Abstract: A portable apparatus for use by first responders comprises at least one receiver configured to receive input from at least one medical sensor; a display device configured to display first response guidance to a user; user input device configured to receive input from the user; and processing circuitry configured to process the input from the at least one medical sensor and the input from the user; select the first response guidance to be displayed to the user via the display device, the selecting of the first response guidance comprising: estimating a status of the human subject based on the input from the at least one sensor, and selecting at least one item of first response guidance from a plurality of stored items of first response guidance based on the estimated status; wherein the first response guidance comprises at least one action to be performed by the user.