Table 2 Participant eligibility criteria for participation in the POMS2a trial

1

Recruitment will be through sickle cell clinics at Guy’s and St Thomas’ (including Evelina Children’s Hospital)

2

Age > 8 years

3

Informed consent with assent in accordance with the institutional policies (UK ethical committee) and European or US Federal guidelines must be signed by the participant or participant's parent or legally authorised guardian acknowledging written consent to join the study. Where appropriate, participants < 16 years will be requested to give their assent to join the study

4

HbSS diagnosed by standard techniques (HPLC, IEF and MS). Participating institutions must submit documentation of the diagnostic haemoglobin analysis

5

Able to speak and understand English

6

Participant or parent/guardian able to use iPad mini via wireless

1

Participant already on overnight respiratory support, or has used it in the past

2

Hospital admission for acute sickle complication within the past 1 month

3

Participant with > 6 admissions for acute sickle complications within the past 12 months

4

Existing respiratory failure

5

Decompensated cardiac failure

6

History of severe epistaxis

7

Trans-sphenoidal surgery, or trauma that could have left a cranio-nasopharyngeal fistula

8

Perforated ear drum

9

Bullous lung disease

10

Bypassed upper airway

11

Pneumothorax

12

Participant at increased risk of aspiration

13

Pneumocephalus has been reported in a participant using nasal Continuous Positive Airways Pressure. Caution should be used when prescribing APAP for susceptible participants such as those with: cerebral spinal fluid (CSF) leaks, abnormalities of the cribriform plate, prior history of head trauma, and/or pneumocephalus

14

Pregnancy

15

Participants on chronic blood transfusion regimes, or has had blood transfusion within past 3 months

16

Any acute or chronic condition which would limit the participant’s ability to complete the study

17

Sinus or middle ear infection