0576 Variation in Night to Night Home Sleep Testing

Abstract

Abstract Introduction Home sleep testing (HST) is becoming common in the evaluation of Obstructive Sleep Apnea (OSA). Studies confirmed good HST AHI correlations from different nights in a single patient. The following reviewed AHI and additional measures from HST’s. (Alice Night One)) Methods We collected data from 20 patients from two consecutive nights of HST’s. 5 F 15 M, means AGE 49 (sd 14) and BMI 36 (sd 8). Both studies had over 4 hours of good sleep and acceptable data. Measures include abs(Night 1- Night 2) of AHI (Diff.AHI), of mean EKG (Diff.EKG) mean time SaO2 less than 90% (Diff.SaO2). Results These results reproduced the strong correlation of AHI, Time SaO2 less than 90 %: and mean EKG between two nights, .96, .72, .87 respectively. There was a strong correlation between Diff.AHI and Diff.SaO2, .63 (p .003). There were weaker correlations between AHI and Time SaO2 less than 90% on Night 1, .67 and Night 2, .75. Linear regression: Diff.AHI on Age (p=.2), BMI (p = .9), and Diff.EKG (p=.4). Conclusion These results again validate the small degree of AHI variation in night to night HST. They confirm a small degree of variation in the mean EKG and Time SaO2 less than 90%. There is a high correlation between AHI and time SaO2 less than 90% as these variables are dependent and the fall in SaO2 is used to define an event, especially on the HST. The BMI did not explain variation in AHI, there is a low correlation between AHI and BMI. Age could be a factor in AHI variation; yet, this is highly speculative with an N = 20. The correlations between AHI and Time SaO2 less than 90% are likely to be due to the relative health of the subjects and small number of subjects. One night of good, greater than 4 hours HST may be sufficient. This study did not evaluate success in meeting these parameters with a single night of testing. Support Louis B Stokes VHA, Cleveland, OH