Isabel Algaze’s research while affiliated with University of California, Irvine and other places

Introduction We explored the incidence of acute mountain sickness (AMS) and extravascular lung water (ELW) in children in relation to changes in body composition and peripheral blood oxygenation (SpO2) during 1 week of acclimatization to 3800 m. Methods In a prospective cohort study, 10 children (7 female, ages 7–14 y) and 10 sex-matched adults (ages 23–44 y) traveled via automobile from sea level to 3000 m for 2 nights, followed by 4 nights at 3800 m. Each morning, body mass and body water (bioelectrical impedance), SpO2 (pulse oximetry), AMS (Lake Louise Questionnaire), and ELW (transthoracic echocardiography) were measured. Results No differences were found between children and adults in SpO2 or ELW. At 3800 m 7 of 10 children were AMS+ vs 4 of 10 adults. Among those AMS+ at 3800 m, the severity was greater in children compared to adults (5±1 vs 3 ± 0; P=0.005). Loss of body mass occurred more quickly in children (day 5 vs day 7) and to a greater extent (–7±3% vs –2±2%; P<0.001); these changes were mediated via a larger relative loss in total body water in children than in adults (–6±5% vs –2±2%; P=0.027). Conclusions Children demonstrated a higher incidence of AMS than adults, with greater severity among those AMS+. The loss of body water and body mass at high altitude was also greater in children, albeit unrelated to AMS severity. In addition to awareness of AMS, strategies to maintain body weight and hydration in children traveling to high altitudes should be considered.

Introduction: Search and rescue (SAR) is vital for visitor safety in US national parks, which are popular destinations for tourists. Previous studies have described SAR and seasonal visitation patterns, but not in the context of overall visitation. In addition, studies on the association between SAR and developed park areas remain limited. Concurrently, social media can be valuable for sharing information about conservation awareness and the joy of being outdoors. However, social media can potentially be an avenue for users to share risky and dangerous behaviors performed during attempts to obtain photos and videos. The associations between SAR and social media have not been discussed in existing literature. Methods: Variables included recreational visits, developed site stay visits, backcountry visits, SAR incidents, and tweets. Data from 2017 were obtained from National Park Service visitor use statistics, the SAR incident dashboard, and the University of California, Irvine, Cloudberry application. Correlation analysis was performed using nonparametric Kendall rank correlation coefficients. Results: Recreational visits were correlated with SAR incidents (rτ=0.415, P<0.001). Developed site stays were similarly correlated with SAR incidents (rτ=0.447, P<0.001), as were backcountry visits (rτ=0.428, P<0.001). Backcountry visits had a stronger correlation with fatalities (rτ=0.380, P<0.001) compared to developed site stays (rτ=0.304, P<0.001). Tweets were correlated with SAR incidents (rτ=0.468, P<0.001), recreational visits (rτ=0.403, P<0.001), and fatalities (rτ=0.367, P<0.001). Conclusions: Our findings demonstrate associations between national park visitation, SAR incidents, fatalities, and Twitter use and provides a concept framework for future prospective studies to further investigate the relationships between visitation, SAR, and social media.

Objective Hypothermia secondary to environmental exposure is a serious condition. Active external warming measures to treat it may prove challenging in the prehospital setting. We conducted an experimental study to measure the ability of commercially available heating elements to warm intravenous (IV) fluids during infusion. Methods 250-milliliter bags of dextrose 10% solution were suspended inside a refrigerator. IV tubing was coiled, and the tubing output was placed inside a thermally insulated cup. The tubing was heated directly with a hand warmer, a meals ready-to-eat heater, or a heating blanket. Fluids were run through the IV line. The temperature of the fluid at the tubing output was measured. The initial and final infusion temperatures for the methods were compared. Results The use of hand warmers, meals ready-to-eat heaters, and heating blankets to warm IV tubing did increase the temperature of the fluids but was ineffective at achieving the desired mean infusion temperature of 35°C to 42°C. Conclusion Although the mean temperature increase did not meet the established experimental threshold, further research is needed to determine whether the fluid warming effect of these commercial heating elements used in the prehospital environment is significant enough to limit heat loss while repleting the dextrose of a hypothermic, hypoglycemic patient.

Background: This study aimed to longitudinally quantify the prevalence of mild cognitive impairment (MCI) in individual trekkers at three different ascending altitudes (Site 1: ∼3500 m, Site 2: ∼4400 m, and Site 3: ∼5100 m). We correlated these findings with the presence of acute mountain sickness (AMS). Materials and Methods: We performed serial assays using the environmental quick mild cognitive impairment (eQMCI) score on 103 English-speaking 18- to 65-year-old volunteers trekking to Everest Base Camp in Nepal during spring 2016. We defined MCI as a score less than 67 (lower scores indicating more cognitive impairment). Additional data collected included the Lake Louise Score, demographics, and other possible confounders. Results: eQMCI scores significantly decreased with ascent from Site 1 to 2 (a score of 78.95 [SD = 7.96] to 74.67 [SD = 8.8] [Site 1-2 p = 0.04]), but then increased on ascent to Site 3 to 83.68 (SD = 8.67) (Site 1-3 p = <0.0001, Site 2-3 p = <0.0001). However, subjects who fulfilled eQMCI criteria for MCI increased despite the overall improvement in score: 6.8% (N = 7) at Site 1, 18.7% (N = 14) at Site 2, and 3.3% (N = 2) at Site 3. Incidence of AMS at Sites 1, 2, and 3 was 22.3% (N = 23), 21.3% (N = 16), and 48.3% (N = 29), respectively. Of those with MCI, 1.94% met criteria for AMS at Site 1 (p = 0.0017), 2.67% at Site 2 (p = 0.6949), and 3.33% at Site 3 (p = <0.0001). Conclusions: There is a significant incidence of MCI at high altitude, even in those without subjective findings of AMS. Interestingly, subjects with a decline in cognitive function show an increasing trend for developing AMS at higher altitude. Future research on the clinical impact of MCI on a subject's health, judgment, and performance remains to be elucidated.

This is the first study to provide national estimates of pediatric door-related injuries in the United States. Data from the National Electronic Injury Surveillance System were analyzed for patients ≤17 years who were treated in US emergency departments for a door-related injury from 1999 through 2008. An estimated 1 392 451 US children ≤17 years received emergency treatment for door-related injuries, which averages approximately 1 injury every 4 minutes in the United States. Both the frequency and rate of injury increased significantly. Boys accounted for 55.4% of injuries, and 41.6% of children were ≤4 years. The most common mechanism of injury was a “pinch in the door” (54.8%) or an “impact to the door” (42.0%). Patients admitted to the hospital were most frequently treated for amputations (32.0%) or lacerations (25.2%). The frequency of injuries associated with glass doors increased significantly with increasing age, in contrast to injuries from other types of doors.

1. Prey interact with multiple kinds of enemies such as predators, parasites, and pathogens. Interactions among enemies can alter prey dynamics but they are often studied separately. 2. During the summers of 2005–2006, we conducted a field experiment to examine interactions among grasshoppers, spider predators, and a lethal fungal pathogen of grasshoppers. Grasshopper nymphs were stocked into field enclosures. Predation was manipulated by adding spiders to enclosures on day 1, day 5, or day 10 of the experiment, or no spiders were added. We monitored grasshopper survival and grasshopper mortality from fungal pathogens for 4 weeks. 3. Fungal pathogens were abundant in 2005 but not in 2006, probably because of favourable weather conditions in 2005. When fungal pathogens were abundant, spider presence reduced grasshopper mortality from fungal pathogens, but only when spiders were present early in the experiment (added on day 1 or day 5). 4. The outcome of predator–prey interactions varied between years, probably as a result of differences in pathogen prevalence. In 2005, spider presence reduced the number of deaths from the pathogen, leading to a slight trend of increased grasshopper density. However, in 2006, when pathogens were not an important source of mortality, spider predation was compensatory.