Clinical significance of pulse rate rise during sleep as a screening marker for the assessment of sleep fragmentation in sleep-disordered breathing

To assess the clinical utility of the frequencies of transient increases of pulse rate, non-invasively measured with a pulseoximeter, as an indirect indication of the degree of cortical arousal, measured conventionally on an electroencephalogram (EEG), in obstructive sleep apnea–hypopnea syndrome (OSAHS) patients. Thirty-three consecutive patients referred with suspected OSAHS were studied. Polysomnography (PSG) with determination of esophageal pressure (Pes) and pulseoximetry was monitored to identify breathing-related EEG arousal (B-Ar) associated with apnea, hypopnea or respiratory effort and the frequencies of pulse rate increases. We also assessed the association of B-ArI (defined as the number of B-Ar per hour) with the pulse rate rise index ( PRRI)-X (X=4–10) (defined as the number of pulse rate increases per hour). In addition, the sensitivity and specificity of PRRI for the assessment of a B-ArI cutoff point of 30 were calculated. The sensitivity and specificity of pulseoximetry for different thresholds of PRRI-X (X=4–10) demonstrated that the greatest diagnostic accuracy for detecting frequent arousal (B-ArI≥30) occurs at a cutoff point of 40 PRRI-6 with a sensitivity of 0.88 and specificity of 0.86. This point shows a significant area under the curve of 0.84. In addition, a statistically significant correlation between PRRI-6 and B-ArI ( r=0.68, P