Effect of nasal-valve dilation on obstructive sleep apnea

OBJECTIVE: Nasal-valve dilation reduces nasal resistance and increases air flow. It is possible that this mechanism prevents hypopharyngeal collapse and sleep apneas. We investigated the effect of a plastic device (Nozovent; Prevancure AB; V?stra Fr?lunda, Sweden)-which dilates the nasal valve-on patients with obstructive sleep apnea (OSA). DESIGN: Prospective interventional study. SUBJECTS: Twenty-six consecutive patients with OSA were included (22 men; mean +/- SD age, 54.8+/-11.3 years; respiratory disturbance index [RDI], 34.4+/-18.5 events/h; body mass index, 31.6+/-5.7 kg/m(2)). INTERVENTION: The nasal dilator was inserted during sleep into the nares and fitted to exert a dilating force on the nasal valves by means of its elasticity. MEASUREMENTS: Polysomnographic studies were performed before and after 1 month of treatment. A responder is defined as one with a reduction in RDI to < 50% of the baseline value and RDI of < or =10 events/h during treatment. RESULTS: Five patients dropped out. As a result, only 21 patients were analyzed. Four patients responded, and 17 patients were nonresponders. In the whole population, neither the mean values for respiration during sleep nor sleep staging changed significantly with the device. CONCLUSIONS: The investigated nasal dilator had no effect on sleep-related breathing disorders in patients with moderate to severe OSA. The reduction in nasal resistance does not prevent hypopharyngeal obstruction.     

Nasopharyngeal symptoms in patients with obstructive sleep apnea syndrome. Effect of nasal CPAP treatment

BACKGROUND: Nasal side effects are often reported during nasal continuous positive airway pressure (CPAP) treatment of obstructive sleep apnea syndrome (OSAS) and may make the use of nasal CPAP difficult. OBJECTIVE: The aim of this study was to evaluate the effect of nasal CPAP on nasopharyngeal symptoms in OSAS patients. METHODS: The frequency and severity of nasopharyngeal symptoms and signs were prospectively evaluated in 49 consecutive OSAS patients (37 men, 12 women, mean (SD) age 54 (7) years, body mass index 35 (6) kg/m2) immediately before and after 6 months' treatment with nasal CPAP. RESULTS: Nasopharyngeal symptoms were common already before starting nasal CPAP: 74% of patients reported dryness, 53% sneezing, 51% mucus in the throat, 45% blocked nose, and 37% rhinorrhea. During nasal CPAP treatment, severity and frequency of sneezing (75%) and rhinorrhea (57%) increased. This increase was related to the season when nasal CPAP was applied, and was more profound in winter than in summer. Mild abnormalities on rhinoscopy and paranasal sinus X-rays were common both at baseline and at follow-up with no significant change during treatment. CONCLUSIONS: Nasopharyngeal problems were found to be frequent in patients with OSAS before nasal CPAP treatment, and tended to increase during the treatment.     

Effect of obstructive sleep apnea on mitral valve tenting

Obstructive apneas produce high negative intrathoracic pressure that imposes an afterload burden on the left ventricle. Such episodes might produce structural changes in the left ventricle over time. Doppler echocardiograms were obtained within 2 months of attended polysomnography. Patients were grouped according to apnea-hypopnea index (AHI): mild/no obstructive sleep apnea (OSA; AHI <15) and moderate/severe OSA (AHI ≥15). Mitral valve tenting height and area, left ventricular (LV) long and short axes, and LV end-diastolic volume were measured in addition to tissue Doppler parameters. Comparisons of measurements at baseline and follow-up between and within groups were obtained; correlations between absolute changes (Δ) in echocardiographic parameters were also performed. After a mean follow-up of 240 days mitral valve tenting height increased significantly (1.17 ± 0.12 to 1.28 ± 0.17 cm, p = 0.001) in moderate/severe OSA as did tenting area (2.30 ± 0.41 to 2.66 ± 0.60 cm(2), p = 0.0002); Δtenting height correlated with ΔLV end-diastolic volume (rho 0.43, p = 0.01) and Δtenting area (rho 0.35, p = 0.04). In patients with mild/no OSA there was no significant change in tenting height; there was a borderline significant increase in tenting area (2.20 ± 0.44 to 2.31 ± 0.43 cm(2), p = 0.05). Septal tissue Doppler early diastolic wave decreased (8.04 ± 2.49 to 7.10 ± 1.83 cm/s, p = 0.005) in subjects with moderate/severe OSA but not in in those with mild/no OSA. In conclusion, in patients with moderate/severe OSA, mitral valve tenting height and tenting area increase significantly over time. This appears to be related, at least in part, to changes in LV geometry.     

Overnight nasal CPAP improves hypersomnolence in sleep apnea

Eleven adult men with sleep apnea underwent nocturnal polysomnography on two successive nights. The first study, done without NCPAP, served as the control. The second (treatment) was done with the application of 7.5 to 15 cm H2O nasal continuous positive airway pressure (NCPAP). A subjective sleepiness index (SSI) was noted upon awakening from each night of polygraphic recording. During the control night, the mean frequency of apnea episodes/sleep hr was 35.95 +/- 4.5 SE, and the mean duration was 28.68 +/- 2.7 sec. Mean frequency of disorder of breathing (DOB) episodes/sleep hr was 19.25 +/- 6.2 and mean duration of DOB episodes was 23.1 +/- 2.8 sec. During the treatment night, all obstructive apnea episodes were abolished. During the control night, the mean decrease in arterial oxygen saturation during obstructive apnea episodes was 11.2 +/- 1.9 percent and the mean lowest saturation was 67.6 +/- 4.0 percent. NCPAP eliminated arterial oxygen desaturation. While 44.5 +/- 5.7 percent of total sleep time was spent in either apnea or disordered breathing during the control night, NCPAP decreased this to 0.73 +/- 0.3 percent. In addition to the improvement in respiration during sleep, SSI decreased from a mean of 3.73 +/- 0.49 after the control night to 1.64 +/- 0.24 after treatment, reflecting an improvement in daytime hypersomnolence. We conclude that nasal CPAP is effective in eliminating obstructive apnea episodes, and results in a marked decrease in daytime hypersomnolence after one treatment night.     

The effect of short-term nasal CPAP therapy in cases of obstructive sleep apnea syndrome

Recent studies have shown that nasal CPAP is very effective in the treatment of patients with obstructive sleep apnea syndrome (OSA). To clarify the characteristics of pulmonary function testing and to evaluate the effect of short term nasal CPAP therapy in 13 cases of OSA patients, nasal CPAP was used for 10 to 14 days and polysonography was performed on two consecutive nights without nasal CPAP and at one night with nasal CPAP. Pulmonary function tests and the Uchida-Kraepelin test were performed before the initiation of nasal CPAP therapy and also 7 to 14 days after the nasal CPAP therapy. Apnea index reduced significantly in all cases from 5.10 +/- 19.6 episodes/hour without therapy to 3.1 +/- 3.5 with nasal CPAP (p less than 0.001). Nasal CPAP significantly reduced the frequency of obstructive (p less than 0.001) and mixed apnea (p less than 0.01), but the frequency of central apnea did not change with nasal CPAP. During the nasal CPAP, mean nadir SaO2 rose from 87.3 +/- 2.9% to 92.7 +/- 1.1% (p less than 0.001) and the lowest SaO2 rose from 73.3 +/- 6.4% to 92.0 +/- 2.1% (p less than 0.001). Before the nasal CPAP therapy, daytime PaO2 was 80.6 +/- 6.4 Torr and closing capacity (CC)/FRC ratio was higher when patients were in a supine than in a sitting position. After short term nasal CPAP therapy, daytime PaO2 increased significantly (p less than 0.001), and FRC/TLC in a supine position increased and CC/FRC in a supine position decreased in some patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Transtracheal oxygen, nasal CPAP and nasal oxygen in five patients with obstructive sleep apnea.

The effect of transtracheal oxygen administration by means of a 9-French (2.7 mm) percutaneous catheter was assessed in five patients with severe obstructive sleep apnea. We hypothesized that the delivery of oxygen below the site of airway obstruction should reduce the arterial oxygen desaturation during apneas and hypopneas, thereby increasing respiratory stability. Standard sleep and respiratory measurements were recorded in these subjects with all-night polysomnography on nonconsecutive nights during four experimental conditions: room air (BL), nasal continuous positive airway pressure (CPAP), nasal O2 (NC O2), and transtracheal O2 (TT O2). In three of these subjects, room air was infused (TT RA) at flow rates comparable to TT O2. Compared with baseline room air measurements, TT O2 not only significantly increased the SaO2 nadir from 70.4 percent to 89.7 percent (p less than 0.01), but it also reduced the frequency of sleep apnea/hypopnea from 64.6 to 26.2/h sleep (p less than 0.01). NC O2 ameliorated desaturation during apnea/hypopnea (mean SaO2 nadir, 86.2 percent; p less than .01) but did not significantly alter frequency (59.0/h sleep). Nasal CPAP was the most effective means of reducing sleep apnea/hypopnea (13.8/h sleep) but did not abolish desaturations when apneas occurred (mean SaO2 nadir, 80.0 percent). Compared with oxygen, transtracheal infusion of room air appeared to be somewhat effective; however, the small number of studies with TT RA precluded statistical analysis. We believe that TT O2 is superior to NC O2 for some patients with obstructive sleep apnea because continuous oxygen flow below the site of airway obstruction more reliably prevents alveolar hypoxia and respiration is stabilized. Infusion of air or oxygen through the tracheal catheter flow may also increase mean airway pressure and reduce obstructive apnea similar to nasal CPAP. We conclude that TT O2 may be an effective alternative mode of therapy for some patients with severe sleep apnea/hypopnea when nasal CPAP is not tolerated or when combined oxygen and nasal CPAP are required.     

Reversal of central sleep apnea using nasal CPAP

Based on the theory that obstructive (OSA) and central (CSA) sleep apneas share common pathophysiologic mechanisms, we attempted to treat eight patients with predominantly CSA by continuous positive airway pressure (CPAP). All patients exhibited repetitive episodes of CSA and mixed sleep apneas (MSA) in the supine position with a mean duration of 23.7 +/- 0.7 s and 34.5 +/- 1.3 s, respectively. The pattern of apnea changed when the subject lay in the lateral position. Five patients were observed to develop OSA in the lateral position with a mean duration of 27.2 +/- 1.5 s, while the other three patients snored continuously. High levels of CPAP (range 9.0 to 16.5 cm H2O) prevented all CSA and MSA and resulted in quiet breathing in all eight patients. Intermediate levels of CPAP produced firstly MSA, then purely OSA and/or continuous snoring. Low levels of nasal CPAP also prevented OSA and snoring occurring in the lateral posture in all subjects (range 2.0 to 8.3 cm H2O). Three patients are currently on home CPAP therapy for a range of four to 36 months. We conclude that upper airway collapse in the supine posture has a key role in the induction of CSA. We suggest that a reflex inhibition of respiration through activation of supraglottic mucosal receptors during passive oropharyngeal airway closure caused CSA in these patients.     

The effect of nightly nasal CPAP treatment on underlying obstructive sleep apnea and pharyngeal size

Nasal continuous positive airway pressure (CPAP) is an effective treatment for obstructive sleep apnea (OSA). It is usually prescribed for nightly use; however, recent studies show that patients often do not wear the appliance consistently. Previous studies have also suggested that nasal CPAP may improve a patient's underlying OSA even when the mask is not in place. We investigated 12 men with OSA to see if nasal CPAP used nightly for six weeks would improve their underlying sleep-disordered breathing. We also studied pharyngeal volumes measured using magnetic resonance imaging and a computer-controlled digitizing pad. Patients with more severe OSA had improvement after six weeks; however, they still demonstrated significant OSA. Patients with less severe OSA did not have significant change. We were unable to show a significant difference in any patient's awake pharyngeal volumes. We conclude that patients with OSA should be encouraged to wear their nasal CPAP machines regularly.     

Upper airway finding on CT scan with and without nasal CPAP in obstructive sleep apnea patients

The area of upper airway (from the nasopharynx to the hypopharynx) was measured by means of computed tomography (CT) scan in 15 confirmed cases of obstructive sleep apnea (OSA) and in 4 normal controls while they were awake. The minimum cross-sectional area (MA) of the upper airway was 14.7 +/- 20.0 mm2 in OSA patients and 80.0 +/- 33.1 mm2 in normal controls and the difference was statistically significant (p less than 0.01). In OSA patients, MA did not correlate with age, body weight, apnea index, desaturation index, mean nadir-SO2 and lowest SO2. MA was also measured with OSA patients while nasal continuous positive airway pressure (NCPAP) of 10 cmH2O was applied and it was found that MA was significantly widened when NCPAP therapy was performed. We conclude that upper airway narrowing is consistent finding in OSA patients but the degree of narrowing does not correlate with parameters of apnea and gas exchange during sleep, and NCPAP is effective to widen the area of upper airway in OSA patients.     

CPAP compliance in patients with obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) is characterized by repeated cessations of breathing during sleep. Major symptoms of this disease are excessive daytime sleepiness, snoring, and witnessed apnea. Most of the patients are treated with CPAP. In this study, we aimed to evaluate the factors affecting adherence to the CPAP treatment. Seventy-one patients were enrolled to this study. Patients were divided into three groups according to CPAP usage. Group I consisted of patients who had never used CPAP, group II consisted of patients who had used CPAP occasionally, and group-III patients had used CPAP treatment regularly. Group-III patients had higher apnea–hypopnea index (AHI) than groups I and II (respectively, 56.6 ± 27.7, 26.3 ± 7.5, and 32.3 ± 7.06; p < 0.000 for both). Oxygen desaturation index was significantly higher in group-III patients comparing to groups I and II (44.6 ± 22.3, 15.9 ± 8.3, and 25.6 ± 9.5; p < 0.000 for all). Our findings have shown that only very severe patients use the CPAP device regularly (mean AHI 56.6 ± 27.7). Compliance to CPAP treatment seemed to be poor in patients with moderate to severe, AHI about 30, OSAS. Considering the well-established benefits of CPAP treatment in patients with true indications, patients should be encouraged to use CPAP regularly, and complications of OSAS should be keynoted.     

Long-term effects and complications of home nasal CPAP therapy for obstructive sleep apnea patients]

We treated 23 patients with obstructive sleep apnea syndrome (OSAS) by nasal continuous positive airway pressure (NCPAP) at home, and examined the long-term compliance, clinical effects, and complications after NCPAP therapy. Nineteen patients continued and four patients discontinued the therapy during the mean observation period of 15 months, and the compliance was 83%. There was no significant difference in age, weight, and sleep data between the compliant group (C) and non-compliant group (NC). The causes of discontinuation of therapy were lack of adaptation to the apparatus (2 cases), improvement of clinical symptoms due to weight reduction (1 case), and induction of asthma attack (1 case). Disappearance of excessive daytime sleepiness, improvement of sleep quality, and disappearance of nocturia were observed in most cases, and disappearance of morning headache and improvement of sexual ability and emotional instability were also observed in several cases. Nine cases (39%) complained of discomfort due to the nasal mask and 6 cases (26%) complained of dryness of the mouth and nose, whereas 10 cases (43%) experienced no adverse effects. No serious complications were observed. These findings suggest that long-term home NCPAP is an effective and safe treatment for OSAS patients.     

Maxillofacial surgery and nasal CPAP. A comparison of treatment for obstructive sleep apnea syndrome

Nasal continuous positive airway pressure (CPAP) is the primary therapy for obstructive sleep apnea syndrome (OSAS). Recent reports have indicated, however, that there is a small but significant number of failures related to patient compliance. Primary surgical treatment, which has been uvulopalatopharyngoplasty (UPPP), has declined because of poor results. A reviewed of UPPP failures has shown that while UPPP eliminated palatal obstruction, it failed to eliminate base of tongue obstruction. Maxillofacial surgery has been reported as treatment of OSAS by correcting base of tongue obstruction. Thirty patients with severe OSAS were evaluated to compare nasal CPAP and maxillofacial surgery. The goal was to determine if our surgical protocol was as effective as nasal CPAP. All patients initially underwent baseline diagnostic polysomnography to document OSAS. A nasal CPAP study was performed to determine the appropriate positive end-expiratory pressure. The patients in this study were using nasal CPAP, but they found it unacceptable as long-term treatment and elected surgery. Maxillofacial surgery consisted of maxillary, mandibular, and hyoid advancement. Polysomnography was performed six months following surgery and compared with the night 2 CPAP results. The parameters included in the investigation were the respiratory disturbance index (RDI), lowest SaO2, number of SaO2 falls below 90 percent, total sleep time (TST), REM sleep percent, stage 3-4 sleep percent, and wake after sleep onset. The mean RDI before treatment was 72.0 (SD 25.7). After completing therapy, the RDI from surgery and CPAP was 8.8 (SD 6.0) and 8.6 (SD 4.1), respectively. The mean low SaO2 prior to treatment was 61.0 (SD 13.5), and the CPAP results and postsurgical results were 86.2 (SD 5.5) and 86.1 (SD 4.2), respectively. An analysis of variance was used to examine the results, and there was no statistical difference between nasal CPAP and surgery for all respiratory variables.     

Patient compliance with nasal CPAP therapy for sleep apnea

Continuous positive airway pressure via the nasal route (nasal CPAP) is effective in reducing the frequency of occlusive and mixed patterns 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 system for 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). Twenty patients (83 percent) responded to the questionnaire. Sixteen responders used nasal CPAP during all nightly sleep time, and two used it for all but one and 2.5 hours of nightly sleep time, respectively. One individual used it on alternate nights, and one patient did not use it all. Thus, 17 of 20 (85 percent) responders were compliant. Including information about 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 is conscientiously applied and well-tolerated by most sleep apnea patients.     

Sleepwalking precipitated by treatment of sleep apnea with nasal CPAP

A 33-year-old man with a long history of snoring, observed apneic episodes, and excessive daytime sleepiness, underwent all-night polysomnography, which demonstrated severe obstructive sleep apnea. During the nasal CPAP trial, two episodes of sleepwalking were observed during a period of delta sleep rebound.     

Treatment of obstructive sleep apnea. A preliminary report comparing nasal CPAP to nasal oxygen in patients with mild OSA

Nasal CPAP is presently accepted as first-line therapy for obstructive sleep apnea, but a significant minority of patients do not tolerate nasal CPAP. The purpose of this study was to compare the benefits of nasal CPAP, nasal oxygen (O2), and placebo (air) using patients as their own controls. We studied eight men, aged 33 to 72 (mean 57 years), who had mild obstructive sleep apnea. To be eligible for study, patients had to have an apnea plus hypopnea index greater than or equal to 5, plus one or more of the following: blood pressure greater than 150/95 mm Hg, multiple sleep latency test mean score less than or equal to 10 minutes, or significant nocturnal cardiac ectopy. After a baseline study, patients received a month each of nocturnal O2 at 4 LPM and air at 4 LPM, presented in random order. The third month of treatment consisted of nasal CPAP (range 2.5 to 12.5 cm H2O). Patients underwent evaluation at baseline and after each month of treatment. It was concluded that oxygen was more effective in improving oxygenation and hypopneas than is nasal CPAP. However, oxygen did not reduce apneas or improve daytime hypersomnolence as well as nasal CPAP in patients with mild OSA. Oxygen might be considered as an alternate form of treatment for patients who are not hypersomnolent, or as an adjunct to nasal CPAP.     

Long-term nasal CPAP does not ameliorate obstructive sleep apnoea

Fifty-seven patients with obstructive sleep apnoea (OSA) were treated for at least six months with nasal continuous positive airway pressure (CPAP). At follow-up, sleep studies were performed in which CPAP was not used for the first half of the night. We compared the severity of OSA at follow-up without CPAP to the severity of OSA during the patient's initial diagnostic study. Apnoea and hypopnoea index (AHI) fell from 41.4 ± 7.5 (mean ±95% CI) to 34.8 ± 7.9 (p= 0.06 by Wilcoxon test) and minimum oxygen saturation rose from 71.6 ± 3.2 to 78.5 ± 2.6 (p<0.001). Some of this change may have been due to reduced REM sleep in the follow-up study (10.5±2.1% Total Sleep Time vs 7.4±2.4% TST, p<0.05). Long-term nasal CPAP was not associated with any reduction of obesity (BMI before CPAP 31.9 ± 1.0, after CPAP 31.7 ± 1.0 (p= 0.39). Systolic arterial pressure fell (before CPAP 143.0 ±4.5 mmHg, after CPAP 136.3 ± 4.6, p < 0.05) but diastolic pressure did not (before CPAP 88.5 ± 3.0 mmHg, after CPAP 85.6 ±2.9 mmHg, p = 0.11). We concluded that the effect of CPAP treatment for six or more months was a small fall in AHI and a small rise in minimum Sa0₂, but that this would be of marginal clinical significance, and may be artefactual. (Aust NZ J Med 1991; 21: 235–238.)