Eligibility criteria | |
Inclusion criteria |
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Exclusion criteria |
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Study definitions | |
Epoch | A 60 s period of time |
Breath | One cycle of neonate-initiated inhalation and exhalation |
Breath start | End of a waveform trough (low point) where the carbon dioxide level starts to ascend |
Respiratory rate (RR) manual counting protocol | A breath was counted if the waveform peak reached either 15 mmHg or the average peak of the epoch, AND the waveform trough dipped below the average trough of the epoch plus 10 mmHg
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RR epoch exclusion criteria | RR epoch excluded if (i) the difference between the epoch count and median RR was >10, (ii) either value was <15, (iii) the capnogram contained a digital artefact or (iv) if there was lack of inter-reader manual count agreement |
RR median calculation | For each breath in an epoch, an instantaneous RR could be calculated by the breath duration, and the median of all these instantaneous RR values in an epoch was then calculated |
Heart rate (HR) median calculation | Heart beats were identified by the timing of the Masimo Rad-97 reference device plethysmograph quality index (PO-SQI) which occur at the peak of each heart beat. For each heart beat in an epoch, an instantaneous HR could be calculated by the time between the previous heart beat peak and current heart beat peak, and the median of all these instantaneous HR values in an epoch was then calculated |
Adequate signal quality | EarlySense device: A signal quality score ≥0.7 for at least 50% of the epoch Masimo Rad-97 reference device: plethysmograph quality index (PO-SQI) threshold >150 for 100% of the epoch for HR, and capnography quality score (CO2-SQI) threshold ≥2 for at least 90% of the epoch for RR |