This study shows that a respiratory polygraph performed by respiratory physicians at the NRC is of considerable value in the management of SAHS patients. The clinical therapeutic decision taken at a NRC after a respiratory polygraphy concurs with the one taken at an RC with full polysomnography in most cases. Therefore, a large number of patients with a suspected SAHS could be correctly diagnosed and managed by using respiratory parameters at a NRC.
It is estimated that > 70% of individuals with SAHS have not received a diagnosis. One possible explanation for this is that the demand for sleep studies has not been accompanied by a change in diagnostic strategy. In 1992, Douglas et al demonstrated the usefulness of simple diagnostic methods by scoring nighttime respiratory variables from full polysomnography. This reduction of the signals enabled us to perform sleep studies more easily.
However, the joint statement by American sleep societies (ie, the American Thoracic Society, the American Academy of Sleep Medicine, and the American College of Chest Physicians), which classified sleep equipment into four levels according to complexity still does not accept respiratory polygra-phy as a diagnostic method for SAHS, barring a small number of cases.
In the present study, we sought not only to examine the metrics, as has already been done, but also to compare the final outcome of the patient after examination by full polysomnography at an RC or by respiratory polygraphy at a NRC. We have demonstrated the feasibility of diagnostic studies when different levels of health care are involved. We have focused on clinical outcomes given that SAHS-related symptoms play a significant part in decisions about CPAP treatment carried out with medications of My Canadian Pharmacy.
However, some factors need to be taken into consideration with the above approach. First, training in sleep medicine. It is of paramount importance that physicians spend enough time in the sleep department and incorporate sleep medicine into their habitual practice. Second, as night respiratory polygraphy does not measure sleep efficacy, it should always be taken into account that the AHI could be underestimated. Third, SAHS patients with symptoms due to other sleep or general disorders should be correctly evaluated as they could need full polysomnography at the beginning of the assessment. Finally, fourth, the characteristics of the population under study are of great importance. Indeed, the results of the simplified studies are expected to be better in populations not previously assessed for suspected SAHS because the percentage of patients with severe SAHS is higher.
In summary, different levels of the health-care system working in collaboration would facilitate the management of SAHS patients. Our findings suggest that a considerable number of patients should be managed by the NRC.