Patient Compliance with Nasal CPAP Therapy for Sleep Apnea* Mark H. Sanders, M.D., F.G.G.P.; Gynthia A Gruendl, R.R.T., R.Psg.T.; and Robert M. Rogers, M.D., F.G.G.P.
Continuous positive airway pressure via the nasal route (nasal CPAP) is effective in reducing the frequency of occlusive and mixedpatterns of sleep apnea. Little is known about long-term patient compliance with this therapeutic modality, however. In order to evaluate this, questionnaires were mailed to 24 sleep apnea patients who had received a nasal CPAP systemfor nightly use. Patients were requested not to sign the questionnaire. At the time of mailing, the patients had possessed their nasal CPAP equipment for 10.3 ± 8 months (mean ± SD). Twentypatients (83 percent) responded to the questionnaire. Sixteen responders used nasal CPAP during all nightlysleep time, and two used it for all but one and 2.5 hours of nightlysleep time, respectively. One individual used it on alternate nights, and one patient
did not use it aU. Thus, 17of 20 (85 percent) responders were compliant. Includinginformationabout the four nonresponders, obtained by means other than questionnaire, 18 of 24 (75 percent) patients were compliant with therapy. All but two patients were obese at the time sleep apnea was diagnosed. Only 50 percent of questionnaire responders reported weight loss after receiving nasal CPAP, and these individuals were frequent nasal CPAP users. The most common complaints were mask discomfort (14 responders) and nasal dryness and congestion (13 responders). We conclude that long-term home nasal CPAP is a viable therapy that isconscientiously applied and well-tolerated by most sleep apnea patients.
Cmtinuous positive airway pressure via the nasal route (nasal CPAP) has been convincingly shown to reduce the frequency of occlusive and mixed patterns of sleep apnea. 1... In addition, we have recently demonstrated that a single night of nasal CPA~ applied in a hospital setting, is well-tolerated by a majority of sleep apnea patients. Although long-term patient compliance is a critical determinant of the success of home nasal CPAP therapy, few data addressing this issue are available. Sullivan et alS reported continued abatement of daytime somnolence in 35 patients during three to 30 months of home nasal CPAP therapy. Similarly, Frith et al" described long-term nasal CPAP therapy (seven to 22 months) in five of seven patients. In neither study, however, was information provided regarding the nightly frequency of nasal CPAP use or the fraction of nightly sleep time during which nasal CPAP was employed. In a small number of patients, McEvoy and coworkers' reported that the use of home nasal CPAP varied from three to seven nights per week. This study did not address the use of nasal CPAP in terms of the fraction of nightly sleep time during which the device was applied. If patients do not use nasal CPAP during all sleep time, the therapeutic results may be suboptimal. Comprehensive informa-
tion about long-term compliance would allow a greater understanding of the utility of nasal CPAP as a therapy for sleep apnea. Accordingly, we sent questionnaires to our patients on chronic nasal CPAP therapy. The responses extend our previous findings and indicate that, although this treatment modality is not without its discomforts and inconveniences, it is well-tolerated and conscientiously used on a long-term basis by most patients.
Division of Pulmonary Medicine, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh. Supported in part by the Veterans Administration. Manuscript received November 18; revision accepted February 19. Reprint requests: Dr. Sanders, 440 Scaife Hall, University of Pittsburgh School of Medicine, Pittsburgh 15261 330
MATERIALS AND METHODS
Questionnaires were sent to all sleep apnea patients for whom nasal CPAP had been prescribed. Accompanying letters requested cooperation and instructed the patients not to identify themselves on the questionnaire. The questionnaires were coded, however, to identify the respondents. All patients had been referred to the Pulmonary Sleep Evaluation Laboratory, University Health Center, University of Pittsburgh with complaints of excessive daytime sleepiness. Each had undergone two polysomnographic studies. The first was a diagnostic study and the second a therapeutic trial of nasal CPA~ as described previously," All but one patient had both polysomnographic studies performed in our laboratory. Due to time and travel constraints, one individual had a diagnostic study at another laboratory and a therapeutic trial of nasal CPAP at our facility. The patients were 50.6 ± 11 years old (mean ± SD, range 18 to 66 years). Twenty-two individuals had primarily occlusive apneas and two had a predominance of obstructive hypopneas on diagnostic polysomnographic examination. All patients exhibited a reduction in apnea index during the therapeutic trial of nasal CPAP (mean apnea index 51 vs 1.5, without and with nasal CPAP respectively; mean of the differences 50.9 ± 22, p
nasal mask to maintain acceptable oxygenation during sleep. Effective levels of nasal CPAP ranged from 7.5 to 15 ern H 20 (10.1±3 em H 20). All patients tolerated the application of nasal CPA~ and this was considered the treatment of choice by the patients' physicians. After all other therapeutic options were presented, each patient elected to use nasal CPAP at home. Subsequently, the patients purchased a commercially available unit (SleepEasy, Respironics Inc, Monroeville, PA) and were instructed regarding the application and care of the mask and tubing. Patients were required to demonstrate the ability to put the mask on themselves. Each individual was told to wear the nasal CPAP system nightly during sleep. It is routine in our laboratory to make telephone contact with each patient after one week at home with nasal CPAP therapy in order to answer any questions and evaluate the patients progress. Patients are seen in the officeat clinically appropriate intervals. They are also periodically visited by the nasal CPAP supplier. Toobtain the most comprehensive view of patient compliance with nasal CPA~ we reviewed the records of the three non-responders who are regularly seen with their spouses in clinical follow-up. In addition, telephone contact was made with the fourth non-responder who, due to distance considerations, is not seen on a regular basis. Due to possible bias introduced by direct contact, these data are reported separately from those obtained by questionnaire. RESULTS
Of the 24 questionnaires mailed, 20 were returned (83 percent). At the time of mailing, the patients had possessed nasal CPAP systems for 10.3 ± 8 months (mean ± SD, range 1 to 30 months, median duration 9 months). Of the 20 responding patients, 16 (80 percent) reported using nasal CPAP during all nightly sleep time. Two patients wore nasal CPAP nightly for all but one and 2.5 hours of sleep time, respectively. One individual used nasal CPAP on an alternate night basis and one did not use it all, finding it too difficult to put on (Table 1). Of the 19 responding nasal CPAP users, 18 put the device on themselves while the other required assistance from a spouse. Fourteen of the 17 married nasal CPAP users characterized spousal adjustment to the presence of the system as satisfactory. Of these 14 patients, ten slept alone, however. Noise of the blower was cited as the reason by four patients, although an explanation was not requested on the questionnaire. Eighteen of the 19 responding nasal CPAP users reported improved quality of sleep and noted feeling either "rested" or "alert and wide-awake" during the day since beginning nasal CPAP therapy. Eighteen users reported favorable personality and quality of life changes including less depression and irritability, Table I-Nasal CPAP Use in Questionnaire Responders Pattern of Use
Number (% of total)
Nightly use, all sleep time Nightly use, all but 1 hour of sleep Nightly use, all but 2.5 hours of sleep Alternate night use Never used
1 (5) 1 (5) 1 (5) 1 (5)
better ability to function, and improved general wellbeing. The patient who used alternate night nasal CPAP reported no change in these respects. Fourteen of the 19 (74 percent) responding nasal CPAP users reported that the mask was uncomfortable and inconvenient. Most commonly, discomfort was localized to the bridge of the nose. Five individuals coped with this problem by applying a band-aid, piece of gauze or cotton to this area. Thirteen nasal CPAP users (68 percent) reported a dry, congested nose on awakening in the morning but in only five did this require intervention. Two patients used saline nasal sprays and three regularly used an alpha-adrenergic nasal spray. Other complaints included occasional morning rhinorrhea (two patients), excessive blower noise (five patients) and diffuse chest discomfort with variable day-to-day intensity (two patients). One patient developed small, painful intra-nasal abrasions and mild epistaxis, which resolved after application of a topical antibiotic. Six patients volunteered particularly favorable comments such as being "grateful for the relief" and "lucky to have a machine like this." One individual noted that nasal CPAP is "habit forming." The weight of our patients at the time of diagnosis was 107.1 ± 23 kg (mean ± SD). All but two were obese. The responses to the questionnaires indicated that ten patients lost 6.8 ± 5 kg, (mean ± SD) since beginning nasal CPAP therapy. All those who lost weight used nasal CPAP nightly. However, 'not all frequent nasal CPAP users lost weight. Despite using nasal CPAP during all nightly sleep time, eight questionnaire responders failed to lose weight. In fact, one of these individuals reported a 4.5 kg weight gain. Both the patient who used nasal CPAP on alternate nights and the patient who never used nasal CPAP reported no weight change. Of the four patients who did not respond to the questionnaire, one uses nasal CPAP during all sleep time with relief of daytime somnolence. This patient, who also has a bipolar depression disorder, has lost 9 kg since beginning home nasal CPAP therapy. The other three individuals use nasal CPAP in a sporadic fashion, variously citing mask discomfort, inconvenience and warmth of the air provided by the blower during summer as reasons. Only one of these individuals has lost weight (9 kg). The six individuals in this study who did not use nasal CPAP during all sleep time reported daytime sleepiness on presentation and had substantially abnormal breathing during sleep (mean apnea index, 57.2). They all had a significant improvement in breathing during sleep on nasal CPAP (mean apnea index 2.2; mean of the differences 55 ± 13, p <0.001, Student's paired r-test), Thus, failure to use nasal CPAP during all sleep time did not reflect milder sleep CHEST / 90 / 3 / SEPTEMBER, 1986
apnea, less severe symptoms or less effectiveness of nasal CPA~ DISCUSSION
In a recent study," we found nasal CPAP to be a successful therapeutic modality for sleep apnea. In that report, success was defined as both a reduction in apnea index during a single night therapeutic trial and patient willingness to use nasal CPAP at home if recommended by a physician. In practical terms, however, success also requires chronic patient compliance. Importantly, information is incomplete in this regard. There are no data on the fraction of nightly sleep time during which patients use nasal CPAP at home. Since the long-term impact of varying degrees and durations of nocturnal hemoglobin desaturation have not been defined," it seems prudent to try to maintain normal or nearly normal oxygenation during all sleep time. This is a particularly critical consideration when treating patients with cor pulmonale secondary to sleep apnea. Q Elimination of apnea-related sleep fragmentation is also an important goal of nasal CPAP therapy. We have recently demonstrated a substantial increase in objectively assessed daytime sleepiness in a patient with severe sleep apnea after a single night without nasal CPAE 10 Thus, until more information is available, our recommendation is that patients use nasal CPAP during all nightly sleep. Sleeping without nasal CPAP for longer than one hour a night or using it on alternate nights does not constitute adequate compliance. Given these considerations, 18 of our 24 patients (75 percent) are compliant with nasal CPAP therapeutic recommendations. One explanation for the high degree of long-term compliance is our patient selection and education process. All patients in this study had documented reduction of sleep-disordered breathing during one night of nasal CPAP and elected to try chronic nasal CPAP in lieu of other therapeutic interventions. Other patients who had a reduction in apnea frequency during a single night trial of nasal CPAP but who required substantial encouragement before accepting chronic nasal CPAP therapy were not considered good candidates. In these individuals, other therapeutic options were pursued. Prior to beginning home therapy, patients selected for chronic nasal CPAP therapy received extensive education as outpatients. In our opinion, these two approaches-careful selection and education-are requisites for the success of nasal CPA~ One area for future investigation is the application of standard personality scales to characterize the likelihood of compliance with long-term nasal CPAE We believe that the questionnaire-derived information reliably reflects the patterns of nasal CPAP use in the responding individuals. Since patients were asked not to sign the questionnaires, it is not likely that 332
answers were influenced by concern over identification. Additionally, in the course of clinical follow-up, direct contact has been made with the spouses of ten responding patients as well as the parents and adult children of two other responding patients, respectively. In all cases, these contacts substantiated the data recorded on the questionnaires. On presentation, none of the nasal CPAP users had physical or laboratory evidence of end-organ damage attributable to sleep apnea (ie, polycythemia, cor pulmonale). Accordingly, reassessment of physical and laboratory variables could not be used to support or refute questionnaire data indicating compliance with therapy. It might be argued that multiple sleep latency tests (MSLTs)14 reflecting decreased sleepiness during nasal CPAP therapy would substantiate patient compliance. In the clinical setting of this study, however, where patients were clearly functionally impaired due to hypersomnolence prior to nasal CPAP therapy and much improved after initiation of therapy, MSLTs were not justified. In addition, the utility of MSLTs in assessing patient compliance may be compromised by patients adhering to therapy for a few days prior to testing, specifically in order to perform well. On the other hand, MSLTs may have a role in determining the probability of compliance with chronic nasal CPAP therapy. Conceivably, patients with marginal hypersomnolence are less likely to tolerate the inconvenience and discomfort of nasal CPAE Important information might, therefore, be obtained from MSLTs in individuals with documented sleep apnea but an equivocal history for excessive daytime sleepiness. At the present time, we think it is reasonable to initiate nasal CPAP therapy in those patients who have a reduction in sleep-disordered breathing on nasal CPAP and who express a desire to try it on a long-term basis. The utility of MSLTs in selecting patients for chronic nasal CPAP therapy deserves study, however. Our experience with nasal CPAP has expanded since the questionnaire mailing. To date, only six of 40 patients (15 percent) in whom nasal CPAP was effective during a one night evaluation and in whom it was considered the treatment of choice, either refused home therapy or were judged insufficiently motivated to warrant a trial of home therapy. Thus, 85 percent of patients in whom nasal CPAP ameliorates sleep apnea are, on clinical grounds, good candidates for chronic therapy. Data from the current study suggest that 75 percent of these individuals will be compliant over the long term. The most common problem described by our patients, mask discomfort, may have been overstated since some individuals were not using the latest and most comfortable model nasal mask when the questionnaire was sent. The other common problem, nasal dryness, has been lessened by the use of saline nasal Patient Compliance with Nasal CPAP Therapy
(Sanders, Gruendl, Rogers)
sprays at bedtime and in the morning. We do not advocate routine use of vasoconstrictive nasal sprays. For those patients who complain of intolerable nasal dryness despite the use of saline sprays, we have suggested placing a room vaporizer near the air-intake of the nasal CPAP blower, We also insist that the mask and tubing be washed with soap and water at least weekly. In prescribing nasal CPAP for our sleep apnea patients, we had hoped that relief of daytime somnolence would, in conjunction with dietary instruction, be associated with weight loss. This in turn might obviate the need for any mechanical or pharmacologic intervention.P'" Disappointingly, only about half of the compliant patients reported weight reduction, and this was modest in degree. In these patients, weight reduction might be due to fluid loss, increased energy expenditure accompanying increased daytime alertness, and/or simply reflect a personality that is compliant with medical therapy, both dietary and nasal CPA~ Unfortunately, it appears that compliance with nasal CPAP therapy does not assure weight reduction. From a somewhat different perspective, we cannot exclude the possibility that weight reduction will alter the pattern of nasal CPAP use by virtue of improvement in the underlying sleep-disordered breathing. After weight loss, patients may learn that they can maintain satisfactory performance levels despite a reduction in nasal CPAP use. This emphasizes the need for on-going physician-patient communication in order to evaluate compliance with, and continuing need for nasal CPAP therapy. Two patients complained of chest discomfort in the course of routine medical follow-up. This complaint was subsequently expressed on the questionnaire returned by these individuals. The discomfort was described as an aching sensation across the anterior and lateral rib cage which was non-pleuritic, unrelated to exertion, and variable in daily intensity. Comprehensive evaluations did not reveal a cardiopulmonary etiology for this discomfort, which is thought to be musculoskeletal in nature, perhaps secondary to elevation of lung volume during nasal CPAP use.
In summary, our results indicate that selected patients with sleep apnea use nasal CPAP in a conscientious manner for prolonged periods of time. Weight loss in compliant individuals should not be taken for granted, however, ACKNOWLEDGMENTS: The authors thank Ms. Lucy Seger for her assistance in preparing the questionnaires.
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