1. A method for managing blood loss of a patient, performed by one or more processors executing instructions in memory, the method comprising: receiving an image of a physical sample; extracting a color-related value from an area of the image corresponding to the physical sample; estimating a blood volume indicator of the physical sample according to the extracted color-related value; estimating a patient blood loss based on the blood volume indicator; estimating a euvolemic patient hematocrit based on an estimated patient blood volume and the estimated patient blood loss; receiving a measured patient hematocrit; generating a volemic status indicator based on a comparison between the measured patient hematocrit and the estimated euvolemic patient hematocrit; and displaying the volemic status indicator on a display.