An external defibrillator is customized for at least one person, i.e., an anticipated patient, through creation of a profile for the anticipated patient that allows the defibrillator and users of the defibrillator to provide customized treatment to the patient. The profile may include treatment parameters for the anticipated patient, such as defibrillation therapy parameters selected for the patient. The profile may also include a baseline recording of a physiological parameter of the patient, and medical history and personal information regarding the patient. In some embodiments, the external defibrillator stores a profile for each of one or more anticipated patients within a memory. In other embodiments, a profile for an anticipated patient is stored within a medium associated with that anticipated patient. The medium may, for example, be a removable medium for external defibrillators.