2.2 Patient characteristics
Age, sex, past medical and surgical history were noted. Based upon medical records, patients were divided into DS and non-DS cohorts. Within the DS cohort, any co-morbidity associated with DS was recorded. In particular, past cardiothoracic surgical history was noted, as was a history of upper airways surgery. Within the non-DS cohort the diagnosis of OSA or a syndrome or genetic alteration associated with sleep disordered breathing was recorded. The cohorts were divided into three age groups; age group one (0-5years), age group two (5-10years) and age group three (>10years).