A Geographical Analysis of Access to Trauma Centers from US National Parks in 2018.

INTRODUCTION: Millions of people visit US national parks annually to engage in recreational wilderness activities, which can occasionally result in traumatic injuries that require timely, high-level care. However, no study to date has specifically examined timely access to trauma centers from national parks. This study aimed to examine the accessibility of trauma care from national parks by calculating the travel time by ground and air from each park to its nearest trauma center. Using these calculations, the percentage of parks by census region with timely access to a trauma center was determined. METHODS: This was a cross-sectional study analyzing travel times by ground and air transport between national parks and their closest adult advanced trauma center (ATC) in 2018. A list of parks was compiled from the National Parks Service (NPS) website, and the location of trauma centers from the 2018 National Emergency Department Inventory (NEDI)-USA database. Ground and air transport times were calculated using Google Maps and ArcGIS, with medians and interquartile ranges reported by US census region. Percentage of parks by region with timely trauma center access-defined as access within 60 minutes of travel time-were determined based on these calculated travel times. RESULTS: In 2018, 83% of national parks had access to an adult ATC within 60 minutes of air travel, while only 26% had timely access by ground. Trauma center access varied by region, with median travel times highest in the West for both air and ground transport. At a national level, national parks were unequally distributed, with the West housing the most parks of all regions. CONCLUSION: While most national parks had timely access to a trauma center by air travel, significant gaps in access remain for ground, the extent of which varies greatly by region. To improve the accessibility of trauma center expertise from national parks, the study highlights the potential that increased implementation of trauma telehealth in emergency departments (EDs) may have in bridging these gaps.

Safety and practicality of high dose inhaled nitric oxide in emergency department COVID-19 patients.

BACKGROUND: Inhaled nitric oxide (iNO) is a selective pulmonary vasodilator and mild bronchodilator that has been shown to improve systemic oxygenation, but has rarely been administered in the Emergency Department (ED). In addition to its favorable pulmonary vascular effects, in-vitro studies report that NO donors can inhibit replication of viruses, including SARS Coronavirus 2 (SARS-CoV-2). This study evaluated the administration of high-dose iNO by mask in spontaneously breathing emergency department (ED) patients with respiratory symptoms attributed to Coronavirus disease 2019 (COVID-19). METHODS: We designed a randomized clinical trial to determine whether 30 min of high dose iNO (250 ppm) could be safely and practically administered by emergency physicians in the ED to spontaneously-breathing patients with respiratory symptoms attributed to COVID-19. Our secondary goal was to learn if iNO could prevent the progression of mild COVID-19 to a more severe state. FINDINGS: We enrolled 47 ED patients with acute respiratory symptoms most likely due to COVID-19: 25 of 47 (53%) were randomized to the iNO treatment group; 22 of 47 (46%) to the control group (supportive care only). All patients tolerated the administration of high-dose iNO in the ED without significant complications or symptoms. Five patients receiving iNO (16%) experienced asymptomatic methemoglobinemia (MetHb) > 5%. Thirty-four of 47 (72%) subjects tested positive for SARS-CoV-2: 19 of 34 were randomized to the iNO treatment group and 15 of 34 subjects to the control group. Seven of 19 (38%) iNO patients returned to the ED, while 4 of 15 (27%) control patients did. One patient in each study arm was hospitalized: 5% in iNO treatment and 7% in controls. One patient was intubated in the iNO group. No patients in either group died. The differences between these groups were not significant. CONCLUSION: A single dose of iNO at 250 ppm was practical and not associated with any significant adverse effects when administered in the ED by emergency physicians. Local disease control led to early study closure and prevented complete testing of COVID-19 safety and treatment outcomes measures.

Siamit: A Novel Academic-Tribal Health Partnership in Northwest Alaska.

PROBLEM: American Indians and Alaska Natives hold a state-conferred right to health, yet significant health and health care disparities persist. Academic medical centers are resource-rich institutions committed to public service, yet few are engaged in responsive, equitable, and lasting tribal health partnerships to address these challenges. APPROACH: Maniilaq Association, a rural and remote tribal health organization in Northwest Alaska, partnered with Massachusetts General Hospital and Harvard Medical School to address health care needs through physician staffing, training, and quality improvement initiatives. This partnership, called Siamit, falls under tribal governance, focuses on supporting community health leaders, addresses challenges shaped by extreme geographic remoteness, and advances the mission of academic medicine in the context of tribal health priorities. OUTCOMES: Throughout the 2019-2020 academic year, Siamit augmented local physician staffing, mentored health professions trainees, provided continuing medical education courses, implemented quality improvement initiatives, and provided clinical care and operational support during the COVID-19 pandemic. Siamit began with a small budget and limited human resources, demonstrating that relatively small investments in academic-tribal health partnerships can support meaningful and positive outcomes. NEXT STEPS: During the 2020-2021 academic year, the authors plan to expand Siamit's efforts with a broader social medicine curriculum, additional attending staff, more frequent trainee rotations, an increasingly robust mentorship network for Indigenous health professions trainees, and further study of the impact of these efforts. Such partnerships may be replicable in other settings and represent a significant opportunity to advance community health priorities, strengthen tribal health systems, support the next generation of Indigenous health leaders, and carry out the academic medicine mission of teaching, research, and service.

Incidence of Mild Cognitive Impairment with Ascending Altitude.

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.

Prospective Double-Blinded Randomized Field-Based Clinical Trial of Metoclopramide and Ibuprofen for the Treatment of High Altitude Headache and Acute Mountain Sickness.

INTRODUCTION: High altitude headache (HAH) and acute mountain sickness (AMS) are common pathologies at high altitudes. There are similarities between AMS and migraine headaches, with nausea being a common symptom. Several studies have shown ibuprofen can be effective for AMS prophylaxis, but few have addressed treatment. Metoclopramide is commonly administered for migraine headaches but has not been evaluated for HAH or AMS. We aimed to evaluate metoclopramide and ibuprofen for treatment of HAH and AMS. METHODS: We performed a prospective, double-blinded, randomized, field-based clinical trial of metoclopramide and ibuprofen for the treatment of HAH and AMS in 47 adult subjects in the Mount Everest region of Nepal. Subjects received either 400 mg ibuprofen or 10 mg metoclopramide in a 1-time dose. Lake Louise Score (LLS) and visual analog scale of symptoms were measured before and at 30, 60, and 120 min after treatment. RESULTS: Subjects in both the metoclopramide and ibuprofen arms reported reduced headache severity and nausea compared to pretreatment values at 120 min. The ibuprofen group reported 22 mm reduction in headache and 6 mm reduction in nausea on a 100 mm visual analog scale at 120 min. The metoclopramide group reported 23 mm reduction in headache and 14 mm reduction in nausea. The ibuprofen group reported an average 3.5-point decrease on LLS, whereas the metoclopramide group reported an average 2.0-point decrease on LLS at 120 min. CONCLUSIONS: Metoclopramide and ibuprofen may be effective alternative treatment options in HAH and AMS, especially for those patients who additionally report nausea.

Ultrasound in Austere Environments.

Ultrasonography is a noninvasive, reliable, repeatable, and inexpensive technology that has dramatically changed the practice of medicine. The clinical use of portable ultrasound devices has grown tremendously over the last 10 years in the fields of intensive care, emergency medicine, and anesthesiology. In this review we present the various ways that handheld portable ultrasound devices can be used in austere environments. The purpose of this review is to consider the wide-ranging applications for providers going into the austere environment, which include pulmonary, ocular, vascular, and trauma evaluations, the postdisaster setting, and the role of ultrasonography in tropical diseases. This review is not meant to be a comprehensive how-to guide for each study type, but an overview of some of the more common wilderness applications. This review also focuses on the limitation of each study type. The goal is to help wilderness medicine providers feel more comfortable incorporating ultrasonography as part of their tool kit when heading into austere environments.

Trends in Skin and Soft Tissue-Related Injuries in NOLS Wilderness Expeditions from 1984 to 2012.

OBJECTIVE: Wilderness expeditions inevitably involve risk to participants. Understanding of expedition-related illnesses and injuries allows institutions and individuals to develop strategies to mitigate risk. We describe findings and trends in soft tissue injuries, the second-most common type of injury, among participants in the National Outdoor Leadership School expeditions from 1984 to 2012. METHODS: Injuries and illnesses sustained by students and staff have been recorded continuously since 1984 in the extensive National Outdoor Leadership School database. We performed a retrospective analysis of incidence of soft tissue injuries in this population. Data before 1996 were standardized in order to make use of the entire dataset. RESULTS: Of 9734 total reported incidents, 2151 (22%) were soft tissue related, 707 (33%) of which required evacuation. The sex distribution of incidents was similar to the sex distribution of participants. The largest incidence of soft tissue injuries occurred independent of activity (711 incidents, 33%). The most commonly associated activities were hiking (528 incidents, 25%), camping (301 incidents, 14%), and cooking (205 incidents, 10%). Over the study period, rates of injury declined overall and in every individual category except cooking. CONCLUSIONS: Over this 28-year period, the incidence of soft tissue injuries associated with the most common activities decreased. Incidence of activity-independent injuries did not change significantly, but reported severity decreased. These data provide unique insights to help improve wilderness risk management for institutions and individuals and suggest areas in which educational efforts may further reduce risk.

Findings of Cognitive Impairment at High Altitude: Relationships to Acetazolamide Use and Acute Mountain Sickness.

Phillips, Lara, Buddha Basnyat, Yuchiao Chang, Erik R. Swenson, and N. Stuart Harris. Findings of cognitive impairment at high altitude: relationships to acetazolamide use and acute mountain sickness. High Alt Med Biol. 18:121-127, 2017. OBJECTIVE: Acute mountain sickness (AMS) is defined by patient-reported symptoms using the Lake Louise Score (LLS), which provides limited insight into any possible underlying central nervous system (CNS) dysfunction. Some evidence suggests AMS might coexist with altered neural functioning. Cognitive impairment (CI) may go undetected unless a sensitive test is applied. Our hypothesis was that a standardized test for mild CI would provide an objective measure of CNS dysfunction, which may correlate with the symptoms of AMS and so provide a potential new tool to better characterize altitude-related CNS dysfunction. We compared a cognitive screening tool with the LLS to see if it correlated with CNS dysfunction. METHODS: Adult native English-speaking subjects visiting Himalayan Rescue Association aid stations in Nepal at 3520 m (11,548 ft) and 4550 m (14,927 ft) were recruited. Subjects were administered the LLS and a slightly modified version of the environmental Quick mild cognitive impairment screen (eQmci). Medication use for altitude illness was recorded. Scores were compared using the Spearman's correlation coefficient. Data also included medication use. RESULTS: Seventy-nine subjects were enrolled. A cut-off of three or greater was used for the LLS to diagnose AMS and 67 or less for the eQmci to diagnose CI. There were 22 (28%) subjects who met criteria for AMS and 17 (22%) subjects who met criteria for CI. There was a weak correlation (r2 = 0.06, p = 0.04) between eQmci score and LLS. In matched subjects with identical LLS, recent acetazolamide use was associated with significantly more CI. CONCLUSION: Field assessment of CI using a rapid standardized tool demonstrated that a substantial number of subjects were found to have mild CI following rapid ascent to 3520-4550 m (11,548-14,927 ft). The weak correlation between the LLS and eQmci suggests that AMS does not result in CI. Use of acetazolamide appears to be associated with CI at all levels of AMS severity.

Effects of a New Hospital-Wide Surgical Consultation Protocol in Patients with Clostridium difficile Colitis.

BACKGROUND: Fulminant Clostridium difficile colitis (fCDC) occurs in 2%-8% of patients with CDC and carries a high death rate. Prompt operation may reduce death. Our aim was to determine whether a standardized hospital-wide protocol for surgical referral in CDC would result in earlier surgical consultation, earlier identification of patients who could benefit from surgical therapy, and reduced deaths from fCDC. METHODS: A multidisciplinary team developed consensus criteria for surgical consultation. Compliance was evaluated by prospective review of all inpatient CDC cases. Outcomes of the prospective cohort (POST) were compared to an historic control group (PRE). RESULTS: From November 1, 2010 to October 31, 2012, we identified 1,106 inpatients with CDC; 339 patients matched the consultation criteria, of whom 213 received a surgical consultation, resulting in an overall compliance rate of 62.8%. All those with fCDC received a surgical consultation, with a median time to surgical referral of three hours. Of 46 patients with fCDC, 11 (23.9%) died, compared with 34.8% in the historical control group (p = 0.15). The death rate was 14.7% in the POST group, when excluding patients with limitations of care and those transferred to our institution in a fulminant state. There was a shorter interval between admission and surgical intervention for those who required operation in the POST group-three (1-11) days versus 1.5 (0-3) days, respectively, in the PRE and POST groups (p = 0.018), and a shorter adjusted median hospital length of stay (adjusted difference 9.0, 95% CI 2.2-12.3, p = 0.007) Conclusions: A hospital-wide protocol with established criteria for surgical consultation resulted in faster intervention and a shorter adjusted median hospital length of stay. The overall death rate for fCDC patients without limitations of life-sustaining treatment who presented to our emergency department or in whom fCDC developed while they were admitted to our hospital was 14.7%.

Acute Mountain Sickness Symptoms Depend on Normobaric versus Hypobaric Hypoxia.

Acute mountain sickness (AMS), characterized by headache, nausea, fatigue, and dizziness when unacclimatized individuals rapidly ascend to high altitude, is exacerbated by exercise and can be disabling. Although AMS is observed in both normobaric (NH) and hypobaric hypoxia (HH), recent evidence suggests that NH and HH produce different physiological responses. We evaluated whether AMS symptoms were different in NH and HH during the initial stages of exposure and if the assessment tool mattered. Seventy-two 8 h exposures to normobaric normoxia (NN), NH, or HH were experienced by 36 subjects. The Environmental Symptoms Questionnaire (ESQ) and Lake Louise Self-report (LLS) were administered, resulting in a total of 360 assessments, with each subject answering the questionnaire 5 times during each of their 2 exposure days. Classification tree analysis indicated that symptoms contributing most to AMS were different in NH (namely, feeling sick and shortness of breath) compared to HH (characterized most by feeling faint, appetite loss, light headedness, and dim vision). However, the differences were not detected using the LLS. These results suggest that during the initial hours of exposure (1) AMS in HH may be a qualitatively different experience than in NH and (2) NH and HH may not be interchangeable environments.

Evidence for cerebral edema, cerebral perfusion, and intracranial pressure elevations in acute mountain sickness.

INTRODUCTION: We hypothesized that cerebral alterations in edema, perfusion, and/or intracranial pressure (ICP) are related to the development of acute mountain sickness (AMS). METHODS: To vary AMS, we manipulated ambient oxygen, barometric pressure, and exercise duration. Thirty-six subjects were tested before, during and after 8 h exposures in (1) normobaric normoxia (NN; 300 m elevation equivalent); (2) normobaric hypoxia (NH; 4400 m equivalent); and (3) hypobaric hypoxia (HH; 4400 m equivalent). After a passive 15 min ascent, each subject participated in either 10 or 60 min of cycling exercise at 50% of heart rate reserve. We measured tissue absorption and scattering via radio-frequency near-infrared spectroscopy (NIRS), optic nerve sheath diameter (ONSD) via ultrasound, and AMS symptoms before, during, and after environmental exposures. RESULTS: We observed significant increases in NIRS tissue scattering of 0.35 ± 0.11 cm(-1) (P = 0.001) in subjects with AMS (i.e., AMS+), consistent with mildly increased cerebral edema. We also noted a small, but significant increase in total hemoglobin concentrations with AMS+, 3.2 ± 0.8 µmolL(-1) (P < 0.0005), consistent with increased cerebral perfusion. No effect of exercise duration was found, nor did we detect differences between NH and HH. ONSD assays documented a small but significant increase in ONSD (0.11 ± 0.02 mm; P < 0.0005) with AMS+, suggesting mildly elevated ICP, as well as further increased ONSD with longer exercise duration (P = 0.005). CONCLUSION: In AMS+, we found evidence of cerebral edema, elevated cerebral perfusion, and elevated ICP. The observed changes were small but consistent with the reversible nature of AMS.

Periodic Breathing and Behavioral Awakenings at High Altitude.

Objectives. To study the relationship between nocturnal periodic breathing episodes and behavioral awakenings at high altitude. Methods. Observational study. It is 6-day ascent of 4 healthy subjects from Besisahar (760 meters) to Manang (3540 meters) in Nepal in March 2012. A recording pulse oximeter was worn by each subject to measure their oxygen saturation and the presence of periodic breathing continuously through the night. An actigraph was simultaneously worn in order to determine nocturnal behavioral awakenings. There were no interventions. Results. 187-hour sleep at high altitude was analyzed, and of this, 145 hours (78%) had at least one PB event. At high altitude, 10.5% (95% CI 6.5-14.6%) of total sleep time was spent in PB while 15 out of 50 awakenings (30%, 95% CI: 18-45%) occurring at high altitudes were associated with PB (P < 0.001). Conclusions. Our data reveals a higher than expected number of behavioral awakenings associated with PB compared to what would be expected by chance. This suggests that PB likely plays a role in behavioral awakenings at high altitude.

Hypoxia, Hypobaria, and Exercise Duration Affect Acute Mountain Sickness.

INTRODUCTION: This study simultaneously quantified the effects of normobaric hypoxia (NH), hypobaric hypoxia (HH), exercise duration, and exposure time on acute mountain sickness severity (AMS-C). METHODS: Thirty-six subjects (27.7 ± 7.8 yr) participated in a partial repeated measures study, completing two of six conditions: normobaric normoxia (NN: 300 m/984 ft equivalent), NH or HH (Po2 = 91 mmHg; 4400 m/14,436 ft equivalent), combined with moderate intensity cycling for 10 or 60 min. Subjects completed the Environmental Symptoms Questionnaire and oxygen saturation (Spo2) was measured before, 1.5 h, 4 h, and 6.5 h into an 8-h exposure, and 1.5 h post-exposure. We fit multiple linear regression models with cluster adjusted standard errors on the exposure times using NH, HH, and long exercise as indicator variables, and AMS-C as the outcome variable. The Spo2and pre-exposure AMS-C score were used as covariates. RESULTS: NH and HH led to substantial and progressively increasing AMS-C, but NN did not. The effect of HH on AMS-C was significantly different from NH, with AMS-C in HH being 1.6 times higher than in NH. HH led to significantly increasing AMS-C, regardless of the exercise duration, while NH only did so in combination with longer exercise. DISCUSSION: Increases in AMS-C were each independently related to NH, HH, and long duration exercise, with HH affecting AMS-C more severely. This suggests that hypobaria may affect AMS development above the level induced by hypoxia alone. This further suggests that NH and HH may not be interchangeable for studying AMS and that exercise duration may impact physiological responses.

Field Ultrasound Evaluation of Central Volume Status and Acute Mountain Sickness.

OBJECTIVE: To investigate whether ultrasonography can be used for field volume status assessment and to determine whether a detectable difference in intravascular volume exists in individuals with acute mountain sickness (AMS) compared with those without. METHODS: Study was performed at the Himalayan Rescue Association Clinic in Manang, Nepal, located on the Annapurna trekking circuit at an altitude of 3519 m (11545 feet). A convenience sample was taken from individuals trekking over 5 to 8 days from 760 m (2490 feet) to 3519 m (11,545 feet), comparing asymptomatic trekkers vs those who experienced AMS. Subjects were evaluated for AMS based on the Lake Louise AMS Questionnaire (LLS ≥ 3 indicates AMS). After medical screening examination, both groups (control, n = 51; AMS, n = 18) underwent ultrasonography to obtain measurements of inferior vena cava collapsibility index (IVC CI) and left ventricular outflow tract velocity-time integral (LVOT VTI) before and after a passive leg raise (PLR) maneuver. RESULTS: There was no statistically significant difference between groups regarding change in heart rate before and after PLR, or IVC CI; however, there was a statistically significant greater increase in LVOT VTI after PLR maneuver in control group subjects compared with those with AMS (18.96% control vs 11.71% AMS; P < .01). CONCLUSIONS: Ultrasonography is a useful tool in the assessment of intravascular volume at altitude. In this sample, we found ultrasonographic evidence that subjects with AMS have a higher intravascular volume than asymptomatic individuals. These data support the hypothesis that individuals with AMS have decreased altitude-related diuresis compared with asymptomatic individuals.

From Matterhorn to Mt Everest: empowering rescuers and improving medical care in Nepal.

This article describes a private initiative in which professional Swiss rescuers, based at the foot of the Matterhorn, trained Nepalese colleagues in advanced high altitude helicopter rescue and medical care techniques. What started as a limited program focused on mountain safety has rapidly developed into a comprehensive project to improve rescue and medical care in the Mt Everest area for both foreign travelers and the local Nepalese people.

A randomized trial of temazepam versus acetazolamide in high altitude sleep disturbance.

This study is the first comparative trial of sleep medications at high altitude. We performed a randomized, double-blind trial of temazepam and acetazolamide at an altitude of 3540 meters. 34 healthy trekkers with self-reports of high-altitude sleep disturbance were randomized to temazepam 7.5 mg or acetazolamide 125 mg taken at bedtime for one night. The primary outcome was sleep quality on a 100 mm visual analog scale. Additional measurements were obtained with actigraphy; pulse oximetry; and questionnaire evaluation of sleep, daytime drowsiness, daytime sleepiness, and acute mountain sickness. Sixteen subjects were randomized to temazepam and 18 to acetazolamide. Sleep quality on the 100 mm visual analog scale was higher for temazepam (59.6, SD 20.1) than acetazolamide (46.2, SD 20.2; p=0.048). Temazepam also demonstrated higher subjective sleep quality on the Groningen Sleep Quality Scale (3.5 vs. 6.8, p=0.009) and sleep depth visual analog scale (60.3 vs. 41.4, p=0.028). The acetazolamide group reported significantly more awakenings to urinate (1.8 vs. 0.5, p=0.007). No difference was found with regards to mean nocturnal oxygen saturation (84.1 vs. 84.4, p=0.57), proportion of the night spent in periodic breathing, relative desaturations, sleep onset latency, awakenings, wake after sleep onset, sleep efficiency, Stanford Sleepiness Scale scores, daytime drowsiness, or change in self-reported Lake Louise Acute Mountain Sickness scores. We conclude that, at current recommended dosing, treatment of high-altitude sleep disturbance with temazepam is associated with increased subjective sleep quality compared to acetazolamide.