EVI describes the amount of variability between individual expirations during a full night’s sleep
Children at a lower risk of bronchial obstruction, or those using correct medication for asthma control, have high variability in the shape of the expiratory flow-volume curves during night-time tidal breathing, and a normal EVI result is therefore high (EVI > 14.0). When an obstruction is present, there is less variability in expiration patterns, and the EVI result is low (EVI <= 14.0).
Analysis of a child’s whole-night respiration data allows for the calculation of the child’s EVI. A Ventica EVI result describes the amount of variability between individual expirations during the night’s sleep. The Ventica software only uses data recorded from periods of restful sleep.
Reliable EVI calculation based on sophisticated artifact-detection and filtering
When calculating the EVI, the Ventica Analytics software only uses breathing recorded from periods of restful sleep. Periods of restless movement, coughing or crying, for example, are automatically filtered out of the full night’s dataset by sophisticated artifact-detection algorithms.