Observational Study of Grand Canyon Rim-to-Rim Day Hikers: Determining Behavior Patterns to Aid in Preventive Search and Rescue Efforts.

Introduction: Grand Canyon National Park has seen an increase in visitors traversing the canyon from rim to rim (R2R) in a single day. R2R hikers travel over 33.8 km (21 mi) over 3300 m (11,000 ft) of elevation change and endure large temperature changes.

Multi-Patient Rabies Exposure on a Colorado River Rafting Expedition: Urgent vs. Emergent Transport Decision Making in an Austere Setting.

We present a case of rabies exposure on a private river rafting trip on Grand Canyon National Park's Colorado River. Five individuals were exposed to an erratically acting bat; one of the individuals sustained a direct bite to the upper lip while sleeping. This case illustrates the challenges of austere medical care and evacuation in remote conditions while highlighting the importance of risk mitigation considerations in all austere situations.

Three cases of severe hyponatremia during a river run in Grand Canyon National Park.

We present 3 cases of severe hyponatremia occurring on a commercially guided river rafting trip on the Colorado River in Grand Canyon National Park. All 3 women appeared to have been overhydrating because of concern about dehydration and required evacuation within 24 hours of each other after the staggered onset of symptoms, which included fatigue and emesis progressing to disorientation or seizure. Each was initially transferred to the nearest hospital and ultimately required intensive care.

Usefulness of cardiovascular magnetic resonance imaging of the superficial femoral artery for screening patients with diabetes mellitus for atherosclerosis.

Cardiovascular magnetic resonance (CMR) of the superficial femoral artery (SFA) allows direct and noninvasive visualization of atherosclerotic plaque burden. We examined atherosclerosis in 3 groups of patients without history or symptoms of peripheral arterial disease with varying expected burdens: those with diabetes mellitus (DM) and known coronary artery disease (CAD) (n = 24), those with DM and a high prevalence of CAD risk factors (n = 20), and controls of similar age without DM or CAD and few CAD risk factors (n = 15). We also assessed the diagnostic accuracy of this technique to differentiate among these 3 groups.