One variation of a method for setting a blood transfusion parameter for a patient includes identifying a blood transfusion bag in a photographic image; extracting a color feature from a region of the photographic image corresponding to the blood transfusion bag; estimating a blood component content within the blood transfusion bag based on the color feature; and triggering transfusion from the blood transfusion bag based on the blood component content within the blood transfusion bag and an estimated volemic status of the patient.