Reliability of respiratory event detection with continuous positive airway pressure in moderate to severe obstructive sleep apnea - comparison of polysomnography with a device-based analysis.

PURPOSE: Monitored polysomnography (PSG) is considered the gold standard technique to diagnose obstructive sleep apnea (OSA) and titrate continuous positive airway pressure (CPAP), the accepted primary treatment method. Currently, the American Academy of Sleep Medicine (AASM) considers automatic PAP therapy initiation at home comparable to laboratory titration and recommends telemonitoring-guided interventions. Advanced CPAP devices evaluate and report the residual apnea-hypopnea index (AHI). However, in order to control the effectiveness of the prescribed therapy outside of a PSG setting, the automatic event detection must provide reliable data. METHODS: A CPAP titration was performed in the sleep laboratory by PSG in patients with OSA. The residual event indices detected by the tested device (prismaLine, Loewenstein Medical Technology) were compared to the manually scored PSG indices. Results of the device (AHIFLOW) were compared according to the AASM scoring criteria 1A (AHI1A, hypopneas with a flow signal reduction of ≥ 30% with ≥ 3% oxygen reduction and/or an arousal) and 1B (AHI1B, hypopneas with a flow signal decrease by ≥ 30% with a ≥ 4% oxygen desaturation). RESULTS: In 50 patients with OSA, the mean PSG AHI1A was 10.5 ± 13.8/h and the PSG AHI1B was 7.4 ± 12.6/h compared to a mean device AHIFlow of 8.4 ± 10.0/h. The correlation coefficient regarding PSG AHI1A and AHIFlow was 0.968. The correlation regarding central hypopneas on the other hand was 0.153. There were few central events to be compared in this patient group. CONCLUSION: The device-based analysis showed a high correlation in the determination of residual obstructive AHI under therapy. The recorded residual respiratory event indices in combination with the data about leakage and adherence of the studied device provide reliable information for the implementation and follow-up of CPAP therapy in a typical group of patients with OSA. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Identifier: NCT04407949, May 29, 2020, retrospectively registered.

Non-invasive Ventilation: Effect of Vented and Non-vented Exhalation Systems on Inspiratory CO2 and O2 Concentrations, Ventilation, and Breathing Pattern.

INTRODUCTION: To increase CO2 elimination and to reduce work of breathing in hypercapnic patients, non-invasive ventilation (NIV) can be applied via mask either with non-vented CO2 exhalation systems or with vented systems with leak port. The effect of the exhalation system on CO2 rebreathing in the mask and total gas exchange remains widely unknown. Aim of this study was to compare the exhalation systems in terms of inspiratory O2 and CO2 concentrations, breathing patterns and gas exchange. METHODS: We prospectively examined 10 healthy subjects and 10 hypercapnic patients with both exhalation systems. O2 and CO2 were measured in the nose, in the mask, and in the ventilation circuit, and respiratory rate, tidal volume, and transcutaneous capnometry (PtcCO2) were recorded during the experiments. RESULTS: Using the non-vented system, CO2 concentrations in the mask were significantly higher in both subject groups, and PtcCO2 values in the patient group increased up to 3.6 mmHg compared to the vented system (p = 0.011). O2 concentrations increased with higher O2 flow rates, but were significantly lower in the vented settings in both groups. No effect in breathing pattern could be demonstrated during the measurement time. CONCLUSION: Using NIV, the chosen exhalation system influences CO2 and O2 concentrations under the mask, CO2 rebreathing from the mask and could influence the effectiveness of the ventilation support with regards to hypercapnia treatment. To compensate for relevant hypoxia, the O2 supplementation must be set up to a sufficient level under a vented system.

Effect of respiratory rate and size of cannula on pressure and dead-space clearance during nasal high flow in patients with COPD and acute respiratory failure.

Nasal high flow (NHF) is an efficient oxygenation tool for the treatment of respiratory failure. The study investigated the effect of breathing pattern on positive airway pressure and dead-space clearance by NHF. The breathing cycle during NHF was characterized in 26 patients with acute respiratory failure (ARF) and stable COPD and after mechanical ventilation (post-MV) via tracheostomy where also pressure was measured in the trachea. Dead-space clearance was measured in airway models during different breathing patterns. NHF reduced the respiratory rate (RR) and TI/TE through prolonging the TE; the TI/TE ranged between ≤0.5 observed in the COPD patients and ∼1.0 in the ARF patients. NHF via a standard medium-sized cannula interface generated a low-level expiratory pressure proportional to NHF rate and breathing flow; the median generated positive end-expiratory pressure was only 1.71 cmH2O at NHF 45 L/min. The dilution and purging of expired gas from a nasal cavity model were observed to occur at the end of expiration as expiratory flow slowed and the dynamic pressure decreased. The higher RR with shorter end-expiratory period resulted in reduced dead-space clearance by NHF; 20 L/min cleared 43 ± 2 mL at RR 15 min-1 vs. 9 ± 5 mL at RR 45 min-1, P < 0.001, which was increased at higher NHF rate. At lower RR, the clearance was similar between NHF rates 20 and 60 L/min. Higher NHF rates elevate positive airway pressure, and at the increased RR can improve the clearance. This may enhance gas exchange and lead to a reduction in the work of breathing.NEW & NOTEWORTHY During nasal high flow (NHF) an increased breathing frequency, which is commonly observed in acute respiratory failure, can lead to decreased dead-space clearance. Higher NHF rates increase the clearance and reduce the rebreathing which may eventually lower the respiratory rate and the work of breathing. Monitoring of the respiratory rate could be an important indicator of not only the respiratory function but also the NHF rate selection and the therapy efficacy.

Effects of endobronchial coils for endoscopic lung volume reduction on sleep in COPD patients with advanced pulmonary emphysema.

PURPOSE: Treatment of advanced pulmonary emphysema with endobronchial coils can improve clinical outcomes like quality of life (QOL). Yet, patients with chronic obstructive pulmonary disease (COPD) are also known to suffer from reduced sleep quality. The effect of coil therapy on sleep has not yet been investigated. The primary aim of this study was to investigate sleep efficiency before and after coil treatment. Secondly, we investigated the effects on nocturnal breathing pattern, QOL, and physical activity. METHODS: Polysomnography (PSG) testing was performed before (T0), 6 month after (T3), and 12 months after (T4) treatment with endobronchial coils. Further examinations included QOL by St George's Respiratory Questionnaire (SGRQ) and COPD assessment test (CAT), and physical activity using an accelerometer for 1 week after each visit. RESULTS: Of 21 patients, 14 completed the study: 6 women; mean age 58.0 ± 4.9 years; BMI 22.6 ± 4.6 kg/m2; FEV1 28.6 ± 7.1% predicted; residual volume (RV) 278.2 ± 49.4% predicted. Sleep efficiency did not vary between baseline and follow-up examinations (T0 69.0 ± 15.8%; T3 70.9 ± 16.0%; T4 66.8 ± 18.9%). Non-REM respiratory rate decreased compared to baseline (T0 19.4 ± 3.9/min; T3 17.8 ± 3.5/min; T4 17.1 ± 3.1/min (p = 0.041; p = 0.030) and QOL improved meeting the minimal clinically important difference (MCID) (SGRQ, T3 -12.8 units; T4 -7.1 units; CAT: T3 -5.6 units; T4 -3.4 units). No increase in physical activity was recorded (light activity T0 31.9 ± 9.9; T3 30.8 ± 16.9; T4 26.3 ± 10.6 h/week). CONCLUSIONS: Treatment with endobronchial coils did not influence objectively measured sleep quality or physical activity, but reduced nocturnal breathing frequency and improved QOL in severe emphysema patients. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02399514, First Posted: March 26, 2015.

Telemedicine Improves Continuous Positive Airway Pressure Adherence in Stroke Patients with Obstructive Sleep Apnea in a Randomized Trial.

BACKGROUND: The prevalence of obstructive sleep apnea (OSA) is very high in stroke patients, whereas the acceptance of positive airway pressure (PAP) therapy is low. Although telemedicine offers new options to increase acceptance, effective concepts and patient groups are not yet known. OBJECTIVE: The aim of this study was to investigate the effect of a telemedicine concept consisting of telemonitoring and support when usage time drops. METHODS: PAP naive stroke patients with apnea-hypopnea index (AHI) >15 were randomized in a prospective parallel design comparing home therapy with standard care (SC) as opposed to telemedicine care (TC) over a period of 6 months. The TC group received a standardized phone call to offer help and advice if the average weekly usage of PAP fell below 4 h/night. RESULTS: Eighty patients were included, 5 were lost to follow-up, 75 (20 females, age: 57.0 ± 9.9, body mass index: 30.9 ± 6.0 kg/m2, AHI: 39.4 ± 18.6) were evaluated. While inpatient usage was similar in both groups, a significant difference was identified after 6 months of receiving home therapy (TC: 4.4 ± 2.5 h, SC: 2.1 ± 2.2 h; p < 0.000063). On average, 4.7 ± 3.1 interventional phone calls were needed (173 calls in total, ranging from 0 to 10 calls per patient), primarily for the purpose of motivation (61.3%), mask problems (16.2%), nasopharyngeal complaints or humidification issues (11.2%), and technical questions (10.6%). Sleepiness (Epworth Sleepiness Scale [ESS]) differed significantly (TC: 3.7 + 3.2, SC: 6.1 + 4.1; p = 0.008), as well as systolic blood pressure, which was available in a subgroup of 55 patients (TC: 129.5 + 15.2 mm Hg, SC: 138.8 + 16.1 mm Hg; p = 0.034). CONCLUSION: A concept of telemonitoring and short telephone calls from the sleep lab raised PAP therapy adherence significantly in a group of stroke patients with moderate to severe OSA.

Mask humidity during CPAP: influence of ambient temperature, heated humidification and heated tubing.

PURPOSE: Mucosal drying during continuous positive airway pressure (CPAP) therapy is problematic for many patients. This study assessed the influence of ambient relative humidity (rH) and air temperature (T) in winter and summer on mask humidity during CPAP, with and without mask leak, and with or without heated humidification ± heated tubing. METHODS: CPAP (8 and 12 cmH2O) without humidification (no humidity [nH]), with heated humidification controlled by ambient temperature and humidity (heated humidity [HH]) and HH plus heated tubing climate line (CL), with and without leakage, were compared in 18 subjects with OSA during summer and winter. RESULTS: The absolute humidity (aH) and the T inside the mask during CPAP were significantly lower in winter versus summer under all applied conditions. Overall, absolute humidity differences between summer and winter were statistically significant in both HH and CL vs. nH (p < 0.05) in the presence and absence of mouth leak. There were no significant differences in aH between HH and CL. However, in-mask temperature during CL was higher (p < 0.05) and rH lower than during HH. In winter, CPAP with CL was more likely to keep rH constant at 80% than CPAP without humidification or with standard HH. CONCLUSION: Clinically-relevant reductions in aH were documented during CPAP given under winter conditions. The addition of heated humidification, using a heated tube to avoid condensation is recommended to increase aH, which could be useful in CPAP users complaining of nose and throat symptoms.

A randomized controlled trial to validate the Alice PDX ambulatory device.

BACKGROUND: Obstructive sleep apnea (OSA) is a highly prevalent condition; however, the majority of patients remain undiagnosed. There is a potential to expand the diagnostic capacity of sleep laboratories. The study objective was to validate a portable respiratory monitoring device (Alice PDX) against polysomnography (PSG) in the laboratory and to assess its reliability at home. METHODS: A total of 85 patients with suspected OSA (80% male, mean age 49.1±13.5 years, body mass index 29.7±6.9 kg/m2, Epworth Sleepiness Scale 10.0±5.1) were randomized to 3 diagnostic nights: 1 night simultaneous in-laboratory PSG and PDX recording; 1 night self-applied PDX at home, and 1 night in-laboratory PSG. Study data were manually scored according to American Academy of Sleep Medicine criteria. RESULTS: The Alice PDX was in diagnostic agreement with simultaneously recorded reference PSG in 96.4% of studies. In 2.4% of studies the in-laboratory PDX underestimated and in 1.2% of studies it overestimated the apnea hypopnea index (AHI). The difference between the AHI from the reference PSG and the home study was similar to the difference between the PSGs (2.79 vs 0.79, p=0.08). CONCLUSION: In a population with a high suspicion of OSA, the Alice PDX showed a high level of diagnostic agreement with a simultaneous PSG and performed valid home diagnostic studies for OSA. If manually scored, the portable device can be used by sleep specialists for diagnosing moderate-to-severe obstructive sleep apnea in cases with a high pretest probability for the disease over a wide range of disease severity. The technology can be deployed reliably outside of the sleep laboratory setting.

Non-invasive ventilation with intelligent volume-assured pressure support versus pressure-controlled ventilation: effects on the respiratory event rate and sleep quality in COPD with chronic hypercapnia.

BACKGROUND: COPD patients who develop chronic hypercapnic respiratory failure have a poor prognosis. Treatment of choice, especially the best form of ventilation, is not well known. OBJECTIVES: This study compared the effects of pressure-controlled (spontaneous timed [ST]) non-invasive ventilation (NIV) and NIV with intelligent volume-assured pressure support (IVAPS) in chronic hypercapnic COPD patients regarding the effects on alveolar ventilation, adverse patient/ventilator interactions and sleep quality. METHODS: This prospective, single-center, crossover study randomized patients to one night of NIV using ST then one night with the IVAPS function activated, or vice versa. Patients were monitored using polysomnography (PSG) and transcutaneous carbon dioxide pressure (PtcCO2) measurement. Patients rated their subjective experience (total score, 0-45; lower scores indicate better acceptability). RESULTS: Fourteen patients were included (4 females, age 59.4±8.9 years). The total number of respiratory events was low, and similar under pressure-controlled (5.4±6.7) and IVAPS (8.3±10.2) conditions (P=0.064). There were also no clinically relevant differences in PtcCO2 between pressure-controlled and IVAPS NIV (52.9±6.2 versus 49.1±6.4 mmHg). Respiratory rate was lower under IVAPS overall; between-group differences reached statistical significance during wakefulness and non-rapid eye movement sleep. Ventilation pressures were 2.6 cmH2O higher under IVAPS versus pressure-controlled ventilation, resulting in a 20.1 mL increase in breathing volume. Sleep efficiency was slightly higher under pressure-controlled ventilation versus IVAPS. Respiratory arousals were uncommon (24.4/h [pressure-controlled] versus 25.4/h [IVAPS]). Overall patient assessment scores were similar, although there was a trend toward less discomfort during IVAPS. CONCLUSION: Our results show that IVAPS NIV allows application of higher nocturnal ventilation pressures versus ST without affecting sleep quality or inducing ventilation- associated events.

Nasal high flow reduces dead space.

Recent studies show that nasal high flow (NHF) therapy can support ventilation in patients with acute or chronic respiratory disorders. Clearance of dead space has been suggested as being the key mechanism of respiratory support with NHF therapy. The hypothesis of this study was that NHF in a dose-dependent manner can clear dead space of the upper airways from expired air and decrease rebreathing. The randomized crossover study involved 10 volunteers using scintigraphy with 81mKrypton (81mKr) gas during a breath-holding maneuver with closed mouth and in 3 nasally breathing tracheotomized patients by volumetric capnography and oximetry through sampling CO2 and O2 in the trachea and measuring the inspired volume with inductance plethysmography following NHF rates of 15, 30, and 45 l/min. The scintigraphy revealed a decrease in 81mKr gas clearance half-time with an increase of NHF in the nasal cavities [Pearson's correlation coefficient cc = -0.55, P < 0.01], the pharynx (cc = -0.41, P < 0.01), and the trachea (cc = -0.51, P < 0.01). Clearance rates in nasal cavities derived from time constants and MRI-measured volumes were 40.6 ± 12.3 (SD), 52.5 ± 17.7, and 72.9 ± 21.3 ml/s during NHF (15, 30, and 45 l/min, respectively). Measurement of inspired gases in the trachea showed an NHF-dependent decrease of inspired CO2 that correlated with an increase of inspired O2 (cc = -0.77, P < 0.05). NHF clears the upper airways of expired air, which reduces dead space by a decrease of rebreathing making ventilation more efficient. The dead space clearance is flow and time dependent, and it may extend below the soft palate. NEW & NOTEWORTHY: Clearance of expired air in upper airways by nasal high flow (NHF) can be extended below the soft palate and de facto causes a reduction of dead space. Using scintigraphy, the authors found a relationship between NHF, time, and clearance. Direct measurement of CO2 and O2 in the trachea confirmed a reduction of rebreathing, providing the actual data on inspired gases, and this can be used for the assessment of other forms of respiratory support.

Telemonitoring of home exercise cycle training in patients with COPD.

BACKGROUND: Regular physical activity is associated with reduced mortality in patients with chronic obstructive pulmonary disease (COPD). Interventions to reduce time spent in sedentary behavior could improve outcomes. The primary purpose was to investigate the impact of telemonitoring with supportive phone calls on daily exercise times with newly established home exercise bicycle training. The secondary aim was to examine the potential improvement in health-related quality of life and physical activity compared to baseline. METHODS: This prospective crossover-randomized study was performed over 6 months in stable COPD patients. The intervention phase (domiciliary training with supporting telephone calls) and the control phase (training without phone calls) were randomly assigned to the first or the last 3 months. In the intervention phase, patients were called once a week if they did not achieve a real-time monitored daily cycle time of 20 minutes. Secondary aims were evaluated at baseline and after 3 and 6 months. Health-related quality of life was measured by the COPD Assessment Test (CAT), physical activity by the Godin Leisure Time Exercise Questionnaire (GLTEQ). RESULTS: Of the 53 included patients, 44 patients completed the study (forced expiratory volume in 1 second 47.5%±15.8% predicted). In the intervention phase, daily exercise time was significantly higher compared to the control phase (24.2±9.4 versus 19.6±10.3 minutes). Compared to baseline (17.6±6.1), the CAT-score improved in the intervention phase to 15.3±7.6 and in the control phase to 15.7±7.3 units. The GLTEQ-score increased from 12.2±12.1 points to 36.3±16.3 and 33.7±17.3. CONCLUSION: Telemonitoring is a simple method to enhance home exercise training and physical activity, improving health-related quality of life.

Nasal high flow reduces hypercapnia by clearance of anatomical dead space in a COPD patient.

Chronic obstructive pulmonary disease (COPD) with hypercapnia is associated with increased mortality. Non-invasive ventilation (NIV) can lower hypercapnia and ventilator loads but is hampered by a low adherence rate leaving a majority of patients insufficiently treated. Recently, nasal high flow (NHF) has been introduced in the acute setting in adults, too. It is an open nasal cannula system for delivering warm and humidified air or oxygen at high flow rates (2-50 L/min) assisting ventilation. It was shown that this treatment can improve hypercapnia. The mechanism of reducing arterial carbon dioxide (CO2) is proposed through a reduction in nasal dead space ventilation, but there are no studies in which dead space volume was measured in spontaneously breathing subjects. In our case report we measured in a tracheostomized COPD patient CO2 and pressure via sealed ports in the tracheostomy cap and monitored transcutaneous CO2 and tidal volumes. NHF (30 L/min mixed with 3 L/min oxygen) was administered repeatedly at 15-minutes intervals. Inspired CO2 decreased instantly with onset of NHF, followed by a reduction in transcutaneous/arterial CO2. Minute ventilation on nasal high flow was also reduced by 700 ml, indicating that nasal high flow led to a reduction of dead space ventilation thereby improving alveolar ventilation. In conclusion, NHF assist ventilation through clearance of anatomical dead space, which improves alveolar ventilation. Since the reduction in hypercapnia was similar to that reported with effective NIV treatment NHF may become an alternative to NIV in hypercapnic respiratory failure.

Effect of APAP and heated humidification with a heated breathing tube on adherence, quality of life, and nasopharyngeal complaints.

PURPOSE: Positive airway pressure (PAP) therapy adherence can be affected by rhinitis sicca and xerostomia complaints. Additional heated humidification (HH) is the appropriate method when such complaints arise. The aim of this study was to determine if HH with a supplementary heated breathing tube can increase adherence, reduce subjective nasopharyngeal complaints (NPC), and improve sleepiness (ESS: Epworth Sleepiness Scale) and quality of life (FOSQ: Functional Outcome of Sleep Questionnaire). METHODS: We subdivided 72 obstructive sleep apnea (OSA) patients into two groups before therapy initiation. The NPC risk group consists of subjects with NPC and the low-risk group without. The risk group was identified by a score of >9 in a 5-item 25-point NPC questionnaire and pathological ESS. All patients were eligible for automatic CPAP devices (APAP), which were randomly configured with or without HH during 6 weeks. RESULTS: The adherence differences with and without HH were not significant in the NPC risk group (330 ± 103 vs. 281 ± 118 min/night) and in the low-risk group (330 ± 116 vs. 321 ± 89). NPC and ESS scores in the risk group were both significantly reduced with HH. Daily function (FOSQ) in the risk group was significantly improved with HH (90.0 ± 11.9 vs. 82.0 ± 12.0 (p < 0.05)). CONCLUSION: HH showed a tendency to improve APAP adherence. The adherence in both groups was quite high, and for that reason, it is difficult to show a statistically significant effect. A differentiation into NPC risk groups before starting PAP treatment is useful. HH reduces side effects and sleepiness and improves quality of life in an NPC risk group.

Transbronchial Catheter Aspiration and Transbronchial Needle Aspiration in the Diagnostic Workup of Peripheral Lung Lesions.

PURPOSE: Increasingly frequent, it is clinically indicated to obtain tissue from a peripheral lung lesion (PLL) to yield a pathological diagnosis. The aim of the present study was to evaluate the diagnostic sensitivity of transbronchial needle aspiration (TBNA) and transbronchial catheter aspiration (TBCA) in addition to transbronchial forceps biopsy (TBB) at conventional bronchoscopy. METHODS: Eligible patients showing a PLL on computed tomography scans were included in the study. In all patients, following TBB, TBNA and TBCA were employed in randomised order under fluoroscopy. RESULTS: Fourty-eight patients were enrolled, of whom 46 patients with 46 PLLs were included in the analysis. The mean ± SD diameter of the PLL was 27.0 ± 13.3 mm. The overall sensitivity for all modalities was 69.6%; PLL ≤20 or >20 and ≤30 mm in diameter showed a sensitivity of 60.0 and 72.2%, respectively. For malignant PLL (n = 33), the combined sensitivity of TBNA + TBCA versus TBB was significantly higher (63.6 vs. 33.3%, p ≤ 0.05), and could not further be improved by TBB. For benign PLL, TBB was superior to TBNA + TBCA (76.9 vs. 38.5%). CONCLUSIONS: TBB, TBNA and TBCA are complementary to one another. Combining the three techniques, even allows transbronchial specimen collection of PLL <3 cm in diameter at conventional bronchoscopy.

Effects of nasal insufflation on arterial gas exchange and breathing pattern in patients with chronic obstructive pulmonary disease and hypercapnic respiratory failure.

High flow nasal insufflations (NI) can improve gas exchange and alleviate dyspnea in patients with acute respiratory failure. In the present study we investigated the effects of high flow nasal insufflations in COPD patients with chronic hypercapnic respiratory failure (HRF). Seventeen patients with severe COPD and HRF were recruited. We delivered a mixture of 20 L/min room air and 2 L/min O(2) through a nasal cannula either into both nostrils (NI) or into one nostril (Partial NI). Respiratory pattern and PaCO(2) responses under NI were compared with low flow oxygen of 2 L/min. High flow nasal insufflations led to a systematic reduction in respiratory rate from 19.8 ± 4.2 at baseline to 18.0 ± 4.7 during NI (p < 0.008) and 18.1 ± 5.2 breaths/min during Partial NI (P < 0.03). The mean group inspiratory duty cycle (T(I)/T(T)) and mean group PaCO(2) remained constant between all experimental conditions. Individual responses to NI were heterogeneous: six patients demonstrated marked reductions in respiratory rate (>20% fall from baseline), another group (n = 6) demonstrated no change in respiratory rate but marked reductions in arterial carbon dioxide of more than 8 mmHg. In conclusion, high flow (20 L/min) nasal insufflations of warm and humidified air during wakefulness for 45 min reduced respiratory rate without deterioration of hypercapnia. Our data indicate that high flow NI improved efficiency of breathing and may be used as an adjunct to low flow oxygen for preventing hypercapnic respiratory failure in severely ill COPD patients.

Quality of life, compliance, sleep and nasopharyngeal side effects during CPAP therapy with and without controlled heated humidification.

PURPOSE: To determine the effect of a controlled heated breathing tube humidifier (cHH) on the quality of life (QOL), compliance and nasopharyngeal side effects during continuous positive airway pressure (CPAP) therapy in patients with obstructive sleep apnea syndrome (OSAS) in comparison with conventional CPAP. METHODS: In this prospective randomised cross-over study, 44 patients with OSAS were investigated. During the first two consecutive treatment nights monitored by polysomnography, patients were randomly assigned to receive CPAP with or without cHH. Patients were then randomised to receive one of the treatment modalities at home for 4 weeks. Compliance was recorded and questionnaires assessing side effects and QOL were administered. RESULTS: Sleep parameters measured during the nights in the sleep laboratory did not change. The same result applied to QOL and compliance measured after 4 weeks. During the first two nights we found significant differences between CPAP with and without cHH for dryness of mouth (2.0 ± 1.4 vs. 1.4 ± 1.6) in favour of cHH (p < 0.05). Evaluation of coldness of the face showed improvement whereas waking up due to wetness on the face (0.3 ± 0.6 vs. 0.6 ± 0.8; p < 0.05) was slightly increased. Data after 4 weeks confirmed these findings with further subjective improvement in the reduction of side effects. CONCLUSIONS: By the using of the technology of cHH QOL and compliance did not improve. The side effects of CPAP therapy without humidification with respect to nasopharyngeal dryness, however, was reduced immediately as well as during the first weeks of treatment.

Pressure-relief continuous positive airway pressure vs constant continuous positive airway pressure: a comparison of efficacy and compliance.

OBJECTIVES: To compare polysomnographic data and compliance in sleep apnea patients receiving continuous positive airway pressure (CPAP) and pressure-relief CPAP (PRCPAP) [C-flex; Respironics; Murrysville, PA] as first treatment in the sleep laboratory and subsequently at home. DESIGN: A prospective, randomized, crossover design was used in the sleep laboratory, and a prospective randomized design was used at home. PATIENTS: Data were collected from 52 sleep apnea patients for whom CPAP was used for the first time. INTERVENTIONS: Treatment with constant CPAP and PRCPAP. MEASUREMENTS AND RESULTS: Patients with a first-time diagnosis of obstructive sleep apnea syndrome (OSAS) underwent conventional CPAP titration. Thereafter, polysomnography was performed at the titrated pressure using both the fixed CPAP pressure mode and the PRCPAP mode in a randomized crossover approach. The patients were then discharged home for 7 weeks of treatment with the last-applied treatment mode, and compliance data were established at the end of that time. The average apnea-hypopnea index was 53.3/h in the "diagnostic night," 5.8/h with CPAP, and 7.0/h with PRCPAP. The native arousal index was 35.2/h, 12.6/h with CPAP, and 12.9/h with PRCPAP (not significant [NS]). The central apnea index was 0.7/h with CPAP and 1.2/h with PRCPAP (p < 0.05). Compliance after 7 weeks was, on average, 9.4 min longer with PRCPAP than with CPAP (NS). Evaluation of a 13-item questionnaire showed scores of 16.4 for PRCPAP and 18.1 for constant CPAP (NS) [the fewer the complaints, the lower the score]. With regard to oral dryness, the score with PRCPAP (1.4) was significantly lower than with constant CPAP (1.9) [p < 0.05]. This difference was no longer detectable after 7 weeks. CONCLUSION: In terms of the effectiveness in treating obstructive sleep apnea, PRCPAP and constant CPAP are comparable. During the first night of treatment, patients receiving PRCPAP had less dryness of mouth; over a period of 7 weeks, this difference disappeared. Nightly use of the device was comparable in both groups. PRCPAP is therefore a new ventilation mode that enables effective treatment of OSAS patients. Further studies should be done to investigate the effects of expiratory pressure lowering in low-compliance patients and patients requiring CPAP > 9 cm H(2)O or experiencing dry mouth with CPAP.

Tongue-muscle training by intraoral electrical neurostimulation in patients with obstructive sleep apnea.

STUDY OBJECTIVES: To investigate the efficacy of tongue-muscle training by electrical neurostimulation of the upper-airway muscles as an alternative therapy option for obstructive sleep apnea syndrome. DESIGN: A randomized, placebo-controlled, double-blind study. SETTING: Department of pneumology and sleep laboratory, University of Witten/Herdecke, Germany. PATIENTS: 67 patients with an apnea-hypopnea index of 10 to 40 per hour were randomly assigned to 2 groups: a treatment group of 33 patients (mean age, 50.8 +/- 12.1 years; mean body mass index, 29.1 +/- 4.4 kg/m2) and a placebo group of 34 patients (mean age, 53.3 +/- 11.3 years; mean body mass index, 28.9 +/- 4.9 kg/m2). Fifty-seven patients completed the study. INTERVENTIONS: Tongue-muscle training during the daytime for 20 minutes twice a day for 8 weeks. MEASUREMENTS AND RESULTS: Treatment efficacy was examined by polysomnography. Snoring, but not apnea-hypopnea index, improved with stimulation (snoring baseline, 63.9 +/- 23.1 epochs per hour; stimulation training, 47.5 +/- 31.2; P < .05) but not with placebo training (snoring baseline, 62.4 +/- 26.1 epochs per hour; placebo, 62.1 +/- 23.8; NS.). CONCLUSIONS: Although tongue-muscle training cannot generally be recommended for the treatment of sleep apnea, the method has proven to be effective in the treatment of snoring.