PURPOSE: To evaluate the relationship between the severity of Obstructive Sleep Apnea and CPAP pressure.
METHODS: We retrospectively reviewed the data from a community sleep lab Center between September 06 –May'07. A total of 275 studies were performed during this period. In this data, 144 were diagnostic NPSG, 122 were CPAP/BiPap study and 27 were MSLT studies. Out of the above, 112 patients had both NPSG AND CPAP/Bipap titration studies. The sleep apnea was divided into mild, moderate and severe on the basis of AHI 5–14.9, 15–39.9 and >/=40 respectively. 48 patients had mild, 39 patients had moderate and 25 patients had severe obstructive sleep apnea.
RESULTS: The data showed a correlation between AHI and CPAP pressure (p <0.001, Pearson correlation coefficient 0.51). The mean optimal CPAP pressure was 10.2cm. The mean CPAP pressure increased from 8.7+/−2.1cm in mild cases to 10.8 +/−2.8cm in moderate and 11.9 +/−3.6cm in severe cases. High CPAP pressure >13.4 cm (mean +SD (SD>or 3.16cm) was needed in 17.9% of the moderate cases and 27% of the severe cases. None of the mild cases of OSA needed high CPAP pressures. CPAP pressure of more than 20 cm was needed in 2.7% of the severe OSA patients. A one way Analysis of Variance (ANOVA) of CPAP pressures according to AHI is highly significant [F(2,109)=13.489; p <0.001]. Post hoc test detected significant differences in mean CPAP pressures between the mild and moderate groups (p<.05) and mild and severe groups (p <.001). The comparison between moderate and severe groups was non-significant.
CONCLUSION: Compared to mild cases, moderate and severe obstructive sleep apnea patients need high CPAP pressures.
CLINICAL IMPLICATIONS: With increasing severity of Obstructive Sleep Apnea from mild to moderate and severe, anticipate requirement of high Continuous Positive Airway Pressures.
DISCLOSURE: Parvathi Theerthakarai, None.