Browsing by Autor "Silvia Ulrich"

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[Acute high-altitude illnesses - Definition, Prophylaxis, Therapy].
(National Institutes of Health, 2025) Dinah Hertig; Mona Lichtblau; M Furian; Silvia Ulrich; Laura Mayer
Acute altitude illnesses are significant can occur in unacclimatized individuals at altitudes above 2,500 meters. They essentially comprise three clinical pictures: Acute Mountain Sickness (AMS), High Altitude Cerebral Edema (HACE), and High Altitude Pulmonary Edema (HAPE), which can manifest alone or in combination. All are triggered by hypobaric hypoxia, with individual predisposition, pre-existing medical comorbidities and in particular ascent rate and destination altitude influencing risk. AMS is the most common, presenting with headache, nausea, dizziness, and fatigue. Prevention includes slow ascent, pre-acclimatization, and eventually acetazolamide or dexamethasone. In severe cases, descent, oxygen therapy, and dexamethasone are key. HACE is considered a life-threatening complication of AMS with ataxia, altered consciousness, and neurological deficits. Pathophysiologically, vasogenic edema, hypoxic cell injury, and disturbed cerebrospinal fluid dynamics play a role. Treatment also includes descent, oxygen therapy, and dexamethasone. HAPE is a non-cardiogenic pulmonary edema due to an excessive hypoxic pulmonary vasoconstriction with consecutive elevation of pulmonary artery pressure and increased capillary pressure. Symptoms include dyspnea and cough; clinically, cyanosis and crackles are evident. Treatment requires descent, oxygen therapy, and possibly nifedipine or PDE-5-inhibitors. If untreated, HACE and HAPE progress rapidly and can be fatal. Prevention, early recognition and immediate treatment are crucial.
Nocturnal Sleep Breathing Patterns in Healthy Adolescents Residing at Very High Altitudes in Bolivia
(Wiley, 2026) Keaton Patterson; Santiago Ucrós Rodríguez; E. Nicolás Arancibia‐Levit; Fernanda Aliaga Raduan; José Antonio Viruez Soto; Max Gassmann; Silvia Ulrich; Michael Furian; Edith M. Schneider Gasser
Data on sleep and respiratory patterns among adolescents residing at very high altitude (> 3500 m) remain scarce, and altitude-related physiological differences may influence these parameters. Studying adolescents at different very high altitudes is crucial, as subtle environmental variations could affect sleep-related oxygenation and respiratory function. This study aimed to characterise sleep-related oxygenation and respiratory parameters in healthy adolescents native to two distinct very high-altitude environments. Overnight sleep polygraphy was performed in 163 healthy adolescents aged 13.5 to < 18 years living in La Paz (3620 m) and El Alto (4060 m), Bolivia. Mean nocturnal oxygen saturation, oxygen desaturation index, and apnea-hypopnea index were assessed alongside subjective sleep quality, morning blood pressure, heart rate, haemoglobin concentration, and Epworth Sleepiness Scale scores. Adolescents at 4060 m had significantly lower mean nocturnal oxygen saturation (84.8% ± 2.2%) compared with those at 3620 m (87.8% ± 1.8%), and a higher oxygen desaturation index (21.2 ± 8.5/h vs. 17.1 ± 9.0/h). The apnea-hypopnea index did not differ significantly between altitudes (6.2 ± 4.8/h vs. 5.6 ± 4.6/h). At 3620 m, females showed lower oxygen desaturation and apnea-hypopnea indices compared with males. Despite the more pronounced nocturnal hypoxemia at 4060 m, haemoglobin concentration did not increase, suggesting limited haematological compensation. Subjective sleep quality, blood pressure, and heart rate were similar between both altitude groups. Healthy adolescents living chronically at very high altitude exhibit altitude-dependent reductions in nocturnal oxygenation and increased desaturation frequency, without evidence of sleep-disordered breathing. These findings underscore the need for altitude-specific normative values to support accurate interpretation of sleep studies in high-altitude populations.