Continuous Positive Airway Pressure Titration Research Articles

The effects of heated humidifier in continuous positive airway pressure titration

BackgroundPrevious studies have shown that routine heated humidifier (HH) do not provide any benefit during continuous positive airway pressure (CPAP) titration if there are no significant naso-pharyngeal symptoms. In clinical practice, nasal diseases and upper airway symptoms are very common. This study investigates the effects of HH during CPAP titration in subjects with or without naso-pharyngeal symptoms.MethodsFifty-two patients who received polysomnography with CPAP titration were randomly assigned to HH and non-HH groups. Their nasal cavity, pharynx, and naso-pharynx were evaluated before CPAP titration, and a questionnaire on subjective sensation, including naso-pharyngeal symptoms, willingness to further use CPAP, and sleep improvement, was used. Objective (e.g., leak, apnea–hypopnea index (AHI) reduction, and optimal CPAP pressure level) and subjective data were analyzed between the two groups.ResultsIn subjective sensation, the HH group did not have any benefit in further willingness to use CPAP and in sleep improvement, but had improved naso-pharyngeal symptoms (p = 0.043). There were no significant differences in leak, AHI reduction, and optimal CPAP pressure, even in patients with significant naso-pharyngeal symptoms.ConclusionRoutine use of HH is not necessary during CPAP titration regardless of naso-pharyngeal symptoms.

Factors that predict adherence to continuous positive airway pressure treatment in obstructive sleep apnea patients: A prospective study in Japan

As adherence to continuous positive airway pressure (CPAP) therapy is crucial in the successful management of obstructive sleep apnea (OSA), identification of the many factors that affect adherence is important. To identify these factors among OSA patients in Japan, a nation with a unique health insurance system, complete sets of data were collected from 101 patients who had undergone overnight diagnostic polysomnography and 6 months of therapy, and the data were subjected to univariate and multivariate analysis. The data included patient responses to sets of questionnaires containing items regarding a variety of factors that the patients had completed before undergoing overnight polysomnography for CPAP titration and initiating use of a treatment device. At the end of the treatment period, the participants were classified into 1 of 3 (nonadherence, poor adherence, and good adherence) CPAP adherence groups for analysis of differences among them. Multiple regression analysis of the variables identified as significant by univariate analysis (adjusted R2= 0.370) indicated that CPAP adherence is positively associated with relatively high sleep efficiency at the time of titration (P < 0.01), earlier bedtime (P < 0.001), worse subjective sleep quality before therapy initiation (P = 0.001), higher motivation to use CPAP before therapy initiation (P < 0.05), and professional status as an occupational driver (P < 0.05). Analysis of the results indicates that CPAP adherence in Japanese OSA patients is associated with higher motivation to use CPAP but not with income level, which may be related to the uniqueness of the Japanese health insurance system.

Comparison of conventional continuous positive airway pressure to continuous positive airway pressure titration performed with sleep endoscopy

To evaluate the effect and obtain a pressure value of continuous positive airway pressure (CPAP) under direct visualization using drug-induced sleep endoscopy (DISE) and compare the pressure values with values obtained using conventional CPAP. Prospective, double-blinded, cohort study. Sixteen patients with obstructive sleep apnea syndrome (OSAS) were included in the study. Each patient underwent polysomnographic evaluation. After diagnosis of OSAS, patients underwent conventional CPAP titration. Patients were then taken to the operating theatre and put under sedation, where CPAP titration with nasendoscopy was performed (DISE CPAP). There were no statistically significant differences between the two techniques regarding pressure levels that decreased apneas in conventional CPAP and provided sufficient opening during DISE CPAP. Results with conventional CPAP titration and endoscopy-assisted CPAP titration showed no statistically significant difference. Endoscopy-assisted CPAP is a cheaper and less time consuming alternative to conventional CPAP and has similar results.

Comparison between the Apnea-Hypopnea Indices Determined by the REMstar Auto M Series and Those Determined by Standard In-Laboratory Polysomnography in Patients with Obstructive Sleep Apnea

Continuous positive airway pressure (CPAP) is an effective treatment for obstructive sleep apnea (OSA). After performing an initial titration study, most physicians do not have the CPAP equipment retitrated unless the patient complains about the CPAP use. Several automated CPAP devices are used clinically that can detect upper airway obstructive events and provide information about residual events while patients are on CPAP. The aim of this study was to compare the apnea-hypopnea index (AHI) determined by automated CPAP devices to that obtained from polysomnography. Patients with OSA underwent polysomnography for CPAP titration using the REMstar Auto M-series. The initial two hours of CPAP titration were spent at a subtherapeutic pressure of 4 cmH(2)O so that more breathing events could be observed. The correlations between the simultaneous determination of the AHI with polysomnography (AHI-PSG) and the automated device (AHI-RAM) during the subtherapeutic, therapeutic and overall phases were evaluated. In addition, the apnea index (AI) and the hypopnea index (HI) were each evaluated separately. Sixty patients were enrolled. The mean AHI on diagnostic PSG was 35.2±2.6 events/hour. Strong correlations were observed between the AHI-PSG and the AHI-RAM (subtherapeutic: r=0.958, p<0.001; therapeutic: r=0.824, p<0.001; overall: r=0.927, p<0.001). A slightly stronger correlation was observed between the AI values, whereas a weaker correlation was observed between the HI values in all three phases. Strong correlations between the AHI-PSG and the AHI-RAM were observed. The correlations were weakened when the analysis was limited to the HI and the therapeutic phase.

The Performance of Two Automatic Servo-Ventilation Devices in the Treatment of Central Sleep Apnea

This study was conducted to evaluate the therapeutic performance of a new auto Servo Ventilation device (Philips Respironics autoSV Advanced) for the treatment of complex central sleep apnea (CompSA). The features of autoSV Advanced include an automatic expiratory pressure (EPAP) adjustment, an advanced algorithm for distinguishing open versus obstructed airway apnea, a modified auto backup rate which is proportional to subject's baseline breathing rate, and a variable inspiratory support. Our primary aim was to compare the performance of the advanced servo-ventilator (BiPAP autoSV Advanced) with conventional servo-ventilator (BiPAP autoSV) in treating central sleep apnea (CSA). A prospective, multicenter, randomized, controlled trial. Five sleep laboratories in the United States. Thirty-seven participants were included. All subjects had full night polysomnography (PSG) followed by a second night continuous positive airway pressure (CPAP) titration. All had a central apnea index ≥ 5 per hour of sleep on CPAP. Subjects were randomly assigned to 2 full-night PSGs while treated with either the previously marketed autoSV, or the new autoSV Advanced device. The 2 randomized sleep studies were blindly scored centrally. Across the 4 nights (PSG, CPAP, autoSV, and autoSV Advanced), the mean ± 1 SD apnea hypopnea indices were 53 ± 23, 35 ± 20, 10 ± 10, and 6 ± 6, respectively; indices for CSA were 16 ± 19, 19 ± 18, 3 ± 4, and 0.6 ± 1. AutoSV Advanced was more effective than other modes in correcting sleep related breathing disorders. BiPAP autoSV Advanced was more effective than conventional BiPAP autoSV in the treatment of sleep disordered breathing in patients with CSA.

Predictors of slow‐wave sleep in a clinic‐based sample

Slow-wave sleep has been associated with several physiological phenomena, including glucose metabolism, sympathetic nervous system activity, hormonal secretion and blood pressure regulation. The aim of these analyses was to determine which sociodemographic and medical factors were associated with slow-wave sleep duration in a large clinical sample. We conducted cross-sectional analysis of clinical data from 1019 consecutive adults over a 10-month period who had their first in-laboratory polysomnogram for suspicion of obstructive sleep apnea. Patients either underwent in-laboratory full-night polysomnogram followed by full-night continuous positive airway pressure titration or split-night polysomnogram. Patients also completed questionnaires to assess race, education, marital status and medical co-morbidities. A multiple linear regression model that predicted the natural log of slow-wave sleep in minutes indicated that African Americans had approximately 48% less slow-wave sleep than non-African Americans. Increasing age and male gender were also associated with less slow-wave sleep. Overweight and obese individuals had significantly less slow-wave sleep than those not overweight, even after adjustment for obstructive sleep apnea severity. Finally, those with severe obstructive sleep apnea had significantly less slow-wave sleep than those with less severe obstructive sleep apnea even after adjustment for obesity. Results remained unchanged when patients who had a split-night polysomnogram were excluded. We observed less slow-wave sleep in African Americans, a group at increased risk of diabetes and hypertension compared with Caucasians, and in those who are overweight and obese and those with severe obstructive sleep apnea. Future research needs to explore potential reasons for reduced slow-wave sleep in these individuals.

Auto bi-level pressure relief–PAP is as effective as CPAP in OSA patients—a pilot study

Continuous positive airway pressure (CPAP) is the therapy of choice for the treatment of obstructive sleep apnea (OSA). Not all patients can use CPAP therapy with adequate compliance. There is a need to develop more comfortable modes. Auto bi-level Pressure Relief-Positive Airway Pressure (ABPR-PAP) can be an alternative. We conducted a prospective double-blind, randomised trial to evaluate the efficacy and compliance of ABPR-PAP compared with CPAP in OSA patients. We included 35 CPAP naive patients (age 53.3 ± 10.3 years, BMI 31.0 ± 5.0 kg/m(2), ESS 10.0 ± 4.2) diagnosed with moderate to severe OSA who underwent a successful CPAP titration. Patients were randomised into the CPAP or the ABPR-PAP treatment group. We used the same device (BIPAP® Auto, Philips Respironics) for CPAP or ABPR-PAP. Apnea-hypopnea index (AHI) was determined using polysomnography before (AHI 40.6 ± 18.3 per hour) and after treatment. Eighteen patients received CPAP and the remaining 17 received APBR-PAP. Groups were similar in terms of demographics and OSA severity. There were no serious adverse events during the trial. CPAP was fixed by a sleep expert and ABPR-PAP varied (range 5-15 cmH(2)O). AHI decreased in the CPAP group to 6.4 ± 5.7 per hour and in the ABPR-PAP group to 4.8 ± 3.6 per hour in the first night (N = 35). After 3 months, the AHI decreased in the CPAP group to 4.4 ± 5.3 per hour and in the ABPR-PAP group to 2.6 ± 3.8 per hour (N = 32). Differences between the groups were not statistically significant. There were no differences in compliance. ABPR-PAP is a promising new ventilation mode that enables effective treatment of OSA patients.

The efficacy of nasal surgery in obstructive sleep apnea syndrome: a prospective clinical study

The aim of this study was to investigate the effects of surgical intervention for nasal pathologies on obstructive sleep apnea syndrome (OSAS) and continuous positive airway pressure (CPAP) titrations in patients with OSAS. The study was designed as a prospective case control study. Between December 2007 and June 2010, 31 patients (26 men and 5 women) who were diagnosed with OSAS with polysomnography and confirmed to have obstructive nasal pathology were enrolled in the study. The average age of the patients was 53 ± 9.6 (range 33-68 years) and the body mass index ranged from 22 to 40.6 kg/m(2) with an average of 30.3 ± 4.1. The patients were evaluated with Epworth Sleepiness Scale, OSAS Complaints Questionnaire, visual analog scale, and CPAP titration before and 3 months after nasal surgery. As three patients did not attend the control polysomnography, data analysis was performed on 28 patients. Although there was a significant improvement in the nasal passage and subjective complaints, namely, snoring frequency, apnea and daytime sleepiness, the difference between preoperative and postoperative AHI values was not statistically significant. Postoperative CPAP titration results indicated a decrease both in pressures and in AHI in comparison to preoperative values. These reductions were not statistically significant, although the decrease in CPAP pressures was close to significance (p = 0.062). Nasal pathologies should be treated in all patients with OSAS, particularly those undergoing CPAP treatment. However, patients should be counseled that favorable results might not be achieved after nasal surgery.

Comparison of two servo ventilator devices in the treatment of complex sleep apnea

Objective Servo ventilation (SV) devices generate positive airway pressure with a variable pressure support that changes in response to a patient’s own respiratory output. Two currently available SV devices—VPAP-AdaptSV® and BIPAP-AutoSV®—have been used in treatment of complex sleep apnea (CompSAS), but no side-by-side comparisons are available. Methods Data of 76 consecutive patients with complex sleep apnea, who were prescribed a VPAP-AdaptSV® or BIPAP-AutoSV® in a non-randomized parallel design, were retrospectively analyzed. Patients underwent a diagnostic polysomnogram followed by a continuous positive airway pressure (CPAP) titration and a SV titration study. Objective compliance with the device was assessed at the first visit at 4–6 weeks of its use. Results Thirty-five patients received a VPAP-AdaptSV® device, while 41 patients were treated with BIPAP-AutoSV®. Patients treated with BIPAP-AutoSV® had a significantly higher apnea–hypopnea index during their CPAP titration study than patients treated with VPAP-AdaptSV® [49/h (28–60) vs. 35/h (19.5–49.5), median (interquartile range), p < 0.001]. On follow-up, 56 patients (73.7%) were using their device. Mean nightly use was 5.0 h (2.8–6.4) for VPAP-AdaptSV® group and 6.0 h (3.5–7.2) for BIPAP-AutoSV® group ( p = 0.081); an improvement in Epworth Sleepiness Scale score was higher in the BIPAP-AutoSV® group than in the VPAP-AdaptSV® group [4 (1–9) vs. 2.5 (0–5), p = 0.02]. Conclusion Our retrospective data indicate that the two servo-ventilation devices are comparable means of controlling complex sleep apnea, and the compliance with them is high.

The effect of one night of continuous positive airway pressure therapy on oxidative stress and antioxidant defense in hypertensive patients with severe obstructive sleep apnea

The purpose of this study was to examine the effects of one night of continuous positive airway pressure (CPAP) therapy on oxidative stress (lipid peroxidation) levels and the antioxidant activities of superoxide dismutase (SOD) in hypertensive patients with severe obstructive sleep apnea (OSA). The study group consisted of 34 hypertensive, non-smoking patients with a mean age of 45.09 ± 11.77years, body mass index of 37.4 ± 8.4kg/m(2), apnea hypopnea index of 79.17 ± 31.35/h, and desaturation index of 55.07 ± 27.06/h. Patients included in the study were not on medications that may affect antioxidant activity. Patients spent four nights in the sleep disorder center as follows: night 1, an adaptation night; night 2, a diagnostic night; night 3, CPAP titration night; and night 4, a therapeutic night for CPAP treatment. Blood samples were collected in the morning upon awakening on nights 2 and 4 and were immediately transferred to the laboratory for SOD and lipid peroxidation measurements. Oxidative stress levels were quantified by measuring thiobarbituric acid reactive substances. SOD enzymatic activity was measured using a purely chemical system based on NAD(P)H oxidation. Mean SOD concentrations were not significantly different in pre-and post-CPAP treatment (0.22 ± 0.09 vs. 0.22 ± 0. U/ml, respectively). However, CPAP treatment significantly inhibited lipid peroxidation levels (2.81 ± 0.27 vs. 2.47 ± 0.35mmol/ml, respectively, p < 0.005). The present study supports the theory that CPAP therapy decreases the levels of oxidative stress in OSA patients but may not affect antioxidant defense.

Complex sleep apnoea in congestive heart failure

BackgroundSleep disordered breathing is common and of prognostic significance in patients with congestive heart failure (CHF). Complex sleep apnoea (complexSA) is defined as the emergence of central sleep apnoea during...

Nocturnal moaning and groaning—catathrenia or nocturnal vocalizations

Descriptions of nocturnal vocalizations, including catathrenia, are few. We undertook a study at our center on patients diagnosed with catathrenia, to evaluate the characteristic features of these events and their response to continuous positive airway pressure (CPAP) treatment. Retrospective study of patients with a diagnosis of catathrenia who had an overnight polysomnogram (PSG) and available synchronized audio video recordings (to confirm the presence of moaning and groaning), at our center between January 2007 and May 2010. Ten patients were included in the analysis. Three (30%) patients presented with the chief complaint of expiratory noises during sleep. The other moaning/groaning sounds were incidental findings noted by the sleep technologist and/or the sleep physician. The number of moaning/groaning events during PSG varied between 2 and 343 per patient with sound duration ranging from 0.4 to 21.4s. Moaning/groaning events during exhalation (1,026 episodes) were separated into typical catathrenia events (as per the International Classification of Sleep Disorders, 2nd edition [ICSD-2] definition) and atypical/nocturnal vocalization events (moaning/groaning events that did not meet the ICSD-2 criteria). Typical catathrenia events (5% or 52/1,026) were experienced by five of the ten patients and had mean exhalation duration of 14.97 ± 5.13s (range 5.8-24s) with a mean sound duration of 8.47 ± 5.97s (range 2-21.4s). The typical and atypical events occurred predominantly in NREM sleep. Six of the ten patients had associated sleep-disordered breathing and four underwent CPAP titration. All four patients had significantly fewer events of moaning/groaning (mean reduction was 75.8 ± 26.2%) with CPAP. New and unique features were identified in our series of patients diagnosed with catathrenia. Though all events had the characteristic moaning and groaning sound during exhalation, only a small percentage (5%) met the catathrenia definition as outlined in ICSD-2. Do we label the atypical events as part of the spectrum of nocturnal vocalizations or consider them as catathrenia by redefining the criteria? CPAP appeared to be a reasonable treatment option.

Is automatic CPAP titration as effective as manual CPAP titration in OSAHS patients? A meta-analysis

It is costly and time-consuming to conduct the standard manual titration to identify an effective pressure before continuous positive airway pressure (CPAP) treatment for obstructive sleep apnea (OSA) patients. Automatic titration is cheaper and more easily available than manual titration. The purpose of this systematic review was to evaluate the effect of automatic titration in identifying a pressure and on the improvement of apnea/hyponea index (AHI) and somnolence, the change of sleep quality, and the acceptance and compliance of CPAP treatment, compared with the manual titration. A systematic search was made of the PubMed, EMBASE, Cochrane Library, SCI, China Academic Journals Full-text Databases, Chinese Biomedical Literature Database, Chinese Scientific Journals Databases and Chinese Medical Association Journals. Randomized controlled trials comparing automatic titration and manual titration were reviewed. Studies were pooled to yield odds ratios (OR) or mean differences (MD) with 95% confidence intervals (CI). Ten trials involving 849 patients met the inclusion criteria. It is hard to identify a trend in the pressures determined by either automatic or manual titration. Automatic titration can improve the AHI (MD = 0.03/h, 95% CI = -4.48 to 4.53) and Epworth sleepiness scale (SMD = -0.02, 95% CI = -0.34 to 0.31,) as effectively as the manual titration. There is no difference between sleep architecture under automatic titration or manual titration. The acceptance of CPAP treatment (OR = 0.96, 95% CI = 0.60 to 1.55) and the compliance with treatment (MD = -0.04, 95% CI = -0.17 to 0.10) after automatic titration is not different from manual titration. Automatic titration is as effective as standard manual titration in improving AHI, somnolence while maintaining sleep quality similar to the standard method. In addition, automatic titration has the same effect on the acceptance and compliance of CPAP treatment as manual titration. With the potential advantage of time and cost savings, automatic titration was recommended to be applied in identifying a proper pressure for CPAP treatment instead of manual titration in clinical practice.

Predictors of Response to a Nasal Expiratory Resistor Device and Its Potential Mechanisms of Action for Treatment of Obstructive Sleep Apnea

A one-way nasal resistor has recently been shown to reduce sleep disordered breathing (SDB) in a subset of patients with Obstructive Sleep Apnea Hypopnea Syndrome (OSAHS). The purpose of this study was to examine characteristics predictive of therapeutic response to the device and provide pilot data as to its potential mechanisms of action. PATIENTS, INTERVENTIONS, AND MEASUREMENTS: 20 subjects (15M/5F, age 54 ± 12 years, BMI 33.5 ± 5.6 kg/m²) with OSAHS underwent 3 nocturnal polysomnograms (NPSG) including diagnostic, therapeutic (with a Provent® nasal valve device), and CPAP. Additional measurements included intranasal pressures and PCO₂, closing pressures (Pcrit), and awake lung volumes in different body positions. In 19/20 patients who slept with the device, RDI was significantly reduced with the nasal valve device compared to the diagnostic NPSG (27 ± 29/h vs 49 ± 28/h), with 50% of patients having an acceptable therapeutic response. Among demographic, lung volume, or diagnostic NPSG measures or markers of collapsibility, no significant predictors of therapeutic response were found. There was a suggestion that patients with position-dependent SDB (supine RDI > lateral RDI) were more likely to have an acceptable therapeutic response to the device. Successful elimination of SDB was associated with generation and maintenance of an elevated end expiratory pressure. No single definitive mechanism of action was elucidated. The present study shows that the nasal valve device can alter SDB across the full spectrum of SDB severity. There was a suggestion that subjects with positional or milder SDB in the lateral position were those most likely to respond.

Telemetric CPAP titration at home in patients with sleep apnea–hypopnea syndrome

Background Home continuous positive airway pressure (CPAP) titration with automatic devices is not possible in a non-negligible percentage of patients with sleep apnea–hypopnea syndrome (SAHS). Objectives To test the feasibility of a novel telemetric system for home CPAP titration. Methods One-night home CPAP titration was carried out on 20 SAHS patients (56 ± 3 years; BMI = 35 ± 2 kg/m 2). A telemetric unit, based on the conventional GPRS mobile phone network and connected to a commercial CPAP device, allowed the hospital technician to monitor flow, pressure and air leaks by remote control and titrate CPAP (elimination of apneas, hypopneas, flow limitation and snoring) in real time. After 1 week, a full hospital polysomnography was performed while the patient was subjected to the value of CPAP that was previously titrated at home via telemetry. Results The home-titrated CPAP systematically improved patients’ breathing: the apnea–hypopnea index and percentage of sleep time with arterial oxygen saturation below 90% were reduced from 58.1 ± 5.1 to 3.8 ± 0.6 events/h and from 19.8 ± 1.1% to 4.4 ± 0.7%, respectively. This CPAP value (9.15 ± 0.47 cmH 2O) was virtually the same as the pressure that optimized breathing during hospital polysomnography (9.20 ± 0.41 cmH 2O; mean difference: 0.02 cmH 2O, limits of agreement: ± 1.00 cmH 2O). Conclusions This pilot study shows that a simple telemetric system, requiring neither a special telemedicine network nor any infrastructure in the patient’s home, made it possible to perform effective remote CPAP titration on SAHS patients.

Predictive equations for CPAP titration in OSAS patients

Continuous positive airway pressure (CPAP) is the elective treatment of obstructive sleep apnea. The therapeutic level of CPAP is generally established by manual titration or an auto CPAP device, but an alternative way involves the use of predictive formulas. The aim of the present study was to test the difference between mathematical equations and CPAP or auto CPAP in terms of therapeutic pressure. A retrospective analysis of 197 subjects with a diagnosis of obstructive sleep apnea needing a CPAP treatment was performed. The patients were divided into two groups: the first one included patients who had received CPAP after manual titration and the second one included patients who had received auto CPAP titration. The therapeutic CPAP pressure was then compared to the pressure calculated by three different equations: Eq. A by Stradling, Eq. B by Sériès, and Eq. C by Hoffstein. One hundred ninety-seven patients were included in the study, 110 were titrated by auto CPAP and 87 by manual titration. There was a positive correlation between the pressure defined by the three equations and both titration methods, but each equation usually gave a higher pressure with patients needing CPAP <8 and lower for patients needing CPAP >11. Equation C normally gave a lower result than the other two equations. Manual or auto CPAP titration remains the best way to define the appropriate CPAP. However, predictive formulas can be useful if used with caution and always after verifying the real efficacy, particularly for patients needing higher pressure.

Use of Bioimpedance to Assess Changes in Hemodynamics During Acute Administration of CPAP.

BackgroundAttempts to investigate the mechanisms by which continuous positive airway pressure (CPAP) therapy improves heart function in patients with obstructive sleep apnea (OSA) have been limited by the lack of non-invasive methods to assess cardiac performance. We used transthoracic electrical bioimpedance (TEB) to assess acute hemodynamic changes including heart rate (HR), stroke volume (SV), cardiac output (CO) and cardiac index (CI) during PAP titration in (1) post-operative cardiac surgery patients, (2) patients with severe OSA, and (3) normal healthy volunteers.MethodsPost-operative cardiac surgery patients were studied via TEB and pulmonary artery catheter (PAC) during acute titration of positive end-expiratory pressure (PEEP) while mechanically ventilated. Patients with severe OSA were studied non-invasively by TEB during acute CPAP titration in supine stage 2 sleep, and normal subjects while awake and recumbent.ResultsIn post-operative cardiac surgery patients (n = 3), increasing PEEP to 18 cmH2O significantly reduced SV and CI relative to baseline. There was no difference between TEB and PAC in terms of ability to assess variations in hemodynamic parameters. In patients with severe OSA (n = 3), CPAP titration to optimal pressure to alleviate obstructive apneas reduced HR, SV, CO and CI significantly compared to without CPAP. In three healthy subjects, maximal tolerated CPAP reduced SV and CO significantly compared to baseline.ConclusionsAcute administration of CPAP causes a decrease in CO and CI, apparently a consequence of a reduction in SV. TEB appears to be an accurate and reproducible non-invasive method of detecting changes in hemodynamics.

Clinical Significance of Sleep Apnea Syndrome (SAS) in Japanese Patients: Efficacy of CPAP Therapy in SAS-associated Arrhythmias

Background: The purpose of this study was to determine the relationship between sleep apnea syndrome (SAS) and cardiovascular disorders, and to assess the efficacy of continuous positive airway pressure (CPAP) in SAS-associated arrhythmias. SAS is associated with cardiovascular disorders, such as hypertension, ischemic heart disease, and arrhythmias. CPAP is one of the effective treatments for SAS; however, this relationship and efficacy remain undefined. Methods and Results: The study population comprised 1413 Japanese subjects (mean age: 56.6 years old, 1123 men and 290 women) who were divided into two groups: SAS group (n=1064, apnea-hypopnea index (AHI)≥20) and control group (n=349, AHI<20) by polysomnography (PSG) analysis. In baseline characteristics, age (58.3±14.7 vs. 50.0±18.4, p<0.0001), gender (male: 88.4% vs. 72.9%, p<0.0001), BMI (25.9±4.4 vs. 23.2±3.7, p<0.0001), hypertension (38.0% vs. 19.3%, p<0.0001), diabetes (10.4% vs. 5.2%, p=0.015), or hyperlipidemia (15.6% vs. 9.3%, p=0.018) were significantly associated with SDB. PSG revealed predominant occurrence of paroxysmal atrial fibrillation (PAF: 108/1064 vs. 3/349, p=0.005), premature ventricular complex (PVC: 359/1064 vs. 17/349, p=0.0012) and pause (sinus arrest ≥2 sec: 172/859 vs. 6/349, p=0.002) in SAS group. In the SAS group, 291 patients underwent CPAP titration and were then re-evaluated. CPAP therapy significantly reduced the occurrences of PAF (59/291 vs. 2/291, p=0.005), sinus bradycardia (18/291 vs. 0/291, p=0.002), and sinus pause (26/291 vs. 4/291, p=0.016). Conclusions: Significant relationship between SAS and several cardiac disorders, and efficacy of CPAP in preventing SAS-associated arrhythmias in a large population of Japanese patients.

Outcome of Continuous Positive Airway Pressure Treatment with Suboptimal Pressure in Obstructive Sleep Apnea

Continuous positive airway pressure (CPAP) is the treatment of choice for obstructive sleep apnea (OSA) and is highly effective particularly in moderate-to-severe OSA, defined as an apnea-hypopnea index (AHI) exceeding 15/h.1,2 CPAP functions as a “pneumatic splint” by delivering an intraluminal pressure, thereby preventing the upper airway from collapsing during sleep in OSA.3 Following diagnostic polysomnography (PSG), patients who meet the diagnostic criteria for OSA and is regarded as candidates for CPAP and undergo CPAP titration in the sleep laboratory. Although the optimal end point of titration has not been scientifically determined, most laboratories titrate to eliminate obstructive apnea, hypopnea, snoring, oxygen desaturation, and respiratory effort-related arousals.4 The target AHI with CPAP treatment is usually between 5 and 10/h.5 However, during positive pressure titration, it may be difficult to determine the optimal pressure in some patients. If the pressure is too low, it fails to eliminate obstructive apnea adequately, and if the pressure is too high, it could interfere the sleep itself. In addition, “CPAP-related central sleep apnea (CSA)” could appear during CPAP titration.4 Due to these reasons, some patients inevitably undergo CPAP treatment with suboptimal pressure. To date, the efficacy of CPAP treatment with suboptimal pressure in OSA remains controversial. In this study, we aimed to evaluate the treatment outcome of CPAP with suboptimal pressure in OSA.

Influence of gender on continuous positive airway pressure requirements in patients with obstructive sleep apnea syndrome

Gender differences have been noted in key aspects of upper airway physiology and pathophysiology of obstructive sleep apnea (OSA). We postulate that these will lead to disparities in pharyngeal collapsibility and, consequently, positive airway pressure requirements of patients with OSA. A retrospective review of 95 adult patients (56 women, 39 men) with OSA was done. Patients who underwent continuous positive airway pressure (CPAP) titration were included in the study. The study groups were similar with regard to the severity of OSA (median apnea-hypopnea index of 34 in men and 24 in women, p = 0.13). The men were older and less obese than the women (mean age of 46 and 41 years, p = 0.03, BMI of 42 and 49 kg/m(2), p < 0.001, in men and women, respectively); Epworth score was similar in the two groups (12 vs.11, p = 0.91). CPAP requirement was higher in men than in women (12.7 vs. 10.2, p < 0.0001). The effect of gender on CPAP requirement was found to be significant even when confounding variables were accounted for using linear regression. Men with OSA are more likely to require higher levels of CPAP support than women. The effect of gender on CPAP requirement persisted even after correcting for the severity of OSA.