Relationship between Restless legs syndrome associated symptoms and presence of depression during pregnancy.

Restless legs syndrome (RLS) is associated with depression in the general population. Although depression can lead to adverse events during the perinatal period, the association between RLS and depression remains under debate. Thus, we examined the association between depression and RLS, including RLS-associated symptoms, in pregnant women. We evaluated the presence of RLS and RLS-associated symptoms in 135 pregnant women using questionnaires on RLS symptoms based on Allen's symptoms and the International Restless Legs Syndrome Rating Scale (IRLS), respectively. We defined RLS as 4/4 on Allen's symptoms. Depressive status was evaluated using the Edinburgh Postnatal Depression Scale. The mean±SD of age was 31.8 ± 4.3 years, and none of the participants had a family history of RLS. Ten percent of women had depression during their pregnancy and demonstrated higher IRLS scores than those without depression (6.1 ± 10.5 vs. 0.7 ± 3.8 points, P = 0.001). A significant association between IRLS score, including its subscales, and depression was observed, even after adjusting for confounders. It was concluded that RLS-associated symptoms may be indicators of depression during pregnancy. Comprehensive sleep evaluations and examinations of RLS-associated symptoms are needed to improve psychiatric health during pregnancy.

Successful Total Management of Multi-Causative Sleep-Disordered Breathing Complicated with Patient with Adult Congenital Heart Disease.

Sleep-disordered breathing is one of the complications commonly seen in patients with adult congenital heart disease (ACHD) due to multiple causes including complex underlying cardiac defects, cardiomegaly, previous thoracotomies, obesity, scoliosis, and paralysis of the diaphragm. It is often hard to determine its main cause and predict the efficacy of each treatment in its management. We herein report a 30-year-old woman after biventricular repair of pulmonary atresia with intact ventricular septum diagnosed as sleep-related hypoventilation disorder. Simultaneous treatment targeting obesity, paralysis of the diaphragm, and cardiomegaly followed by respiratory muscle reinforcement through non-invasive ventilation resolved her sleep-related hypoventilation disorder. Such management for each factor responsible for the hypoventilation is expected to provide synergetic therapeutic efficacy and increase daily activity in a patient with ACHD.

Changes in lung to finger circulation time measured via cardiopulmonary polygraphy in patients with varying types of heart disease.

Cardiopulmonary polygraphy (PG) demonstrates not only parameters for sleep disordered breathing (SDB) but also hemodynamics. We previously developed a software that detects lung to fingertip circulation time (LFCT) derived from PG dataset and reported that those LFCT reflected the cardiac output. The purpose of this study is to investigate how the LFCT changes during clinical course and whether reflects the impact of in-hospital treatment on cardiac function. Consecutive patients (N = 89) who admitted to the cardiovascular division, underwent PG at the early and late phase of admission. Parameters for SDB and LFCT were compared between an acute decompensated heart failure (ADHF) group (n = 51) and non-ADHF group (n = 38). ADHF group was further divided into subgroups: preserved ejection fraction (pEF) (EF > 40%) and reduced EF (rEF) (EF ≤ 40%). Using our original algorithm, we obtained LFCT values from all of the patients, though 29.4% of ADHF and 44.7% of non-ADHF had no or mild SDB. LFCT significantly shortened in the ADHF-rEF group, in contrast to ADHF-pEF group or non-ADHF group (ADHF-rEF group: 26.9 ± 7.6 to 24.2 ± 6.1 s, p = 0.01; ADHF-pEF group: 25.3 ± 7.3 to 25.3 ± 6.9 s, p = 0.98; non-ADHF group: 21.5 ± 5.5 to 21.9 ± 5.0 s, p = 0.65). The respiratory disorder index in the ADHF group improved after treatment, irrespective of EF (pEF: 26.9 ± 16.1 to 15.8 ± 11.9/h, p < 0.01; rEF: 27.0 ± 16.5 to 20.7 ± 13.6/h, p = 0.03). Automatic detection of LFCT was feasible in almost all cardiac patients. LFCT value changed according to the heart failure treatment in ADHF-rEF patients and reflected cardiac function. LFCT might be a useful indicator of effective cardiac disease treatment.

Accumulated nocturnal hypoxemia predict arterial endothelial function in patients with sleep-disordered breathing with or without chronic heart failure.

ABTSRACT: Sleep-disordered breathing (SDB) is often accompanied with the chronic heart failure (CHF). Hypoxemia due to pulmonary congestion from CHF and concurrent SDB might synergistically impair endothelial function and worsen the prognosis. However, the main factors affecting deterioration of endothelial function are unknown and whether the influence of hypoxemia differs in SDB patients with and without CHF remains unclear. Fifty-three patients (CHF group, n = 23; non-CHF group, n = 30) underwent polysomnography to evaluate their SDB and flow-mediated vasodilation (FMD) measurements to assess arterial endothelial function. We examined the relationships between FMD and SDB-related parameters, including our original index of accumulated hypoxemia by SDB throughout one-night sleep: the time desaturation summation index (TDS), calculated as follows: (100% - averaged arterial oxygen saturation during sleep) × total sleep time. The mean age in the CHF and non-CHF groups was 59.0 ± 13.5 and 57.7 ± 11.4 years, respectively. Although the FMD in the 2 groups were not significantly different, well-known adverse factors for FMD such as serum lipid profiles, blood pressure levels, and conventional indices of SDB were worse in the non-CHF group. Only the TDS was not significantly different between 2 groups and associated with FMD as shown by the univariate analysis (CHF: p < 0.05, non-CHF: p < 0.01) and multivariate analysis (CHF: p < 0.05, non-CHF: p < 0.01). Accumulated hypoxemia (TDS) rather than the frequency of hypoxemia might more influence on the endothelial function irrespective of the cardiac state. Removal of accumulation of nocturnal hypoxemia might be a target for treatment equally in the patients with and without CHF.

Factors limiting habitual exercise in patients with chronic heart failure: a multicenter prospective cohort study.

Physical activity (PA) in the daily life is strongly related to prognosis in patients with or at high risk of heart failure (HF). However, factors limiting habitual exercise and their prognostic impacts remain unknown in HF patients. We sent questionnaires asking factors limiting habitual exercise in the daily life to 8370 patients with Stage A/B/C/D HF in our nationwide registry and received valid responses from 4935 patients (mean age 71.8 years, 71.0% male). Among the 5 components consisting of "busyness", "weak will", "dislike, "socioeconomic reasons" and "diseases" in the questionnaires, "busyness" (34.5%) and "diseases" (34.7%) were the most frequently reported factors limiting habitual exercise, while "socioeconomic reasons" were the least (15.3%). Multiple Cox proportional hazard models indicated that "busyness"and "diseases" were associated with better (hazard ratio (HR) 0.53, 95% confidence interval (CI) 0.39-0.72, P < 0.001) and worse prognosis (HR 1.57, 95% CI 1.21-1.98, P < 0.001), respectively, while other components were not. Furthermore, it was noted that, while prognostic relevance of "busyness" limiting exercise did not differ by age or sex, negative impact of "diseases" was particularly evident in patients with age < 75 years (P for interaction < 0.01). Factors limiting habitual exercise were associated with "busyness" and "diseases", but not with "weak will", "dislike, or "socioeconomic reasons". While "busyness" was associated with better prognosis regardless of age and sex, "diseases" was associated with worse prognosis in younger populations. Thus, physicians may pay more attentions to the reasons that limit exercise in the daily lives of HF patients rather than the low amount of exercise itself.

Crossover comparison between CPAP and mandibular advancement device with adherence monitor about the effects on endothelial function, blood pressure and symptoms in patients with obstructive sleep apnea.

Mandibular advancement device (MAD) is an alternative therapeutic option for CPAP to treat obstructive sleep apnea (OSA). While MAD showed the better adherence, patients with over moderate OSA have been treated more frequently with CPAP despite increasing positive evidence on the cardiovascular outcome with MAD, even in severe patients. Thus, more information is needed regarding the cardiovascular and symptomatic outcome of MAD treatment objectively compared to CPAP. Forty-five supine-dependent OSA patients (apnea-hypopnea index 20-40/h) were randomized to either CPAP or MAD and treated for 8 weeks and switched to another for 8 weeks. The primary endpoint was improvement in the endothelial function, indexed by the flow-mediated dilatation (FMD), and the secondary endpoint was the sleep-time blood pressure (BP). The duration of MAD use was evaluated objectively by an implanted adherence monitor. Treatment efficacy was also evaluated by home sleep monitor and a questionnaire about the symptoms. The adherence was not significantly different (CPAP vs. MAD: 274.5 ± 108.9 min/night vs. 314.8 ± 127.0 min/night, p = 0.095). FMD and sleep-time mean BP were not markedly changed from the baseline with either approach (CPAP vs. MAD: FMD, + 0.47% ± 3.1% vs. + 0.85% ± 2.6%, p = 0.64; BP, - 1.5 ± 5.7 mmHg vs. - 1.2 ± 7.5 mmHg, p = 0.48), although sleepiness, nocturia, and sleep-related parameters were similarly improved and more patients preferred MAD. As MAD and CPAP showed similar effects on cardiovascular outcome and symptomatic relief even with a comparable length of usage, we might expect MAD as an alternative treatment option for CPAP in this range of OSA group.

Multicenter, Prospective Study on Respiratory Stability During Recovery From Deterioration of Chronic Heart Failure.

BACKGROUND: The respiratory instability frequently observed in advanced heart failure (HF) is likely to mirror the clinical status of worsening HF. The present multicenter study was conducted to examine whether the noble respiratory stability index (RSI), a quantitative measure of respiratory instability, reflects the recovery process from HF decompensation. Methods and Results: Thirty-six of 44 patients hospitalized for worsening HF completed all-night measurements of RSI both at deterioration and recovery phases. Based on the signs, symptoms, and laboratory data during hospitalization, the Central Adjudication Committee identified 22 convalescent patients and 14 patients with less extent of recovery in a blinded manner without any information on RSI or other respiratory variables. The all-night RSI in the convalescent patients was increased from 27.8±18.4 to 34.6±15.8 (P<0.05). There was no significant improvement of RSI, however, in the remaining patients with little clinical improvement. Of the clinical and laboratory variables, on stepwise linear regression modeling, body weight, peripheral edema, and lung congestion were closely related to the RSI of recovered patients and accounted for 56% of the changes in RSI (coefficient of determination, R2=0.56). CONCLUSIONS: All-night RSI, a quantitative measure of respiratory instability, could faithfully reflect congestive signs and clinical status of HF during the recovery process from acute decompensation.

Risk Profile and 1-Year Outcome of Newly Diagnosed Atrial Fibrillation in Japan　- Insights From GARFIELD-AF.

BACKGROUND: Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective non-interventional study of stroke prevention in patients with newly diagnosed non-valvular AF (NAVF) that is being conducted in 35 countries. Methods and Results: A total of 52,081 patients with a new diagnosis of NVAF were enrolled prospectively in GARFIELD-AF. Of these, 4859 (9.3%) were recruited in Japan (2010-2016). In cohort 1 (2010-2011), few patients were on non-vitamin K antagonist oral anticoagulants (NOAC) globally. From cohort 2 onwards (2011-2016), however, there was a rapid increase in NOAC use around the globe, especially in Japan. By the last year of enrolment (2015-2016), 67.9% of patients in Japan and 43.1% of patients globally were on NOAC±antiplatelet therapy (AP). In Japan and globally, 17.0% and 12.2% of patients, respectively, did not receive stroke prevention treatment. Few patients in Japan (5.7%) received AP only. Compared with the other countries, the unadjusted rates of all-cause mortality and major bleeding were low, while rates of stroke/systemic embolism were similar after 1 year of follow-up. CONCLUSIONS: GARFIELD-AF continues to provide important information on the homogeneity and heterogeneity of baseline characteristics and treatment patterns in patients with newly diagnosed NVAF. This diversity reflects the differences in outcomes in Japan compared with the rest of the world.

Three nights leg thermal therapy could improve sleep quality in patients with chronic heart failure.

Sleep quality is often impaired in patients with chronic heart failure (HF), which may worsen their quality of life and even prognosis. Leg thermal therapy (LTT), topical leg warming, has been shown to improve endothelial function, oxidative stress, and cardiac function in patients with HF. However, its short-term influence to sleep quality has not been evaluated in HF patients. Eighteen of 23 patients with stable HF received LTT (15 min of warming at 45 °C and 30 min of insulation) at bedtime for 3 consecutive nights and 5 patients served as control. Subjective sleep quality was evaluated by St. Mary's Hospital Sleep Questionnaire, Oguri-Shirakawa-Azumi Sleep Inventory, and Epworth sleepiness scale, and also objectively evaluated by polysomnography. LTT significantly improved subjective sleep quality indicated by depth of sleep (p < 0.01), sleep duration (p < 0.05), number of awaking (p < 0.01), nap duration (p < 0.01), sleep quality (p < 0.05), and sleep satisfaction (p < 0.05). It was also objectively affirmed by a slight but significant decrease of sleep stage N1 (p < 0.01), and increase in sleep stage N2 (p < 0.05). No significant changes occurred in the controls. Hence, the short-term LTT could improve subjective and objective sleep quality in patients with HF. LTT can be a complimentary therapy to improve sleep quality in these patients.

Seasonal ambient changes influence inpatient falls.

Background: falls by inpatients often result in serious injuries and deterioration in a patient's physical abilities and quality of life, especially among older individuals. Although various factors have been found to be associated with falls, the combined effects of behavioural and ambient factors are not fully evaluated. Objective: we investigated the influence of both behavioural and ambient factors on inpatient falls, focusing on seasonal and diurnal variations. Design: retrospective study. Methods: we surveyed the incident reports related to falls from April 2010 to March 2014 and examined the relationship between the incidents and seasonal and diurnal variations in behavioural and ambient factors, including the sunrise time, the night-time length and temperature. Results: we identified 464 fallers from 3,037 incident reports. The average fall-rate of the study population was 1.4 ± 0.5/1,000 occupied bed-days. The seasonal and diurnal variations in falls were compared. The number of falls around dawn in October-February was higher than that in April-September. Toileting was the behaviour most frequently related to the falls (56.9%, n = 264), and 57.1% of the falls occurred at night. A multivariate analysis showed that the night-time length was significantly related to an increase in night-time falls (P = 0.047). Conclusion: these results suggested that the inpatient falls increased in the early morning from November to March and tended to be related to toileting activities. Considering these results, additional attention and support during the higher risk hours and seasons, especially in relation to toileting activities, might help to reduce the incidence of falls. Clinical trial name, URL and registration number: N/A (Because of retrospective nature).

Improved Accuracy of Automated Estimation of Cardiac Output Using Circulation Time in Patients with Heart Failure.

BACKGROUND: Lung-to-finger circulation time of oxygenated blood during nocturnal periodic breathing in heart failure patients measured using polysomnography correlates negatively with cardiac function but possesses limited accuracy for cardiac output (CO) estimation. METHODS AND RESULTS: CO was recalculated from lung-to-finger circulation time using a multivariable linear model with information on age and average overnight heart rate in 25 patients who underwent evaluation of heart failure. The multivariable model decreased the percentage error to 22.3% relative to invasive CO measured during cardiac catheterization. CONCLUSIONS: This improved automated noninvasive CO estimation using multiple variables meets a recently proposed performance criterion for clinical acceptability of noninvasive CO estimation, and compares very favorably with other available methods.

Prognostic Impacts of Metabolic Syndrome in Patients With Chronic Heart Failure　- A Multicenter Prospective Cohort Study.

BACKGROUND: Metabolic syndrome (MetS) is involved in the increased risk of atherosclerotic cardiovascular diseases. We have previously reported that the prevalence of MetS is more than 2-fold greater in patients with chronic heart failure (CHF) than in the general population in Japan. However, the prognostic impact of MetS in CHF patients remains to be elucidated. METHODS AND RESULTS: In the present nationwide, large-scale clinical study in Japan, we enrolled 4,762 patients with Stage C/D CHF. The prevalence of MetS by the definition of the Japanese Committee for the Diagnostic Criteria in 2005 was 41.3% (50.6% in males, 21.5% in females). MetS was characterized by higher prevalence of males, obesity and lifestyle-related comorbidities, including glucose intolerance, dyslipidemia and hypertension. Multivariate Cox hazard analysis showed that MetS was associated with increased incidence of the composite of all-cause death and atherosclerotic events in males (hazard ratio [HR] 1.28; 95% confidence interval [CI] 1.06-1.54, P=0.011) but not in females (HR 1.23, 95% CI 0.87-1.75, P=0.241). Among the components of MetS, over waist circumference and glucose intolerance were significantly associated with increased incidence of the composite endpoint (HR 1.23, P=0.038, and HR 1.29, P<0.001, respectively) in males but not in females. CONCLUSIONS: The results indicate that MetS only has a negative prognostic impact in male CHF patients. (Circ J 2016; 80: 677-688).

Hemodynamic response during standing test after blood donation can predict the late phase vasovagal reaction.

A major complication of blood donation is vasovagal reaction (VVR) with or without syncope. VVR occurs not only in the early phase, but also in the late phase after blood donation. We previously reported the hemodynamic characteristics of blood donors susceptible to early phase VVR. In the present study, we investigated the hemodynamic characteristics of those who developed late VVR. Ninety-six healthy volunteers donating 400 ml of whole blood were studied. After asking about their physical condition or routine questions for blood donation, blood pressure (BP) and heart rate (HR) were recorded while the donors were kept standing up for 3 min before and after blood collection. Questionnaires were distributed to all donors for reporting late VVR symptoms within 24 h. Those with younger age and lower diastolic blood pressure were more susceptible to late VVR (both p < 0.05). Furthermore, we identified the increase in HR during the standing test after blood collection as a good predictor of late VVR (odds ratio 1.063, 95 % CI 1.005-1.124; p = 0.031). Also, analysis of questions asked before donation revealed that significantly more donors considered themselves as sensitive to pain in the late VVR group (Odds ratio 0.070, 95 % CI 0.008-0.586; p = 0.014). Excessive HR response to standing after blood collection and subjective sensitivity to pain as well as younger age and lower diastolic BP may be useful to detect donors at high risk for late VVR.

Comparable accuracy of micro-electromechanical blood flowmetry-based analysis vs. electrocardiography-based analysis in evaluating heart rate variability.

BACKGROUND: Because the conventional evaluation of autonomic nervous system (ANS) function inevitably uses long-lasting uncomfortable electrocardiogram (ECG) recording, a more simplified and comfortable analysis system has been sought for this purpose. The feasibility of using a portable micro-electromechanical system (MEMS) blood flowmeter to analyze heart rate variability (HRV) for evaluating ANS function was thus examined. METHODS AND RESULTS: Measurements of the R-R interval (TRR) derived from an ECG, simultaneously with the pulse wave interval (TPP) derived from a MEMS blood flowmeter, in 8 healthy subjects was performed and resultant HRV variables in time and frequency domains were compared. The TRR- and TPP-derived variables were strongly correlated (coefficients of regression for low frequency (LF), high frequency (HF), and LF/HF of 1.1, 0.66, and 0.35, respectively; corresponding coefficients of determination of 0.92, 0.63, and 0.91, respectively (P<0.01)). In addition, the values of LF, HF, and LF/HF, as analyzed using TPP, changed significantly from the supine to the standing position in another 6 subjects. CONCLUSIONS: Miniaturized-MEMS blood flowmetry can be used to perform HRV analysis for the evaluation of ANS function, which is as accurate as analysis based on ECG within comparable tolerances. As MEMS blood flowmetry can more easily and comfortably record physiological variables for longer durations than ECG recording, and can further capture skin blood flow information, this device has great potential to be used in a wider area of physiological analyses.

Obstructive sleep apnea-related symptoms in Japanese people with Down syndrome.

This study evaluated the prevalence of obstructive sleep apnea-related symptoms and assessed the relationship with obesity or unusual sleep postures in Down syndrome patients in Japan. We obtained the demographic characteristics, sleep postures, and obstructive sleep apnea-related symptoms experienced by 90 people as reported by their caregivers. Although 71% reported snoring and 59% arousals, obstructive sleep apnea-related symptoms were not significantly different between obese and non-obese participants. The youngest age group had the fewest obstructive sleep apnea-related symptoms, especially symptoms of snoring. The odds for arousal, nocturia, and apnea tended to be higher in the unusual sleep-postures group. Unusual sleep postures were most frequent in the group 6-15 years of age. People with Down syndrome might sleep in unusual postures to avoid upper airway obstruction caused by other anatomical factors. For nurses and other health professionals working in mainstream service, it is important to screen all persons with Down syndrome for symptoms suggestive of obstructive sleep apnea, particularly those six years of age and older, and to refer them for further evaluation for sleep disorders.

Nocturnal difference in the ultra low frequency band of heart rate variability in patients stratified by Kampo medicine prescription.

BACKGROUND: The Yo/Yin concept is fundamental to making a Kampo (sho) diagnosis and may be deeply related to the autonomic nervous system. There is, however, little objective data to confirm the validity of these concepts. METHODS AND RESULTS: After diagnosis using standardized Kampo techniques, 20 men and 67 women (mean age, 52.4 years) for whom the prescribed Kampo medication was effective were judged to be correctly classified as Yo- (n=49) or Yin-sho (n=38) and enrolled. Autonomic nervous function was assessed at first visit using HRV obtained from 24-h Holter ECG. Nocturnal ultra low frequency-1 (ULF-1, 0.0001-0.0003 Hz) and ULF-2 (0.0003-0.003 Hz) were significantly higher in the Yin-sho than in the Yo-sho group (P=0.030, P=0.016), suggesting a higher variation of autonomic nervous activity according to sleep stage. On multivariate analysis BMI (≥ 23.0 kg/m(2)) and ULF-1 (≥ 1,150 ms(2)) were identified as independent factors associated with a differential diagnosis of Yo- or Yin-sho (odds ratio [OR], 11.63, P=0.002; OR, 0.30, P=0.038, respectively). When the sleep period was divided into 3 phases, the ULF-1 of the Yin-sho group was significantly higher than that of the Yo-sho group in the late phase of sleep (P=0.023). CONCLUSIONS: On heart rate variability analysis there was a sleep stage-related difference in the autonomic nervous activity of patients treated with standard Yo- and Yin-sho Kampo medicines.

Difference in the Dynamics of Antibody Titers between COVID-19 Vaccination and SARS-CoV-2 Infection in Healthcare Workers - A Case Study Based on Long-Term and Densely Repeated Measurements of Antibody Titers.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is prevalent worldwide, and effective and safe vaccines against this virus have been developed. Although trends in antibody titers after vaccination and/or SARS-CoV-2 infection have been reported, long-term studies with high frequency of measurements are limited. This report describes the long-term and detailed trends in the antibodies against SARS-CoV-2 S protein receptor-binding domain (S-RBD) measured repeatedly after vaccination and/or infection in 3 healthcare workers. All healthcare workers were administered 30 µg of the messenger RNA vaccine, BNT162b2, during all vaccinations. The peak value of the SARS-CoV-2 S-RBD titer was reached at 1-2 weeks after vaccination and then decreased by half within 8 weeks after vaccination; the peak values of the antibody titer increased with repeated vaccinations. In contrast, after SARS-CoV-2 infection, the peak value of the antibody titer was reached at 4-8 weeks after infection, and the antibody titer remained elevated up to 16-40 weeks after the peak. This report describes the long-term and detailed trends in the anti-SARS-CoV-2 S-RBD titers, showing different patterns after vaccination and/or SARS-CoV-2 infection.

Impact of zolpidem and lemborexant on sleep and morning symptoms when used as a single dose for polysomnography.

This study evaluated the effect of zolpidem and lemborexant on sleep and morning symptoms in patients undergoing type-1 polysomnography for suspected sleep-disordered breathing based on questionnaires and polysomnography results. We enrolled 127 patients (lemborexant: N = 57, zolpidem: N = 25, without hypnotics: N = 45). Rapid eye movement sleep in patients on lemborexant was higher than that in patients without hypnotics (P = 0.02). Frequency of unsteadiness in the morning was higher in patients on zolpidem than that in patients without hypnotics (P = 0.04), which remained after adjustment for potential confounders (P = 0.03). Low-dose lemborexant might be suitable when administered as a single dose during polysomnography.

The relationships between intermittent hypoxia and oxidative stress in patients with sleep apnea syndrome.

Intermittent hypoxia in sleep apnea syndrome (SAS) patients increases the oxidative stress and can cause serious cardiovascular diseases such as hypertension or atherosclerotic diseases through endothelial dysfunction. The evaluation of risk caused by oxidative stress, however, is not easy in a clinical setting. Thus, we intended to evaluate the changes in oxidative stress by SAS treatment using a simple method that can be easily used in the clinical testing. We enrolled 42 consecutive newly diagnosed severe SAS patients (30 men). Reactive oxygen species metabolites (d-ROMs) for oxidative stress and biological antioxidant (BAP) in blood samples were estimated using FREE Carrio Duo® before and 3 months after continuous positive airway pressure (CPAP) treatment. SAS parameters were obtained by polysomnography before CPAP and endothelial function was measured twice as well. The body mass index and apnea hypopnea index (AHI) were 29.1 ± 5.3 and 57.9 ± 19.7/h. The d-ROMs and BAP were 317.4 ± 71.8 CARR U and 2121.2 ± 299.6 µmol/L. Although no significant correlation was found between hypoxia parameters and d-ROMs or BAP before CPAP treatment, we found a significant negative correlation between basal AHI or basal oxygen desaturation index representing intermittent hypoxia and the change in d-ROMs (r = - 0.31, p = 0.046/r = - 0.33, p = 0.03) and between the change in SpO2 < 90% duration (min) representing continuous hypoxia and the change in BAP (r = - 0.35, p = 0.03) after CPAP treatment. The changes in d-ROM and BAP might reflect the different kind of reduction of oxidative stress by CPAP treatment and, thus, can be used as handy indicators of the treatment effect.

Analysis of the effect of CPAP on hemodynamics using clinical data and a theoretical model: CPAP therapy decreases cardiac output mechanically but increases it via afterload reduction.

BACKGROUND: Noninvasive positive pressure ventilation (NIPPV) has been established as an effective treatment for heart failure. Positive airway pressure such as continuous positive airway pressure (CPAP) increases cardiac output (CO) in some patients but decreases it in others. However, the mechanism behind such unpredictable responses remains undetermined. METHODS AND RESULTS: We measured hemodynamic parameters of 38 cases using Swan-Ganz catheter before and after CPAP in chronic heart failure status. In those whose CO increased by CPAP, pulmonary vascular resistance (PVR) was significantly decreased and SpO2 significantly increased, but the other parameters were not changed. On the other hand, PVR was not changed, but systemic vascular resistance (SVR) was increased in those whose CO decreased by CPAP. To explain this phenomenon, we simulated the cardiovascular system using a cardiac model of time-varying elastance. In this model, it was indicated that CPAP decreases CO irrespective of cardiac function or filling status under constant PVR condition. However, when reduction of PVR by CPAP was taken into account, an increase in CO was expected especially in the hypervolemic and low right ventricle (RV) systolic function cases. CONCLUSIONS: CPAP would increase CO only where PVR can be reduced by CPAP therapy, especially in the case with hypervolemia and/or low RV systolic function. Understanding the underlying mechanism should help identify the patients for whom NIPPV would be effective.