The long-term effects of CPAP therapy.
Innovations in CPAP and related bilevel and variable PAP therapies continue to reach the marketplace. Some are refinements in pressure delivery, and many are improvements in the interfaces that connect the pressure source to the patient (and keep it there). Consequently, it may be easier than before for clinicians to address the compliance problems that previously created high CPAP dropout rates1 among patients with OSA.
As more patients’ compliance problems are solved, the number who stay with CPAP treatment over long periods of time should be increasing. Long-term CPAP has been associated with varying degrees of benefit and risk. The advantages seen after prolonged CPAP use include weight loss, reduced risk of the major medical consequences of OSA, decreased somnolence, and improved vigilance.2 Mood disorders may or may not be improved.2
Many of the adverse effects reported in the past for long-term CPAP use,3 such as erosions and irritations caused by air flow and the pressure of masks and headgear, can be eliminated by changing the patient interface and its accessories or by trying other PAP delivery protocols. Clinicians should bear in mind, however, that rare (but more serious) adverse effects, such as pneumothorax and other types of barotrauma, have also been reported.4 In this roundtable discussion, three experts in the field relate their experiences in caring for long-term CPAP patients and outline promising directions for future research.
Allen Boon, RPSGT, is associate director of clinical operations at SleepMed, Columbia, SC.
Michael Breus, PhD, DABSM, is cofounder of Sleep Center Management Institute, Atlanta.
Taj M. Jiva, MD, DABSM is director of the Sleep Disorders Clinic, Orchard Park, NY.
In your experience, does long-term CPAP therapy typically change the patient’s need for CPAP?
Breus: Often, this will depend on the situation with the patient. In our clinics, for example, once CPAP has been successful (defined as used for 6 hours on 6 or 7 nights per week), we try to get patients to begin losing weight through proper diet and exercise. Although this is one of our largest challenges, it does occur. In addition, we know that a better night’s rest with CPAP can contribute to weight loss. Furthermore, patients report to me, in the clinical setting, that their energy levels increase and that they are less likely to snack on what they refer to as energy food throughout the day.
Thus, with this type of body-mass change, we see that the pressure requirements for CPAP are often reduced. Individuals, upon retesting, have lowered the respiratory disturbance index enough to discontinue CPAP. Therefore, with long-term use of CPAP, I would have to say that there can be indirect physiological changes that can change the need for CPAP.
Boone: Long-term, CPAP-compliant patients frequently need to have minor pressure adjustments over time. Usual adjustments are generally deviations of 2 to 3 cm H2O from the original pressure. The need for adjustment stems from a variety of reasons, most commonly weight loss, apnea-treatment surgery, or increased/decreased upper-airway tone. Unfortunately, no one can avoid the loss of muscular tone associated with age. The majority of patients titrated on CPAP, however, will remain on the treatment as a life-long therapy.
Jiva: Yes, long-term use of CPAP decreases soft tissue edema of upper airways and decreases the need for high levels of CPAP pressure. Uvula inflammation and size decrease, which is associated with the beating of the uvula against the pharynx during snoring, increased stimulation of upper airway muscles, and increased stiffness of the upper airway with CPAP therapy. Weight loss associated with CPAP may also decrease the need for higher pressure levels.
Apart from control of OSA symptoms, are there other beneficial effects of long-tern CPAP therapy?
Boone: An unfortunate aspect of many presenting OSA patients is the length of time that it took them to get the help that they needed. Because of this slow progression, with equally lengthy times for self-realization and subsequent diagnosis, many patients have become unwitting candidates for hypertension, stroke, and diabetes. Nearly anyone diagnosed with OSA has an increased risk factor for these maladies; thus, treatment with CPAP contributes secondarily to risk reduction. Despite this, these patients remain predisposed due to the prior OSA diagnosis.
Many of the common complaints of apneic patients (such as short-term memory loss, nocturia, mood reduction, and excessive daytime sleepiness) dissipate in time with prolonged CPAP use. Many patients voice frustration with the amount of time that it has taken them to realize their individual accomplishments. As they no longer have the same exhilarating feeling that they felt initially, they tend to falter with compliance.
Breus: Many of our patients report having more energy, feeling less sleepy, and that their concentration improves. Anxiety and depression appear to have so many different variables associated with them; it would seem to make sense, to me, that just getting a better night’s sleep is unlikely to correct these issues (but it is more than likely to have an impact on them). We have had the experience, however, in which cases of undiagnosed narcolepsy or severe OSA were mistaken for depression, and once we were able to diagnose and treat these individuals, their need for depression or anxiety medications was alleviated.
Jiva: Yes, somnolence, vigilance, concentration, memory, and alertness improve with CPAP therapy. After a couple of months of CPAP therapy, anxiety and depression, reaction time, and ejection fraction of the heart improve. The idiopathic dilated cardiomyopathy may also improve significantly and prevent episodes of congestive heart failure.
Which long-term adverse effects of CPAP might be inevitable for some patients? Are there any warning signs that can help clinicians predict which patients are at higher risk of rare adverse effects?
Breus: To date, we have been fortunate not to see many of the rare side effects in our clinics. In my experience, I did see one case in which a CPAP user was involved in a motor vehicle accident (having been hit by someone); after use of CPAP, there was significant facial edema. This patient discontinued CPAP for approximately 2 months, and upon reinitiation of treatment, was fine.
Jiva: The most common side effects are nasal dryness, rhinitis, and bleeding. Using saline irrigation, and then using nasal steroids before putting the mask on, may decrease this effect. Warm humidification may decrease risk of nasal bleeding.
In patients with one lung, small volumes lungs, idiopathic pulmonary fibrosis, honeycomb lungs, or bullous emphysema, we need to be careful about high-pressure CPAP because of the risk of volume and barotrauma. Bilevel PAP may be a better choice in these cases.
When using a full face mask, there can be a risk of aerophagia, stomach distension, food regurgitation, and aspiration. Hence, the patient should eat dinner early and go to sleep on an empty stomach to avoid these adverse effects.
Boone: Warnings signs of adverse effects are many and are easily picked up by an astute health care provider. For example, masks that look nearly brand new after 6 months of use are the giveaway for inconsistent use. Other tools, such as the Epworth Sleepiness Scale, are very helpful for the determination of treatment efficacy. Follow-up telephone calls by the provider also give patients the opportunity to discuss issues that they might not otherwise have brought up.
At this time, greater weight is given to immediate treatment and the subsequent improvement in quality of life. While remaining cognizant of the potential (yet limited) effects of long-term CPAP use, greater emphasis is placed on delivering treatment that can reduce more immediate threats.
Which long-term effects of CPAP need not become problems because they can be corrected?
Jiva: If CPAP pressure is too high or difficult to handle, use bilevel PAP. Nasal prongs may help with anxiety and claustrophobia associated with full face mask.
Boone: One complaint that has been voiced by patients involves orthodontia (specifically, loose teeth). The situation is generally caused by larger-than-needed masks, overtightened headgear, or changes in the facial contour (weight loss). Frequent (and encouraged) contact with the patient helps to reveal these situations before the problem gets out of hand.
While they are sometimes difficult to start, apnea support groups help patients stay informed and keep up with new developments in CPAP treatment. Offering patients the opportunity to discuss their experiences, as well as a forum for new equipment presentations, extends the educational aspect of care. As many have experienced in the sleep laboratories, the better educated patient tends to be the more compliant patient. Likewise, convincing patients to set realistic goals and expectations for their individual treatment will help build their confidence in the treatment.
Which scientific uncertainty concerning the long-term effects of CPAP would be the best focus for future research?
Jiva: CPAP supports the heart and pressure around the heart to decrease preload and afterload, whether nighttime echo may help, monitoring of ejection fraction? whether all patients with stage III and IV should be placed on CPAP at night to see improvements on their function.
Breus: Obviously, long-term studies are needed to show the efficacy of treatment; we need to make sure that patients need neither a decrease nor an increase in pressure over time. In many cases, we will retitrate CPAP after 5 to 7 years, but not if the patient is asymptomatic.
Boone: Predictive factors for pathology are probably the greatest focus of research. We have many factors that we rely upon (such as obesity and behavior), yet it is the refined factors that we hope to gain. Many technologists will try to predict pressure prior to titration, but the fine-tuned ability to predict CPAP pressure still eludes the discipline. More important, who are the patients most likely to succeed with CPAP treatment and which are those who might fail? What and where are the physiological attributes that will provide that indication?
I would say that one of the prevalent thoughts on patients’ minds concerns discontinuation of therapy. Even the most compliant patients express the wish for a time when they would not need to sleep with CPAP. Will there come a time when, using a combination of therapies, a patient could expect to have a transient need for CPAP treatment?
Kris Kyes is technical editor of Sleep Review.
1. American Thoracic Society. Indications and standards for use of nasal continuous positive airway pressure (CPAP) in sleep apnea syndromes. Am J Respir Crit Care Med. 1994;150:1738-1745.
2. Munoz A, Mayoralas LR, Barbe F, Pericas J, Agusti AG. Long-term effects of CPAP on daytime functioning in patients with sleep apnoea syndrome. Eur Respir J. 2000;15:676-681.
3. Stauffer JL, Fayter NA, McClure BJ. Conjunctivitis from nasal CPAP apparatus. Chest. 1984;86:802.
4. Lloberes P. Comparison of manual and automatic CPAP titration in patients with sleep apnea/hypopnea syndrome. Am J Respir Crit Care Med. 1996;154:1755-1758.