First, the "A" correctly indicates that a patient with this order will not necessarily be deprived of cardiopulmonary resuscitation. For many hospital inpatients, it is unlikely that CPR would be effective even if it were attempted. Instead, a patient with this order is only being saved from an "attempt" at CPR. Many U.S. providers already designate orders as "DNAR" instead of "DNR" for this reason.
Second, the "CPR" correctly indicates that a patient with this order is still supposed to get interventions other than CPR. Unfortunately, "DNAR" is often interpreted to mean that the patient does not get other treatments such as fluids and antibiotics. The term "resuscitation" is vague. The more narrow and precise "DNACPR" term better indicates the narrow and precise scope of the order.