A device for monitoring an analyte in tissue of a human or animal subject, the device comprising: a measurement body having a contact surface suitable to be brought in contact with a skin of the subject, said contact permitting heat and/or pressure waves generated by absorption of excitation radiation in the tissue to be transferred to said measurement body; an excitation radiation source configured for irradiating excitation radiation at a plurality of wavelengths into the tissue to be absorbed by the analyte contained therein; a detection device (28, 30) for detecting a physical response of the measurement body or of a component included therein to a heat and/or pressure wave received from the tissue upon absorption of the excitation radiation and for generating a response signal based on said detected physical response, said response signal being indicative of a degree of absorption of excitation radiation; a controller to control the excitation radiation source to irradiate excitation radiation into the tissue to be absorbed by the analyte contained therein and to control the detection device (28, 30) to detect said physical response and to generate a response signal indicative of the degree of absorption of said excitation radiation; a holding portion for securing the device to a body part, in particular a limb of the subject; and a communication unit configured to provide monitoring information pertaining to the degree of absorption of said excitation radiation and/or a first aid instruction based on the degree of absorption of said excitation radiation by acoustic, optical, and/or wireless communication means; characterized in that the controller is configured to: determine a state of consciousness of the subject that characterizes whether the subject is conscious and/or responsive, wherein the state of consciousness is determined based on said response signal and/or based on a sensor signal from one or more auxiliary sensors (110, 112) configured to measure a parameter indicative of whether the subject is conscious and/or responsive; and in response to the state of consciousness indicating that the subject is unconscious and/or unresponsive, provide monitoring information pertaining to the degree of absorption of said excitation radiation and/or a first aid instruction based on the degree of absorption of said excitation radiation via the communication unit by one or more of said acoustic, optical, and/or wireless communication means. a measurement body having a contact surface suitable to be brought in contact with a skin of the subject, said contact permitting heat and/or pressure waves generated by absorption of excitation radiation in the tissue to be transferred to said measurement body; an excitation radiation source configured for irradiating excitation radiation at a plurality of wavelengths into the tissue to be absorbed by the analyte contained therein; a detection device (28, 30) for detecting a physical response of the measurement body or of a component included therein to a heat and/or pressure wave received from the tissue upon absorption of the excitation radiation and for generating a response signal based on said detected physical response, said response signal being indicative of a degree of absorption of excitation radiation; a controller to control the excitation radiation source to irradiate excitation radiation into the tissue to be absorbed by the analyte contained therein and to control the detection device (28, 30) to detect said physical response and to generate a response signal indicative of the degree of absorption of said excitation radiation; a holding portion for securing the device to a body part, in particular a limb of the subject; and a communication unit configured to provide monitoring information pertaining to the degree of absorption of said excitation radiation and/or a first aid instruction based on the degree of absorption of said excitation radiation by acoustic, optical, and/or wireless communication means; determine a state of consciousness of the subject that characterizes whether the subject is conscious and/or responsive, wherein the state of consciousness is determined based on said response signal and/or based on a sensor signal from one or more auxiliary sensors (110, 112) configured to measure a parameter indicative of whether the subject is conscious and/or responsive; and in response to the state of consciousness indicating that the subject is unconscious and/or unresponsive, provide monitoring information pertaining to the degree of absorption of said excitation radiation and/or a first aid instruction based on the degree of absorption of said excitation radiation via the communication unit by one or more of said acoustic, optical, and/or wireless communication means.