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.

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.

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.

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.

Ultrasound and ski resort clinics: mapping out the potential benefits.

BACKGROUND: Skiing and snowboarding are popular activities that involve high kinetic energies, often at altitude, and injuries are common. As a portable imaging modality, ultrasound may be a useful adjunct for mountainside clinics. This review briefly discusses skier and snowboarder injury profiles and focuses on the role of ultrasound for each injury type. METHODS: Twenty-two sources including 17 reviews and observational studies were obtained describing skier and snowboarder injuries. Forty-nine studies were identified defining ultrasound applications for these injuries, including 38 reviews and observational studies, 6 case reports or case series, 3 cross-sectional studies, and 2 randomized, blinded studies. RESULTS: Approximately 200 000 rider injuries are evaluated in the Unites States seasonally. Musculoskeletal injuries are the most common, and head, face, neck, and abdominal injuries are also prevalent, as are exacerbations of preexisting disease. Ultrasound has been shown to be useful and accurate for evaluating the aforementioned injury types, including joint, ligament, tendon, and fracture evaluation. Ultrasound has not been extensively studied in the prehospital setting, and only limited data address the utility of how it might influence management in a mountainside clinic setting. CONCLUSIONS: Ultrasound has the potential to be a useful diagnostic modality in ski resort clinics. The most promising areas for future, applied studies include evaluation of musculoskeletal injuries (especially injuries to joints and tendons and ruling out fractures), assessing for elevated intracranial pressure in minor head injuries and symptoms of altitude illness, and focused assessment with sonography for trauma and extended focused assessment with sonography for trauma examinations for cases of chest and abdominal trauma of unknown significance.

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.

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.

The disposition decision on emergency department patients with chest pain is affected by the results of multi-detector computed axial tomography scan of the coronary arteries.

BACKGROUND: Few data exist on the frequency with which multidetector computed axial tomography (MDCT) scan of the coronary arteries changes the admission decisions of emergency physicians (EP) caring for patients with possible acute coronary syndrome (ACS). We measured if and how often these changes in decision-making would occur. METHODS: The theoretical dispositions of 27 emergency department patients who presented with possible ACS were determined by four board-certified EPs after case presentations. Paired disposition decisions were made before and after knowledge of the MDCT scan results. Patients were selected from a sample of 103 from a prior study. RESULTS: The study included 27 patients with a mean age of 55 +/- 9 years; 58% were male. The low-, intermediate-, and high-risk MDCT scan results were evenly distributed, as were the original providers' standard clinical risk assessments of ACS. Three patients had ACS and all were admitted both before and after review of MDCT scan results. Among 24 patients without ACS, a decision to admit was changed to discharge in 16 of 90 admission decisions (18%, 95% confidence interval [CI] 10-26%). Among 6 patients with projected discharges, 2 were inappropriately admitted after review of MDCT scan results. The odds ratio of discharge for patients without ACS increased by 3.95 (95% CI 1.96-7.95) after introduction of the MDCT scan results. CONCLUSION: An MDCT scan of the coronary arteries will likely change emergency physicians' decisions on the disposition of patients presenting with possible ACS, many to appropriate discharges but also a minority to inappropriate admissions.

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.

Optic nerve sheath diameter correlates with the presence and severity of acute mountain sickness: evidence for increased intracranial pressure.

Increased intracranial pressure is suspected in the pathogenesis of acute mountain sickness (AMS), but no studies have correlated it with the presence or severity of AMS. We sought to determine whether increased optic nerve sheath diameter, a surrogate measure of intracranial pressure, is associated with the presence and severity of AMS. We performed a cross-sectional study of travelers ascending through Pheriche, Nepal (4,240 m), from March 3 to May 14, 2006. AMS was assessed using the Lake Louise score. Optic nerve sheath diameter was measured by ultrasound. Ultrasound exams were performed and read by separate blinded observers. Two-hundred eighty seven subjects were enrolled. Ten of these underwent repeat examination. Mean optic nerve sheath diameter was 5.34 mm [95% confidence interval (CI) 5.18-5.51 mm] in the 69 subjects with AMS vs. 4.46 mm (95% CI 4.39-4.54 mm) in the 218 other subjects (P < 0.0001). There was also a positive association between optic nerve sheath diameter and total Lake Louise score (P for trend < 0.0001). In a multivariate logistic regression model of factors associated with AMS, optic nerve sheath diameter was strongly associated with AMS (odds ratio 6.3; 95% CI, 3.7-10.8; P < 0.001). In 10 subjects with repeat examinations, change in Lake Louise score had a strong positive correlation with change in optic nerve sheath diameter (R(2) = 0.84, P < 0.001). Optic nerve sheath diameter, a proxy for intracranial pressure, is associated with the presence and severity of AMS.

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.

Increasing United States hospital admissions for acute pancreatitis, 1988-2003.

PURPOSE: To examine the epidemiology of hospital admissions for acute pancreatitis in the United States. METHODS: We compiled data from the 1988-2003 National Hospital Discharge Survey and analyzed it with respect to patient demographics, hospital type and region, procedures performed, length of hospital stay, and inpatient mortality. RESULTS: Hospital admissions for acute pancreatitis increased from a 1988 low of 101,000 (95% confidence interval [CI]: 87,000-116,000) to a 2002 peak of 210,000 (95% CI: 186,000-234,000). The corresponding admission rate increased from 0.4 to 0.7 hospitalizations per 1000 U.S. population (p = 0.001). The patients' average age was 53 years, 51% were male, and 23% were black. The hospitalization rate was higher among blacks (0.9; 95% CI, 0.6-1.1) than among whites (0.4; 95% CI, 0.3-0.5). The mean length of stay was 6.9 days and decreased over the study period. Overall mortality was 2%, with increasing age and male gender comprising independent risk factors for death. CONCLUSIONS: The hospitalization rate for acute pancreatitis in the United States is rising and is higher in blacks than in whites. Further research is necessary to identify the cause(s) of increasing pancreatitis admissions, the observed racial disparity, and the cost of these admissions.

Chest ultrasonography for the diagnosis and monitoring of high-altitude pulmonary edema.

BACKGROUND: The comet-tail technique of chest ultrasonography has been described for the diagnosis of cardiogenic pulmonary edema. This is the first report describing its use for the diagnosis and monitoring of high-altitude pulmonary edema (HAPE), the leading cause of death from altitude illness. METHODS: Eleven consecutive patients presenting to the Himalayan Rescue Association clinic in Pheriche, Nepal (4,240 m) with a clinical diagnosis of HAPE underwent one to three chest ultrasound examinations using the comet-tail technique to determine the presence of extravascular lung water (EVLW). Seven patients with no evidence of HAPE or other altitude illness served as control subjects. All examinations were read by a blinded observer. RESULTS: HAPE patients had higher comet-tail score (CTS) [mean +/- SD, 31 +/- 11 vs 0.86 +/- 0.83] and lower oxygen saturation (O(2)Sat) [61 +/- 9.2% vs 87 +/- 2.8%] than control subjects (p < 0.001 for both). Mean CTS was higher (35 +/- 11 vs 12 +/- 6.8, p < 0.001) and O(2)Sat was lower (60 +/- 11% vs 84 +/- 1.6%, p = 0.002) at hospital admission than at discharge for the HAPE patients with follow-up ultrasound examinations. Regression analysis showed CTS was predictive of O(2)Sat (p < 0.001), and for every 1-point increase in CTS O(2)Sat fell by 0.67% (95% confidence interval, 0.41 to 0.93%, p < 0.001). CONCLUSIONS: The comet-tail technique effectively recognizes and monitors the degree of pulmonary edema in HAPE. Reduction in CTS parallels improved oxygenation and clinical status in HAPE. The feasibility of this technique in remote locations and rapid correlation with changes in EVLW make it a valuable research tool.

Treatment of high altitude pulmonary edema at 4240 m in Nepal.

High altitude pulmonary edema (HAPE) is the leading cause of death from altitude illness and rapid descent is often considered a life-saving foundation of therapy. Nevertheless, in the remote settings where HAPE often occurs, immediate descent sometimes places the victim and rescuers at risk. We treated 11 patients (7 Nepalese, 4 foreigners) for HAPE at the Himalayan Rescue Association clinic in Pheriche, Nepal (4240 m), from March 3 to May 14, 2006. Ten were admitted and primarily treated there. Seven of these (6 Nepalese, 1 foreigner) had serious to severe HAPE (Hultgren grades 3 or 4). Bed rest, oxygen, nifedipine, and acetazolamide were used for all patients. Sildenafil and salmeterol were used in most, but not all patients. The duration of stay was 31 +/- 16 h (range 12 to 48 h). Oxygen saturation was improved at discharge (84% +/- 1.7%) compared with admission (59% +/- 11%), as was ultrasound comet-tail score (11 +/- 4 at discharge vs. 33 +/- 8.6 at admission), a measure of pulmonary edema for which admission and discharge values were obtained in 7 patients. We conclude it is possible to treat even serious HAPE at 4240 m and discuss the significance of the predominance of Nepali patients seen in this series.

Evidence for increased intracranial pressure in high altitude pulmonary edema.

We sought to determine if optic nerve sheath diameter (ONSD), a surrogate measure of ICP, is increased in high altitude pulmonary edema (HAPE). Five HAPE patients (one with a codiagnosis of high altitude cerebral edema [HACE]) treated at the Himalayan Rescue Association clinic in Pheriche, Nepal (4240 m), underwent optic nerve sheath ultrasonography (ONSU) at admission to determine ONSD. Results were compared to ONSD in 32 control subjects at the same altitude without evidence of altitude illness. Four of the five HAPE patients underwent repeat ONSU at discharge. All exams were read by two blinded observers. The mean ONSD for HAPE patients on presentation was 5.7 +/- 0.44 mm and for controls was 4.7 +/- 0.56 mm (p = 0.003). Excluding the patient with a coexistent clinical diagnosis of HACE, mean ONSD at presentation for the other four HAPE patients was 5.7 +/- 0.50 mm and was significantly different from controls (p = 0.007). In the four HAPE patients with repeat exams, ONSD decreased by 17% +/- 15% (95% CI 4-30%) between admission and discharge. We conclude that HAPE is associated with increased ONSD, a surrogate measure of increased ICP.

Arterial thrombosis at high altitude resulting in loss of limb.

Vascular thrombosis is an uncommon but recognized peril of high altitude travel. Traditionally, this has been associated with prolonged exposure to extreme altitudes where dehydration, hemoconcentration, cold, use of constrictive clothing, and enforced stasis due to severe weather have been named as contributing factors. It is widely hypothesized that hypoxia itself alters the coagulation cascade to create a prothrombotic milieu, though evidence thus far is limited and frequently conflicting. Case reports have described venous thrombosis, pulmonary embolism, cerebrovascular accidents, transient ischemic attacks, and thromboses of the portal circulation at altitude. We report a unique case of aortic thrombosis presenting with critical lower extremity ischemia in a previously healthy individual after a brief exposure to altitudes up to 4620 m. None of the frequently invoked risk factors of dehydration, cold, enforced use of constrictive clothing, weather-imposed inactivity, or extreme altitude were present, and no medical predisposition to thrombosis was identified, suggesting hypoxia as the most likely prothrombotic stimulus. We discuss the treatment of this problem and the application of Doppler ultrasonography in a wilderness setting.