Peripheral arterial tonometry events and electroencephalographic arousals in children

Abstract

Study objectives: Peripheral arterial tonometry (PAT) is a sensitive measure of moment-to-moment changes in sympathetic activity and reliably identifies arousals in adult subjects. We investigated whether PAT events during sleep are associated with visually recognizable electroencephalographic arousals in healthy children and in children with sleep-disordered breathing.

Design: Prospective cohort.

Setting: Pediatric Sleep Research Laboratory.

Participants: Twenty children with obstructive sleep apnea syndrome, 20 children with mild sleep-disordered breathing, and 20 control children with a mean age of 7.6 +/- 2.6 years (range: 5.7-16.5 years); 53% of children were boys.

Interventions and measurements: Polysomnographic evaluation in the sleep laboratory with concomitant recording of PAT. PAT events were defined as attenuations from immediately preceding baseline of 20% to 50% (PAT20) and > 50% (PAT50) for at least 5 seconds and the indexes calculated per hour of sleep time that included good-quality PAT signals. Total PAT index (the sum of PAT20 index and PAT50 index) was also calculated.

Results: Total PAT index correlated with total arousal index and spontaneous arousal index (r = 0.55, P < .0001, r = 0.64, P < .001, respectively), especially in the group with obstructive sleep apnea syndrome (r = 0.71, P < .0001). The sensitivity and specificity of PAT for identifying electroencephalographic arousals were 95% and 35%, respectively. The PAT device identified pathologic arousals indexes (> or = 16 per hour) (area under the curve 0.79, P = .002). Thirty-five percent of respiratory events (eg, obstructive apnea or hypopnea) were associated with a visual electroencephalographic arousal, compared to 92% being associated with PAT attenuation events.

Conclusions: Arousals in sleeping children are associated with increased sympathetic discharge, as evidenced by attenuations in PAT signal. However, a significant proportion of PAT attenuations were not accompanied by visual electroencephalographic arousals. Thus, the importance of these autonomic arousals has yet to be explored in association with morbidities related to sleep-disordered breathing and, therefore, PAT technology cannot be recommended as an alternative tool for measuring arousals in children. Nevertheless, these data further support the contention that adult criteria for the measurement for arousals may not be adequate in children.