Altitude-related illness in two California national parks.

High-altitude illness encompasses a spectrum of disorders related to the hypoxia experienced by individuals at elevation. Altitude-related illness has been well described in the United States, but there are no studies published in the medical literature looking at the occurrence of high-altitude illness within the US National Parks system. The purpose of this study is to describe the incidence, treatment, and outcomes of visitors to Sequoia and Kings Canyon National Parks who presented to emergency medical services (EMS) personnel with signs and symptoms consistent with high-altitude illness. We conducted a retrospective review of all EMS patient care records (PCRs) from Sequoia and Kings Canyon National Parks during the study period of June 1992 to August 1995. There were 23 cases of altitude-related illness identified by EMS personnel in the parks during the 38-month study period, including five cases of high-altitude pulmonary edema and 19 cases of acute mountain sickness. One patient died, nine patients were transported to local hospitals, nine patients were assisted in their descent and then released from medical care, and four patients were treated and then allowed to continue their travels. There was an average of 5.9 cases per year of high-altitude illness and an incidence of one case per 27 EMS contacts. We conclude that altitude-related illness does occur in Sequoia and Kings Canyon National Parks and, although high-altitude illness accounts for only 4% of EMS contacts, caring for these patients uses a significant amount of national park resources. We suggest continued training of emergency medical technicians and park medics in the recognition and treatment of these disorders. We also support education of hikers to reduce or prevent the morbidity associated with altitude-related illness.