Women at Altitude: Menstrual-Cycle Phase, Menopause, and Exogenous Progesterone Are Not Associated with Acute Mountain Sickness.

Gardner, Laurel, Linda E. Keyes, Caleb Phillips, Elan Small, Tejaswi Adhikari, Nathan Barott, Ken Zafren, Rony Maharjan, and James Marvel. Women at altitude: Menstrual-cycle phase, menopause, and exogenous progesterone are not associated with acute mountain sickness. High Alt Med Biol. 00:000-000, 2024. Background: Elevated progesterone levels in women may protect against acute mountain sickness (AMS). The impact of hormonal contraception (HC) on AMS is unknown. We examined the effect of natural and exogenous progesterone on the occurrence of AMS. Methods: We conducted a prospective observational convenience study of female trekkers in Lobuche (4,940 m) and Manang (3,519 m). We collected data on last menstrual period, use of exogenous hormones, and development of AMS. Results: There were 1,161 trekkers who met inclusion criteria, of whom 307 (26%) had AMS. There was no significant difference in occurrence of AMS between women in the follicular (28%) and the luteal (25%) phases of menstruation (p = 0.48). The proportion of premenopausal (25%) versus postmenopausal women (30%) with AMS did not differ (p = 0.33). The use of HC did not influence the occurrence of AMS (HC 23% vs. no HC 26%, p = 0.47), nor did hormonal replacement therapy (HRT) (HRT 11% vs. no HRT 31%, p = 0.13). Conclusion: We found no relationship between menstrual-cycle phase, menopausal status, or use of exogenous progesterone and the occurrence of AMS in trekkers and conclude that hormonal status is not a risk factor for AMS. Furthermore, women should not be excluded from future AMS studies based on hormonal status.

Prior Ambulatory Mild Coronavirus Disease 2019 Does Not Increase Risk of Acute Mountain Sickness.

Small, Elan, Caleb Phillips, William Bunzel, Lakota Cleaver, Nishant Joshi, Laurel Gardner, Rony Maharjan, and James Marvel. Prior ambulatory mild coronavirus disease 2019 does not increase risk of acute mountain sickness. High Alt Med Biol. 24:201-208, 2023. Background: Given its long-term morbidity, understanding how prior coronavirus disease 2019 (COVID-19) may affect acute mountain sickness (AMS) susceptibility is important for preascent risk stratification. The objective of this study was to examine if prior COVID-19 impacts risk of AMS. Materials and Methods: This was a prospective observational study conducted in Lobuje (4,940 m) and Manang (3,519 m), Nepal, from April to May 2022. AMS was defined by the 2018 Lake Louise Questionnaire criteria. COVID-19 severity was defined using the World Health Organization-developed criteria. Results: In the Lobuje cohort of 2,027, 46.2% of surveyed individuals reported history of COVID-19, with 25.7% AMS point-prevalence. There was no significant relationship between prior ambulatory mild COVID-19 and AMS (p = 0.6) or moderate AMS (p = 1.0). In the Manang cohort of 908, 42.8% reported history of COVID-19, with 14.7% AMS point-prevalence. There was no significant relationship between prior ambulatory mild COVID-19 and AMS (p = 0.3) or moderate AMS (p = 0.4). Average months since COVID-19 was 7.4 (interquartile range [IQR] 3-10) for Lobuje, 6.2 (IQR 3-6) for Manang. Both cohorts rarely exhibited moderate COVID-19 history. Conclusions: Prior ambulatory mild COVID-19 was not associated with increased risk of AMS and should not preclude high-altitude travel.

Older Age as a Predictive Risk Factor for Acute Mountain Sickness.

BACKGROUND: Older populations are increasing and comprise a substantial portion of high-altitude travelers. Aging physiology may influence susceptibility to acute mountain sickness, though prior research remains inconclusive. The goal of this study was to investigate the relationship between increasing age and acute mountain sickness. METHODS: This study was a pooled analysis of 5 prospective randomized controlled trials conducted at White Mountain, California from 2010, 2016-2019 with identical 4-hour rapid ascent from 1242 m to overnight sojourn at 3810 m. Acute mountain sickness was defined by the 2018 Lake Louise Questionnaire criteria. RESULTS: There were 491 participants analyzed, 234 (48%) diagnosed with acute mountain sickness and 71 (14%) with moderate acute mountain sickness. Mean age was 37 years (±13). There was no significant correlation between Lake Louise Questionnaire severity and age (r = -0.02; 95% confidence interval [CI], -0.11-0.07, P = .7), 40-year-old dichotomy (t = -0.6; 95% CI, -0.53-0.28, P = .6), or decade of life (P = .4). Logistic regression found no increased odds of acute mountain sickness for increasing age by decade of life (odds ratio [OR] 1.0; 95% CI, 0.97-1.0) or 40-year-old dichotomy (OR 1.4; 95% CI, 0.97-2.1). A history of acute mountain sickness increased odds of acute mountain sickness (OR 3.2; 95% CI, 1.5-7.7). CONCLUSIONS: Older age was not associated with incidence nor severity of acute mountain sickness. A history of altitude illness increased odds of acute mountain sickness and should be used for pre-ascent risk stratification.

A Randomized Controlled Trial of the Lowest Effective Dose of Acetazolamide for Acute Mountain Sickness Prevention.

BACKGROUND: Acetazolamide is the most common medication used for acute mountain sickness prevention, with speculation that a reduced dose may be as efficacious as standard dosing with fewer side effects. METHODS: This double-blind, randomized, controlled noninferiority trial compared acetazolamide 62.5 mg twice daily to the standard dose acetazolamide 125 mg twice daily starting the evening prior to ascent from 1240 m (4100 ft) to 3810 m (12,570 ft) over 4 hours. The primary outcome was acute mountain sickness incidence (ie, headache, Lake Louise Questionnaire ≥3, and another symptom). RESULTS: A total of 106 participants were analyzed, with 51 (48%) randomized to 125 mg and 55 (52%) to 62.5 mg, with a combined acute mountain sickness incidence of 53 (50%) and mean severity of 3 (± 2.1). The 62.5-mg group failed to fall within the prespecified 26% noninferiority margin for acute mountain sickness incidence (62.5 mg = 30 [55%] vs 125 mg = 23 [45%], 95% confidence interval [CI] -11% to 30%). Participants in the 62.5-mg group had a higher risk of acute mountain sickness (odds ratio = 1.5, 95% CI 0.7-3.2) and moderate acute mountain sickness (odds ratio = 1.8, 95% CI 0.6-5.9), with a number needed to harm (NNH) of 9, with a number needed to treat (NNT) in the 125-mg group of 4.8. Increased acute mountain sickness incidence and symptom severity corresponded to lower weight-based and body mass index dosing, with similar side effects between groups. CONCLUSION: Acetazolamide 62.5 mg twice daily failed to demonstrate equal effectiveness to 125 mg twice daily for prevention of acute mountain sickness. With increased risk and no demonstrable symptomatic or physiologic benefits, acetazolamide 62.5 mg twice daily should not be recommended for acute mountain sickness prevention.

Neighborhood-level stroke hot spots within major United States cities.

OBJECTIVE: Identifying communities at high risk of stroke is an important step in improving systems of stroke care. Stroke is known to show spatial clustering at the state and county levels, but it is not known if clusters are present within city boundaries. METHODS: We performed a geospatial analysis of the prevalence of stroke within 500 major cities in the United States using the Centers for Disease Control and Prevention 500 Cities Project. For each city, we calculated the Moran's I statistic, which looks for evidence of spatial clustering, and used Monte Carlo simulation to assess for clustering significance. RESULTS: The mean overall crude prevalence of self-reported history of stroke at the city level was 2.8% (IQR 2.4-3.2%). Monte Carlo simulations of spatial patterns of stroke were successfully performed for 497 cities, of which 136 (27.3%) showed significant spatial clustering at the neighborhood level. All nine cities with more than one million inhabitants in 2010 showed significant spatial clustering. CONCLUSIONS: This is the first study to demonstrate that stroke shows clustering at the neighborhood level within many major cities in the United States and within all of the largest cities. Understanding where stroke clusters exist within cities can form the basis of optimizing emergency medical services deployment and improving systems of stroke care.

Improving Emergency Department Airway Preparedness in the Era of COVID-19: An Interprofessional, In Situ Simulation.

Audience: The target audience for this airway simulation includes all emergency department (ED) staff who are potential members of a COVID-19 intubation team, including emergency medicine attendings, emergency medicine residents, nurses, respiratory therapists, pharmacists, and ED technicians. Introduction: As of May 7, 2020 there were 1,219,066 diagnosed cases of COVID-19 in the U.S. and 73,297 deaths.1 A special report from the Centers for Disease Control and prevention on infections in healthcare personnel reported 9,282 cases between February 12th and April 9th.2 Sars-CoV-2 is a novel virus that requires a careful, coordinated approach to airway management given the high risk of aerosolization.3 It is essential to train ED staff (1) to appropriately care for patients with suspected COVID-19 disease and (2) to provide an organized, safe working environment for providers during high-risk, aerosolizing procedures such as intubation. In addition to providing a set of airway management guidelines, we aimed to educate the staff through participation in a simulation activity. Due to the multiple team members involved and the array of equipment needed, an in-person in situ strategy was implemented. The goals of the simulation were to optimize patient care and minimize viral exposure to those involved during intubation. Educational Objectives: At the conclusion of the simulation session, learners will be able to: 1) Understand the need to notify team members of a planned COVID intubation including: physician, respiratory therapist, pharmacist, nurse(s), and ED technician. 2) Distinguish between in-room and out-of-room personnel during high-risk aerosolizing procedures. 3) Distinguish between in-room and out-of-room equipment during high-risk aerosolizing procedures to minimize contamination. 4) Appropriately select oxygenation therapies and avoid high-risk aerosolizing procedures. 5) Manage high risk scenarios such as hypotension or failed intubation and be prepared to give push-dose vasoactive medications or place a rescue device such as an I-gel ®. Educational Methods: This is a high-fidelity, interprofessional, in-situ simulation used to train a team of providers that would normally participate in the management of a patient with suspected COVID-19 requiring endotracheal intubation. Participants might include emergency medicine attendings, emergency medicine residents, nurses, respiratory therapists, pharmacists, and ED technicians. The patient is best represented by a high-fidelity mannequin such as Trauma HAL® (Miami, FL USA) https://www.gaumard.com/products/trauma/trauma-halr), with a monitor displaying vital signs and voice-response capabilities. The simulation includes an interprofessional debriefing session, during which an airway checklist, communication strategies, and best practices are reviewed. Research Methods: Airway management guidelines were developed by an interdisciplinary team at our institution. We used these guidelines from Stanford Health Care and best practices from a literature review to create a checklist of recommended steps. Two assessors used the checklist to track team actions. Any missed items were discussed in the team debrief and participants were encouraged to ask questions. At the end of the session, to check for understanding, participants were provided with a brief anonymous online survey accessed by a QR code. These assessments allowed the simulation team to iteratively edit the case before future simulations. Results: From 3/23/20-4/23/20, we held 12 in-situ simulations with 62 participants, including emergency medicine physicians, nurses, technicians, respiratory therapists, and pharmacists. Two individuals observed each simulation and compared team performance to the checklist of recommended steps. The actions that were not completed during the simulation served as teaching points during the simulation debrief. The debrief discussions helped to identify misconceptions regarding oxygenation strategies, difficulties in staff communication due to physical barriers, and various other quality or safety concerns. Participant reactions following the simulation and debriefs were overwhelmingly positive. Discussion: This simulation was an effective, easy-to-implement method of interprofessional team training for a risk-inherent procedure in the ED. We learned that the deliberate simulation of each step of the COVID19-specific intubation procedure with all team members provided opportunities to identify safety challenges in communication, equipment, and approach. Each debrief stimulated an excellent discussion among team members, and allowed for interprofessional feedback, clarification of questions, and recommendations for areas of improvement. Our main take-away from the pilot of this novel simulation case is that new, high-risk procedures require a coordinated team effort to minimize risks to patients and staff, and that team training is feasible and effective using frequent in situ simulations. Topics: Medical simulation, in-situ simulation, interprofessional, COVID-19, novel coronavirus, SARS-CoV-2, intubation, medical education, health professions education, team training, airway management.