CPR is the resuscitation of an animal that has stopped breathing or has stopped breathing and whose heart is not beating. Resuscitation of an animal that has stopped breathing but still has a heartbeat is more likely to succeed than resuscitation of an animal with no breathing and no heartbeat. DNR means “do not resuscitate”. This is a decision that CPR is not to be performed in the event that the pet stops breathing or has no heartbeat. If you chose DNR and your pet stops breathing or his/her heart stops beating, then we will not attempt to revive your pet and your pet will die. Animals that have survived cardiopulmonary arrest and have been successfully resuscitated (CPR) are extremely critical and unstable. Survival of respiratory arrest in which the heart has continued to beat carries a slightly better prognosis. The likelihood of re-arrest is high and usually occurs within 4 hours of the initial arrest. This means that there is only about a 20% chance that your pet will stay alive for the first 4 hours after resuscitation. Long term survival is even more grave and may be as low as 1%. Management of the post-arrest patient requires vigilant monitoring and the technical expertise of dedicated critical care personnel. This care is costly, and the outcome is uncertain.