A medical device, comprising: an optical transceiver, comprising a light emitting tube and a receiving tube, wherein the light emitting tube emits at least one light signal to penetrate through human tissue, and the receiving tube receives the at least one light signal which has passed through the human tissue and includes at least partial hemodynamic characteristics and converts the at least one light signal into at least one electric signal; a digital processor to convert the at least one electric signal into at least one digital signal and process the at least one digital signal to obtain peripheral circulation relevant parameters; wherein the at least one digital signal includes the at least partial hemodynamic characteristics; the digital processor obtains the peripheral circulation relevant parameters by identifying a fluctuation component and a constant component of the at least one digital signal; and an output module to output associated information corresponding to the peripheral circulation relevant parameters based on the fluctuant component or a ratio between the fluctuant component and the constant component; wherein the peripheral circulation relevant parameters are related to pulsatile perfusion characteristics of the human tissue, during CPR, the peripheral circulation relevant parameters include peripheral circulation parameters related to CPR quality; wherein the peripheral circulation parameters related to CPR quality include a first reflecting parameter that reflects frequency variation characteristic of CPR compression, a second reflecting parameter that reflects depth variation characteristic of CPR compression, and/or a third reflecting parameter that reflects variation characteristics of frequency and depth of CPR compression; and characterized in that : depth variation characteristics are obtained from an amplitude characteristic and/or area characteristic of the fluctuation component an optical transceiver, comprising a light emitting tube and a receiving tube, wherein the light emitting tube emits at least one light signal to penetrate through human tissue, and the receiving tube receives the at least one light signal which has passed through the human tissue and includes at least partial hemodynamic characteristics and converts the at least one light signal into at least one electric signal; a digital processor to convert the at least one electric signal into at least one digital signal and process the at least one digital signal to obtain peripheral circulation relevant parameters; wherein the at least one digital signal includes the at least partial hemodynamic characteristics; the digital processor obtains the peripheral circulation relevant parameters by identifying a fluctuation component and a constant component of the at least one digital signal; and an output module to output associated information corresponding to the peripheral circulation relevant parameters based on the fluctuant component or a ratio between the fluctuant component and the constant component; wherein the peripheral circulation relevant parameters are related to pulsatile perfusion characteristics of the human tissue, during CPR, the peripheral circulation relevant parameters include peripheral circulation parameters related to CPR quality; wherein the peripheral circulation parameters related to CPR quality include a first reflecting parameter that reflects frequency variation characteristic of CPR compression, a second reflecting parameter that reflects depth variation characteristic of CPR compression, and/or a third reflecting parameter that reflects variation characteristics of frequency and depth of CPR compression; and characterized in that : depth variation characteristics are obtained from an amplitude characteristic and/or area characteristic of the fluctuation component <EOS>