Results
A total of 40 infants were identified out of 525 children with DS who underwent PSG. Mean age was 6.6 (3.0) months and male comprised 65% of the cohort. The PSG studies included diagnostic (n=13, 33%) and split night (n=27, 67%) cases. The demographic characteristics and comorbidities of included I-DS are shown in the Table 1. PSG sleep characteristics are described in Table 2. All met criteria for OSA with mean oAHI 34.6 (32.3). Severe OSA was present in 34 (85%) infants. CSA was present in 11 (27.5%) of infants. No association was found between age and oAHI or CAI (Pearson correlation(r): -0.1 and 0.02 respectively, P=NS for both). Infants who underwent split studies had more severe OSA when compared with those who underwent diagnostic study. (AHI: 44.7/hr (33.7) vs. 14.8 (9.0), p=0.003), T88 (Mean 12.5 min vs. 0.2 p=0.03) and minO2sat (77.6% vs. 85.8, p=0.01). A total of 11 (27.5%) infants had T88 >5 min qualifying for hypoxemia. Hypoxemia was more common in I-DS with hypoventilation (60 vs. 16.7%, p=0.008). Hypoxemia was also more common among those with severe OSA vs. no severe OSA (32.4 vs. 0%, p=0.16) but this difference was not statistically significant. Hypoventilation was present in 10 (25%) infants. Characteristics of infants with hypoventilation is depicted in Table 3. In logistic regression there was a trend of association between hypothyroidism and hypoventilation (OR: 5.5 [0.96-34.4], p=0.056).
There were 13 infants who underwent AT and had a follow up PSG allowing us to compare the SDB metrics. Time interval between the two PSGs ranged 6 months to 2 years. Severity of OSA markedly decreased (Mean oAHI reduction: 34/hr [29], p=0.0002) (Figure 1). minO2sat also improved post AT (Mean minO2sat increase 9.7% (11.1), P=0.009).