Randomization
hemopathy, pain
Randomization was planned by minimization upon inclusion of patients in the study and programmed using ENNOV clinical data management software (ENNOV; Paris, France). Patients were randomly assigned 1:1 to a pain prevention program using MEOPA or VR. Treatment allocation was stratified by center, age, sex, and hemopathy. In case of intolerance in the VR arm, a change to MEOPA was permitted.