High-rise syndrome : comparative and retrospective study of 204 cases. The high-rise syndrome (HRS) is used to describe traumatic injuries resulting from falls from a height greater than two stories. Apart from the shock, lesions most frequently include the triad of lung injury (contusion, pneumothorax), appendicular fractures and contusions of the head. The average mortality rate is 11% in cats. Unlike humans and dogs, cats are able to survive falls from heights greater than 6 stories, due to the effectiveness of their vestibular system and low body mass.