Persistent hypercapnia in children after treatment of obstructive sleep apnea syndrome by adenotonsillectomy.

Obstructive sleep apnea syndrome (OSAS) in childhood is frequently in part a consequence of enlarged adenoids and/or tonsils and may lead to hypoxemia and hypercapnia during sleep. Whereas long-term blood gas alterations are well documented in adults, only few polygraphic data are available for children. It was the aim of this study to document blood gas alterations before and after treatment in this population. 9 children with OSAS (6 male, 3 female, median age 5.9 years, range 1.1-13.5 years) were investigated by polysomnography before and after adenotonsillectomy. Prior to intervention most children presented with moderate hypercapnia (ETCO2 mean 44.3 +/- 3.8 mm Hg, ETCO2 maximum 53.2 +/- 5.2) and hypoxemic episodes (oxygen saturation mean 93.2 +/- 3.2%, minimum 74.4 +/- 16.5%). Following adenotonsillectomy subsequent polygraphic investigations displayed normalisation of oxygen saturation (saturation mean 96.1 +/- 0.8%, minimum 90.1 +/- 3.1%). In contrast, moderate hypercapnia in several patients persisted up to five months after treatment (ETCO2 mean 44.9 +/- 2.8 mm Hg, ETCO2 maximum 51.2 +/- 3.6). Persistent hypercapnia most likely reflects an adaptation process of chemosensitivity and respiratory control due to preceding long-term hypercapnia.