POLYSOMNOGRAPHY IN OBESE CHILDREN WITH A HISTORY OF SLEEP-ASSOCIATED BREATHING DISORDERS

We hypothesized that obese children with a history of breathing diffic ulty during sleep would demonstrate (1) evidence of complete and parti al obstructive sleep apnea (OSA) with hypercarbia and/or hypoxemia; an d (2) correlation between symptoms, degree of obesity, adenoid and ton sil size, and polysomnography (PSG) results. We evaluated 32 obese chi ldren % ideal body weight (IBW), 196 +/- 45%! with a sleep history qu estionnaire, airway radiographs, electrocardiograms (ECG), and PSG. By history, we found snoring (100%), difficulty breathing (59%), sweatin g (44%), restlessness (53%), arousals (41%), apnea (50%), worsening wi th upper respiratory infection (URI) (81%), hypersomnolence (59%), and mouth breathing (59%). We found adenoid and/or tonsil enlargement on 75% of airway x-ray pictures. ECGs were abnormal in 5 patients. Among all patients, mean sleep study oxyhemoglobin saturation (S(aO2)) was 8 5 +/- 16% and mean end-tidal CO2 (P(etCO2)) was 51 +/- 7 torr; 84% had paradoxical inward movement of the chest on inspiration, 59% had OSA, and 66% had partial OSA. In those with greater-than-or-equal-to 200% IBW and adenotonsillar enlargement, elevated P(etCO2) and the presence of hypoxemia (S(aO2) < 90%) for greater-than-or-equal-to 5% of the to tal sleep time (TST) were correlated, unlike in patients of similar we ight but without adenotonsillar enlargement. Individual symptoms did n ot correlate with the severity of PSG abnormalities. By discriminant a nalysis, using three variables (IBW, presence of adenotonsillar tissue , and presence of greater-than-or-equal-to 5 symptoms), we could predi ct PSG abnormalities with up to 81% reliability. Our findings indicate that in obese children, particularly those with %IBW greater-than-or- equal-to 200 and adenotonsillar hypertrophy, with sleep-disordered bre athing evaluation by polysomnography should be considered. (C) 1993 Wi ley-Liss, Inc.