CPAP to BiPAP Concern

Hi,

I just finished my first month of employment at a DME, this is my first job since becoming a LPN. In nursing school, we don't cover a ton of specific information about sleep disorders or therapy, just the basics. Perhaps just enough to make us scary lol. I was a bit surprised that I actually got the job instead of a RT, who is undoubtedly better suited for this job. I enjoy my co-workers and the patients very much.

I am concerned about a situation that occurred and I'd like to share it here. My hope is that I can help the patient and become educated at the same time. Here goes:

Patient was set up on autocpap with pressures of 10 and 18. Things were going fine until one night his machine broke down. He called our company and he met with a RN who swapped out his unit for another one. Except...she set him up on a bipap machine. She used the same pressure settings and the patient was happy again. Because the patient was on a "loaner" machine, I ordered him a new autocpap unit and set the pressure according to the Rx, which was the same as the pressure that was on the loaner machine (he brought it in when I set him up on his new autocpap).

The patient has COPD and will also be undergoing heart valve replacement surgery soon; he's very ill.

The very next morning I received a call from the patient. He explained that he could not sleep a wink because the pressure was too weak. He has been insistent that he is supposed to be on BiPAP, not CPAP. I assumed the reason for his confusion was that the loaner machine actually says "bipap" on it, whereas his original unit and the new unit had the word "Auto" on it. I was concerned, so I called his doctor's office and explained the situation. Both the assistant and I scoured his chart for any indication that he had been switched over to bipap without us being alerted to the fact, but all we found was his 2009 sleep study which resulted in a Rx for autocpap at the above mentioned pressures.

The assistant at the doctors office spoke with the on-call doc (of course his main doc is on vacation lol) and I was faxed a Rx for Bipap with a IPAP of 10 and EPAP of 18...the same pressure settings that were Rx'd for his autocpap.

Once I received the Rx, I took the patient's loaner unit back to his house. He was very happy to have it back. I am worried, though. It seems like the pressures would be different for bipap. But like I said, I am new to this entire field. I've lurked for the past month and when I do a CPAP or BiPAP set up and the patient has internet access, I encourage them to come to this site to learn more about there condition and become part of a community.

Any feedback would be appreciated.

Hi - nice to hear of someone from a DME who is conscientious! The difference (among others) between systems is that on Apap, you're set up with a low pressure, e.g. 8, and a higher one, e.g. 12 (narrow is more effective, the low being set at the scripted pressure), whereas on Bipap, you have two as well, but in opposite values, i.e. a high pressure, then the lower one... if you follow (and I think you probably do from what you said), the idea being that exhalation is often at least as much of a problem (beyond the scope of c-flex to fix) as is inhaling.

O'Rilly? wrote:The assistant at the doctors office spoke with the on-call doc (of course his main doc is on vacation lol) and I was faxed a Rx for Bipap with a IPAP of 10 and EPAP of 18...the same pressure settings that were Rx'd for his autocpap.
Any feedback would be appreciated.

I am sure you meant an EPAP of 10 and IPAP of 18 which may in fact be a bit too low for him.

When setting up an auto say at 10-18 ten would be the starting pressure from there it would increase the pressure each time it sensed an event but would not go up higher than 18 (the Max. Press.). So say he had an avg press. of 13 - then he is actually exhaling against 13 (or whatever the pressure increased to) and would certainly notice the difference from a BiPap set to 10.
The 10 on the BiPap would be (the Exhale Pressure) too low and allow events to occur.

HTH if it doesn't reply back with more questions.
You are certainly on a forum to get the answers you need.

Welcome to the BEST forum on the Internet.

fwiw - it is the exhale pressure (EPAP) which does all the work on a BiPap. Cause that is the lowest pressure the airway will see. So when switching from CPAP to BiPap you want to set the BiPap to a pressure that will keep the airway from collapsing. That may be a bit higher than any auto cpap is set too.

The IPAP can be tolerated much easier because you don't really feel it when you are inhaling. The IPAP mainly suppresses Hypops, Snores, & Flow Limitations or precursors to Apneas.

Welcome and congratulations on your new job!

A loaner BiPAP set at 10 and 18 will give very, VERY, V E R Y different treatment than an ordinary autocpap set between 10 and 18. Okay, now the explanation for that:

Any ordinary autocpap set between 10 and 18 will deliver the same inhale and exhale pressure---even though that pressure very gradually migrates up and down throughout the night to address upper-airway obstructions. Some autocpaps give just a little pressure drop on exhale as a comfort measure only. By stark contrast, the loaner BiLevel set at 10 and 18 will deliver 10 cm for each exhale and 18 cm for each inhale. That vast difference between EPAP and IPAP is very different than the gradually changing static pressure that autocpap delivers to stent upper-airway obstruction...

The BiLevel's pressure difference between inhale and exhale is called "Pressure Support" or "PS". And in this case, the patient received BiLevel pressure support of 8cm (again the "PS" value is IPAP minus EPAP). Since the autocpap delivered the same inhale and exhale pressures for each breath, that autocpap machine provided a PS of 0 (or close to 0---depending on exhale comfort settings). By contrast the BiLevel machine's pressure support value of 8cm mechanically offloaded much more Work of Breathing (WOB) than ordinary autocpap ever could with its PS value of 0.

That's what large BiLevel PS values are for: helping with Work of Breathing (WOB) or helping with central ventilation. By contrast the ordinary autocpap, with its PS=0, simply inflates the upper airway with static pressure to address obstruction. So your patient understandably felt very, VERY, V E R Y different treatment between those two platforms. He probably even acclimated to having his COPD breathing assisted by the BiLevel's PS value of 8cm. He probably missed that large 8cm Pressure Support when he went back to ordinary autocpap.

I'm very glad you asked that question! Please check with your patient's prescribing doctor for any followup suggestions. Good luck with your new job!

O'Rilly, others have addressed your question much better than I could, but I wanted to welcome you to the forum. Thank you for doing your best to take good care of your clients, and for referring them to this forum. What you learn by reading here will benefit many people.

Welcome, O'Rilly!! We are delighted to have you join us here.

brazospearl wrote:O'Rilly, others have addressed your question much better than I could, but I wanted to welcome you to the forum. Thank you for doing your best to take good care of your clients, and for referring them to this forum. What you learn by reading here will benefit many people.

Ditto.

And ditto again to:

Slinky wrote:Welcome, O'Rilly!! We are delighted to have you join us here.

Great explanation, -SWS!

rested gal wrote:

brazospearl wrote:O'Rilly, others have addressed your question much better than I could, but I wanted to welcome you to the forum. Thank you for doing your best to take good care of your clients, and for referring them to this forum. What you learn by reading here will benefit many people.

Ditto.

And ditto again to:

Slinky wrote:Welcome, O'Rilly!! We are delighted to have you join us here.

Great explanation, -SWS!

Ditto, Ditto, Ditto --

On all counts.

Welcome, O'Rilly. I look forward to reading your posts and getting to know you here.

Wowza---thank you for the warm welcome and the really awesome explanations. This forum is a veritable treasure trove of wisdom!

The thing that I have a hard time wrapping my head around is the fact that the IPAP is indeed 10 and the EPAP is 18! I understand that on the auto cpap the 10 and 18 were the range of pressure, but I don't understand how it's possible that this patient, who has emphysema, could tolerate a high EPAP. He not only tolerates it, but he says that he feels so much better at night because he can use his (now) bipap. Amazing! It's really weird and I'd love to know by what mechanism this unorthodox setting could be working for him.

O'Rilly? wrote:Wowza---thank you for the warm welcome and the really awesome explanations. This forum is a veritable treasure trove of wisdom!

The thing that I have a hard time wrapping my head around is the fact that the IPAP is indeed 10 and the EPAP is 18! I understand that on the auto cpap the 10 and 18 were the range of pressure, but I don't understand how it's possible that this patient, who has emphysema, could tolerate a high EPAP. He not only tolerates it, but he says that he feels so much better at night because he can use his (now) bipap. Amazing! It's really weird and I'd love to know by what mechanism this unorthodox setting could be working for him.

I agree with your Wowza! Well, there is absolutely no medical reason for an EPAP to ever be set higher than IPAP---let alone 8cm higher. I'm also unaware of any BiLevel machines that would allow EPAP to be set higher than IPAP.

So what model BiLevel machine is that anyway?

I agree, most machines would not allow EPAP greater than IPAP and actually work.... it's possible that it will accept such a setting and then work as a fixed CPAP at the EPAP pressure.

More importantly, the RN committed malpractice by setting him up on a bilevel machine blindly using the autopap settings without consulting the doctor. Clearly he/she did not know what he/she was doing which gives even more credence to the idea that the EPAP/IPAP were not set correctly.

As mentioned above, a bilevel machine is different from, is used differently, and is for different problems than a straight or auto CPAP.

O'Rilly? wrote: The thing that I have a hard time wrapping my head around is the fact that the IPAP is indeed 10 and the EPAP is 18! ...but I don't understand how it's possible that this patient, who has emphysema, could tolerate a high EPAP. He not only tolerates it, but he says that he feels so much better at night because he can use his (now) bipap. Amazing! It's really weird and I'd love to know by what mechanism this unorthodox setting could be working for him.

Assuming his EPAP really is way the heck up there (8cm higher than IPAP!), and assuming your COPD patient really does prefer that.... then my best guess is that the extra back-pressure that EPAP sources does essentially the same thing as PLB: http://www.copd-international.com/library/plb.htm

Regardless, unless the doctor actually ordered those unorthodox settings----rather than the DME shop having mistakenly initiated a request for those settings on a loaner BiLevel---this is a case of a mistake having been made. If you don't understand the long-term consequences of running the COPD patient's machine that way, then I think it's essential to get some pulmo doctor(s) and/or RTs in on this issue of mistaken BiLevel settings. But if a knowledgeable doctor intentionally prescribed those unorthodox settings, then that's another thing altogether IMHO.

But please get those BiLevel settings reviewed by knowledgeable respiratory-trained health workers. Irreversible alveolar stretch, for instance, might be one possible complication with 18cm of expiratory back-pressure---since an advanced emphysema patient's alveoli sacs are unfortunately inelastic. Good luck.

RDawkinsPhDMPH wrote:I agree, most machines would not allow EPAP greater than IPAP and actually work.... it's possible that it will accept such a setting and then work as a fixed CPAP at the EPAP pressure.

More importantly, the RN committed malpractice by setting him up on a bilevel machine blindly using the autopap settings without consulting the doctor. Clearly he/she did not know what he/she was doing which gives even more credence to the idea that the EPAP/IPAP were not set correctly.

As mentioned above, a bilevel machine is different from, is used differently, and is for different problems than a straight or auto CPAP.

I agree that the RN acted in error. The machine he is on is an older Respironics M series. I spoke with my RT trainer about this the other day and he said that he'd never heard of such a setting and didn't know how it could be comfortable for the patient. I'm so intrigued by this that I am going to call his doctors office (yet again lol) and ask if the doc can actually talk to me (instead of the on-call doc, med assistants, etc) and educate me about how this is working for this particular patient. The patient continues to report feeling "great at night" when using his machine and it is awfully hard to argue with success, but still! LOL.

I'm living in CPAP-ville at work; a lot of people are wanting to get set up before the end of the year. I really like doing set ups and I learn so much from my patients. Many of them have been on CPAP before. It's a high stress job (I'm only supposed to spend 50% of my time on CPAP stuff according to company policy) but it's more like 90%. OSA awareness is high in our area; my husband has a sleep study on 12/27. He's had OSA for years but thought that losing weight would alleviate it. Very cool stuff!

O'Rilly? wrote:The machine he is on is an older Respironics M series.

That M-Series is a fairly modern BiLevel---and I'm pretty sure it won't even allow EPAP to be set higher than IPAP. Once EPAP increments reach the same value as IPAP during clinician setup, the EPAP and IPAP values simply increment together in CPAP mode---if I recall correctly. Bear in mind that my recall is not the best...

But I'm back to thinking the RN probably mechanically offloaded your COPD patient's Work of Breathing (WOB) with a common and positive PS value of 8cm:
http://scholar.google.com/scholar?hl=en ... =&as_vis=0