What is polysomnography you ask? It is a medical sleep study device. A patient wears sensors in order to detect sleep apnea. Polysomnography is a multi-parametric machine. Each sensor detects specific aspects of your sleep such as EEG, ECG, EMG, EOG and Oxygen saturation (SpO2). EEG stands for electroencephalography which measures and records brainwaves. The ECG, electrocardiography, follows your cardiac electrical activity. The EOG, electrooculargraphy, monitors eye movements and rapid eye movements (deep sleep). The EMG, electromusculargraphy, evaluates electrical activity of the skeletal muscles. We must mention that the polysomnography is used to find out if a patient's sleep apnea is neurological or obstructive or both. We use an oximeter to measure non-invasively your heart rate and your oxygen saturation in your blood. We sometimes use the oximeter as a pre-polysomnography. Oximetrie is simple test to see if it warrants a more extensive exam like polysomnography. Oximetrie is a good indicator to detect sleep apnea or to rule it out, but it does not tell us if sleep apnea is neurological or obstructive or both. We will need the polysomnography for specifics.

We will apply sensors on your scalp and temples in order to pick up brain waves and rapid eye movements. Microphones near your mouth and nose to record snoring. It can be done at a sleep laboratory or at home. Ambulatory polysomnography is recent. Technology has enabled patients to bring the polysomnography exam at home, thanks to advances in technology such as smaller and lighter devices with virtual storage. A patient brings the device home for one night. He or she follows the directions and installs the sensors and goes the bed with the activated device. The next morning, the patient brings it back to the sleep laboratory. The technician uses a computer to retrieve all the events that occured during the night while the patient slept. The data is compiled. The doctor interprets the polysomnogram and sees if the patient suffers indeed from sleep apnea or if it should be ruled out. If the doctor concluded that the results are positive, he or she will prescribe a cpap machine that will push continuous positive airway pressure when the patient sleeps.

The cpap will need to be worn every night for the rest of our life if we want to avoid sleep apnea. It will take some time to adapt to the small noise and air pressure. It can take days, weeks or even months before we can get a really good night sleep. The polysomnogram and cpap titration will allow sleep professionals to determine at what pressure the cpap should be adjusted in order to optimize its effectiveness. If you are sick, have nausea or a nose bleed, you need to take the cpap off immediately. Cpap air needs to be humidified at all times with sterile water. The cpap keeps the airway open, so that the soft tissus in the back of your throat does not obstruct air.

Not only does positive pressure keep the airway open, but it also opens up the lungs and recruits additional alveoli. Alveoli are small sacs of membranes in the lungs where oxygen permeates through into the blood stream. You will be able to breath. Oxygen will be able to pass and reach your lungs, heart and cells. If little air travels to your lungs, heart and cells, it will lead to a lack of oxygen to your cells. It can temporarily or permenantly damage your organs such as lungs, heart (heart failure) or other organs. It can be very serious. We must mention also the BIPAP which is similar to the CPAP in some respects. The difference is that the BIPAP pushes more air when you inxhale than when you exhale. The CPAP creates a positive airway pression which remains the same for inspiratory and expiratory movements. The BIPAP varies according to your breathing state. No cure exists for sleep apnea. We can only compensate by using different strategies in order to relieve sleep apnea. We can change our position in bed by sleeping on our side. We can try sleeping with our mouth open. In some cases, surgery may be a solution. We can lose weight if our body mass index is higher than average. For more severe sleep apnea, the cpap is the only option.