Chemosensitivity and Regulation of Ventilation during Sleep at High Altitudes

Lahiri, S.; Data, P. G.

doi:10.1055/s-2007-1024585

Cited by 20 publications

(12 citation statements)

References 6 publications

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“…Anholm et al (1992) specified that at 282 mmHg, the mean SaO 2 during the night was 52%. Subsequent investigations have revealed that both PB and sleep apnea during exposure to altitude are related to ventilatory sensitivity to hypoxia (Lahiri et al, 1983;Lahiri and Data, 1992). Specifically, a higher HVR entails a more extended PB during the night.…”

Section: Sleep Alteration and Neuropsychological Functioningmentioning

confidence: 98%

Neuropsychological Functioning Associated with High-Altitude Exposure

et al. 2004

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This article focuses on neuropsychological functioning at moderate, high, and extreme altitude. This article summarizes the available literature on respiratory, circulatory, and brain determinants on adaptation to hypoxia that are hypothesized to be responsible for neuropsychological impairment due to altitude. Effects on sleep are also described. At central level, periventricular focal damages (leuko-araiosis) and cortical atrophy have been observed. Frontal lobe and middle temporal lobe alterations are also presumed. A review is provided regarding the effects on psychomotor performance, perception, learning, memory, language, cognitive flexibility, and metamemory. Increase of reaction time and latency of P300 are observed. Reduced thresholds of tact, smell, pain, and taste, together with somesthetic illusions and visual hallucinations have been reported. Impairment in codification and short-term memory are especially noticeable above 6,000 m. Alterations in accuracy and motor speed are identified at lower altitudes. Deficits in verbal fluency, language production, cognitive fluency, and metamemory are also detected. The moderating effects of personality variables over the above-mentioned processes are discussed. Finally, methodological flaws found in the literature are detailed and some applied proposals are suggested.

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Section: Sleep Alteration and Neuropsychological Functioningmentioning

confidence: 98%

Neuropsychological Functioning Associated with High-Altitude Exposure

et al. 2004

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“…Furthermore, ventilatory instability and periodic breathing have been shown to depend on the proximity of the eupnoeic carbon dioxide tension (PCO 2 ) to the apnoeic and hypopnoeic threshold PCO 2 , as well as on the ventilatory sensitivity to CO 2 below eupnoea [14]. These factors may differ between children and adults and may affect ventilation, oxygenation and thereby well-being and performance at high altitude [15][16][17]. As respiratory adaptation to acute altitude exposure has not been studied in detail in children, the current authors performed unobtrusive breathing pattern recordings by calibrated respiratory inductive plethysmography and actimetry in pre-pubertal children and their fathers.…”

mentioning

confidence: 99%

Children at high altitude have less nocturnal periodic breathing than adults

Kohler¹,

Kriemler²,

Wilhelm³

et al. 2008

European Respiratory Journal

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Although children commonly travel to high altitudes, their respiratory adaptation to hypoxia remains elusive. Therefore, in the present study respiratory inductive plethysmography, pulse oximetry (Sp,O 2 ) and end-tidal CO 2 tension (PET,CO 2 ) were recorded in 20 pre-pubertal children (aged 9-12 yrs) and their fathers during 1 night in Zurich (490 m) and 2 nights at the Swiss Jungfrau-Joch research station (3,450 m) following ascent by train within ,3 h.In children, mean¡SD nocturnal Sp,O 2 fell from 98¡1% at 490 m to 85¡4 and 86¡4% at 3,450 m (nights 1 and 2, respectively); PET,CO 2 decreased significantly from 37¡6 to 32¡3 and 33¡4 mmHg (3,450 versus 490 m). In adults, changes in nocturnal Sp,O 2 and PET,CO 2 at 3,450 m were similar to those in children.Children spent less time in periodic breathing at 3,450 m during night 1 and 2 (8¡11 and 9¡13%, respectively) than adults (34¡24 and 22¡17%, respectively), and their apnoea threshold for CO 2 was lower compared with adults (27¡2 and 30¡2 mmHg, respectively, both nights). Sp,O 2 , PET,CO 2 and time in periodic breathing at altitude were not correlated between children and their fathers.In conclusion, children revealed a similarly reduced nocturnal O 2 saturation and associated hyperventilation at high altitude as adults but their breathing pattern was more stable, possibly related to a lower apnoea threshold for CO 2 .

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“…However, besides the eects of increased chemosensitivity (Ponikowski et al 1999), ventilatory control may be additionally destabilized by a prolonged circulation time in these patients (Millar et al 1990;Hall et al 1996). Several authors found that the periodicity of breathing control at high altitude was related to HVR (Goldenberg et al 1992;Lahiri and Data 1992), and could be attenuated by increasing the inspiratory oxygen fraction, but not by carbon dioxide inhalation (Lahiri et al 1983). The fact that high-altitude natives do not suer from nocturnal periodic breathing has been explained by a lower chemoreceptor responsiveness of this population (Severinghaus et al 1966;Milledge and Lahiri 1967;Lahiri et al 1983).…”

Section: Discussionmentioning

confidence: 96%

“…Less attention has been paid to the in¯uence of respiration on the autonomic control of the heart at altitude. It is well known that lowlanders, but not Himalayan Sherpas, suer frequently from nocturnal periodic breathing, indicating an impaired regulation of respiration, at altitude (Goldenberg et al 1992;Lahiri and Data 1992). Breathing periodicities may have a major in¯uence on the autonomic cardiocirculatory regulation (West et al 1986;Pinna et al 1996;Ponikowski et al 1996); however, the in¯uence of breathing control on the autonomic cardiac control at altitude in the awake subject is unknown.…”

Section: Introductionmentioning

confidence: 96%

Effects of breathing control on cardiocirculatory modulation in Caucasian lowlanders and Himalayan Sherpas

Keyl¹,

Schneider²,

Greene

et al. 2000

European Journal of Applied Physiology

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This study was performed to investigate the influence of breathing control on the autonomic cardiac regulation at high altitude in adapted and non-adapted awake subjects. We recorded electrocardiogram and pulse oximetry in 14 short-term acclimatized lowlanders and 14 Himalayan Sherpas during resting conditions at an altitude of 5,050 m. Spectrum analysis was performed on synchronized 15 min periods of R-R intervals and the oxygen saturation of arterial blood (SaO2). Despite mean SaO2 being similar in lowlanders and Himalayan Sherpas [78.5 (SD 7.0)% compared to 79.4 (SD5.8)%, respectively], fluctuations in SaO2 were significantly increased in lowlanders compared to Sherpas, thus indicating an unstable regulation of respiration control in lowlanders. Regression analysis demonstrated a significant relationship between spectrum power of SaO2 and the relative power of R-R intervals in the frequency band between 0.01 and 0.08 Hz in lowlanders, but not in Sherpas. Our results demonstrate differences in respiratory and autonomic cardiac control between non-adapted lowlanders and Himalayan high-altitude residents and indicate that unstable breathing control during chronic hypobaric hypoxia is significantly correlated with the autonomic cardiocirculatory regulation.

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Chemosensitivity and Regulation of Ventilation during Sleep at High Altitudes

Cited by 20 publications

References 6 publications

Neuropsychological Functioning Associated with High-Altitude Exposure

Neuropsychological Functioning Associated with High-Altitude Exposure

Children at high altitude have less nocturnal periodic breathing than adults

Effects of breathing control on cardiocirculatory modulation in Caucasian lowlanders and Himalayan Sherpas

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