Upper Airway Dilator Muscle Activity During Sleep Onset.
Funder
National Health and Medical Research Council
Funding Amount
$211,320.00
Summary
Disorders of breathing during sleep are recognised as a major health problem. Of these, Obstructive Sleep Apnoea is the most prevalent, occurring in approximately 4% of the male and 2% of the female population. In this disorder the upper airway collapses during sleep causing cessation of airflow and subsequent oxygen desaturation. The airway is thought to occlude because dilator muscles are unable to sustain patency in the face of the negative pressures generated by inspiratory effort. In order ....Disorders of breathing during sleep are recognised as a major health problem. Of these, Obstructive Sleep Apnoea is the most prevalent, occurring in approximately 4% of the male and 2% of the female population. In this disorder the upper airway collapses during sleep causing cessation of airflow and subsequent oxygen desaturation. The airway is thought to occlude because dilator muscles are unable to sustain patency in the face of the negative pressures generated by inspiratory effort. In order for patency of the airway to be re-established some form of arousal from sleep must occur . As the UA is likely to collapse on the resumption of sleep, the cycle becomes repetitive, causing significant sleep disruption. OSA is a significant health risk, being associated with increased risk of cardiovascular disorders, increased mortality, excessive daytime sleepiness, reduced daytime performance and increased risk of accidents. In previous work we have demonstrated that normal sleep related changes in the activity of upper airway dilator muscles result in a reduction in the calibre of the airway at sleep onset. This exposes some individuals, such as those with narrow airways, to airway obstruction during sleep. We have also reported that elderly men have larger reductions in upper airway muscle activity at sleep onset than younger men, suggesting one reason why they may have a higher prevalence for Obstructive Sleep Apnea. The aim of the present project is to determine what causes the larger reductions in upper airway muscle activity in older males. The answer to this question will contribute to understanding why this group is so susceptible to Obstructive Sleep Apnea and will elucidate the mechanisms leading to the disorder.Read moreRead less
Obstructive Sleep Apnea And Androgen Dysregulation
Funder
National Health and Medical Research Council
Funding Amount
$537,041.00
Summary
Obstructive Sleep Apnea (OSA) is a serious public health problem associated with increased sleepiness, heart disease and metabolic dysfunction. Obesity and male gender are important predisposing factors for OSA. This study will determine if short-term testosterone therapy can help improve OSA in men who are also dieting and exercising. It will also determine the genetic mechanisms by which testosterone might influence breathing during sleep and obesity.
Sleep Disordered Breathing In Pregnancy: Frequency And Impact.
Funder
National Health and Medical Research Council
Funding Amount
$607,034.00
Summary
Sleep disordered breathing (SDB)affects up to 15% of women during pregnancy. There is some evidence that it may have adverse effects on both mother and baby, particularly it may be associated with a 7-8 fold increase risk of developing hypertension during pregnancy. This study aims to measure breathing during sleep in pregnant women to determine its role in pregnancy-related hypertension and diabetes, then treat the SDB to assess its effect on maternal and foetal outcomes.
A Randomised Controlled Trial Of A Simplified Management Strategy Versus Standard Care In Moderate To Severe OSA
Funder
National Health and Medical Research Council
Funding Amount
$561,400.00
Summary
Currently breathing difficulties during sleep known as obstructive sleep apnea (OSA) are undertreated in our community. This reflects an inability of the current diagnostic and treatment strategies to deal with the high clinical burden of OSA. As a result, in particular in rural and remote areas, many have long waits for treatment, or no access to therapy at all. The purpose of this project is to evaluate a simplified protocol for the management of OSA. This will be done using diagnostic devices ....Currently breathing difficulties during sleep known as obstructive sleep apnea (OSA) are undertreated in our community. This reflects an inability of the current diagnostic and treatment strategies to deal with the high clinical burden of OSA. As a result, in particular in rural and remote areas, many have long waits for treatment, or no access to therapy at all. The purpose of this project is to evaluate a simplified protocol for the management of OSA. This will be done using diagnostic devices and treatment strategies that are more widely available than the current approaches to the diagnosis and management of obstructive sleep apnea. This will involve measurement of the numbers of falls in oxygen levels in a patient via a device to measure oxygen levels called an oximeter. These falls in oxygen levels correlate well with breath holding episodes during sleep characteristic of OSA. Treatment can be commenced in the patient's home depending on these results. We intend to compare these new approaches with the current best practice in OSA. If the outcomes are good these stategies could be applied to reduce the waiting times for to diagnose and manage OSA and make therapy more widely available throughout the community.Read moreRead less
Role Of Load Detection And Compensation In Pathogenesis Of Obstructive Sleep Apnea.
Funder
National Health and Medical Research Council
Funding Amount
$340,867.00
Summary
This proposal will use novel techniques to explore how defective responses to the threat posed by a collapsing upper airway contribute to the Obstructive Sleep Apnea syndrome, a disease involving repetitive collapse of the upper airway in sleep. Responses to small increases in the resistance to inspiratory airflow will be examined by measuring the small electrcal responses in the brain to these loads, and the response of the muscles responsible for maintaining airway patency to the collapsing fo ....This proposal will use novel techniques to explore how defective responses to the threat posed by a collapsing upper airway contribute to the Obstructive Sleep Apnea syndrome, a disease involving repetitive collapse of the upper airway in sleep. Responses to small increases in the resistance to inspiratory airflow will be examined by measuring the small electrcal responses in the brain to these loads, and the response of the muscles responsible for maintaining airway patency to the collapsing forces induced by these loads, in both wakefulness and sleep. The brain's response to resistive loads will also be evaluated using the techique of functional magnetic resonance imaging, which demonstrates areas of the brain activated by a stimulus.Read moreRead less
The Diagnosis Of Obstructive Sleep Apnea In Primary Care
Funder
National Health and Medical Research Council
Funding Amount
$295,075.00
Summary
The gold standard method for diagnosis of sleep apnea is the overnight sleep study. These tests are expensive, have long waiting lists and are hard to access outside larger cities. We aim to determine if general practitioners can combine information from questionnaires and a simple home diagnostic test, to confirm or rule out sleep apnea. The results of this study will eventually lead to more accessible and efficient diagnosis and treatment of this common condition.
The Role Of Arousal And Diaphragm Displacement In The Pathogenesis Of Obstructive Sleep Apnoea
Funder
National Health and Medical Research Council
Funding Amount
$410,875.00
Summary
Obstructive sleep apnea (OSA) affects 4% of men and causes excessive daytime sleepiness leading to increased accidents, high blood pressure and premature cardiovascular disease e.g. heart attacks and strokes. OSA is characterized by repetitive obstructions of the floppy portion of the throat during sleep with adverse effects on oxygen levels and sleep quality. OSA is strongly associated with obesity and is 2-3 times more common in men than women. How obesity and male gender predispose to OSA is ....Obstructive sleep apnea (OSA) affects 4% of men and causes excessive daytime sleepiness leading to increased accidents, high blood pressure and premature cardiovascular disease e.g. heart attacks and strokes. OSA is characterized by repetitive obstructions of the floppy portion of the throat during sleep with adverse effects on oxygen levels and sleep quality. OSA is strongly associated with obesity and is 2-3 times more common in men than women. How obesity and male gender predispose to OSA is not known. We will investigate two factors that we believe are most likely involved in causing and explaining this gender difference in OSA. We will examine if breathing responses with brief awakening are sufficient to promote OSA patterns of breathing in snorers and if they are greater in male than female OSA patients. We have already shown that healthy men have greater breathing response to arousal compared to women. These brief arousals occur hundreds of times a night in OSA patients, and over-breathing on arousal may increase the probability of upper airway obstruction on falling back to sleep. We will also investigate why even healthy men show greater breathing responses compared to women. Men tend to accumulate fat centrally, particularly in the abdomen, whereas in women fat tends to be distributed more to the hips and thighs. This could be very important in OSA because downward pull exerted on the upper airway by the diaphragm is likely to be reduced in people with more abdominal obesity. This mechanisms has not yet been studied in humans. We will therefore investigate if increased forces placed on the diaphragm during sleep make the upper airway more prone to collapse. We will also investigate these effects during sleep onset, when there may well be important changes in diaphragm position as muscles relax.Read moreRead less
Ageing, Obstructive Sleep Apnea (OSA) and obesity are becoming more common in the community. Each is associated with increased heart disease and metabolic disorders. Understanding how androgen dysregulation exacerbates OSA, obesity and ageing and how androgen treatments alter these conditions may lead to reduced cardiometabolic dysfunction and improved health.
The Effect Of CPAP On Erectile And Endothelial Dysfunction In Impotent Men With Obstructive Sleep Apnea
Funder
National Health and Medical Research Council
Funding Amount
$609,559.00
Summary
Erectile dysfunction is common in men with obstructive sleep apnea, due to vascular damage, which leads to heart attack. CPAP is the preferred treatment for patients with OSA because of its well-proven ability to decrease sleepiness and improve blood pressure control. This study will establish if CPAP can also improve erectile and vascular endothelial dysfunction. These results will shed light on the mechanisms that underpin the relationship between OSA and Erectile Dysfunction.
The Role Of Respiratory And Upper Airway Neural Control In Sleep Disordered Breathing
Funder
National Health and Medical Research Council
Funding Amount
$346,018.00
Summary
Obstructive Sleep Apnea (OSA) is a disorder associated with snoring. It affects 4% of adult men and causes excessive daytime sleepiness leading to increased accidents, high blood pressure and premature cardiovascular disease eg. heart attacks and strokes. Patients with OSA obstruct the floppy portion of the upper airway (UA) during sleep and consequently experience frequent episodes of oxygen deprivation as well as sleep fragmentation. OSA is at least 2-3 times more common in men than women. Whi ....Obstructive Sleep Apnea (OSA) is a disorder associated with snoring. It affects 4% of adult men and causes excessive daytime sleepiness leading to increased accidents, high blood pressure and premature cardiovascular disease eg. heart attacks and strokes. Patients with OSA obstruct the floppy portion of the upper airway (UA) during sleep and consequently experience frequent episodes of oxygen deprivation as well as sleep fragmentation. OSA is at least 2-3 times more common in men than women. While OSA patients seem, on average, to have smaller upper airways than normal subjects, the cause of OSA cannot be attributed to this factor alone. For example, a small UA cannot explain the male tendency for OSA. Abnormalities in breathing control or the control of upper airway muscles that normally hold the airway open might also be important in OSA. Men have previously been shown to have a greater increase in UA resistance during sleep than women, consistent with the idea that a gender difference in UA muscle control partly explains why more men than women have OSA. We aim to investigate how changes in breathing and UA dilator muscle control might lead to unstable patterns of breathing and to OSA. We propose that protective UA muscle reflexes are reduced during sleep more in men than women, and are reduced by low blood oxygen levels and alcohol (a known aggravator of sleep apnea). We further propose that low blood oxygen levels not only result from OSA but may also aggravate OSA by preferentially reducing the activity of UA dilating muscles, by making breathing patterns overall less stable and by depressing the ability of subjects to arouse from sleep to an airway blockage. We believe that this tendency to decrease UA activity may be exaggerated in OSA patients. We also propose that men are more vulnerable to the deleterious effects of low oxygen than women. We will also examine if men and snorers have exaggerated breathing responses on arousal from sleep.Read moreRead less