Is cardiopulmonary resuscitation useful for sudden cardiac arrest? Of course, it is useful. The emergency measure for sudden cardiac arrest is to perform cardiopulmonary resuscitation. If the patient receives CPR within four minutes, they are very likely to survive. If there is a delay beyond four minutes, the patient’s life might still be prolonged if resuscitated, but they might suffer brain death and potentially become vegetative. Therefore, it is crucial to administer immediate cardiopulmonary resuscitation to a patient experiencing sudden cardiac arrest, as this is the primary method of resuscitation.