Sleep related upper airway obstruction and hypoxaemia in sickle cell disease

A cohort of 53 patients (age range 1.9-16.5 years) with sickle cell disease (49 homozygous SS and four S beta zero-thalassaemia) was studied for evidence of sleep related upper airway obstruction (UAO). This involved (i) a clinical assessment based on a history of snoring, a score of tonsillar size, and (for 50 patients) overnight multichannel respiratory recordings, and (ii) a blinded analysis of arterial oxygen saturation (SaO2) from the above recordings, and comparison with results from 50 healthy age matched controls of both white (n = 25) and Afro-Caribbean race. There was no difference in the baseline SaO2 values of the white and Afro-Caribbean controls. Eighteen patients with sickle cell disease (36%) were found to have sleep related UAO. The blinded analysis showed that eight patients (16%) had episodic hypoxaemia (SaO2 less than or equal to 80%, a value not observed in controls) and/or low baseline SaO2 values (less than 95.8%, the lowest value seen in the controls). Postoperative assessment was undertaken in 15 patients who underwent adenotonsillectomy. All demonstrated an improvement in symptoms and a reduction or abolition of episodic hypoxaemia. Of the 47 patients assessed when free of UAO (not demonstrated on screening, n = 32, or resolved following surgery, n = 15), seven continued to show baseline hypoxaemia. Sleep related UAO and baseline hypoxaemia are common complications of sickle cell disease in children.