Ageing does not influence the sleep-related decrease in the hypercapnic ventilatory response

Browne, Helen A. K.; Adams, Lewis; Simonds, Anita K.; Morrell, Mary J.

doi:10.1183/09031936.03.00039002

Cited by 44 publications

(31 citation statements)

References 43 publications

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“…1 The reasons for age being an influence on AHI in only certain age ranges are unclear. Several studies of the influence of age on upper airway mechanics and control of breathing do not show an aging effect [36][37][38][39] and of those that do, the decrement in function is present in an older age group, not younger.…”

Section: Potential Mechanismsmentioning

confidence: 99%

The Influence of Race on the Severity of Sleep Disordered Breathing

Pranathiageswaran

Badr

Severson

et al. 2013

Journal of Clinical Sleep Medicine

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Background: Studies have indicated that the prevalence of obstructive sleep apnea-hypopnea syndrome (OSAHS) is similar between white and African American patients, but it is unclear if there are differences in the severity of OSAHS. We hypothesized that in patients with diagnosed OSAHS, African Americans would have higher apnea-hypopnea index (AHI) and higher mortality than white individuals. Methods: We analyzed a prospectively collected database of 512 patients studied between July 1996 through February 1999. Inclusion criteria included age ≥ 18 y, AHI ≥ 5/h, and full-night PSG. Statistical analysis was performed to determine the association between race and AHI while controlling for the effect of confounders and effect modifi ers, which included gender, age, body mass index, and comorbidities.

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Section: Potential Mechanismsmentioning

confidence: 99%

The Influence of Race on the Severity of Sleep Disordered Breathing

Pranathiageswaran

Badr

Severson

et al. 2013

Journal of Clinical Sleep Medicine

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“…12,13 Each subject was supplied with a range of flow rates (0, 100, 200, 400, 600, 800 mL/min 79% CO 2 /21% O 2 ) each being maintained constant for 5 minutes.…”

Section: Hypercapnic Interventionmentioning

confidence: 99%

Overnight Changes in the Cerebral Vascular Response to Isocapnic Hypoxia and Hypercapnia in Healthy Humans

Meadows

Kotajima

Vazir

et al. 2005

Stroke

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Background and Purpose-The reduction in hypercapnic cerebral vascular reactivity that occurs in the morning after sleep is associated with an increased risk of cerebral ischemia and stroke. It is not known if the cerebral vascular response to hypoxia is similarly reduced in the morning, but such a reduction could be considered a further risk factor for cerebral vascular disease. Methods-To test if the cerebral vascular response to hypoxia is reduced in the morning, the overnight changes in the left middle cerebral artery velocity (MCAV) in response to isocapnic hypoxia (IH) and hypercapnia before and after a normal night sleep were determined in 18 individuals. Results-From evening to morning, hypercapnic cerebral vascular reactivity decreased significantly (evening 2.0Ϯ0.4, morning 1.3Ϯ0.2 cm/sec/mm Hg; PϽ0.05); in contrast, the increase in MCAV in response to IH (Ϫ10% SaO 2 ) was unchanged (evening 9.0Ϯ1.4, morning 8.7Ϯ2.2%; PϾ0.05). Conclusions-Our findings indicate that substantial differences exist in the regulation of the cerebral circulation in response to hypoxia and hypercapnia on waking from sleep. An intact cerebral vascular response to IH, during this time period, could be interpreted as a protective mechanism against cerebral ischemia and stroke; this is of particular relevance to patients with obstructive sleep apnea who arouse from sleep during hypoxia.

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“…In the current model, this is taken into account by adjusting the overall blood flowQ. Finally, the sleep state is characterized by decreased ventilatory response to CO 2 as compared to wakefulness (Caruana-Montaldo et al, 2000), and this sleep onset-induced decrease in relation to the awake response is of similar magnitude in young and elderly subjects (Browne et al, 2003). These experimental findings led us to choose the representative parameter settings (Table 3), as indicated by the arrows in the simulation results.…”

Section: Q (L/min)mentioning

confidence: 97%

Model-Based Analysis of Mechanisms Responsible for Sleep-Induced Carbon Dioxide Differences

et al. 2006

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This work describes a comprehensive mathematical model of the human respiratory control system which incorporates the central mechanisms for predicting sleep-induced changes in chemical regulation of ventilation. The model integrates four individual compartments for gas storage and exchange, namely alveolar air, pulmonary blood, tissue capillary blood, body tissues, and gas transport between them. An essential mechanism in the carbon dioxide transport is its dissociation into bicarbonate and acid, where a buffering mechanism through hemoglobin is used to prevent harmfully low pH levels. In the current model, we assume high oxygen levels and consider intracellular hydrogen ion concentration as the principal respiratory control variable. The resulting system of delayed differential equations is solved numerically. With an appropriate choice of key parameters, such as velocity of blood flow and gain of a non-linear controller function, the model provides steady-state results consistent with our experimental observations measured in subjects across sleep onset. Dynamic predictions from the model give new insights into the behaviour of the system in subjects with different buffering capacities and suggest novel hypotheses for future experimental and clinical studies.

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Ageing does not influence the sleep-related decrease in the hypercapnic ventilatory response

Cited by 44 publications

References 43 publications

The Influence of Race on the Severity of Sleep Disordered Breathing

The Influence of Race on the Severity of Sleep Disordered Breathing

Overnight Changes in the Cerebral Vascular Response to Isocapnic Hypoxia and Hypercapnia in Healthy Humans

Model-Based Analysis of Mechanisms Responsible for Sleep-Induced Carbon Dioxide Differences

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