A system for managing an active compression decompression cardiopulmonary resuscitation treatment to a patient in need of emergency assistance, the system comprising: an applicator device (400, 500) configured to provide the ACD CPR treatment to the patient's chest according to a plurality of phases, the phases comprising at least an elevated compression phase (108, 228), a non-elevated compression phase (102, 222), an elevated decompression phase (106, 226), and a non-elevated decompression phase (104, 224); at least one sensor (532, 533, 534, 539) configured to be coupled to the patient's chest and to measure at least one parameter related to the ACD CPR treatment; and one or more processors (535, 1310) configured to: process the at least one parameter related to the ACD CPR treatment to determine the phase (102-108, 222-228) of the ACD CPR treatment wherein the determination of the phase of the ACD CPR treatment is based on information for determining whether at least one transition point (110, 230) in the ACD CPR treatment has been reached, wherein the information comprises at least one of displacement information and force information, and generate a phase-specific feedback signal for administering the ACD CPR treatment to the patient's chest based on the determination, wherein the feedback signal is selected according to a predetermined treatment protocol; wherein the at least one transition point (110, 230) includes (i) a transition between an elevated position above a neutral point (116, 236) and a non-elevated position below the neutral point, or (ii) a transition between a non-elevated decompression phase (104, 224) and an elevated decompression phase (106, 226), or (iii) a transition between an elevated compression phase (106, 226) and a non-elevated compression phase (104, 224), or (iv) a transition between an elevated decompression phase (106, 226) and an elevated compression phase (108, 228), or (v) a transition between an elevated decompression phase (106, 226) and a hold time (114, 234) above a neutral point, or (vi) a transition between a hold time (114, 234) above a neutral point and an elevated compression phase (106, 226), or (vii) a transition between a non-elevated compression phase (102, 222) and a non-elevated decompression phase (104, 224), or (viii) a transition between a non-elevated compression phase (102, 222) and a hold time (112, 232) below a neutral point (116, 236), or (ix) a transition between a hold time (112, 232) below a neutral point and a non-elevated decompression phase (104, 224). an applicator device (400, 500) configured to provide the ACD CPR treatment to the patient's chest according to a plurality of phases, the phases comprising at least an elevated compression phase (108, 228), a non-elevated compression phase (102, 222), an elevated decompression phase (106, 226), and a non-elevated decompression phase (104, 224); at least one sensor (532, 533, 534, 539) configured to be coupled to the patient's chest and to measure at least one parameter related to the ACD CPR treatment; and one or more processors (535, 1310) configured to: process the at least one parameter related to the ACD CPR treatment to determine the phase (102-108, 222-228) of the ACD CPR treatment wherein the determination of the phase of the ACD CPR treatment is based on information for determining whether at least one transition point (110, 230) in the ACD CPR treatment has been reached, wherein the information comprises at least one of displacement information and force information, and generate a phase-specific feedback signal for administering the ACD CPR treatment to the patient's chest based on the determination, wherein the feedback signal is selected according to a predetermined treatment protocol; process the at least one parameter related to the ACD CPR treatment to determine the phase (102-108, 222-228) of the ACD CPR treatment wherein the determination of the phase of the ACD CPR treatment is based on information for determining whether at least one transition point (110, 230) in the ACD CPR treatment has been reached, wherein the information comprises at least one of displacement information and force information, and generate a phase-specific feedback signal for administering the ACD CPR treatment to the patient's chest based on the determination, wherein the feedback signal is selected according to a predetermined treatment protocol; wherein the at least one transition point (110, 230) includes (i) a transition between an elevated position above a neutral point (116, 236) and a non-elevated position below the neutral point, or (ii) a transition between a non-elevated decompression phase (104, 224) and an elevated decompression phase (106, 226), or (iii) a transition between an elevated compression phase (106, 226) and a non-elevated compression phase (104, 224), or (iv) a transition between an elevated decompression phase (106, 226) and an elevated compression phase (108, 228), or (v) a transition between an elevated decompression phase (106, 226) and a hold time (114, 234) above a neutral point, or (vi) a transition between a hold time (114, 234) above a neutral point and an elevated compression phase (106, 226), or (vii) a transition between a non-elevated compression phase (102, 222) and a non-elevated decompression phase (104, 224), or (viii) a transition between a non-elevated compression phase (102, 222) and a hold time (112, 232) below a neutral point (116, 236), or (ix) a transition between a hold time (112, 232) below a neutral point and a non-elevated decompression phase (104, 224).