Wilderness & Environmental Medicine

To determine if serum vascular endothelial growth factor (VEGF) and ultrasonic monitoring of vascular dynamics with dynamic vascular analysis at sea level and high altitude correlate with acute mountain sickness symptoms.

Nine volunteers participated in a staged ascent from sea level to 4300 m undergoing complete transcranial Doppler studies with dynamic vascular analysis. Serum VEGF levels, Lake Louise scores, Spielberger-1 scores, Subjective Exercise Experiences Scale positive scores, and Symptom Checklist-90 surveys were collected after 24 hours at each altitude.

Symptom scores, index of pulsatility, and dynamic flow index differentiated the subjects into 2 distinct groups. Symptomatic subjects had increased VEGF levels at sea level but decreased levels at 4300 m. The dynamic flow index increased in symptomatic subjects at 4300 m compared with the asymptomatic subjects. The mean flow velocity increased in both groups and could not be used to differentiate the subjects.

Altered vascular physiology is associated with acute mountain sickness. Increased vascular permeability increases vascular capacitance, with an increase in dynamic flow index to meet these demands. Altered vascular dynamics were associated with high-altitude cerebral edema in 1 subject. Dynamic vascular analysis demonstrated altered vascular pathophysiology associated with acute mountain sickness. Changes in VEGF were meaningful when interpreted with the dynamic vascular analysis findings. These physiological findings may help explain the vascular changes associated with hypocarbic hypoxemia at altitude.

To study the influence of current trends in alpine sports on the frequency and types of injuries handled by a helicopter-based emergency medical system (HEMS) in a wilderness mountain region.

A retrospective review of medical reports at a single emergency helicopter port (Christophorus-1 air rescue) in Innsbruck, Austria, was conducted for comparison between two 3-year periods (1998–2000 and 2001–2003).

Comparing the two 3-year periods, the proportion of leisure-time injuries leading to HEMS activation increased, whereas the frequency of life-threatening injuries significantly declined (P = .001). There was significant increase in injuries during mountain hiking and rock climbing (P = .002), during swimming (P = .013), and in avalanches (P = .019). Most injuries (70.1%) were recorded for skiers, and 68.3% involved tourists. During the investigation period, the high National Advisory Committee of Aeronautics scores showed a decreasing trend, whereas Glasgow Coma Scale scores and low National Advisory Committee of Aeronautics scores tended to increase (P = .048).

For the HEMS in this study, there has been an increasing number of calls for help from persons involved in outdoor leisure activities. As the number of life-threatening injuries declines, HEMSs more frequently serve as means of rescue rather than as providers of emergency treatment.

The presence of coliform bacteria indicates a watershed risk for harboring microbes capable of causing human disease. We hypothesized that water from watersheds that have different human- or animal-use patterns would have differing risks for the presence of coliform bacteria.

Water was collected in wilderness areas of the Sierra Nevada range in California. A total of 60 sites from lakes or streams were selected to statistically differentiate the risk categories: 1) high use by backpackers, 2) high use by pack animals, 3) cattle- and sheep-grazing tracts, and 4) natural areas rarely visited by humans or domestic animals. Water was collected in sterile test tubes and Millipore coliform samplers during the summer of 2004. Water was analyzed at the university microbiology lab, where bacteria were harvested and then subjected to analysis by standardized techniques. Confirmation was performed with a Phoenix 100 bacteria analyzer. Statistical analysis to compare site categories was performed with Fisher exact test.

Only 1 of 15 backpacker sites yielded coliforms. In contrast, 12 of 15 sites with heavy pack-animal traffic yielded coliforms. All 15 sites below the cattle-grazing areas grew coliforms. Differences between backpacker and cattle or pack-animal areas were significant (P ≤ .05). Only 1 of the 15 wild sites rarely visited by humans grew coliforms. All coliforms were identified as Escherichia coli. All samples grew normal aquatic bacteria of the genera Pseudomonas, Ralstonia, and Serratia and nonpathogenic strains of Yersinia. No correlation could be made with temperature or elevation. Sites below cattle-grazing tracts and pack-animal usage areas tended to have more total bacteria.

Alpine wilderness water below cattle-grazing tracts or areas used by pack animals are at risk for containing coliform organisms. Areas exclusively used by backpackers were nearly free of coliforms.

To evaluate the efficacy of the commercially available product Mitigator Sting and Bite Treatment in reducing the pain after imported fire ant stings.

Twenty-four volunteer subjects were exposed to imported fire ant stings on both forearms. The subjects received Mitigator paste on 1 arm and calamine lotion on the opposite arm, in a blinded manner, from 90 seconds to 10 minutes after exposure. Subjects recorded pain on a 100-mm visual analog scale 60 seconds, 20 minutes, and 3 days after exposure. A 2-tailed paired t test was used to compare the difference in reduction of pain over time between the Mitigator-treated arms and the calamine-treated arms.

At 60 seconds, the mean visual analog scale pain score was 23.9 mm for the Mitigator group and 24.5 mm for the calamine group. At 20 minutes, the mean score was 7.6 mm (Δ = 16.3) for the Mitigator group and 12.7 mm (Δ = 11.8) for the calamine group. At 3 days, the mean score was 2.4 mm (Δ = 21.5) for the Mitigator group and 2.9 mm (Δ = 21.6) for the calamine group. There was no significant difference between groups for change in visual analog scale pain score at 60 seconds, 20 minutes (P = .256), or 3 days (P = .64).

There was no significant difference in pain relief between calamine and Mitigator for imported fire ant stings.