Polygraphic findings of 47 cases with respiratory inhibition after crying.

Objective: To report the polygraphic findings of infants with respiratory inhibition after crying (RIAC).

Methods: We screened for RIAC among infants with a gestational age ≥36 weeks using our established method with cranial ultrasonography, SpO(2) monitoring and polygraphy. RIAC is defined as central apnea that occurred immediately after crying with a decrease in SpO(2) to <60%, followed by repeated irregular respiration and apnea as the respiration gradually recovered. The subjects were infants with RIAC for whom we could study the polygraphic findings in detail.

Results: Forty-seven RIAC cases were included in the present analysis. The frequency of RIAC was 2.1 (1.2-7.0) times per 24 h. The maximum duration of respiratory inhibition was 78.0 (52.6-109.0) s. The maximum duration of SpO(2) <60% during RIAC was 39.0 (9.8-93.2) s. The minimum SpO(2) value during RIAC was 53.0% (42.2-58.0%). The minimum heart rate during RIAC was 103.0 (79.1-127.1) bpm.

Conclusions: RIAC is observed among healthy infants, and they experience repeated prolonged hypoxemia.