The Effect of Path and Beginning Time of Ascending on Incidence of Acute Mountain Sickness around Mount Damavand in Iran (5671 m)

A study of survival strategies for improving acclimatization of lowlanders at high-altitude

Human Acclimatization and therapeutic approaches are the core components for conquering the physiological variations at high altitude (≥2500 m) exposure. The declined atmospheric pressure and reduced partial pressure of oxygen at high altitudes tend to decrease the temperature by several folds. Hypobaric hypoxia is a major threat to humanity at high altitudes, and its potential effects include altitude mountain sickness. On severity, it may lead to the development of conditions like high-altitude cerebral edema (HACE) or high-altitude pulmonary edema (HAPE) and cause unexpected physiological changes in the healthy population of travelers, athletes, soldiers, and low landers while sojourning at high altitude. Previous investigations have been done on long-drawn-out acclimatization strategies such as the staging method to prevent the damage caused by high-altitude hypobaric Hypoxia. Inherent Limitations of this strategy hamper the daily lifestyle and time consuming for people. It is not suitable for the rapid mobilization of people at high altitudes. There is a need to recalibrate acclimatization strategies for improving health protection and adapting to the environmental variations at high altitudes. This narrative review details the geographical changes and physiological changes at high altitudes and presents a framework of acclimatization, pre-acclimatization, and pharmacological aspects of high-altitude survival to enhance the government efficacy and capacity for the strategic planning of acclimatization, use of therapeutics, and safe de-induction from high altitude for minimizing the life loss. It's simply too ambitious for the importance of the present review to reduce life loss, and it can be proved as the most essential aspect of the preparatory phase of high-altitude acclimatization in plateau regions without hampering the daily lifestyle. The application of pre-acclimatization techniques can be a boon for people serving at high altitudes, and it can be a short bridge for the rapid translocation of people at high altitudes by minimizing the acclimatization time.

Low back pain and its related risk factors in health care providers at hospitals: A systematic review

Background

Health care personnel are exposed to ergonomic hazards, musculoskeletal disorders, and other work-related injuries. Low back pain is the most common musculoskeletal disorder. The aim of this study was to determine the prevalence of low back pain and the risk factors in health care personnel at the hospital in a form of a systematic review and meta-analysis.

Methods

In this systematic review and meta-analysis, the articles published in international electronic databases including Web of Knowledge, Embase, Scopus, PubMed were searched until May 2019. We included cohort, case-control and cross-sectional studies estimate the prevalence and risk factors for low back pain in health personnel. Data were analyzed using Stata-14 software and random effect model at 95% confidence level.

Findings

154 studies were included in the study for analysis. The estimated lifetime prevalence of lower back pain in health care personnel was 54.8%. The estimated odds ratios were as follows: age 1.23, female gender 1.11, BMI 1.17, lack of regular physical activity 1.56 occupational factors 1.12, patient related factors 1.24, body position at work 2.55, and stress 1.67.

Conclusions

/application to practice: The prevalence of low back pain in health care personnel is high. Body position at work, stress and lack of physical activity were the strongest risk factors, respectively. Future studies and educational programs are required to reduce the incidence of low back pain in health care personnel.

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Health care personnel are exposed to ergonomic hazards, musculoskeletal disorders.

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Low back pain is the most common musculoskeletal disorder.

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The prevalence of low back pain in health care personnel is high.

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Body position at work, stress and lack of physical activity were the strongest risk factors.

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Future studies and educational programs are required to reduce the incidence of low back pain.

Does age have an impact on acute mountain sickness? A systematic review

Acute mountain sickness (AMS) is the most common form of illness at high altitude; however, it is still unclear whether age is a protective factor or a risk factor for the development of AMS in travellers. In recent decades, the number of travellers aged 60 years or older is increasing. Thus, the care of older travellers is a long-standing issue in travel medicine. This study aims to systematically review the current state of knowledge related to the effect of old age on the risk of AMS. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used, and the following databases were consulted: PubMed/Medline, Embase, Europe PubMed Central (EuropePMC), World Health Organization Library Database (WHOLIS) and Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS). The search yielded a total of 532 articles, of which 25 met the inclusion criteria, corresponding to 26 reports. Although the approaches, methods and quality were heterogeneous among the included studies, 12 reported a negative correlation between AMS prevalence and age, 11 detected no relationship and three papers indicated that the age of AMS subjects was significantly higher than controls. Despite these differences, old age does not seem to be a contraindication for travelling at high altitude. Thus, the presented synthesis will be useful for health professionals in travel medicine to better tailor their appropriate care for older adults who travel to destinations at high altitude.

Cerebral volumetric changes induced by prolonged hypoxic exposure and whole-body exercise

The present study assessed the isolated and synergetic effects of hypoxic exposure and prolonged exercise on cerebral volume and subedema and symptoms of acute mountain sickness (AMS). Twelve healthy males performed three semirandomized blinded 11-hour sessions with (1) an inspiratory oxygen fraction (FiO2) of 12% and 4-hour cycling, (2) FiO2=21% and 4-hour cycling, and (3) FiO2=8.5% to 12% at rest (matching arterial oxygen saturation measured during the first hypoxic session). Volumetric, apparent diffusion coefficient (ADC), and arterial spin labelling 3T magnetic resonance imaging sequences were performed after 30 minutes and 10 hours in each session. Thirty minutes of hypoxia at rest induced a significant increase in white-matter volume (+0.8±1.0% compared with normoxia) that was exacerbated after 10 hours of hypoxia at rest (+1.5±1.1%) or with cycling (+1.6±1.1%). Total brain parenchyma volume increased significantly after 10 hours of hypoxia with cycling only (+1.3±1.1%). Apparent diffusion coefficient was significantly reduced after 10 hours of hypoxia at rest or with cycling. No significant change in cerebral blood flow was observed. These results demonstrate changes in white-matter volume as early as after 30 minutes of hypoxia that worsen after 10 hours, probably due to cytotoxic edema. Exercise accentuates the effect of hypoxia by increasing total brain volume. These changes do not however correlate with AMS symptoms.

Fatalities Among Iranian High-altitude Outdoor Enthusiasts: Causes and Mechanisms

Purpose

This study was performed to determine the possible causes and mechanisms of fatalities among Iranian mountaineers during climbing.

Methods

By contacting several sources, deceased mountaineers were identified. Data about the causes and mechanism of death was retrospectively obtained using a standard questionnaire for each case.

Results

A total of 29 deaths were identified from March 2006 to June 2010. Deceased subjects had a mean age of 39 years (SD: 12.8, Range: 20-67). Falling was the most common accident leading to death of outdoor enthusiasts (n = 14, 48%). Asphyxia (n = 6, 24%) was the most common cause of death among the subjects, followed by heart attack, internal bleeding, cerebral hemorrhage and hypothermia (17%, 17%, 17% and 10%, respectively).

Conclusions

Our findings suggest that education of medical service providers of the climbing groups on facing victims in high altitude areas, where they have limited resources, can be particularly helpful. In addition, a national program to educate mountaineers might help to reduce fatalities.

The effect of hypoxemia and exercise on acute mountain sickness symptoms

Performing exercise during the first hours of hypoxic exposure is thought to exacerbate acute mountain sickness (AMS), but whether this is due to increased hypoxemia or other mechanisms associated with exercise remains unclear. In 12 healthy men, AMS symptoms were assessed during three 11-h experimental sessions: 1) in Hypoxia-exercise, inspiratory O(2) fraction (Fi(O(2))) was 0.12, and subjects performed 4-h cycling at 45% Fi(O(2))-specific maximal power output from the 4th to the 8th hour; 2) in Hypoxia-rest, Fi(O(2)) was continuously adjusted to match the same arterial oxygen saturation as in Hypoxia-exercise, and subjects remained at rest; and 3) in Normoxia-exercise, Fi(O(2)) was 0.21, and subjects cycled as in Hypoxia-exercise at 45% Fi(O(2))-specific maximal power output. AMS scores did not differ significantly between Hypoxia-exercise and Hypoxia-rest, while they were significantly lower in Normoxia-exercise (Lake Louise score: 5.5 ± 2.1, 4.4 ± 2.4, and 2.3 ± 1.5, and cerebral Environmental Symptom Questionnaire: 1.2 ± 0.7, 1.0 ± 1.0, and 0.3 ± 0.4, in Hypoxia-exercise, Hypoxia-rest, and Normoxia-exercise, respectively; P < 0.01). Headache scored by visual analog scale was higher in Hypoxia-exercise and Hypoxia-rest compared with Normoxia-exercise (36 ± 22, 35 ± 25, and 5 ± 6, P < 0.001), while the perception of fatigue was higher in Hypoxia-exercise compared with Hypoxia-rest (60 ± 24, 32 ± 22, and 46 ± 23, in Hypoxia-exercise, Hypoxia-rest, and Normoxia-exercise, respectively; P < 0.01). Despite significant physiological stress during hypoxic exercise and some AMS symptoms induced by normoxic cycling at similar relative workload, exercise does not significantly worsen AMS severity during the first hours of hypoxic exposure at a given arterial oxygen desaturation. Hypoxemia per se appears, therefore, to be the main mechanism underlying AMS, whether or not exercise is performed.

Characteristics of Headache at Altitude among Trekkers; A comparison between Acute Mountain Sickness and Non-Acute Mountain Sickness Headache

Purpose

Headache at altitudes has had an incidence of 25-62% through many related studies. Many reasons are identified concerning headache at altitudes such as acute mountain sickness (AMS), sinus headache, migraine, tension type headache, and frontal tension headache. This study tried to compare different types of headache among trekkers on Mount Damavand, a 5671m mountain, Iran, to find their incidence and related symptoms and signs.

Methods

Through a cross-sectional study, we evaluated headache incidence and its correlation to AMS among people who climbed Mount Damavand. Lake Louise Score, a self-report questionnaire, was applied to make AMS diagnosis through three separate stages of trekking programs. Chi-square test was employed as the main mean of analysis.

Results

Totally, 459 between 13-71 year olds participated in the study among which females were 148 (32.1%) and males 311 (67.8%). Headache was found in 398 (86.7%) among whom 279 (70%) were proved as AMS. Investigating the types of headache in the cases of AMS showed 64.5% to be of steady, 31% throbbing and 4.5% stabbing characters which had significant differences with a P value = 0.003. The majority of headaches were stated as frontal (38.9%) and the least prevalence belonged to the parietal area (4.4%), while global headache was reported in 27%.

Conclusions

This study specifies the exact location of headaches at altitude in cases of AMS and non-AMS headaches. Many cases of high altitude non-AMS headache are resulted by tension and light reflection at altitude.