A dog model to investigate the relationship between obstructive sleep apnoea and blood pressure regulation

Patients exhibiting obstructive sleep apnoea (OSA) do not display a normal circadian pattern of blood pressure. It is not clear whether this disruption of the circadian blood pressure pattern is a result of the intermittent airway obstruction during sleep or is the result of confounding factors, such as obesity and age, which are common in OSA and may independently affect blood pressure. To determine if a cause and effect relationship exists between repetitive airway obstruction during sleep and blood pressure regulation a chronically instrumented canine model of OSA has been developed. This canine model has been shown to reproduce the characteristic apnoea and hypersomnolence of human OSA. Furthermore, in this model a 12-h nocturnal period of repetitive airway obstruction during sleep caused an increase in baseline blood pressure of more than 10 mmHg that was sustained for at least two hours following the restoration of normal airway patency. These results imply that there is a cause and effect relationship between intermittent airway obstruction during sleep and elevated blood pressure.