STUDY OBJECTIVES: We describe the respiratory, cardiac, and sleep-related characteristics of two types of sleep-related respiratory pauses in children that can fulfill current criteria of pathological apnea, but often seem to be benign: prolonged expiratory apnea (PEA) and post-sigh central apnea (PSCA). METHODS: All outpatient comprehensive overnight polysomnography completed on children without significant underlying medical conditions completed during an 18-month period were retrospectively reviewed for the presence of augmented breaths followed by a respiratory pause. Events were identified as a PEA or PSCA based on characteristic features. Physiologic parameters associated with the respiratory events were recorded and compared. RESULTS: Fifty-seven (29 PEA and 28 PEA) events were identified in 17 patients (8.5 +/- 3.5 years old). Median durations of PEA and PSCA were not significantly different. For both PEA and PSCA, average heart rate (HR) during the augmented breath before the respiratory pause differed from lowest instantaneous HR during the first half of the pause. When compared to each other, the lowest instantaneous HR recorded in the first half of PEA was lower than that for PSCA (63.9 [59.41-68.3] vs 66.75 [61.7-80.75]) beats per min, p = 0.03. No PEA or PSCA event was associated with an oxygen desaturation more than 3% from baseline. CONCLUSION: PEA and PSCA have stereotypic HR changes and resemble pathologic apneas but appear to be benign. Clinical significance of PEA and PSCA is yet to be determined. Consistent recognition of the events is required, given their frequency of occurrence and potential for misclassification. CITATION: Haupt ME; Goodman DM; Sheldon SH. Sleep related expiratory obstructive apnea in children. J Clin Sleep Med 2012;8(6):673-679.