public function audit($target, $action, $data = null, $log = false, $properties = array())
 {
     $properties['event_id'] = $this->event_id;
     $properties['episode_id'] = $this->event->episode_id;
     $properties['patient_id'] = $this->getPatient()->id;
     return parent::audit($target, $action, $data, $log, $properties);
 }