Determination of Upper Airway Collapsibility During Routine CPAP Titration
| Status: | Terminated |
|---|---|
| Conditions: | Insomnia Sleep Studies, Pulmonary |
| Therapuetic Areas: | Psychiatry / Psychology, Pulmonary / Respiratory Diseases |
| Healthy: | No |
| Age Range: | 18 - 79 |
| Updated: | 1/7/2018 |
| Start Date: | October 20, 2015 |
| End Date: | July 25, 2016 |
The investigators hypothesis is that upper airway collapsibility (Pcrit) in patients with
obstructive sleep apnea (OSA) can be measured using equipment found in the clinical sleep
laboratory and these Pcrit measurements obtained using clinical sleep laboratory equipment is
comparable to those obtained using research equipment. OSA is a common disease characterized
by repetitive collapse of the upper airway during sleep, leading to hypoxemia and arousals,
and which has important neurocognitive and cardiovascular consequences. The single most
important factor in the development of OSA is upper airway collapsibility: those with a more
collapsible upper airway tend to have OSA while those with a stiffer upper airway do not. The
gold standard treatment for OSA is continuous positive airway pressure (CPAP), which acts by
stenting open the collapsible airway. Upper airway collapsibility can be measured during
sleep by changing the CPAP level and assessing the change in inspiratory flow through the
upper airway. Although technically feasible, these measurements are typically only undertaken
in research laboratories with specialized equipment. The purpose of this study is to measure
upper airway collapsibility using clinically available (i.e. equipment found in a clinical
sleep laboratory) equipment only. If successful, upper airway collapsibility could be
routinely measured in clinical practice, which could help inform treatment decisions and help
individualize therapy for OSA.
obstructive sleep apnea (OSA) can be measured using equipment found in the clinical sleep
laboratory and these Pcrit measurements obtained using clinical sleep laboratory equipment is
comparable to those obtained using research equipment. OSA is a common disease characterized
by repetitive collapse of the upper airway during sleep, leading to hypoxemia and arousals,
and which has important neurocognitive and cardiovascular consequences. The single most
important factor in the development of OSA is upper airway collapsibility: those with a more
collapsible upper airway tend to have OSA while those with a stiffer upper airway do not. The
gold standard treatment for OSA is continuous positive airway pressure (CPAP), which acts by
stenting open the collapsible airway. Upper airway collapsibility can be measured during
sleep by changing the CPAP level and assessing the change in inspiratory flow through the
upper airway. Although technically feasible, these measurements are typically only undertaken
in research laboratories with specialized equipment. The purpose of this study is to measure
upper airway collapsibility using clinically available (i.e. equipment found in a clinical
sleep laboratory) equipment only. If successful, upper airway collapsibility could be
routinely measured in clinical practice, which could help inform treatment decisions and help
individualize therapy for OSA.
OSA is defined by total or partial intermittent collapse of the upper airway, resulting in
nocturnal hypoxemia and arousals from sleep. OSA is incredible common and has important
cardiovascular (e.g. hypertension, coronary artery disease, stroke, atrial fibrillation) and
neurocognitive consequences (e.g. depression, motor vehicle accidents). Thus, OSA results in
significant morbidity and mortality and a substantial economic burden. The best studied
treatment of OSA is continuous positive airway pressure (CPAP), which effectively stents the
upper airway open, however, many patients are not able to tolerate it. Other treatments are
available, such as oral appliances or upper airway surgery, however these are much more
variable in their effectiveness.
Although other factors are important, the most important factor in OSA pathogenesis is upper
airway collapsibility. The upper airway collapsibility can be determined during sleep when
patients with OSA are on CPAP. The CPAP level is decreased until flow limitation and finally
collapse is achieved. The pressure at which the airway collapses is called the pharyngeal
critical closing pressure, or Pcrit. When measured in research laboratories, the Pcrit
correlates with OSA severity. Subjects with a high Pcrit (e.g. 5cm of water pressure)
typically have severe OSA, while those with a lower Pcrit (e.g. 2cm of water pressure) have
mild OSA, and those with a negative Pcrit (e.g. -4cm of water, the airway must be sucked
closed to collapse) typically have no disease. The Pcrit may also have important implications
for treatment. For example, patients with OSA and a very high Pcrit may require CPAP,
however, those with a lower or slightly negative Pcrit might be successfully treated by an
oral appliance. Thus, knowledge of the Pcrit might be useful in clinical practice, but it is
rarely measured outside of the research lab.
To measure Pcrit, patients sleep with a mask over their nose or nose and mouth, and CPAP is
applied using a custom made machine that can rapidly change mask pressures. The idea is that
rapid changes in airway pressure produce a clear step change in airflow that will be observed
quickly. In contrast, during clinical titrations, the CPAP machines change pressure much more
slowly to help promote patient comfort. The goal of this research is to determine whether
these slower pressure changes could still be used to gather useful information about upper
airway collapsibility.
nocturnal hypoxemia and arousals from sleep. OSA is incredible common and has important
cardiovascular (e.g. hypertension, coronary artery disease, stroke, atrial fibrillation) and
neurocognitive consequences (e.g. depression, motor vehicle accidents). Thus, OSA results in
significant morbidity and mortality and a substantial economic burden. The best studied
treatment of OSA is continuous positive airway pressure (CPAP), which effectively stents the
upper airway open, however, many patients are not able to tolerate it. Other treatments are
available, such as oral appliances or upper airway surgery, however these are much more
variable in their effectiveness.
Although other factors are important, the most important factor in OSA pathogenesis is upper
airway collapsibility. The upper airway collapsibility can be determined during sleep when
patients with OSA are on CPAP. The CPAP level is decreased until flow limitation and finally
collapse is achieved. The pressure at which the airway collapses is called the pharyngeal
critical closing pressure, or Pcrit. When measured in research laboratories, the Pcrit
correlates with OSA severity. Subjects with a high Pcrit (e.g. 5cm of water pressure)
typically have severe OSA, while those with a lower Pcrit (e.g. 2cm of water pressure) have
mild OSA, and those with a negative Pcrit (e.g. -4cm of water, the airway must be sucked
closed to collapse) typically have no disease. The Pcrit may also have important implications
for treatment. For example, patients with OSA and a very high Pcrit may require CPAP,
however, those with a lower or slightly negative Pcrit might be successfully treated by an
oral appliance. Thus, knowledge of the Pcrit might be useful in clinical practice, but it is
rarely measured outside of the research lab.
To measure Pcrit, patients sleep with a mask over their nose or nose and mouth, and CPAP is
applied using a custom made machine that can rapidly change mask pressures. The idea is that
rapid changes in airway pressure produce a clear step change in airflow that will be observed
quickly. In contrast, during clinical titrations, the CPAP machines change pressure much more
slowly to help promote patient comfort. The goal of this research is to determine whether
these slower pressure changes could still be used to gather useful information about upper
airway collapsibility.
Inclusion Criteria:
- Diagnosis of OSA and stable on CPAP treatment > 3 months
Exclusion Criteria:
- Pregnancy
- Currently smoking
- Any respiratory disorder other than OSA or well controlled asthma
- Medications known to affect respiratory function (e.g. opioids, benzodiazepines, etc)
We found this trial at
1
site
Click here to add this to my saved trials
