cpap-bipap for copd-severe emphysema?

This forum has been so helpful to me in my first month of therapy. Have a question about emphysema and therapy. My husband's doctor just recommended a sleep study for him due to difficulty sleeping and a few other symptoms and said his pulmo would take charge of that. He is one who has great difficulty getting rid of co2 with just normal breathing, gets into serious trouble often with shortness of breath on little exertion or coughing, almost passing out at times. So..I'm worried that the constant air flow in and trouble getting air out that cpap might be harmful. We just assumed his trouble sleeping came from his respiratory problems and it would be great if therapy could help his sleeping and fatigue. I don't fully understand bipap, but wonder if the help breathing out can help severe cases. eHe has seen the great change in me since being on cpap, I am scared he could get in a bad situation and know someone here can provide reassurance and info. Thanks so much.

if you husband has copd-severe emphysema, he needs to stick to the advice from his Pulmonologist doctor as his case is way too severe for any advice from a website.

I agree wholeheartedly with Snoredog. Once your husband has actually had the PSG (and if it is determined he has sleep apnea) his doctor will prescribe a machine based upon the test results and your husband's medical conditions. If you have any doubts as to the doctor's experience in this matter, I'd suggest getting a second and third opinion (with sleep study and medical records in hand). The doctor would be the one to know which machine is best. By all means, tell him your concerns and ask about bi-level therapy. He should be able to tell you why it is or isn't the best alternative and allay your fears about getting the right type of treatment.

Found this interesting article regarding COPD and CPAP:

http://www.jems.com/jems/31-11/243901/

I appreciate both responses. I found the article very interesting. I will be anxious to find out how much his pulmo doc deals with cpap treatment for lung problems. It will be quite a journey, I'm sure. Thanks again.

You might want to be a little careful of the statement in JEMS where they say:

Chronic obstructive pulmonary disease (COPD) is another condition often treated with CPAP.

because this reference is in regards to treating the acute exacerbation of COPD (acute respiratory failure), and these guys are putting patients on a somewhat arbitrary setting of CPAP (course, they have a paramedic continuously monitoring them with about $10,000 worth of technology, so maybe it's not that arbitrary).

Anyway, right, you need to get that PSG before you can even start considering any kind of plan. However, to respond directly to your question:

Nocturnal BiPAP is not generally recommended for the routine treatment of COPD in the chronic, stable state. However, nocturnal BiPAP may be effective in COPD with substantial CO2 retention (like maybe about >55 mmHg).

The co-existence of COPD and OSA is termed Overlap Syndrome, and BiPAP (or CPAP) is probably very beneficial in that case.

If, after pressure therapy has been instituted and oxygen levels remain low, then supplemental oxygen is necessary.

If there's a history of blebs, bullae or pneumothorax, the use of improperly-applied pressure therapy will get you into BIG trouble REALLY quick.

Successful treatment of the Overlap Syndrome requires a physician skilled in both Sleep and Pulmonology, since there will probably be multiple goals, none of which should be overlooked. These goals will include pCO2 management (and you can go too far either way), OSA management, COPD management, and other underlying causes of sleep fragmentation.
SAG

Good information to be aware of. He has had 3 pneumothorax with 2 surgeries. He has blebs, large bullae and damage in lower and upper lobes. Too much damage for LVRS which was our hope this summer and not bad enough for transplant also FEV is 38. He makes oxygen just fine, its the co2 retention that rules his life. He's only 56 and what a price to pay for smoking. Any hope for quality of life improvement is explored, so when dr. recommended sleep study, I started asking questions. Meds don't do a great job but helps. I guess I logically questioned if he can breathe air in and has trouble getting rid of co2, would forced air in be safe. I don't quite know the mechanics of bipap andhow or if it helps get air out or just makes breathing out easier. Thanks for info.

Well, it boils down to figuring out what you're trying to fix, then getting a plan together how to fix it. Getting PSG results will, of course, be helpful. Then you can see if there's an OSA component than can be addressed, as well as seeing what nocturnal oxygen levels do. BTW, what's his pCO2 level? That is probably the best gauge of determining improvement with nocturnal BiPAP.

In 20 words or less, BiPAP is simply pressure therapy that starts out with a baseline pressure (like your CPAP, only now it is termed EPAP), but then applies bursts of pressure to support inspiration. The peak of this pressure burst is termed IPAP. These pressures can be adjusted independently, and here's where treatment philosophies diverge in the treatment of OSA vs some sort of respiratory failure.

If you're addressing OSA, then EPAP is increased to take care of apneas (total closure, or near total closure of the airway), and IPAP is increased to take care of hypopneas (partial closure of the airway), flow limitations and snoring.

If you're addressing respiratory failure, then EPAP is set at a minimum level, and IPAP is increased until a desired volume is supplied to the lungs. So an IPAP pressure could be considerably higher in this case, and it's the pressure differential between EPAP and IPAP that supplies the volume. The bigger the differential the higher the resulting volume.

OK, how this relates to COPD. In acute exacerbations of COPD, respirations become shallow and rapid, so BiPAP is the first-line attack in the ED because it will increase the individual breath volume. It's much tougher to gain benefit in stable COPD because the volume of each breath may be normal, or near-normal, but much of the breath goes to areas of lung that don't do anything, CO2 is not exchanged, and this becomes "wasted ventilation." Or technically, increased dead space ventilation or Vd/Vt. A normal Vd/Vt is about 30% (only 30% of each breath is dead space) but Vd/Vt in COPD can be about 60%. You can jack up the amount of each breath (tidal volume) with BiPAP, and thus temporarily reduce pCO2, but the disease state remains unchanged.

Which brings us to what good is nocturnal BiPAP. In severe COPD, with pCO2 in the neighborhood of pCO2 >55 mmHg, nocturnal BiPAP may afford the respiratory muscles some rest, and permit a little more energy during the day. In addition, there could be a residual drop in daytime pCO2. Studies, or summaries of studies, will typically say something like:

COPD
In contrast to the consistently favorable results of studies on the use of NIV in patients with restrictive pulmonary disease, those on patients with severe obstructive lung disease yield conflicting results. A review of these studies is beyond the scope of the present study. However, the long-term follow-up study by Leger et al found not only a sustained reduction in PaCO2 in patients with severe COPD but also a significant drop in hospital days for 2 years after starting NPPV. A similar finding was recently reported by Janssens et al who found that NPPV decreased the number of hospitalizations for cardiac or respiratory failure in patients with hypercapnic COPD for up to 2 years and thus may improve QoL. These latter studies suggest that the effect of NPPV on health resource utilization in severe COPD deserves examination. The conflicting results of studies on the use of NIV for severe stable COPD make it virtually impossible to assemble guidelines based on solid evidence. Nevertheless, a number of inferences can be drawn. First, NPPV appears to be well tolerated in this patient population. Ease of administration, potentially favorable effects of EPAP on intrinsic PEEP and work of breathing, as well as the ability to eliminate obstructive sleep apneas (overlap syndrome, present in 15% of COPD) makes NPPV the noninvasive mode of first choice. Patients with little or no CO2 retention, regardless of the severity of airway obstruction, appear to gain little or no benefit from NIV. This may be because these patients tend to have less nocturnal hypoventilation and fewer episodes of sleep-disordered breathing in the first place, and have less to gain from nocturnal ventilatory assistance. Also, respiratory muscle fatigue is probably not an important contributing factor at rest during periods of clinical stability. Rather, the studies suggest that if any patient subpopulation is likely to benefit, it is those with substantial daytime CO retention. This contention is supported by the fact that average initial PaCO2 values were 10 mm Hg higher (57 vs 47 mm Hg) among studies using negative pressure ventilation that showed a clinical benefit compared to those showing none. In conclusion, although the evidence is conflicting and far from definitive, COPD patients with severe CO2 retention appear most apt to respond favorably to nocturnal NPPV.

From Contribution of polygraphy and polysomnography to nocturnal monitoring of patients with obesity-hypoventilation syndrome (OHS) and non-invasive ventilation (NIV) by Dr Yan Fei Guo at University of Geneva 2004

If there does turn out to be an OSA component, and there is an Overlap Syndrome, then that will have to be factored in as well. And obviously, it will up to your physicians to determine the risk/benefit of pressure therapy vs additional barotrauma.

But a good example of how not to go about it was posted here by Slinky (and thank you Slinky, because that information will be critically important to a lot of people):

The Slinky Experience

So anyway, you may have a ways to go before you decide on the treatment approach.
SAG

SAG,
I can't thank you enough for the explanations. I learned some new terms, pitfalls, benefits (maybe) for pursuing the possibility that pap might help from reading and rereading your reply. I have a better understanding of the bipap, the precariousness of any therapy with multiple fronts to consider. Hubby is very good at reckoning the risk/benefit balance for a quality of life improvement. Your reply will be useful to me for understanding the process as he goes through it. Many thanks.

Glad to help in whatever small way.

As RG would say, that's one big potful of grits you've got to cook there.

Good luck.
SAG