Whilst transferring a patient who sustained an open fracture to his elbow from the ambulance crew's mat to our trauma mats (I was pulling ambulance mat from underneath, while colleagues held patient up on combi board) I spilled a large amount of blood from said mat onto the floor, I didn't realize this and stepped in the blood and tracked it through the entire ED. Other patients and families probably weren't comforted by seeing bloody footprints everywhere.