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Fig. 2 | BMC Pulmonary Medicine

Fig. 2

From: Receiver operating characteristics of impulse oscillometry parameters for predicting obstructive sleep apnea in preobese and obese snorers

Fig. 2

(a) Patients without and with OSAS. Rrs measured at low-frequency in the sitting position subjected to linear regression analysis of resistance vs frequency; Rrs at 0 Hz was back-extrapolating using equation of Rrs(f) = Rrs0 + S × f, (where f represents the frequency, S is the slope of the linear relationship of resistance versus frequency, Rrs0 is equivalent to zero-order frequency resistance, namely intercept), and then respiratory conductance at 0Hz(Grs) was obtained as reciprocal of Rrs0, which calculated for each subject in every condition according to linear model. The solid lines show the fit of linear regression mode. (b) Rrs measured at low-frequency (from 5 to 15 Hz) in the supine position subjected to linear regression analysis and resistance at the point of zero-frequency (Rrs0) was extrapolated using equation of Rrs(f) = Rrs0 + S × f . Grs in the supine position was obtained as the reciprocal of Rrs0, which calculated for each subject in every condition according to linear model. The solid lines show the fit of linear regression mode

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