M. Willemen

A promising concept of combination therapy for positional obstructive sleep apnea

PurposeThe objective of this randomized controlled trial was to assess the additional effect of a chest-worn sleep position trainer (SPT) in patients with residual supine-dependent obstructive sleep apnea (sdOSA) under mandibular advancement device (MAD) therapy.MethodsBaseline and follow-up polysomnography with MAD were performed. Twenty patients with sdOSA under MAD therapy underwent two consecutive randomized polysomnographies: one with SPT and one with combination of SPT + MAD. Data are presented as median (quartile 1, quartile 3).ResultsThe SPT reduced the time spent in supine sleeping position compared to baseline and MAD therapy. Both MAD and SPT were individually effective in reducing the overall apnea/hypopnea index (AHI) significantly when compared to baseline from 20.8 (15.1; 33.6)/h at baseline to 11.0 (6.7; 13.8)/h and to 11.1 (3.5; 17.7)/h with MAD or SPT, respectively. The combination of SPT + MAD further reduced the overall AHI to 5.7 (3.6; 7.4), which was significantly lower than with MAD alone (p < 0.001) and SPT alone (p < 0.008), respectively.ConclusionsThe results of this study indicate that combination of SPT + MAD leads to a higher therapeutic efficacy in patients with sdOSA under MAD therapy when compared to one of the treatment modalities alone.

Two months follow up of auto-CPAP treatment in patients with obstructive sleep apnoea

BACKGROUND Continuous positive airway pressure (CPAP) with fixed mask pressure is the current standard treatment for obstructive sleep apnoea (OSA). Auto-CPAP devices apply at any time the minimally required pressure to normalise breathing and may improve patient comfort and compliance. We present an open descriptive study of auto-CPAP treatment at home in patients previously managed with conventional CPAP. METHODS Fifteen patients with obstructive sleep apnoea (OSA), previously treated for at least one year with standard CPAP, were followed prospectively for a two month period on auto-CPAP. Outcome measures were both subjective evaluation by the patients and objective (polysomnographic) data obtained at one and two months of follow up. RESULTS The Epworth sleepiness score did not change significantly between baseline and follow up after one and two months and no systematic changes in CPAP related side effects were reported. Compared with the baseline polysomnographic values without treatment, a significant improvement in both respiratory and sleep parameters was observed during auto-CPAP. These results were not significantly different from those obtained with standard CPAP. A significant correlation was found between the effective CPAP pressure (Peff) and the amount of time spent below Peff during auto-CPAP treatment (r = 0.6, p = 0.01). CONCLUSION Long term auto-CPAP treatment in these patients with severe OSA appears to provide comparable efficacy to that of standard CPAP treatment.

Pilot Study of a Novel Mandibular Advancement Device for the Control of Snoring

Objective Mandibular advancement devices (MADs) have been introduced as a conservative, non-invasive treatment for socially disturbing snoring and mild obstructive sleep apnea (OSA). A prospective, non-randomized pilot study was conducted to investigate the efficacy, feasibility, side-effects and compliance of Somnoguard®, an immediately intraorally adaptable MAD made from thermoplastic material. Material and Methods Twenty consecutive heavy snorers with a respiratory disturbance index of <20 events/h were prospectively selected. Prior to the adaptation of the appliance, ambulatory polygraphy was carried out without a MAD. After a 1-month habituation period, a polygraphic evaluation was carried out with the device. Treatment success was defined as a reduction in the apnea–hypopnea index (AHI) of at least 50%. Results The results indicated a success rate of 65%. The AHI decreased from 8.4±2.9 events/h at baseline to 3.9±1.8 events/h with the device (p=0.001). At 1-month follow-up, significant reductions in the snoring index (p<0.001) and the Epworth Sleepiness Scale (ESS) score (p=0.036) were noted. At 6-month follow-up, similar results were achieved, with significant drops in the snoring index (p=0.025) and ESS score (p=0.033). Conclusion We conclude that immediate intraoral adaptation of a low-cost fabricated “one-size-only” MAD is a feasible and well-tolerated treatment for snoring and mild OSA. Further research is needed to evaluate this thermoplastic appliance as a strategy to “screen” the efficacy of MAD treatment in the individual patient with a less expensive appliance before constructing a more expensive custom-made MAD.

Adjustable Tongue Advancement for Obstructive Sleep Apnea: A Pilot Study

Objectives: Surgical treatment of obstructive sleep apnea (OSA) caused by hypopharyngeal collapse of the upper airway can be considered in patients who are intolerant to continuous positive airway pressure (CPAP). The present procedures addressing the hypopharynx are invasive and have substantial morbidity and limited efficacy. Methods: Ten patients (mean age, 44 years) with moderate to severe OSA, ie, an apnea-hypopnea index (AHI) between 15 and 50, with CPAP intolerance were included in a prospective, nonrandomized, multicenter study to evaluate the feasibility, safety, and efficacy of a novel tongue advancement procedure. The procedure consists of the implantation of a tissue anchor in the tongue base and an adjustment spool at the mandible. Titration of this tissue anchor results in advancement of the tongue and a patent upper airway. Results: The mean AHI decreased from 22.8 at baseline to 11.8 at the 6-month follow-up (p = 0.007). The Epworth Sleepiness Scale score decreased from 11.4 at baseline to 7.7 at the 6-month follow-up (p = 0.094), and the snoring score decreased from 7.5 at baseline to 3.9 at the 6-month follow-up (p = 0.005). Four technical adverse events were noted, and 1 clinical adverse event occurred. Conclusions: Adjustable tongue advancement is a feasible and relatively safe way to reduce the AHI and snoring in selected patients with moderate to severe OSA and CPAP intolerance. Technical improvements and refinements to the procedure are ongoing.

Central sleep apnea after interrupting longterm acetazolamide therapy

One month administration of acetazolamide (ACET) (at sea level) improves periodic breathing and decreases the number of central apneas (CA) (De Backer et al., 1995 Am. J. Respir. Crit. Care Med. 151, 87-91) in nonhypercapnic central apnea syndrome. It remains unclear whether cessation of therapy would provoke recurrence of symptoms. In the present study we evaluated the number of CA after 1 and 6 months interruption of ACET therapy. Eight patients with central sleep apnea were included [central apnea index (CAI) > 5 or apnea and hypopnea index (AHI) > 10 and obstructive apnea index (OAI) < 5]. Polysomnography was repeated once after 1 month treatment (N2), after 1 month off treatment (N3) and after 6 months off treatment. CAI (25 +/- 10 at N1) decreased during N2 (4 +/- 2) and N3 (5 +/- 3) and remained low after N4 (3 +/- 1). However an increase in the number of obstructive apneas and central hypopneas could be observed together with a shift from central apnea to hypopnea after N4. Maybe ACET induces a long lasting resetting of the CO2 threshold which is still present after interruption of the therapy.

Influence of longterm CPAP therapy on CO2 drive in patients with obstructive sleep apnea

According to recent publications, the values of the hypercapnic ventilatory responses (HCVR) in normocapnic obstructive sleep apnea (OSA) patients are highly variable, but they are usually within the normal range. In our study, CPAP therapy during 1 month did not seem to influence the HCVR [Verbraecken, J., De Backer, W., Willemen, M., De Cock, W., Wittesaele, W., Van de Heyning, P., 1995. Respir. Physiol. 101, 279-287]. It is, however, not well studied whether long term (1 year) CPAP therapy can influence HCVR in normocapnic patients. Therefore, we evaluated the effect of 1 year CPAP therapy on CO(2) drive in 20 OSA patients. The slope of HCVR (SHCVR) changed from 2.35+/-0.21 L min(-1) mmHg(-1) (control) to 1.66+/-0.16 L min(-1) mm Hg(-1) (P=0.04), but the mean within subject coefficient of variation in repeated measurements of SHCVR in treated and untreated OSA patients was not statistically different. Pa(O(2)) increased from 72+/-2 mm Hg to 80+/-2 (1 year) mm Hg. We conclude that CPAP therapy improves daytime gas exchange in normocapnic OSA and may possibly decrease CO(2) drive (slope) after a treatment period of 1 year.

Aortic root diameter and nasal intermittent positive airway pressure treatment in Marfan's syndrome

We report on a patient with Marfans syndrome, with coexistent obstructive sleep hypopnea (OSH) and restrictive lung disease, complicated by respiratory insufficiency, who was successfully treated with nasal intermittent positive airway pressure (NIPPV) and oxygen. NIPPV therapy turned out to be effective on arterial gas exchange and well tolerated. Moreover, progressive dilatation of the aortic root was attenuated during NIPPV, but could, however, not be reversed. We hypothetized that (at least partially) a decrease of nocturnal intrathoracic pressures could explain this.

Continuous Positive Airway Pressure and Lung Inflation in Sleep Apnea Patients

Background: It was shown in normals that an important decrease in upper airway resistance can be obtained with continuous positive airway pressure (CPAP). It was suggested that lung inflation in patients with sleep apnea syndrome (SAS) could also be a mechanism of action of CPAP. Objective: In the present study we wanted to evaluate the effects of nocturnal CPAP on the daytime lung function pattern in patients with SAS. Methods: We measured arterial blood gases and possible changes in static lung volumes in 57 SAS patients (37 with normal lung function, 10 with COPD and 10 with restrictive lung disease) after at least one month of CPAP therapy. Results: A significant increase in PaO2 (from 79 to 84 mm Hg, p = 0.01) and a decrease in AaDO2 (from 23 ± 1 to 16 ± 1, p < 0.01) was only observed in SAS patients with normal lung function. This improved gas exchange was parallelled by a small but non significant change in the FRC (from 96.5 ± 3.2 to 105.4 ± 3.7%pred, p = 0.07) and TLC (from 101.3 ± 1.7 to 104.1 ± 1.4%pred, p = 0.15). Similar changes in TLC and FRC were also observed in SAS patients with obstructive and restrictive lung disease. Conclusions: Chronic nocturnal CPAP therapy can improve daytime gas exchange and may influence lung inflation during the daytime. The small changes seem to be a functional effect but of no clinical relevance.

Influence of uvulopalatopharyngoplasty on α-EEG arousals in nonapnoeic snorers

Arousals are more numerous in heavy snorers than in nonsnorers and might be a cause of excessive daytime sleepiness (EDS) in these patients. The present study investigated whether treatment of snoring by uvulopalatopharyngoplasty (UPPP) had an influence on sleep microstructure in nonapnoeic snorers. The polysomnographic records of 10 nonapnoeic snorers were reviewed retrospectively and arousals scored according to the American Sleep Disorders Association (ASDA) 3 s definition. Scores for snoring, EDS and polysomnographic data were compared before and after UPPP (mean (+/-SD) time interval 249 +/- 183 days). UPPP resulted in a subjective improvement of snoring and a significant decrease in the arousal index (mean 14.6, 95% confidence interval (95% CI) 8.5-20.8 vs mean 9.1, 95% CI 6.6-11.5) (p = 0.01). EDS and the amount of slow-wave sleep remained unchanged. Uvulopalatopharyngoplasty resulted in an improvement of subjective snoring and a significant decrease of arousals in nonapnoeic snorers. Although these data do not provide any insight into whether the improvement observed can be maintained on a long-term basis, uvulopalatopharyngoplasty can be considered as a useful treatment modality to reduce sleep fragmentation and snoring in nonapnoeic snorers.

Relationship between CO2 drive and characteristics of apneas in obstructive and central sleep apnea

Previously we showed that CO2 drive is increased in patients with obstructive sleep apnea (OSA). In the present study we would like to evaluate a possible relationship between CO2 drive and characteristics of apneas in obstructive and central sleep apnea (CSA). We compared the hypercapnic ventilatory response (HCVR) between patients with OSA and CSA. HCVR was correlated with total event time and mean event duration in both groups. 17 normocapnic patients in each group and 14 controls were studied. The apnea patients were matched for apnea-hypopnea index, age, sex, and BMI. SHCVR (slope) tended to be higher in apnea patients than in controls without statistical significancy: controls 1.65 (0.16), CSA 2.17 (0.22), OSA 2.55 (0.35) (l/min per mmHg) (P = 0.13). A significant correlation was found between HCVR and event time in CSA (0.52, P = 0.04) and between HCVR and apnea mean duration in OSA (r = 0.52, P = 0.04). We conclude that while CO2 drive was not statistically increased in both apnea types, small changes can contribute to breathing instability and may increase the total event time (in CSA) but may also shorten the apnea duration (in OSA).