Gli indici per la diagnosi strumentale delle apnee nel sonno: standardizzazione del calcolo con polisonnografia e monitoraggio cardiorespiratorio

The aim of this document is to standardize the national definition of respiratory events during sleep when they are obtained through polysomnography or level III monitoring systems ("cardiorespiratory"). Since the identification of the respiratory events during sleep depends on the instrumentation used to detect airflow, the document recommends the use of nasal cannulas coupled with pressure transducers for airflow recording. The Authors defined the following indices obtained by polysonmography: - Apnea-hypopnea index (AHI): the number of apneas and/or hypopneas per hour of sleep. - Respiratory disturbance index (RDI): the number of apneas, hypopneas and Respiratory Effort Related Arousals (RERA) or Flow Limitation Arousals (FL-Arousal) per hour of sleep. In clinical practice, the RDI will be given by the sum of "apneas-hypopneas plus RERA" (when intrathoracic pressure is monitored) or "apneas-hypopneas plus FL-arousal" (when nasal pressure is recorded). - Oxyhaemoglobin desaturation index (ODI): the number of desaturations >= 4% per hour of sleep. The Authors defined the following indices derived by the cardiorespiratory monitoring systems: - Apnea-hypopnea index (AHIa): the number of apneas and/or hypopneas for hour of useful recording. - Oxyhaemoglobin desaturation index (ODI): the number of desaturations >= 4% per hour of useful recording. The "time of useful recording", which will be used for the calculation of the indices derived by the cardiorespiratory monitoring, means the number of hours spent in lateral or supine decubitus minus the recording time in orthostatism and the time spent with the lights on.