COMPARISON OF POLYSOMNOGRAPHY WITH RESCARE AUTOSET IN THE DIAGNOSIS OF THE SLEEP-APNEA HYPOPNEA SYNDROME

Background - Increasing referral numbers make the development of simpl ified accurate methods of diagnosing the sleep apnoea/hypopnoea syndro me highly desirable. The accuracy of one such system - the ResCare Aut oset - has been examined. Methods - Thirty one consecutive patients as sessed by polysomnography had simultaneous monitoring of their respira tory pattern using the Autoset system. The Autoset detects episodes of flattening of the flow/time profile using nasal cannulae. Results - T here was a good correlation (r = 0.85) between the number of apnoeas hypopnoeas/hour in bed recorded using polysomnography and the Autoset system, The median difference in such events was 3.1 (95% confidence interval 8.4 to -1.6)/hour in bed, In two patients the Autoset scored 70 apnoeas + hypopnoeas/hour in bed compared with 34 apnoeas + hypopno eas with 35 arousals/hour in bed by polysomnography; however, this did not alter the diagnostic category of either patient; Autoset gave a s ensitivity of 100%, specificity of 92%, positive predictive value of 9 2%, and negative predictive value of 100%, which was better than oxime try alone. A sleep study using the Autoset system costs 14 pound compa red with 126 pound for polysomnography. Conclusions - The Autoset is c linically useful for diagnosing the sleep apnoea/hypopnoea syndrome.