A DOG-MODEL TO INVESTIGATE THE RELATIONSHIP BETWEEN OBSTRUCTIVE SLEEP-APNEA AND BLOOD-PRESSURE REGULATION

Patients exhibiting obstructive sleep apnoea (OSA) do not display a no rmal 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 conf ounding factors, such as obesity and age, which are common in OSA and may independently affect blood pressure, To determine if a cause and e ffect 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 airwa y obstruction during sleep caused an increase in baseline blood pressu re of more than 10 mmHg that was sustained for at least two hours foll owing the restoration of normal airway patency, These results imply th at there is a cause and effect relationship between intermittent airwa y obstruction during sleep and elevated blood pressure.