Evaluation of a portable respiratory recording device for detecting apnoeas and hypopnoeas in subjects from a general population

This study was designed to validate a new home portable respiratory recordi ng device (PRRD) to identify sleep apnoea and hypopnoea in a group of subje cts (n=116), from a sample of the general population. Pull night polysomnography (PSC) was used as the gold standard and simultan eously performed with PRRD, PRRD measurements included oronasal airflow (th ermistry), chest wall impedance, oxygen saturation, snoring and body positi on. The sensors were unique for each recording system, Data obtained was bl indly reviewed and analysed. A high level of agreement between both methods apnoea/hypopnoea index by PS G and the respiratory disturbance index (RDI) by PRRD was observed. Accurac y of the PRRD was evaluated in terms of sensitivity and specificity for dif ferent RDI-PRRD cut-off points with respect to AHI-PSG > 10 and AHI-PSG > 3 0. A logistic regression model was performed to estimate the chance per uni t of RDI of apnoeas, A received operating characteristic (ROC) curve was dr awn to obtain the sensitivity/specificity profile for each observed RDI val ue obtained. From the ROC curve the authors identified the better cut-off p oints, which represent a balanced sensitivity/specificity. Through a classi fication table defined by the cut-off point, the post-odds to exhibit the d isease! was calculated. For a full PSG cut-off point of 10 a PRRD of six sh owed a balanced sensitivity of 95% and a specificity of 92%, For a full PSC cut-off point of 30 a PRRD of 16 shows a balanced sensitivity/specificity (100% and 97%, respectively). Post odds of apnoea were calculated for each cut-off point, In conclusion, these data suggest that the portable respiratory recording d evice is an effective device to identify apnoeas and hypopnoeas in a genera l population and is therefore a suitable device to be used in epidemiologic al studies.