of the ‘soft palate’ (roof of the mouth) blocks one’s air entry. Sleep apnea can cause choking, alarm and arousal followed by deep inspiration. Once one settles back to sleep, the process then repeats.
Sleep apnea causes significant sleep interruption with low oxygenation and an accumulation of blood carbon dioxide. Effective treatment of the condition can be achieved by feeding air into the mouth and nose at a positive pressure while sleeping. A fan assembly then feeds air at a raised pressure to a sealing face mask over the nose and mouth. The higher pressure prevents the person’s soft palate from collapsing, and reduces sequential airway blockages.
With a CPAP machine, the person has to work harder to exhale against the increased air-delivery pressure. A more sophisticated version of this type of machine (which has also been developed for home-use) drops the pressure of air delivery as expiration starts, while increasing it again for the next breath. These dual- pressure devices (BiPAP machines) use a sealing face mask to deliver oxygenated air to the lungs. BiPAP machines provide passive ventilation.
Passive ventilation with a BiPAP machine can be of significant benefit to a COVID sufferer who has compromised lung function. This is because the raised air pressure keeps the lungs better aerated, and reduces collapse of the alveoli. Passive ventilation can also lower fluid exudate into the lungs. While not as effective as full, active ventilation CPAP and BiPAP machines are much cheaper and easier to fit. And, as there is no throat tube, the person receiving the passive ventilation is conscious and can still communicate.