Comparison of the longitudinal effects of persistent periodic breathing and apnoea on cerebral oxygenation in term- and preterm-born infants

Abstract

Key points: Periodic breathing and apnoea were more common in preterm compared to age-matched term-born infants across the first 6 months after term-corrected age. Periodic breathing decreased with age in both term and preterm infants. Apnoea duration was not different between groups; however, the decline in apnoea index with postnatal age observed in the term infants was not seen in the preterm infants. Falls in tissue oxygenation index (brain TOI) associated with apnoeas were greater in the preterm infants at all three ages studied. The clinical significance of falls in brain TOI during periodic breathing and apnoea on neurodevelopmental outcome is unknown and warrants further investigations.

Abstract: Periodic breathing and short apnoeas are common in infants, particularly those born preterm, but are thought to be benign. The aim of our study was to assess the incidence and impact of periodic breathing and apnoea on heart rate, oxygen saturation and brain tissue oxygenation index (TOI) in infants born at term and preterm over the first 6 months after term equivalent age. Nineteen term-born infants (38-42 weeks gestational age) and 24 preterm infants (born at 27-36 weeks gestational age) were studied at 2-4 weeks, 2-3 months and 5-6 months post-term-corrected age during sleep. Periodic breathing episodes were defined as three or more sequential apnoeas each lasting ≥3 s and apnoeas as ≥3 s in duration. The mean duration of periodic breathing episodes was longer in term infants than in preterm infants at 2-4 weeks (P < 0.05) and at 5-6 months (P < 0.05); however, the nadir in TOI was significantly less in the term infants at 2-3 months (P < 0.001). Apnoea duration was not different between groups; however, the decline in apnoea index with postnatal age observed in the term infants was not seen in the preterm infants. Falls in TOI associated with apnoeas were greater in the preterm infants at all three ages studied. In conclusion, periodic breathing and short apnoeas were more common in infants born preterm and falls in cerebral oxygenation were greater than in the term group. The clinical significance of this on neurodevelopmental outcome is unknown and warrants further investigations.

Keywords: apnoea; cerebral oxygenation; infant.

Figure 1. A, comparison of periodic breathing episode duration between term and preterm infants at 2–4 weeks, 2–3 months and 5–6 months corrected age. ^* P < 0.05. B, comparison of percentage sleep time spent in periodic breathing episode duration between term and preterm infants at 2–4 weeks, 2–3 months and 5–6 months corrected age

Figure 2. Comparison of baseline heart rate (A), peripheral oxygen saturation (B), cerebral oxygenation (C) and fractional tissue oxygen extraction (D) between term and preterm infants at 2–4 weeks, 2–3 months and 5–6 months corrected age. ^*** P < 0.001

Figure 3. Comparison of percentage change in heart rate (A), peripheral oxygen saturation (B) and cerebral oxygenation (C) during periodic breathing between term and preterm infants at 2–4 weeks, 2–3 months and 5–6 months corrected age. ^* P < 0.05, ^** P < 0.01, ^*** P < 0.001

Figure 4. A, comparison of apnoea duration between term and preterm infants at 2–4 weeks, 2–3 months and 5–6 months corrected age. B, comparison of apnoea index between term and preterm infants at 2–4 weeks, 2–3 months and 5–6 months corrected age. ^* P < 0.05, ^*** P < 0.001

Figure 5. A, comparison of percentage nadir in cerebral oxygenation between term and preterm infants at 2–4 weeks, 2–3 months and 5–6 months corrected age. ^*** P < 0.001. B, effects of postnatal age on percentage nadir in cerebral oxygenation between term and preterm infants. ^** P < 0.01, ^*** P < 0.001