Chronic high-altitude exposure and the epidemiology of ischaemic stroke: a systematic review

Ortíz-Prado, Esteban; Cordovez, Simone; Vásconez, Eduardo; Viscor, Ginés; Roderick, Paul

doi:10.1136/bmjopen-2021-051777

Cited by 34 publications

(35 citation statements)

References 49 publications

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“…Although the ramifications of high-altitude hypoxia might have been well appreciated [3,[19][20][21][22][23], there have been few reports on the influence of high-altitude hypoxia on anesthesia management. Compared with previous studies, [8,[24][25][26][27] the occurrence of moderate hypoxia was more common in the nasal cannula group (47.2%).…”

Section: Discussionmentioning

confidence: 99%

Supraglottic jet oxygenation and ventilation decreased hypoxemia during gastrointestinal endoscopy under deep sedation at high altitudes: a randomized clinical trial

Jiang

Ciren

et al. 2022

BMC Anesthesiol

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Background Hypobaric hypoxia is common at high altitudes. Whether this exacerbates hypoxia during procedural sedation and whether hypoxia can be alleviated by the use of supraglottic jet oxygenation and ventilation (SJOV) are unknown. This study aimed to compare the incidence of hypoxia during gastrointestinal endoscopy under deep sedation at high altitudes with oxygen supply techniques using either a nasal cannula or SJOV. Methods This study was conducted from April 2022 to July 2022 in a tertiary hospital located 3650 m above sea level. Adult patients scheduled for routine gastrointestinal endoscopy under sedation were enrolled and randomized 1:1 to receive SJOV or a nasal cannula during sedation. Moderate hypoxia was the primary outcome, defined as an SPO2 of 75–89% for < 60 s. The secondary outcomes were respiratory-, cardiovascular-, and SJOV-related complications. The influence of characteristics regarding acclimatization to high altitudes (Tibetan ethnic group and erythrocytosis) on the occurrence of hypoxia was analyzed. Results None of the patients were lost to follow-up. A total of 72 patients were included in the analysis (36 patients in each group). There were 20 (27.8%) patients who experienced moderate hypoxia events. Significantly fewer hypoxic events occurred in the SJOV group than in the nasal cannula group [3 (8.3%) vs. 17 (47.2%), absolute risk difference (95% CI): − 38.9 (− 57.5, − 20.2) %, risk ratio (RR, 95% CI): 0.18 (0.06, 0.55), P < 0.001]. Significantly fewer patients in the SJOV group experienced mild hypoxia (P < 0.001) and severe hypoxia (P = 0.002). No serious adverse events occurred in either of the groups. The Tibetan ethnic group (P = 0.086) and erythrocytosis (P = 0.287) were not associated with the occurrence of hypoxia events. Conclusions The incidence of hypoxia was lower with SJOV than with nasal cannula in patients undergoing gastrointestinal endoscopy under deep sedation at high altitudes. The Tibetan ethnic group and erythrocytosis did not influence the occurrence of hypoxia. Trial registration This study was registered at ClinicalTrials.gov (NCT05304923) before enrollment by Dr. Yi Feng on 31/03/2022.

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Section: Discussionmentioning

confidence: 99%

Supraglottic jet oxygenation and ventilation decreased hypoxemia during gastrointestinal endoscopy under deep sedation at high altitudes: a randomized clinical trial

Jiang

Ciren

et al. 2022

BMC Anesthesiol

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“…As altitude increases, the amount of gas molecules in the air decreases, resulting in a drop in barometric pressure and partial pressure of oxygen. People who ascend to high altitude and exposed to hypobaric hypoxia will suffer a significant decrease of arterial and tissue partial pressure of oxygen in the brain ( 9 ). A series of physiological responses will be triggered.…”

Section: Introductionmentioning

confidence: 99%

Cerebral small-vessel disease at high altitude: A comparison of patients from plateau and plain

Shu

Wen²,

Zhang³

et al. 2023

Front. Neurol.

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Background and purposeCerebral small-vessel disease (CSVD) is prevalent worldwide and one of the major causes of stroke and dementia. For patients with CSVD at high altitude, a special environmental status, limited information is known about their clinical phenotype and specific neuroimaging change. We investigated the clinical and neuroimaging features of patients residing at high altitude by comparing with those in the plain, trying to explore the impact of high altitude environment on CSVD.MethodsTwo cohorts of CSVD patients from the Tibet Autonomous Region and Beijing were recruited retrospectively. In addition to the collection of clinical diagnoses, demographic information and traditional vascular risk factors, the presence, location, and severity of lacunes and white matter hyperintensities were assessed by manual counting and using age-related white matter changes (ARWMC) rating scale. Differences between the two groups and influence of long-term residing in the plateau were analyzed.ResultsA total of 169 patients in Tibet (high altitude) and 310 patients in Beijing (low altitude) were enrolled. Fewer patients in high altitude group were found with acute cerebrovascular events and concomitant traditional vascular risk factors. The median (quartiles) ARWMC score was 10 (4, 15) in high altitude group and 6 (3, 12) in low altitude group. Less lacunes were detected in high altitude group [0 (0, 4)] than in low altitude group [2 (0, 5)]. In both groups, most lesions located in the subcortical (especially frontal) and basal ganglia regions. Logistic regressions showed that age, hypertension, family history of stroke, and plateau resident were independently associated with severe white matter hyperintensities, while plateau resident was negatively correlated with lacunes.ConclusionPatients of CSVD residing at high altitude showed more severe WMH but less acute cerebrovascular events and lacunes in neuroimaging, comparing to patients residing at low altitude. Our findings suggest potential biphasic effect of high altitude on the occurrence and progression of CSVD.

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“… 11 19 However, stroke epidemiology at high altitudes has not been extensively studied, especially in areas with 4000 m and over. 20 Therefore, a household survey was conducted to explore the prevalence of stroke, the detection rate of individuals at high risk of stroke and the risk factors for stroke among residents living in the Tibetan Plateau of China (2000–4500 m). The results could provide epidemiological data for the primary prevention of stroke in plateau areas.…”

Section: Introductionmentioning

confidence: 99%

“…A study reported that the stroke prevalence in the Northeast was almost three times higher than in the Southwest 11 19. However, stroke epidemiology at high altitudes has not been extensively studied, especially in areas with 4000 m and over 20. Therefore, a household survey was conducted to explore the prevalence of stroke, the detection rate of individuals at high risk of stroke and the risk factors for stroke among residents living in the Tibetan Plateau of China (2000–4500 m).…”

Section: Introductionmentioning

confidence: 99%

Prevalence of stroke and associated risk factors: a population-based cross-sectional study from the Qinghai-Tibet Plateau of China

et al. 2022

BMJ Open

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Background and objectivesThe epidemiology of stroke at high altitudes has not been extensively studied, especially at heights of 4000 m and above. Thus, stroke prevention and treatment at high altitudes are challenging. We conducted a cross-sectional study to estimate the prevalence of stroke, the detection rate of individuals at high risk of stroke and the risk factors for stroke in the Qinghai-Tibet Plateau in China, a high altitude plateau that inhabits approximately 15 million people.DesignA population-based cross-sectional study in the Qinghai-Tibet Plateau.SettingData were collected from participants through face-to-face screening using a primary screening table. The table relied on the China National Stroke Screening and Prevention Project.ParticipantsA total of 10 700 residents aged ≥40 years and living on the Qinghai-Tibet Plateau for more than 6 months participated from January 2019 to December 2021.Main outcome measuresThe primary screening table included basic demographic information, medical history information, personal lifestyle habits and physical examination information.ResultsA total of 10 056 people were included in the analysis. The prevalence of stroke was 2.3% (95% CI 2.0% to 2.6%), and the detection rate of individuals at high risk of stroke was 26.2% (95% CI 25.3% to 27.0%). The prevalence of stroke and the detection rate of individuals at high risk of stroke increased with altitude (p<0.01), and the prevalence of stroke at high altitudes was almost 2.2 times that at mid-altitudes (p<0.01). After full adjustments, age, residence, hypertension, family history of stroke and smoking were significantly associated with stroke (p<0.05).ConclusionsThe prevalence of stroke, the related risk factors and the detection rate of high-risk individuals were clarified. The prevalence rates of hypertension, overweight or obesity and diabetes in the Qinghai-Tibet Plateau were all higher than the Chinese average. Higher-altitude exposure may be an independent risk factor for stroke.

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Chronic high-altitude exposure and the epidemiology of ischaemic stroke: a systematic review

Cited by 34 publications

References 49 publications

Supraglottic jet oxygenation and ventilation decreased hypoxemia during gastrointestinal endoscopy under deep sedation at high altitudes: a randomized clinical trial

Supraglottic jet oxygenation and ventilation decreased hypoxemia during gastrointestinal endoscopy under deep sedation at high altitudes: a randomized clinical trial

Cerebral small-vessel disease at high altitude: A comparison of patients from plateau and plain

Prevalence of stroke and associated risk factors: a population-based cross-sectional study from the Qinghai-Tibet Plateau of China

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