Obstructive Hypopnea, or just, Hypopnea basically means shallow breathing. A hypopnea is when a person is actively trying to breathe, but there is an obstruction that is preventing air from getting into the lungs. This differs from an Obstructive Apnea in that some air is able to get through. The breathing that is allowed is so low, that the effect is the same as an Obstructive Apnea. The obstruction is caused by some type of tissue blocking the airway.
Eventually the blood oxygen level (SpO2) drops, heart rate spikes, and the patient will wake gasping for air often with a snore or a snort. Often the awakening isn’t remembered and they go right back to sleep only to repeat this cycle throughout the night. This can be successfully treated with CPAP.
To the right are several examples of Obstructive Hypopneas (hypopneas or OSH) The belts that are around the chest and abdomen are still moving indicating they are trying to breathe. “Flow” is the sensor that shows breathing. You can see that this patient is still breathing, but that it is less that periods where the patient wakes. The C3,C4,O1, and O2 signals speed up, and the Chin electrodes (EMG2-EMG3) increase. The breathing also resumes at this point. The oxygen level drops by 4% or greater.
It is fair to say that a Hypopnea is just a lesser form of an Apnea, where breathing stops completely. Please don’t think that this diminishes its severity. These still prevent oxygenation of your brain and heart, which kills cells, causes your heart rate to increase, and causes you to wake feeling extremely tired.
The images to the right show clear Hypopneas. These are all 2 minute examples, so you can see how each hypopnea develops and can cause tremendous disruptions to sleep consolidation. Click on the image for a faster loading, but grainy picture. Or click on the Blue icons for the same picture in a much higher resolution. May take 10-30 seconds to completely load depending on your connection speed.