High-flow Oxygen for Vaso-occlusive Pain Crisis

In the control group, standard low-flow oxygen will be delivered via nasal prongs (LFNO), up to hospital discharge or secondary ACS onset, in order to achieve normoxia (target pulse oxymetry saturation of 95%). This strategy is in accordance with current recommendations and usual care

HFNO with low FiO2 (21%-30%) targeting normoxia: to test the effect of improved pulmonary function

In this group, FiO2 will be set at 50% during the first 24 hours of intervention to target moderate hyperoxia, then reduced to 21-3025% during the following 48 hours to target normoxia

In this group, FiO2 will be set at 100% during the first 24 hours of intervention to target intense hyperoxia, then reduced to 21-3025% during the following 48 hours to target normoxia