Nitrous oxide analgesia for bone marrow aspiration and biopsy – A randomized, controlled and patient blinded study

•Bone marrow sampling is a painful procedure.•Inhaled 50% N2O was not a better analgesic than 50% O2 during the procedure.•Patients in both groups were equally satisfied with the analgesia method.•Nitrous oxide inhalation was safe and did not cause any serious adverse effects.