01-18-2024, 04:01 PM
RE: Palate prolapse breathing pattern ?
Vcom is a flow restrictor. The intent is to mellow out the peak flows delivered by the machine on inspiration when there is a pressure drop from airflow but the machine boosts output to compensate for that pressure drop. The Vcom is invisible to the blower, and so when you inhale it allows the flow into your mask to cause that natural pressure drop independent of the machine's supply pressure.
On exhale, it restricts flow from going back into the hose. As such, the pressure inside your mask will be slightly higher than the CPAP supply pressure, because there is a resistance to flow that produces the same kind of pressure drop in reverse. The placement between mask and tube also ensures that CO2 is discharged from the mask vent as it should be.
Palatal prolapse is an expiratory phenomenon. EPR tends to increase the peak expiratory flow because expiration is largely passive. The body does not force the air out, it just relaxes all the respiratory muscles and the thoracic cavity returns to its normal size. The air goes out on its own, which happens more vigorously when the machine backs off the EPAP so that it is less than the pressure delivered to your system when you inhaled. This increase in peak flow makes it more likely for the soft palate to slam shut against the back of the nasal cavity when you are trying to exhale.
What the effects of Vcom mean for people with palatal prolapse is that the peak expiratiory flow may be slightly reduced because a high peak flow is subject to a pressure drop. Assuming EPR is off, supply pressure is constant on the machine side of the Vcom, and slightly higher than this inside the mask and respiratory system. This makes it take longer for the lungs and chest to passively return to their relaxed size. All of the work is done by the natural elasticity of your ribs and diaphragm. Think of it like letting the air out of a balloon: if you put a smaller nozzle on the balloon, the air will still come out, but it won't happen quite so fast, especially at the beginning of the process. This may give you a better chance of keeping your palate where it belongs.
On exhale, it restricts flow from going back into the hose. As such, the pressure inside your mask will be slightly higher than the CPAP supply pressure, because there is a resistance to flow that produces the same kind of pressure drop in reverse. The placement between mask and tube also ensures that CO2 is discharged from the mask vent as it should be.
Palatal prolapse is an expiratory phenomenon. EPR tends to increase the peak expiratory flow because expiration is largely passive. The body does not force the air out, it just relaxes all the respiratory muscles and the thoracic cavity returns to its normal size. The air goes out on its own, which happens more vigorously when the machine backs off the EPAP so that it is less than the pressure delivered to your system when you inhaled. This increase in peak flow makes it more likely for the soft palate to slam shut against the back of the nasal cavity when you are trying to exhale.
What the effects of Vcom mean for people with palatal prolapse is that the peak expiratiory flow may be slightly reduced because a high peak flow is subject to a pressure drop. Assuming EPR is off, supply pressure is constant on the machine side of the Vcom, and slightly higher than this inside the mask and respiratory system. This makes it take longer for the lungs and chest to passively return to their relaxed size. All of the work is done by the natural elasticity of your ribs and diaphragm. Think of it like letting the air out of a balloon: if you put a smaller nozzle on the balloon, the air will still come out, but it won't happen quite so fast, especially at the beginning of the process. This may give you a better chance of keeping your palate where it belongs.
Look, I'm an engineer, not a doctor! Please don't take my opinion as a substitute for medical advice.
