UARS Diagnosis and Treatment: How Pes Reveals Hidden Breathing Problems During Sleep
You wake up tired even after spending eight hours in bed. Maybe you have headaches in the morning, struggle to concentrate during the day, or wake repeatedly without knowing why. Your partner may hear you snore or breathe heavily, but a home sleep test did not find significant sleep apnea. Your symptoms are real, even if an initial test did not explain them.
For some patients, the problem is Upper Airway Resistance Syndrome, or UARS. This sleep-related breathing disorder can repeatedly interrupt sleep without causing the obvious breathing pauses or oxygen drops commonly associated with obstructive sleep apnea.
Because the signs can be subtle, diagnosing UARS may require a closer look at how hard the body is working to breathe. One way to measure that effort is esophageal pressure monitoring, commonly called Pes.
What is Upper Airway Resistance Syndrome?
UARS occurs when the upper airway becomes narrow during sleep. The airway does not necessarily close completely. Instead, the person must make a stronger effort to pull air through the restricted space.
That extra work can cause brief shifts in brain activity known as respiratory effort-related arousals, or RERAs. These arousals may last only a few seconds, and the sleeper may never remember them. When they happen throughout the night, however, they can keep the brain and body from getting enough restorative sleep.
Possible symptoms of UARS include:
Unrefreshing sleep
Persistent fatigue or daytime sleepiness
Frequent nighttime awakenings
Difficulty falling or staying asleep
Morning headaches
Trouble concentrating
Irritability or mood changes
Snoring or labored breathing
Waking with a dry mouth
Feeling lightheaded when standing
Teeth grinding or jaw clenching during sleep
These symptoms can resemble insomnia, anxiety, ADHD, chronic fatigue, or other medical conditions. That overlap is one reason a complete evaluation matters.
Patients looking for help with upper airway resistance syndrome in Houston, TX, or another CSMA service area may have already tried to address their fatigue without realizing that nighttime breathing effort could be part of the problem.
Is UARS the Same as Sleep Apnea?
UARS and obstructive sleep apnea are related, but the terms do not describe exactly the same pattern of breathing.
In obstructive sleep apnea, the airway repeatedly closes or becomes restricted enough to cause apneas and hypopneas. These events may reduce oxygen levels and are counted when calculating the apnea-hypopnea index, or AHI.
With UARS, the airway remains open enough for air to move, but breathing takes more effort. The increased effort can repeatedly disturb sleep even when the patient has a low AHI and few noticeable oxygen drops.
People sometimes search for upper airway sleep apnea treatment when they are experiencing signs of either condition. A sleep specialist can determine whether the symptoms are associated with UARS, obstructive sleep apnea, another form of upper airway obstruction, or a different sleep disorder.
How Can UARS be Missed or Misdiagnosed?
Many patients begin with a home sleep apnea test. These tests can be useful when moderate or severe obstructive sleep apnea is suspected, but they collect less information than an attended polysomnogram performed in a sleep laboratory.
A home test may not measure sleep stages or brief arousals with the same level of detail as an in-lab sleep study. It may also be less equipped to show the increasing breathing effort that can occur before a UARS-related arousal.
UARS can be overlooked when:
The apnea-hypopnea index falls within the normal or mild range.
Oxygen levels remain relatively stable.
Breathing disruptions do not meet the criteria for apneas or hypopneas.
The patient’s main complaint is insomnia rather than snoring.
Daytime symptoms are attributed to stress, mood, or lifestyle.
A limited home study does not capture enough information.
A low apnea score does not automatically mean that nighttime breathing is normal. The score must be considered alongside the patient’s symptoms, medical history, physical examination, and the rest of the sleep data.
What is Pes Monitoring?
Pes stands for pressure in the esophagus. During an overnight sleep study, a thin catheter is placed through the nose and positioned in the lower esophagus. Because the esophagus sits close to the lungs, changes in esophageal pressure can show how much effort the body is making to breathe.
When the upper airway narrows, the chest has to generate stronger negative pressure to draw air into the lungs. Pes records those pressure changes breath by breath.
The Pes measurement is evaluated alongside the other information collected during polysomnography, including:
Brain activity and sleep stages
Airflow
Chest and abdominal movement
Blood oxygen levels
Heart rate
Muscle activity
Respiratory arousals
Pes is more involved than a routine home test and is not necessary for every patient. In selected cases, however, it can provide direct information about respiratory effort that is difficult to obtain from other measurements.
How Does Pes Help to Identify UARS?
A typical UARS-related event develops gradually.
First, the upper airway narrows. Air continues to move, but the body must work harder to maintain each breath. The pressure generated inside the chest becomes increasingly negative until the brain briefly shifts into lighter sleep. Breathing then becomes easier, and the cycle may begin again.
Pes can record that sequence:
The airway becomes restricted.
Breathing effort increases.
Esophageal pressure becomes more negative.
The increased effort ends in a brief arousal.
Sleep resumes without the patient necessarily waking completely.
When this pattern repeats throughout the night, it can explain why someone feels exhausted despite apparently sleeping for an adequate number of hours.
Pes does not replace the physician’s interpretation of the complete sleep study. It adds a direct measurement that may help connect a patient’s symptoms with subtle upper airway resistance and repeated sleep disruption.
Dr. Jerald Simmons and the Early Clinical Study of UARS
Dr. Jerald H. Simmons completed his sleep medicine fellowship at Stanford University, where he trained with Dr. William Dement and Dr. Christian Guilleminault.
During that period, Stanford researchers were studying patients who experienced excessive daytime sleepiness even though they did not meet the conventional criteria for obstructive sleep apnea. Measuring esophageal pressure helped the team identify increasing respiratory effort and sleep disruption in these patients.
In 1992, Dr. Simmons was one of the authors of the paper “From Obstructive Sleep Apnea Syndrome to Upper Airway Resistance Syndrome: Consistency of Daytime Sleepiness.” The paper’s authors were Christian Guilleminault, Riccardo Stoohs, Alex Clerk, Jerald Simmons, and Michael Labanowski. It was part of the early published work that described and named UARS.
Some patients with excessive daytime sleepiness who do not present the features of obstructive sleep apnea syndrome (OSAS) present a sleep fragmentation due to transient alpha EEG arousals lasting between three and 14 seconds. These transient EEG arousals are related to an abnormal amount of breathing effort, indicated by peak inspiratory esophageal pressure (Pes) nadir.
Guilleminault C, Stoohs R, Clerk A, Simmons J, Labanowski M. “From obstructive sleep apnea syndrome to upper airway resistance syndrome: Consistency of daytime sleepiness.” Sleep. 1992;15(6 Suppl):S13–S16. View on PubMed.
Dr. Simmons did not invent esophageal pressure measurement. His contribution was as a member of the Stanford group that applied the measurement to the investigation of subtle sleep-related breathing problems and helped define the clinical pattern now known as UARS.
He later helped turn that research approach into a repeatable sleep-laboratory protocol. At CSMA, Dr. Simmons has continued to use and teach Pes monitoring as part of the evaluation of patients whose symptoms may not be explained by conventional apnea measurements.
What Happens During a Sleep Study with Pes?
Pes monitoring is performed as part of an attended overnight sleep study. Before the study begins, a trained clinician carefully places the thin catheter through the nose and into the esophagus.
The catheter remains in position while the patient sleeps. Although some people notice it at first, the goal is to place and secure it in a way that allows the patient to settle into sleep while the clinical team collects the necessary information.
Throughout the night, the sleep technologist monitors the Pes signal along with the patient’s airflow, oxygen level, sleep stages, respiratory movements, heart rate, and other measurements.
After the study, a sleep physician reviews the complete record. Pes results are not interpreted in isolation. They are considered alongside the patient’s symptoms and the other events recorded during the night.
How is UARS Treated?
There is no single UARS treatment that is right for everyone. The appropriate plan depends on where the airway is narrowing, how severely sleep is being disrupted, the patient’s medical history, and other anatomical or health factors.
Treatment may include one or more of the following approaches:
1) Positive airway pressure therapy
CPAP or another form of positive airway pressure can help prevent the airway from narrowing. Reducing that resistance may decrease respiratory arousals and improve sleep quality.
The pressure settings should be based on the patient’s diagnostic findings and response to treatment. Some patients with UARS need careful adjustment because their breathing events may be subtler than the events typically associated with moderate or severe sleep apnea.
2) Oral appliance therapy
A custom oral appliance may move the lower jaw or tongue forward to create more room in the airway. This may be considered for certain patients who cannot tolerate positive airway pressure or whose anatomy makes them suitable candidates.
Oral appliances should be fitted by a qualified dental professional working in coordination with a sleep physician.
3) Treatment for nasal obstruction
Chronic congestion, allergies, enlarged turbinates, a deviated septum, or nasal valve problems may increase resistance to airflow.
Depending on the cause, treatment could include medication, allergy management, nasal support, or evaluation by an ear, nose, and throat physician.
4) Positional and behavioral changes
Some people experience more airway narrowing while sleeping on their backs. Positional therapy may be helpful when testing shows a relationship between sleep position and breathing difficulty.
Avoiding alcohol or sedating substances near bedtime may also help because these substances can relax the muscles that support the airway. Patients should speak with their healthcare provider before changing any prescribed medication.
5) Dental, orthodontic, or surgical care
Jaw structure, palate shape, tonsil size, tongue position, and other anatomical factors can contribute to upper airway resistance. Certain patients may benefit from an evaluation by a dentist, orthodontist, ENT physician, or sleep surgeon.
Effective upper airway obstruction treatment begins with identifying the source of the obstruction. Treatment should be selected for the individual rather than based on symptoms alone.
UARS Evaluation and Treatment at CSMA
CSMA evaluates patients with possible UARS and other sleep-related breathing disorders at locations serving Austin, Houston, Sugar Land, and The Woodlands.
Patients searching for UARS treatment in Austin, TX, or an upper airway obstruction doctor in Austin, TX, can schedule an evaluation to discuss their symptoms and previous sleep-testing results.
CSMA also serves patients looking for:
These search terms may refer to several different conditions. The purpose of an evaluation is to determine what is actually disrupting the patient’s sleep before recommending treatment.
When Should You See a Sleep Specialist?
Consider speaking with a sleep specialist if you regularly experience:
Daytime fatigue despite allowing enough time for sleep
Unrefreshing sleep
Frequent awakenings without a clear cause
Snoring, labored breathing, or nighttime choking
Morning headaches or dry mouth
Trouble concentrating during the day
Insomnia that has not improved with routine care
Persistent symptoms after a negative or inconclusive home sleep test
Difficulty tolerating your current sleep apnea treatment
Seek immediate medical attention for severe breathing difficulty, chest pain, or any other urgent symptoms.
Your Breathing Can Disrupt Sleep Without Stopping Completely
Sleep-related breathing problems are not limited to obvious pauses in breathing. A narrowed airway can force the body to work harder throughout the night, causing repeated arousals that keep sleep from feeling restorative.
Pes gives the sleep physician a direct way to examine that effort. For patients whose symptoms remain unexplained after a routine evaluation, that additional information may help reveal what is happening breath by breath.
If you still wake up tired despite a previous sleep test, schedule an appointment with CSMA. Our clinical team can review your symptoms, discuss your earlier results, and determine whether a more detailed sleep evaluation may be appropriate.
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