Standalone humi disrupts auto algorithm?

[Wulfman]

This is from the Legacy model REMstar Pro 2 and Auto manual. (obviously using their own humidifier models)

Pressure Drop with Humidifier - 0.3 cm H2O @ 20 cm H2O

That ain't much at 20 cm. of pressure. I doubt that there would be much if any difference going through an HC150. On the other hand, they're using a straight pressure setting. And, in that context (CPAP mode), once you fill the circuit (hose, tank and mask) with air pressure, there shouldn't be much loss. The only things I've wondered about were the event detection in both CPAP and APAP modes and response time/capability in Auto mode.

Den

[rested gal]

Anecdotal reports that "I have had no problem" hardly constitute evidence-based science.

You're absolutely right, Velbor.

In the meantime, in the contraindication you quoted, I kind'a lean toward what you said here:

Might they simply not want to ASSUME that it will work fine, or not want to go through the bother of PROVING that it does work fine? Do they just want to avoid liability issues?

[deerhound]

Just looking at the design of the Remstar Passover Humidifier, which is recommended for use by Respironics on most Remstar CPAP and BiPAP machines according to the instruction manual I cannot see where there is much difference in air and water volume in the tank and what is in the HC150. Since Respironics deems the Remstar Passover Humidifier acceptable for use on most of their machines I don't think the HC150 would have any different effect on the workings of the machines. Both are coupled to the machine by a short length of hose and have considerably a larger volume inside the tank than the integrated humidifiers.

Dale

[Guest]

I was on hc150 for months. Numbers were always consisten, AHI around 1.2. Read this post and decided to go back to my attached humidifier with my auto and first night wasn't good. I know, I know, 1 night doesn't mean squat, but ...... I'll stay on it for a week and see. My AHI jumped up to 2.9 last night for some reason.

[sagesteve]

Yes Dreamstalker...we do know CRAP about---Oh, I'm sorry, CPAP ( go the letters mixed up).

[Velbor]

While looking (unsuccessfully) for patent information regarding the Fisher & Paykel Ambient Tracking system, I came across the FDA 510(k) application and approval documents for the HC150 humidifier:

http://www.fda.gov/cdrh/pdf/k003973.pdf

It is interesting that in F&P's "Indications for Use Statement", the last page of this .pdf file, the company states, seemingly out of the blue, "The HC150 is not for use with auto-titrating positive pressure systems."

This issue is not addressed at all in F&P's application's "Statement of Intended Use", nor in their discussions of testing, nor in FDA's approval letter.

I find this surprising and puzzling, particularly since it is all in reference to the HC150 itself, without mention of any particular humidification chamber. It will surely not deter me from continuing to use my F&P humidifier with AutoPAP. But I do wonder where this comes from. Velbor

[MrSandman]

While looking (unsuccessfully) for patent information regarding the Fisher & Paykel Ambient Tracking system, I came across the FDA 510(k) application and approval documents for the HC150 humidifier:

http://www.fda.gov/cdrh/pdf/k003973.pdf

It is interesting that in F&P's "Indications for Use Statement", the last page of this .pdf file, the company states, seemingly out of the blue, "The HC150 is not for use with auto-titrating positive pressure systems."

This issue is not addressed at all in F&P's application's "Statement of Intended Use", nor in their discussions of testing, nor in FDA's approval letter.

I find this surprising and puzzling, particularly since it is all in reference to the HC150 itself, without mention of any particular humidification chamber. It will surely not deter me from continuing to use my F&P humidifier with AutoPAP. But I do wonder where this comes from. Velbor

There you go So you think you know more than the engineers or manufacturer than accept your possibly faulty response when used with an auto

[dsm]

I've used a HC100 & HC150 with ...
PB330 Knightstar Bilevel
Remstar Auto
Resmed S6
S7 Spirit
Healthdyne Bilevel
Healthdyne Auto
Healthdyne Quest Cpap
Polaris Cpap

All worked to my satisfaction - I think the person advising you may not have tried them himself & was a bit reticent

Good luck

DSM

[Velbor]

The previously-referenced labeling against the use of stand-alone humidifiers with AutoPAP machines does appear to have a simple explanation, regulatory in nature rather than having anything to do with actual performance, and driven by business strategists rather than by scientists, engineers, or clinicians.

In September 2001 Fisher & Paykel Healthcare split off from Fisher & Paykel Appliances. An Information memorandum issued at that time provides considerable insight into F&P’s business position and strategy:

http://www.fphealthcare.com/investor/im/fph_im_full.pdf

(As an aside, note on .pdf file page 18 that the HC100 humidifier was introduced in 1992. Please cross-reference with comments in the thread:
viewtopic/t40236/Business-History-of-ResMed-Link.html
Also as an aside, note on document page 21 – .pdf page 22 – the discussion of intellectual property issues and patents.)

The material relevant to the current issue appears on document page 22 (.pdf page 23):

The FDA requires that a manufacturer introducing a new non-exempt medical device or a new indication for use of an existing medical device obtain either a Section 510(k) pre-market notification clearance or a pre-market approval, called a PMA, prior to it being introduced into the market. The healthcare business has received 510(k) pre-marketing clearance for each of the products currently marketed in the U.S. The PMA process, which is reserved for new devices that are not substantially equivalent to any predicate device and for high risk devices or devices that are used to support or sustain human life, may take several years and would require the healthcare business to submit extensive performance and clinical information. The healthcare business has not sought PMA for any of its products.

The process of obtaining Section 510(k) clearance generally requires the healthcare business to submit performance data and possibly clinical data, which in some cases can be extensive, to demonstrate that the device is “substantially equivalent” to a device that was legally marketed prior to 1976, a device that the FDA has found to be “substantially equivalent” to a pre-1976 device or has specifically exempted, or a device that has obtained Section 510(k) clearance. To demonstrate substantial equivalence, the healthcare business is required to show that the device is as safe and effective and has the same intended use as one of these devices. Fisher & Paykel Healthcare has received Section 510(k) clearance for a total of 37 products, over a period of approximately 19 years. It currently has one Section 510(k) application pending approval with the FDA and is in the process of preparing an additional four applications for submission. FDA clearance may take a considerable length of time and may, in some cases, involve additional review by an advisory panel, which can further lengthen the process. Fisher & Paykel Healthcare generally expects the FDA to approve its applications within 180 days, although they have experienced approval periods of over 600 days in the past.

Thus, as a business strategy, F&P has, as a matter of course, NOT sought approvals for its humidifiers as new devices, but rather has demonstrated that new equipment, regardless of “bells and whistles,” is “substantially equivalent” to pre-1976 devices. And therein lies the rub.

F&P requested (and FDA agreed) that the HC150 would be classified as a “Humidifier, Respiratory Gas (Direct Patient Interface), Anesthesiology Devices, Class II”. The full quotation of F&P’s approved 510(k) “Indications for Use Statement” from the source previously cited reads:

http://www.fda.gov/cdrh/pdf/k003973.pdf

The Fisher & Paykel Healthcare HC150 Humidifier is a Respiratory Gas Humidifier as per 73 BTT, 21 CFR 868.5450. It is intended to add moisture to and warm breathing gases for administration to a patient.

The HC150 is intended to be used to warm and add humidity to gases delivered to patients requiring positive pressure breathing assistance including Continuous Positive Airway Pressure (CPAP) therapy and Bi-Level Positive Airway Pressure therapy. The HC150 is not for use with auto-titrating positive pressure systems.

FDA Regulations and guidance documents, not illogically, hold that “substantial equivalence” certifications for pre-1976 devices can only apply to those “indications for use” of the product which were also in existence pre-1976:

http://www.fda.gov/CDRH/DEVADVICE/314.html

What is Substantial Equivalence
A 510(k) requires demonstration of substantial equivalence to another legally U.S. marketed device. Substantial equivalence means that the new device is at least as safe and effective as the predicate.
A device is substantially equivalent if, in comparison to a predicate it:
• has the same intended use as the predicate; and
• has the same technological characteristics as the predicate;
or
• has the same intended use as the predicate; and
• has different technological characteristics and the information submitted to FDA;
o does not raise new questions of safety and effectiveness; and
o demonstrates that the device is at least as safe and effective as the legally marketed device.
A claim of substantial equivalence does not mean the new and predicate devices must be identical. Substantial equivalence is established with respect to intended use, design, energy used or delivered, materials, chemical composition, manufacturing process, performance, safety, effectiveness, labeling, biocompatibility, standards, and other characteristics, as applicable.

More specifically, applicable sections from the Code of Federal Regulations include statements that:

“If FDA knows that a device being commercially distributed may be a “new” device as defined in this section because of any new intended use or other reasons, FDA may codify the statutory classification of the device into class III for such new use.” 21 CFR 868.3: FDA, Anesthesiology Devices, General Provisions.

Special regulations are applicable if:

“The device is intended for a use different from the intended use of a legally marketed device in that generic type of device; e.g., the device is intended for a different medical purpose” 21 CFR 868.9(a), FDA, Anesthesiology Devices, Limitations of Exemptions from Section 510(k)

Thus, while CPAP as a treatment for OSA was still several years away in 1976, the humidification of medical respiratory gasses, and critical-care use of “continuous positive airway pressure” (CPAP, or then commonly PEEP “positive end-expiratory pressure”) devices, and “bi-level” ventilation, were in use for “substantially equivalent” devices. The concept of “auto-titrating pressure systems,” however, had not yet been developed.

The clearest “official” statement to this point that I have found is a Medicare Decision Coverage Memorandum for CPAP, dated 30 October 2001:

FDA Approval/Clearance
CPAP, BiPAP and related devices have been considered and cleared for marketing by the Food and Drug Administration (FDA) under a 510(k) process. The 510(k) is a notification of intent to market a specific device. The FDA has determined that certain CPAP and BiPAP devices are "substantially equivalent to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act."

Note that AutoPAP devices are not included in this statement.

One of the cleverest wordings I have seen to deal with this situation is in the 2004 510(k) application for the TAGA Velocity Humidifier: “Not recommended for use with auto-titrating (adjusting) CPAP device unless otherwise stated by the CPAP device.” thus throwing the ball back into the AutoPAP manufacturer’s court.

In summary, if a manufacturer (and F&P is not alone in this) claimed that a device could be used with AutoPAP systems, it would be a substantially new and different medical use than the predicate pre-1976 devices, and would require significant time delays and financial expenditure to provide proof of safety and efficacy before US marketing would be allowed. There is no evidence of ANY DATA to suggest problems with humidifier and AutoPAP use. By simply “writing out” the use of the humidifier for AutoPAP applications, manufacturers achieve great business benefit. Particularly when no one pays much attention to, let alone actually sees, such official labeling, anyway.

Velbor

[OldLincoln]

My wife & I just spent a few days visiting out of town and as usual I did not take my HC150. The morning after our first night my wife said my APAP didn't sound right. The second night I felt it change pressure for the first time, a definite 3 pulses when I held my breath. It never did that before or since we got home.

My scores looked OK for the trip so it must have been the lack of a humidifier made it sound different. But actually feeling the 3 pulses tells me something is different. You might check it out.

[MrSandman]

Back from 2005 - read this thread: viewtopic.php?f=1&t=812&p=4321&hilit=+h ... auto#p4321

[DreamStalker]

Back from 2005 - read this thread: viewtopic.php?f=1&t=812&p=4321&hilit=+h ... auto#p4321

Of course Respironics technical support staff is going to say HC150 is not recommended for use with their machines .... F&P is their competitor

The HC150 works just fine with a Respironics machine and I have 2 and a half years proof that it does ... and NO I haven't been faked out!!

It is like a DME saying that cpap.com is not an approved apap distributor cuz they sell apaps to anyone who has a cpap Rx.

[OldLincoln]

Back from 2005 - read this thread: viewtopic.php?f=1&t=812&p=4321&hilit=+h ... auto#p4321

My former DME called Tech Support for that same question. She said they told her they hadn't tested it and so they recommend against it.

It they haven't tested it they really don't know. I wish they would test it and clear this up once and for all.

[-SWS]

Definitely an interesting discussion. I'm thinking about just how many years those external humidifiers and APAP algorithms have existed together in the market place. And the APAP manufacturers have undoubtedly encountered all the major third-party external humidifiers again and again throughout those years.

If those third-party humidifiers were genuine APAP efficacy spoilers, don't you think by now there would be some prominently displayed safety text to warn clinicians and patients of manufacturer-observed humidifier perils?

Instead the manufacturers just mention, but only in passing, that their own auxiliary equipment should be exclusively employed. I think it's possible that some wave shape signals out near the margins of signal detection can, indeed, get dropped. However, I really don't suspect that scenario turns out to be an APAP efficacy spoiler in most cases. Why? Because APAP algorithms by design must cope with an entire variety of equipment combinations imposing equally slight signal skew.

[MrSandman]

Back from 2005 - read this thread: viewtopic.php?f=1&t=812&p=4321&hilit=+h ... auto#p4321

Of course Respironics technical support staff is going to say HC150 is not recommended for use with their machines .... F&P is their competitor

The HC150 works just fine with a Respironics machine and I have 2 and a half years proof that it does ... and NO I haven't been faked out!!

It is like a DME saying that cpap.com is not an approved apap distributor cuz they sell apaps to anyone who has a cpap Rx.

You been faked out,you been faked out - anyway I was saying the machine could have been faked out with a smoothing of the flow curves and such... Who knows. If you feel good than that is what matters!