Influence of setting on unattended respiratory monitoring in the sleep apnoea/hypopnoea syndrome

The high demand for full polysomnography and the better quality of sleep at home are the main reasons for performing home sleep studies. Home respirat ory monitoring has been evaluated in several studies, but the influence of setting on the results of unattended respiratory monitoring has not been as sessed to date. Unattended monitoring of respiratory variables at home and in the sleep lab oratory was conducted in 35 consecutive patients with suspected sleep apnoe a/hypopnoea syndrome. Respiratory variables during sleep, rate of successfu l studies and patient preference were compared. The data acquisition failure rate was 2.8% in the sleep laboratory and 5.7% at home. The mean difference between apnoea/hypopnoea indices (AI-II) obta ined from home and laboratory studies was -0.21 +/-8 (95% confidence interv al 3.27-2.84). Using the method comparison approach of Bland and Altman, th e limits of agreement of the mean difference between AHI home and AHI labor atory were -16.7 and 17.1. No difference was observed between the studies i n time spent in different body positions. When patients were asked where th ey would prefer to repeat the sleep study, 53% replied at home, 28% in hosp ital and 19% showed no preference. It was concluded that the setting of unattended respiratory monitoring (hom e or sleep laboratory) influences neither the number of valid studies nor t he results of the respiratory parameters measured; most patients, however, preferred home studies.