It is well known that arousals are often associated with tachycardia. Because polysomnography is costly as a screening test, we studied the correlation between the pulse rate obtained from overnight oximetry with polysomnographic parameters of sleep efficiency and fragmentation.
Polysomnography and pulse oximetry (Healthdyne Technologies, model 920M) were recorded simultaneously in 31 patients, 13 women and 18 men, referred for sleep studies. Highest, lowest and mean pulse rate, standard deviation and frequency distribution of pulse rate were correlated with parameters related to sleep efficiency and fragmentation using ANOVA. For frequency distribution 25 beats intervals (<50; 50-74; 74-99; 100-124; 125-149; 150-174; 175-199; >200) were used.
Age of the patients ranged from 14 to 77 years (mean 47,52 +- SD 15,91). Body mass index was 27,42 ± 4,44 (range of 17,78 –39,96 kg/m2). The statistical analysis indicated that highest pulse rate and rate> 100/min as a percentage of total recording time are good predictors of a low sleep efficiency (F= 4,841; p<0,008). On the other hand, none of the variables tested can predict arousals, microarousals, reduced REM or reduced delta sleep.
Our data show that tachycardia diagnosed by pulse oximetry can predict low sleep efficiency but not sleep arousals. Nevertheless, further studies can disclose other variables, which can be used in the construction of a model for screening of disturbed sleep.
Low sleep efficiency is associated with tachycardia during sleep. This observation increases the usefullness of pulse oximetry as a screening tool for disturbed sleep.
Laercio Valenca, None.