Endpoints | Prespecified margins* |
LOA of second-to-second HR differences | ±8 bpm |
LOA of RR-trend differences | ±15 bpm |
Sensitivity of brady-/tachycardia detection | 90%† |
PPV of brady-/tachycardia detection | 90%† |
Sensitivity of apnoea/tachypnoea detection | 70% |
PPV of apnoea/tachypnoea alarms | 0%–100%‡ |
Data loss percentage | 5% |
Robust data percentage (HR) | 90% |
Robust data percentage (RR) | 70% |
Data loss is defined as the percentage of data with ‘Leads off’ or ‘Bluetooth Loss Error’ in the belt.
*The prespecified margins are compared to confidence intervals with corresponding confidence levels (see SAP for more details).
†Note: all missed bradycardias are checked for clinical relevance by two independent experts.
‡Since the reference devices for apnoea detection in the clinical practice are the peripheral oxygen saturation (SpO2) and electrocardiogram instead of the respiration signal and the performance for chest impedance to detect tachypnoea is unsatisfactory due to the presence of cardiac interference, all values for PPV for apnoea/tachypnoea are acceptable. Interpretations will be made based on the results.
HR, heart rate; LOA, limits of agreement; PPV, positive predictive value; RR, respiratory rate; SAP, statistical analysis plan.