suffer from inaccuracy. The study assesses the accuracy of a novel modality that monitors lung ventilation with miniature motion sensors.

Study Design: RR was measured by three methods: impedance technology, motion sensors and visual count, in babies (n=9) that breathed spontaneously or with respiratory support and babies (n=12) that received high-frequency oscillatory ventilation (HFOV).

Results: A line close to equality (slope=0.96, r(2)=0.83) was obtained between the motion sensor and the visual count of the RR with narrow 95% limits of agreements (<14.0 b.p.m.). The relationship between the impedance and the visual count showed a lower correlation (r(2)=0.65) and wider 95% limits of agreements (21.4 b.p.m.). The motion sensor- and the ventilator-determined RRs demonstrated a good agreement during HFOV, whereas the impedance failed to measure the RR during HFOV.

Conclusion: Monitoring RR with motion sensors is more accurate compared with the impedance, in infants, in all ventilation modes.