(03-20-2014, 07:45 PM)3porpoise Wrote: So how does the epap, insp press and exp press and min and max pressure support all work? Is the max number for the central component? And the Insp. and Exp press. ( epap)for Obstructives?
Hi 3porpoise, welcome to the forum!
Sounds like your machine had a modem attached, and the respiratory therapist slowly adjusted the EPAP from 4.0 to 6.0, in increments of 0.2, right?
In case you have not yet found answers to your questions:
With most CPAP/APAP/BiPAP machines the EPAP setting needs to be high enough to prevent obstructive events like apneas and hypopneas, but with an ASV machine this is perhaps less important, because the machine will do what it can to keep you breathing even if the EPAP is lower than would be optimal for preventing obstructive events.
Newer S9 VPAP Adapt machines manufactured in Nov 2012 and later can automatically adjust the EPAP within a range (like the AutoSet and other APAP machines adjust EPAP) to minimize obstructive events. My S9 VPAP Adapt (Model# 36007) was built earlier than that and the EPAP does not auto-adjust (only the Pressure Support auto-adjusts).
The difference between EPAP (exhale pressure) and IPAP (inhale pressure) is called Pressure Support (PS):
EPAP + PS = IPAP
On your machine, is it the average PS which is 6.8, or is it the minimum PS which is 6.8, or the Max PS?
The minimum amount of PS (Min PS) is usually adjusted for comfort, but the Min PS also tends to increase/decrease the minimum amount of ventilation we receive, and therefore affects the minimum Saturation Percentage of Oxygen (SpO2) during deep sleep. It is common to have Min PS of 2.0 or 4.0, but if a person has a lung condition or disease, then the Min PS may need to be 6 or higher to maintain good SpO2 while asleep.
It is widely recommended that the SpO2 remain between 94 to 96, but it is not uncommon to dip into the low 90s while asleep, and this is not considered a problem. 88 and lower is considered a problem. 98 and higher can lead to problems if the SpO2 stays that high for long periods, like perhaps hours. Too much O2 can harm our health.
It is recommended to wear a recording pulse oximeter all night (but only occasionally), to see whether our SpO2 tends to be too low or high. The kind that are mounted on the wrist like a watch and have a separate finger sensor are far more comfortable and tend to stay on better and give more consistent results.
I think the Max PS should be set at least 10 (eventually) but may be set lower temporarily while adjusting to therapy. Or, if the patient has a special condition (recent lung or nasal surgery, for example) it might be necessary to have the Max PS much lower than 10, but for healthy patients 10 or higher may be needed to allow the machine to keep them fully ventilated and fully prevent central apneas or central hypopneas.
During a central event, the machine will automatically (and quickly) adjust PS so that a target Minute Ventilation (Vm) is maintained. Vm is the amount (volume) of air we inhale or exhale in one minute. The tidal volume (Vt) is the amount (volume) of air we inhale or exhale during one breath. The Flow is the rate (rate = volume per unit of time) at which air is being inhaled or exhaled.
With the S9 VPAP Adapt, during central events the Target Vm and Target Respiratory Rate (breaths per minute) which the machine targets are automatically chosen by the machine, based on the characteristics of our very recent breathing. There are no settings for target Vm or target backup respiratory rate. However, the Min PS setting will have an indirect influence on the Target Vm. A higher Min PS will tend to increase Target Vm.