Fig. 1

a In this regional modification to the Revised Swiss System, “Alert” corresponds to a GCS score of 15; “Confused” corresponds to a GCS score of 14, “Verbal” corresponds to a GCS score of 9–13; “Pain” and “Unresponsive” correspond to a GCS score < 9. While shivering is not used as a stage-defining sign in this regional modification to the Revised Swiss System, its presence usually means that the temperature is > 30 °C, a temperature at which hypothermic CA is unlikely to occur [6]. b No respiration, no palpable carotid or femoral pulse, no measurable blood pressure. Check for signs of life (pulse and, especially, respiration) for up to 1 min [7]. c The transition of colours between stages represents the overlap of patients within groups. The estimated risk of cardiac arrest is based on accidental hypothermia being the only cause of the clinical findings. If other conditions impair consciousness, such as asphyxia, intoxication, high altitude cerebral oedema or trauma, this regional modification to the Revised Swiss System may falsely predict a higher risk of cardiac arrest due to hypothermia. Caution should be taken if a patient remains “alert”, “confused” or “verbal” while showing signs of haemodynamic or respiratory instability such as bradycardia, bradypnoea, or hypotension because this may suggest transition to a stage with higher risk of cardiac arrest