Manometer and oxygen monitor recommendations?

[Watchmyswag]

Hello, I’ve been trying to find a solution for my sleep apnea for over a decade and after trying everything I found that a bilevel with backup rate finally gets my AHI down from 35 to 5. I’m a 33 year old male, 6”1 200lbs and have treatment emergent central apnea. My pressure settings are very low, as anything higher causes more central apnea. They are 8/4 with a 10 respiratory rate. I use the dreamwear nasal mask.

Although my AHI is lower, I still feel exhausted every day. The sleep doctors out here only know how to turn pressure settings up, and get confused by central apnea. I’ve had brain MRIs, bloodwork...everything comes back negative.

I do, however, get pretty congested at night so I don’t know if that plays a significant role.

Anyway, I’m convinced my machine is not consistent with the pressure it’s pushing out, even though it says 8/4. I want to get a manometer but I’m not sure which would work with a cpap mask and how to measure it.

I’m also wondering if my oxygen levels are dripping too much, causing me to be excessively tired every day, so I’d like to get a monitor for while I sleep but everything I’m seeing is very expensive (at least the ones that will record data at night are).

Does anyone have any recommendations? Anything else I should be looking into or discussing with my doctor?

[palerider]

Anyway, I’m convinced my machine is not consistent with the pressure it’s pushing out, even though it says 8/4. I want to get a manometer but I’m not sure which would work with a cpap mask and how to measure it.

I’m also wondering if my oxygen levels are dripping too much, causing me to be excessively tired every day, so I’d like to get a monitor for while I sleep but everything I’m seeing is very expensive (at least the ones that will record data at night are).

Does anyone have any recommendations? Anything else I should be looking into or discussing with my doctor?

You can pick up a digital manometer on ebay for under 30$.
Get an oxygen port for your hose, hook the manometer to it. read your pressures easily.

CMS50D+, E, F, and I oximeters all record all night and are relatively inexpensive.

[ChicagoGranny]

Anything else I should be looking into

First step: Follow 1 - 3 (see my signature), get OSCAR and let members look at some of your breathing data.

[Julie]

Have you tried lowering or even omitting humidity - if you're using it because you think it's 'therapy' (vs the comfort convenience it's meant to be) and live in an area where ambient humidity's already high so adding more will congest you?

[LSAT]

Please list your exact equipment in your control panel profile.

[JDS74]

Without getting into the really high priced stuff, a fingertip CMS50 series is the way to go for SpO2 measurement.
https://www.amazon.com/CONTEC-CMS50F-ox ... way&sr=8-3

This one is a little pricy but it can be inline with your machine while you are using it so the results might be more useful.
https://www.cpap.com/productpage/guage- ... r-pressure
This one is a little less:
https://www.cpap.com/productpage/fisher ... 25-chamber

And by searching for manometers:
viewtopic/t97040/Manometer.html?hilit=m ... 15#p899065
Or you could build your own.

[biomed]

I'm a new CPAP user - two months with a Philips Respironics DreamStation APAP. As an occasional servo system designer, I was curious about the control loop's pressure/time profile, too inexperienced to dive into the software and too lazy wire up one of my electronic differential pressure sensors.

One of the simplest means to monitor pressure is a vertical U-tube differential manometer, available new on ebay for US $11.95 (plz see link below), or a big box hardware store for around $25. The U-tube manometer is around a foot long.

Don't bother buying a digital manometer or pressure gauge unless it's an overnight recorder with an analog, digital or chart output. Digital LCD displays don't update quickly enough.

The object is to splice the upper right side of the U-tube into a section of plain old (non-electrically heated) CPAP hose via some 1/8 inch, 3/16 or 1/4 inch ID vinyl tubing. Cut or punch a 1/4 inch hole in the CPAP hose a few feet from the CPAP/BIPAP/APAP end and insert about 1/4 inch of the manometer tubing inside. Seal and strengthen the union with 3 or more wraps of electrical tape.

If you're impatient, you can DIY your own cheap, but accurate manometer with the following, but if your time is worth $$$, you may be better off to spend the US $11.95:

a) a nominal 1.5 inch OD, 10 inch long, stiff cylinder of cardboard, PVC pipe, round or square wooden dowel,
b) 6 or more feet of plain old, unheated CPAP hose. You'll be perforating it in one spot, so don't use expensive hose.
c) 2 feet of 1/4 inch ID clear vinyl tubing,
d) a few feet of masking tape,
e) a few feet of electrical tape,
f) a drop of food coloring or India Ink,
g) to cover a pressure range of 30 cm, a minimum 15 centimeter ruler, computer-or-hand generated scale with 5mm or finer divisions.

The cylinder should be the same nominal size as the cardboard tube inside a paper towel roll, but the paper towel roll is a bit too flimsy and will disintegrate if wet.

Tape the vinyl tubing to the two ends of the cylinder with several turns of tape. Don't squeeze the tubing. Run it straight up the sides of the cylinder, without bulging, bowing or kinking. It should look something like this $11.95 Radon Away Easy Read U-tube manometer:

https://www.ebay.com/itm/Radon-Away-Eas ... 0667.m2042

Fasten the scale to the cylinder with tape or rubber bands, so it can be moved up and down if the measuring liquid slowly evaporates or rises with humidity. For accuracy, the manometer body should always be mounted or held vertically.

Add 1 drop of food coloring, India Ink, etc to 2 ounces of water, then carefully fill the vinyl tube to the nominal middle of the cylinder height. Left to itself, the water level on both sides will be equal.

The "puff" or damping test - if water in a purchased OR DIY manometer is subject to a sudden pressure change, it will likely over-or-undershoot the proper equilibrium value and its level will oscillate up and down several cycles, "underdamped" like a bad shock absorber - hardly conducive to accurate readings. A more viscous liquid or one with greater surface tension would be better-behaved, but its different mass might require scale recalibration.

You can observe underdamped behavior by covering one end of the CPAP hose and blowing a very short puff into the other end. If you puff the water level to rise in the filler end about 1/4 of the cylinder's length, it'll return to equilibrium and oscillate before settling down.

One easy fix - pneumatic or gas damping - cover the filler end of the vinyl tubing with electrical tape. If the end is sealed completely, the water will rise sluggishly with the puff test. Now the process is "overdamped" by compressing the air in the sealed fill end.

To produce near-ideal damping, make a tiny pin hole in the electrical tape. If the hole is the correct size, the rate of air leaving then re-entering the vinyl tubing will provide the proper pneumatic damping, just like the oil orifice in a good hydraulic shock absorber. Since the CPAP blower takes time to spool up and down, a tiny bit of over/undershoot won't effect manometer dynamic accuracy. If you make the hole too large, you'll have to remove the electrical tape and start over.

You can also provide hydraulic or fluid damping by stuffing small pieces of open cell foam at the bottom of the U. If you hydraulically overdamp, it may be difficult to remove the excess foam. You can always use foam for most of the damping and fine tune the remainder with pierced electrical tape - hybrid damping.

Observing the BIPAP/APAP inhale/exhale pressure levels: Mount the manometer vertically and securely. You don't want to spill dye or India Ink on a carpet.

With the BIPAP/APAP off, the humidifier tank empty and your mask off, note and record the water level on the scale. Whatever the reading, this is the zero differential pressure point.

With your mask on, turn on the BIPAP/CPAP and don't breathe for a few seconds. As the pressure increases, the fill or electrical-taped end will rise and the end connected to the CPAP tube will fall by the same amount.

Since the manometer is differential, an 8cm pressure will make the fill or electrical tape end rise 4cm and the other end fall 4cm from the recorded zero value. The difference will be 8cm. A 12cm pressure will create + and -6cm, for a 12cm difference.

Once you start breathing, the manometer should rise and fall to the prescribed inhale/exhale pressures. The speed of pressure rise and fall is set by the design team, the provider, by you or all of you. You can also observe both values rise slowly if the BIPAP/APAP has a time ramp function.

APAP dynamics - notice if you select, say, a 3cm pressure relief and exhale hard or puff, the pressure will drop below the preset exhale value and ramp back up to it. The pressure/time dynamics may change, noticeably, as you puff more or less.

As you inhale, you may notice the pressure ramping to around 90% of prescribed value, then coasting upwards the rest of the way. Again, the pressure/time dynamics have been chosen by the design team, the provider, by you or all of you.

If you have the capability of reading recorded CPAP equipment pressure plots with fine time resolution, (I haven't done it yet), they should behave the same as the manometer.

Since I don't use my humidifier, I suspect the manometer may eventually or quickly fill with water or fog over when the humidifier is on.

Good Luck.

[raisedfist]

Get OSCAR sleep software and post some charts so we can help you optimize your therapy

[biomed]

Please Note - while the pressure sensor in your machine lives in a benign environment, downstream of the air filters and upstream of a possible humidifier, if, on the rare occasion of sensor failure, your machine may think it's regulating to the proper pressure and even present "good" OSCAR data, while it's screwing up. It takes an external pressure gauge, sensor, manometer, calibrated balloon or body part (e.g. a piano tuner's ear) to tell if the machine is malfunctioning.