Research

 

OSA Pathogenesis

OSA is increasingly recognized as a multifactorial disorder i.e., different people have OSA for different reasons. Although an anatomical predisposition (collapsibility of the upper airway) is required, other factors are important as well, including a low respiratory arousal threshold (wake up too easily), dysfunction in upper airway dilator muscles and instability in ventilatory control (which we quantify using the engineering term loop gain [LG]), which leads to periods of decreased pharyngeal tone as well periods of increased respiratory effort.  I have been actively involved in efforts to characterize the different endotypes – defined as a subtype of a condition that has a distinct functional or pathobiological mechanism – important for OSA. The ultimate goal of this work is to personalize therapy for OSA one day by addressing the underlying endotype to treat OSA effectively in an individual with targeted therapy


Currently, we can measure these endotypes through careful manipulation of the airway during the night during sleep, and see how the person's muscles, respiratory drive and arousal mechanisms compensate.



In an individual, we can model how the traits go together.


This is important because two people might have the same severity of OSA for DIFFERENT reasons.  Ultimately we hope to treat the underlying cause and personalize therapy.

We do have alternate therapies, such as oral appliances and upper airway surgery, but we are pretty bad at predicting who can use these.  With a knowledge of the underlying physiology we can model outcomes from surgery more accurately.


 

Sleep in HIV

Thankfully, major strides have been made in the treatment of Human Immunodeficiency Virus (HIV) leading to greatly prolonged life expectancy for people on anti-retroviral therapy (ART). However, fatigue and early cardiovascular disease are major problems. Might sleep apnea be a culprit? Here’s what we know about OSA in HIV: 

1. OSA is appears to be common in those with HIV. 

 2. Traditional OSA risk factors may not predict OSA in PLWH. 

3. Untreated OSA may be relevant for symptoms in PLWH. 

4. Untreated OSA is likely to be associated with ongoing inflammation. 

5. Few PLWH with OSA are diagnosed or treated. 



We are conducting experiments to determine: - If people with HIV are predisposed to OSA - What the impact of sleep and sleep apnea are on fatigue and quality of life in people with HIV.

Collaborators: 

Chuck Hicks MD 

Maile Karris MD 

Igor Grant MD 

Sonia Ancoli Israel PhD 

Atul Malhotra MD 

Jeremy Orr MD 

Dae Kang PhD 

Interested in Participating? If you are in the San Diego area and would like to be considered, please call 858-246-2154 or email sleepresearch@ucsd.edu. These studies are NIH funded and registered on Clinicaltrials.gov (NCT03064204, NCT03575143)

 

Sleep in the Hospital

If you’ve ever been an ICU patient, or had to stay overnight in an ICU, you know that ICUs are not conducive to sleep. Increasingly, studies link lack of sleep to delirium, and efforts to promote sleep can reduce delirium rates. We are very interested in careful measurement of the hospital environment, ways to measure sleep in the hospital/ICU, and ultimately ways to improve sleep and delirium in the hospital. Stuti Jaiswal leads this work. 

Here's what we’ve learned: 

1. Hospitals are really loud, but making them more quite might not be the answer. 


2. ICUs aren’t too bright at night, they are TOO DIM during the day. 

3. Sleep is really fragmented in the hospital. 

4. Unfortunately, it doesn’t like seem melatonin or Ramelteon are too helpful to reduce delirium. Also, it seems likely that sleep in the hospital is a problem for family members of ICU patients. 

Giang is an ICU nurse we work with to look at this.

 

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