Obesity hypoventilation syndrome (OHS) is a condition that occurs in obese people, in which poor breathing leads to lower oxygen levels and higher carbon dioxide levels in the blood.
The exact cause of OHS in unknown. Most (but not all) patients with the syndrome have a form of sleep apnea.
OHS is believed to result from both a defect in the brain's control over breathing, and excessive weight (due to obesity) against the chest wall, which makes it hard for a person to take a deep breath. As a result, the blood has too much carbon dioxide and not enough oxygen. People with OHS are often tired due to sleep loss, poor sleep quality, and chronic hypoxia.
Excess (morbid) obesity is the main risk factor.
See also: Respiratory acidosis
The main symptoms of OHS are due to lack of sleep and include:
Symptoms of low blood oxygen level (chronic hypoxia) can also occur, such as shortness of breath or feeling tired after very little effort.
People with OHS are usually very overweight. Symptoms of OHS include:
Tests to confirm OHS include:
Doctors can tell OHS from obstructive sleep apnea by high carbon dioxide levels in the blood when a person is awake.
The treatment involves breathing assistance using special machines (mechanical ventilation). Options include:
Other treatments are aimed at weight loss, which can reverse OHS.
Support groups can help patients with OHS, or their family members, adjust to the lifestyle changes needed for treatment to be successful. Also, support groups can offer information about new treatments.
Untreated, it can lead to serious heart and blood vessel problems, severe disability, or death. Chronic sleeping problems may also increase the chance of having a motor vehicle accident.
Complications of OHS have to do with a lack of sleep, such as:
OHS can also include heart problems, such as:
Call your health care provider if you are very tired during the day, or have any other symptoms that suggest OHS.
Maintain a healthy weight and avoid obesity.