Abstract
Introduction: Hypoxia is detrimental to patients with sickle cell disease (SCD) as it causes polymerisation of sickle haemoglobin. Whilst daytime oxygen saturations in patients with SCD are normal or near normal, overnight oxygen levels are not known and are not routinely assessed in these patients.
Aim: To evaluate and describe the prevalence and characteristics of nocturnal oximetry changes in patients with SCD.
Methods: SCD patients referred by haematology for lung function testing also underwent overnight oximetry. Nocturnal oximetry findings were manually scored and results were correlated with lung function. Nocturnal hypoxia (NH) was defined as 30% total sleep time with SpO2 90%.
Results: Lung function testing showed that one patient had airway obstruction, while the rest had normal spirometry. The average KCO was Mean ± SD 91.63±20.54% predicted. The average daytime saturation in this group was 94.90±2.13%. However, the mean night time oxygen saturation in the group was 91.14±4.32.
NH was evident in 4/10 patients in this group and percentage of sleep time nocturnal desaturation was mean of 83.78±18.02 (SD). NH of < 85% was 7.92±13.10. None of the patients had a 4% oxygen desaturation index 10 events per hour.
Conclusion: Patients with SCD can have a normal gas transfer and a borderline normal daytime oximetry. However, during sleep, SCD patients can have long periods of moderate to severe hypoxia.
Our observation showed NH can be seen in SCD even in the abscence of OSA and COPD.
The pathophysiology of night time hypoxia in SCD and the possible therapeutic potential of night time oxygen for these patients deserve further studies.
- © 2011 ERS
