Effect Of Continuous Positive Airway Pressure Research Articles

High flow nasal cannula versus continuous positive airway pressure on incidence of postoperative pulmonary complications after bariatric surgery

ABSTRACT Background High flow nasal cannula (HFNC) and continuous positive airway pressure (CPAP) can be used postoperatively to decrease postoperative pulmonary complications. Aim This study evaluated and compared the effect of HFNC versus CPAP on postoperative pulmonary complications in bariatric surgery. Patients and Methods Sixty adult ASA class II and III patients scheduled for bariatric operations were divided into two equal groups: the HFNC and CPAP groups. Results No significant variations in HR and MABP were observed between groups. Mean SpO2% and PaO2/FiO2 readings were lower on ICU admission than pre-induction (p < 0.001). However, after the intervention, readings significantly increased (p < 0.001). Respiratory rate and PaCO2 levels were higher upon ICU admission than pre-induction in both groups (p < 0.001). After the intervention, they decreased significantly during all assessment times compared to ICU admission time (p < 0.001). Both groups had lower lung ultrasound scores at ICU discharge than on admission (p < 0.001). Still, no significant variations in scores observed between groups upon admission and before discharge. No significant variations were found in the incidence of postoperative pulmonary complications and duration of stay in hospital. Conclusion HFNC and CPAP decrease atelectasis and improve respiratory parameters postoperatively in morbidly obese persons after bariatric operation.

O50 EFFECT OF LONG-TERM USE OF CONTINUOUS POSITIVE AIRWAY PRESSURE ON BLOOD PRESSURE PATIENTS WITH RESISTANT HYPERTENSION AND OBSTRUCTIVE SLEEP APNEA

Background and Objective: Obstructive Sleep Apnea (OSA) is strongly associated with Resistant Hypertension (RHT). Continuous positive airway pressure (CPAP) is the treatment of choice for moderate-severe OSA. Its benefit in terms of blood pressure (BP) control is still unclear. The objective of the study is to evaluate the effect of CPAP on BP in patients with RHT and moderate-severe OSA. Methods: This was a prospective intervention study that included 124 patients with RHT and moderate/severe OSA (AHI&gt;15/hour) divided in 2 groups. Patients using CPAP uninterruptedly for a minimum period of 12 months (CPAP group) were compared with those who refused to use CPAP despite clinical indication (Control group). Office BP and 24-hour ABPM were obtained at baseline and after follow-up. Primary outcomes were changes in office and ambulatory BPs, and nocturnal BP reduction. Results: 124 individuals were included (37.9% male with a mean age of 60.7 ± 7.8 years), 65 in the CPAP group and 59 in the control group with a median [interquartile range] follow-up time of 68 [49-81] months. There was a reduction in office systolic BP (SBP) of -7.5 mmHg ([CI95%: -16.3 to -1.1],p=0.089), in nocturnal SBP and diastolic BP (DBP) of – 6.1 mmHg ([CI95%: -12.4 to 0.3],p=0.06) and -3.5 mmHg ([CI95%: -7.4 to 0.6],p=0.092), respectively, without reaching statistical significance. Otherwise, after excluding 9 patients of CPAP group with low adherence, we found a reduction in office SBP of -10.3 mmHg ([CI95%: -19.7 to 0.9],p=0.031), in 24-hour SBP and DBP of – 4.8 mmHg ([CI95%: -10.5 to 0.8],p=0.095) and -3.4 mmHg ([CI95%: -6.8 to 0.1],p=0.045), and in nocturnal SBP and DBP of – 8.1 mmHg ([CI95%: -14.7 to -1.5],p=0.017) and -5.3 mmHg ([CI95%: -9.6 to -1.1],p=0.014), respectively. Conclusion: Long term use of CPAP reduced office, 24-hour and nighttime SBP specially in resistant hypertensives with good CPAP adherence.

Outcome of Nasal continuous positive airway pressure in neonates: A cross-sectional study.

This study aimed to assess the efficacy of nasal continuous positive airway pressure (CPAP) in term and preterm neonates with respiratory distress by evaluating successful outcomes, identifying factors contributing to treatment failure, and documenting associated complications. A comparative cross-sectional study design was employed. The research was conducted at Combined Military Hospital (CMH) Rawalpindi from November 2022 to July 2023. All consecutive neonates admitted during the specified period with respiratory distress requiring CPAP treatment and meeting inclusion criteria were enrolled. Pre- and post-CPAP respiratory distress levels, relevant biochemical markers, as well as mortality and morbidity rates were documented. Both descriptive and inferential statistical analyses were employed. The mean age of the study cohort was 53.3±85.6 minutes. The average time to initiate CPAP was 82.4 ± 94.7 minutes. Mean gestational age stood at 34.68±2.8 weeks. CPAP was successful in 97% of babies. The low birth weight below 1200grams was the main factor related to failure of CPAP. The mean Downes score decreased from 5.8±1.3 before CPAP to 3.3±1.6 after 12 hours of CPAP and further to 1.85±2 after 24 hours. Significant improvements in Downes score were noted after 24 hours of CPAP usage (p < 0.05) using paired sample T-test. This study affirms the effectiveness of CPAP in addressing neonatal respiratory distress. The utilization of CPAP emerges as a valuable intervention that not only reduces the requirement for invasive ventilation but also exhibits the potential to alleviate morbidity and mortality rates among neonatal populations.

Adherence to CPAP Therapy in Obstructive Sleep Apnea: A Prospective Study on Quality of Life and Determinants of Use.

Obstructive sleep apnea (OSA) often goes unrecognized despite common symptoms, such as excessive daytime sleepiness, fatigue, and impaired quality of life (QoL). Continuous positive airway pressure (CPAP) is the gold standard treatment for OSA, but optimal daily usage and time needed for observable effects remain unclear. This study aimed to investigate the short-term effects of CPAP on daytime sleepiness and QoL in patients with severe OSA. Medical records were collected from 87 patients with severe OSA who initiated CPAP therapy. Also, validated questionnaires were used before and after one month of CPAP to analyze QoL-the Calgary Sleep Apnea Quality of Life Index (SAQLI), the Cues to CPAP Use Questionnaire (CCUQ), and daytime sleepiness-the Epworth Sleepiness Scale (ESS). Multiple regression analysis was conducted to identify predictors of CPAP usage. Of the total participants aged 55.6 ± 12.5, 77% were males, and 62% were CPAP adherent. Reductions in daytime sleepiness (ESS) were noted, as well as improvements in both overall QoL (SAQLI) and specifically in the domains of daily functioning, social interactions, emotional well-being, and symptom perception. Important cues for CPAP usage recognized by patients were physicians' instructions and physicians' concern regarding their patients' condition. Furthermore, multiple regression revealed higher SAQLI scores and lower ESS scores as positive predictors of CPAP usage, along with lower AHI after one month of CPAP being associated with sufficient adherence.

Is the Epworth Sleepiness scale a valid outcome measure to evaluate the effectiveness of positive airway pressure treatments on daytime sleepiness? Psychometric insights from measurement invariance and response shifts.

Although the validity of the Epworth Sleepiness Scale (ESS) as an effectiveness measure for sleep apnea treatments such as continuous positive airway pressure (CPAP) has been supported by multiple studies, some researchers continue to challenge it. They suggest that in addition to its impact on relieving patients' daytime sleepiness, CPAP also alters the internal standards patients use to evaluate their sleepiness (i.e., response shift; RS), confounding the meaning of the difference in the ESS scores. We believe an issue yet to be addressed in this debate is that all existing evidence of RS has been obtained through the then-test approach, a retrospective method sensitive to various cognitive mechanisms. Thus, in the current study, we re-examined this issue using the structural equation modeling (SEM) approach, a method that can be directly applied to randomized clinical trial (RCT) data without retrospective measures. With the ESS data from two independent RCTs, we conducted cross-sectional and longitudinal measure invariance tests in SEM to examine whether CPAP would lead to RS. The ESS demonstrated cross-sectional and longitudinal scalar invariance against CPAP treatments. Its factorial pattern, loadings, and thresholds were invariant between the treatment and control groups and pre- and post-treatment, supporting the comparability of the observed mean ESS scores across time and groups. Our results support the validity of the average difference scores of the ESS for quantifying the effectiveness of CPAP on group-level daytime sleepiness in RCTs with relatively large sample sizes.

Implementation of Nasal CPAP Weaning Guidelines in Preterm Infants.

Continuous positive airway pressure (CPAP) benefits preterm infants with respiratory distress, including reduced bronchopulmonary dysplasia (BPD) incidence, surfactant use, and extubation failure. Successful CPAP weaning also promotes oral feeding. However, there is no consensus on the optimal weaning of CPAP in neonates. This study aims to determine the effects of CPAP (CPAP) weaning guideline implementation on neonatal outcomes. CPAP gradual pressure weaning guidelines were implemented in the Penn State Children's Hospital NICU in 2020. We included baseline data from infants (Epoch1) before bubble CPAP implementation in 2018-19. We included infants (Epoch2) after implementing the guidelines during 2020-21. The inclusion criteria were infants <32 weeks gestation with CPAP support. Compliance with the CPAP weaning guidelines was the primary process measure. Primary outcome measures included successful CPAP wean on the first attempt. Balancing measures used were total days on respiratory support and length of hospital stay. 195 infants were included in this study, 95 infants in Epoch 1 before bubble CPAP implementation and 100 infants in Epoch 2 after implementing guidelines. Infants in the two Epochs were similar in median gestational age at 29 vs 30 weeks (p=0.47) and were similar in median birth weight at 1190 vs 1130 grams (p=0.73). After implementing weaning guidelines, the successful weaning off CPAP improved from 9.5% to 54% (p<0.001). The total days needed to achieve full oral feeds decreased by 7 days (29 vs 22 median days, p<0.001). The BPD incidence was not significantly different between the two Epochs at 17% vs 16%, p= 0.87. There was no difference in total days of respiratory support, total length of stay, the number of infants discharged on home nasogastric feeding, and demographic variables. The implementation of the bubble CPAP weaning guideline improves the successful weaning of CPAP and promotes oral feeding in preterm infants.

Novel physiologic predictors of positive airway pressure effectiveness (NICEPAP) study: rationale, design and methods.

Continuous positive airway pressure (CPAP) is the primary therapy for obstructive sleep apnea (OSA); however the effectiveness of CPAP remains suboptimal. We describe the Novel PhysIologiC prEdictors of Positive Airway Pressure Effectiveness (NICEPAP) study. Its purpose is to determine whether physiological traits of OSA contribute to CPAP effectiveness. NICEPAP (NCT05067088) is a prospective, observational cohort study conducted at an academic sleep center. Adults newly diagnosed with OSA (n = 267) are assessed for OSA traits of loop gain, arousal threshold, pharyngeal collapsibility, and muscle compensation from baseline polysomnography. We perform a comprehensive assessment of covariates relevant to CPAP adherence, efficacy, and patient-centered outcomes. Participants are followed for 12 months. Primary outcomes include (1) CPAP adherence (hours/night), (2) CPAP efficacy (apneas-hypopneas/hour), and (3) quality of life at six months measured by objective CPAP data and Functional Outcomes of Sleep Questionnaire. Secondary outcomes include sleep quality, sleepiness, insomnia, and neurocognitive function. Data on covariates, including demographics, sleep symptoms, medical history, medications, sleep quality, OSA and treatment self-efficacy, decisional balance, and socio-economic and social and partner support, are collected using validated instruments. The analysis for primary outcomes includes a generalized linear mixed model for an outcome (e.g., CPAP adherence) with OSA traits as exposures followed by the addition of relevant covariates. The findings of the NICEPAP study will inform research aimed to enhance CPAP effectiveness. Understanding the role of physiological OSA traits in CPAP effectiveness is a crucial step toward a precision medicine approach to OSA.

#1105 Prognosis of dialysis patients with obstructive sleep apnea syndrome diagnosed by polysomnography

Abstract Background and Aims Obstructive Sleep Apnea Syndrome (OSA) is common among CKD, in particular dialysis patients. However, it is not yet studied in a large polysomnography (PSG) database. Randomized controlled trials (RCTs) proved the effectiveness of continuous positive airway pressure (CPAP) for the SAS-related symptoms, but not for lowering the mortality risk of all-cause and cardiovascular disease. However, the effect of CPAP on mortality risk is not examined among dialysis patents. Method We identified dialysis patients by reviewing medical records in the Okinawa Nakamura Clinic (ONSLEEP). (J Clin Sleep Med 2021). In the ONSLEEP, a total of 10,856 Japanese patients received PSG from September 1990 to December 2010. We defined patients who were on CPAP more than one month as CPAP user. Patients qualified and eligible for CPAP but refused it were assigned as CPAP non-users. Median observation was 6.6 years. We studied 9,841 PSG patients after excluding those with insufficient data, age&amp;lt;20 years, and central SAS. Among them, we found 195 dialysis patients: 16 (1.0%) dialysis patients with AHI&amp;lt;5/hour in 1,665 subjects and 164 (2.5%) in 8,176 OSA patients. Mortality rate was compared between CPAP users and nonusers by multivariate logistic analysis adjusted for age, gender, body mass index (BMI), and apnea hypopnea index (AHI). Results Among the OSA dialysis patients (men 127, women 37), there were 116 (2.6%) in the CPAP users and 48 (2.2%) in the CPAP non-users, respectively. Number of deaths was 65 (39 CPAP users, 26 CPAP non-users) during the follow-up. The death rate was 33.6% in the CPAP users and 54.2% in the CPAP non-users, respectively. CPAP users showed better survival after starting dialysis; hazard ratio (HR) 0.52 and 95% confidence interval (CI) of 0.31 to 0.88 (P = 0.015). Age was also a significant predictor of death; HR (95% CI) 1.04 (1.02-1.06, P &amp;lt; 0.0001). Conclusion Dialysis patients with OSA showed better survival by use of CPAP. In dialysis patients, screening of OSA is recommended if they complained sleep problems such as insomnia, daytime sleepiness, headache, and fatigue. Also, we need further study for those CPAP nonusers.

Impact of posture and CPAP on nasal airflow

Obstructive sleep apnea (OSA) patients who use continuous positive airway pressure (CPAP) often complain of nasal dryness and nasal obstruction as side effects of CPAP. The physiological mechanisms by which CPAP may cause nasal dryness and nasal obstruction remain poorly understood. It has been hypothesized that CPAP interferes with the nasal cycle, abolishing the resting phase of the cycle and leading to nasal dryness. We performed rhinomanometry measurements in 31 OSA patients sitting, laid supine, and supine after 10 min of CPAP at 10 cmH2O. A posture change from sitting to supine led to more symmetric airflow partitioning between the left and right nostrils in the supine position. CPAP did not have a significant impact on nasal resistance, unilateral airflows, or airflow partitioning. Our results suggest that airflow partitioning becomes more symmetric immediately after changing to a supine position, while CPAP had no effect on nasal airflow, thus preserving the nearly symmetric airflow partitioning achieved after the posture change.

Airway stability in sleep apnea: Assessing continuous positive airway pressure efficiency

Obstructive Sleep Apnea Syndrome (OSAS) disrupts millions of lives with its burden of airway obstruction during sleep. Continuous Positive Airway Pressure (CPAP) therapy has been scrutinized for its biomechanical impact on the respiratory tract. This study leverages computational fluid dynamics to investigate CPAP's effects at 9 cm H2O (882.6 Pa) on the computed-tomography-based nasal-to-14-generation full respiratory tract model compared to ambient conditions, focusing on static pressure, airflow velocity, and shear stress. Our findings reveal that CPAP significantly increases static pressure, enhancing airway patency without adverse changes in airflow velocity or harmful shear stress on lung tissue, challenging prior concerns about its safety. Notably, the larynx experiences the highest shear stress due to its narrow anatomy, yet CPAP therapy overall supports airway walls against collapse. This investigation highlights CPAP's critical role in OSAS treatment, offering reassurance about its safety and efficacy. By clarifying CPAP therapy's physiological impacts, our study contributes vital insights for optimizing OSAS management strategies, affirming CPAP's benefit in maintaining open airways with minimal tissue strain.

Mandibular Advancement vs CPAP for Blood Pressure Reduction in Patients With Obstructive Sleep Apnea

BackgroundHypertension guidelines recommend diagnosis and treatment of obstructive sleep apnea (OSA) in patients with hypertension. The mandibular advancement device (MAD) is an oral appliance therapy for patients who decline or cannot tolerate continuous positive airway pressure (CPAP). ObjectivesWe compared the relative effectiveness of MAD vs CPAP in reducing 24-hour ambulatory blood pressure (BP). MethodsIn an investigator-initiated, randomized, noninferiority trial (prespecified margin 1.5 mm Hg), 321 participants aged ≥40 years with hypertension and increased cardiovascular risk were recruited at 3 public hospitals for polysomnography. Of these, 220 participants with moderate-to-severe OSA (apnea-hypopnea index ≥15 events per hour) were randomized to either MAD or CPAP (1:1). The primary outcome was the difference between the 24-hour mean arterial BP at baseline and 6 months. ResultsCompared with baseline, the 24-hour mean arterial BP decreased by 2.5 mm Hg (P = 0.003) at 6 months in the MAD group, whereas no change was observed in the CPAP group (P = 0.374). The between-group difference was −1.6 mm Hg (95% CI: −3.51 to 0.24, noninferiority P < 0.001). The MAD group demonstrated a larger between-group reduction in all secondary ambulatory BP parameters compared with the CPAP group, with the most pronounced effects observed in the asleep BP parameters. Both the MAD and CPAP improved daytime sleepiness, with the between-group difference similar (P = 0.384). There were no between-group differences in cardiovascular biomarkers. ConclusionsMAD is noninferior to CPAP for reducing 24-hour mean arterial BP in participants with hypertension and increased cardiovascular risk. (Cardiosleep Research Program on Obstructive Sleep Apnea, Blood Pressure Control and Maladaptive Myocardial Remodeling—Non-inferiority Trial [CRESCENT]; NCT04119999)

Effect of Continuous Positive Airway Pressure on Blood Pressure in Patients with Resistant Hypertension and Obstructive Sleep Apnea: An Updated Meta-analysis.

The effect of continuous positive airway pressure (CPAP) on resistant hypertension in patients at high risk with obstructive sleep apnea (OSA) needs further investigation. We aimed to determine the effect of CPAP on blood pressure in patients with resistant hypertension and OSA. Databases including PubMed, EMBASE, MEDLINE, the Cochrane Library, and CMB were searched. Data were pooled using a random-effects or fixed-effects model to derive weighted mean differences (WMDs) and 95% confidence intervals (CIs). A total of 12 trials and 718 participants were included. Compared with control, CPAP significantly reduced 24-h systolic blood pressure (SBP) (WMD: - 5.92 mmHg [ - 8.72, - 3.11]; P＜0.001), 24-h diastolic blood pressure (DBP) (WMD: - 4.44 mmHg [- 6.26 , - 2.62]; P ＜0.001), daytime SBP (WMD: - 5.76 mmHg [ - 9.16, - 2.36]; P ＜0.001), daytime DBP (WMD: - 3.92 mmHg [- 5.55, - 2.30];nighttime SBP (WMD: - 4.87 mmHg [ - 7.96 , - 1.78]; P = 0.002), and nighttime DBP (WMD: - 2.05 mmHg [- 2.99, - 1.11]; P＜0.001) in patients with resistant hypertension and OSA. CPAP improved theblood pressure bothin the short(＜3 months) and long term (≥ 3 months). No significant impact on mean heart rate was noted (WMD: -2.76 beats per min [- 7.50, 1.97]; P = 0.25). CPAP treatment was associated with BP reduction in patients with resistant hypertension and OSA.

Dosimetric Comparison of CPAP and DIBH for Left-sided Breast Cancer Radiation Therapy

PurposeDespite the increasing interest in using continuous positive airway pressure (CPAP) in radiotherapy (RT), direct comparisons with the more widely employed deep inspiration breath-hold (DIBH) have been limited. This planning study aimed to offer comprehensive geometric and dosimetric evidence by comparing CPAP and DIBH-based RT plans. Materials and MethodsA retrospective dataset of 35 left-sided breast cancer patients with planning CT (pCT) scans under three breathing conditions (free breathing, CPAP with 10 cmH2O pressure, and DIBH) was collected. Volumetric arc therapy plans aimed for 95% dose coverage to 95% of the planning target volume with a maximum dose below 107%. A comparative dosimetric analysis among the three plans was conducted. Additionally, geometric differences were assessed by calculating the minimum distance between the heart and the clinical target volume (CTV) in each pCT. ResultsCPAP and DIBH plans demonstrated comparable mean heart doses (1.05 Gy), which were significantly lower than the FB plan (1.34 Gy). The maximum dose to the left anterior descending artery was smallest in the CPAP plan (4.44 Gy), followed by DIBH (4.73 Gy) and FB (7.33 Gy). Other organ-at-risk doses for CPAP and DIBH were similar, with mean contralateral breast doses of 2.27 and 2.21 Gy, mean ipsilateral lung doses of 4.09 and 4.08 Gy, V20 at 6.11 and 6.31%, and mean contralateral lung doses of 0.94 and 0.92 Gy, respectively. No significant difference was found in the minimum heart-to-CTV distance between CPAP and DIBH. DIBH exhibited the greatest lung volume (3908 cc), followed by CPAP (3509 cc), and FB (2703 cc). ConclusionThe comparison between CPAP and DIBH shows their similarity in both geometric and dosimetric aspects, providing strong evidence for CPAP's effectiveness and feasibility in RT. This suggests its potential as an alternative to DIBH for left-sided breast cancer patients.

Heterogeneous Effects of Continuous Positive Airway Pressure in Non-Sleepy Obstructive Sleep Apnea on Cardiovascular Disease Outcomes: Post Hoc Machine Learning Analysis of the ISAACC Trial (ECSACT Study).

Rationale: Randomized controlled trials of continuous positive airway pressure (CPAP) therapy for cardiovascular disease (CVD) prevention among patients with obstructive sleep apnea (OSA) have been largely neutral. However, given that OSA is a heterogeneous disease, there may be unidentified subgroups demonstrating differential treatment effects. Objectives: We sought to apply a novel data-drive approach to identify nonsleepy OSA subgroups with heterogeneous effects of CPAP on CVD outcomes within the Impact of Sleep Apnea Syndrome in the Evolution of Acute Coronary Syndrome (ISAACC) study. Methods: Participants were randomly partitioned into two datasets. One for training (70%) our machine-learning model and a second (30%) for validation of significant findings. Model-based recursive partitioning was applied to identify subgroups with heterogeneous treatment effects. Survival analysis was conducted to compare treatment (CPAP vs. usual care [UC]) outcomes within subgroups. Results: A total of 1,224 nonsleepy OSA participants were included. Of 55 features entered into our model, only two appeared in the final model (i.e., average OSA event duration and hypercholesterolemia). Among participants at or below the model-derived average event duration threshold (19.5 s), CPAP was protective for a composite of CVD events (training hazard ratio [HR], 0.46; P = 0.002). For those with longer event duration (>19.5 s), an additional split occurred by hypercholesterolemia status. Among participants with longer event duration and hypercholesterolemia, CPAP resulted in more CVD events compared with UC (training HR, 2.24; P = 0.011). The point estimate for this harmful signal was also replicated in the testing dataset (HR, 1.83; P = 0.118). Conclusions: We discovered subgroups of nonsleepy OSA participants within the ISAACC study with heterogeneous effects of CPAP. Among the training dataset, those with longer OSA event duration and hypercholesterolemia had nearly 2.5 times more CVD events with CPAP compared with UC, whereas those with shorter OSA event duration had roughly half the rate of CVD events if randomized to CPAP.

Relación entre la apnea obstructiva del sueño y la diabetes mellitus tipo 2

IntroductionThe association between obstructive sleep apnea (OSA) and glucose metabolism remains controversial. This study investigates the relationship between OSA and incident type 2 diabetes (DM) and prediabetes (preDM), as well as the effect of long-term CPAP (continuous positive airway pressure) treatment. MethodsFollow-up study in a retrospective clinical cohort of patients with OSA and randomly selected controls. Data on incident DM and preDM as well as CPAP were obtained from hospital records. The relationship between baseline OSA and incident DM was examined using COX regression models. ResultsThree hundred and fifty-six patients, 169 with OSA and 187 controls were followed for a median of 98 months; 47 patients (13.2%) developed DM and 43 (12.1%) developed preDM. The 5-year cumulative incidence of DM was 10.7% (6.5–13.9%). 87% of subjects with preDM in the baseline sample progressed to incident DM. It is shown that body mass index (BMI), nocturnal hypoxia and apnea hypopnea index (AHI) are risk factors for the development of DM and that CPAP reduces this risk. ConclusionsPatients with OSA have a higher risk of developing DM. The risk factors involved are BMI, nocturnal hypoxia and AHI. Regular long-term CPAP use was associated with a decreased risk.

Mask Continuous Positive Airway Pressure Increases Diaphragm Thickening Fraction in Healthy Subjects

Introduction: The most widespread treatment for obstructive sleep apnoea and obesity hypoventilation syndrome is continuous positive airway pressure (CPAP). The addition of inspiratory support is a potential alternative. This is a physiological study to determine the effect of CPAP and inspiratory support pressure on respiratory effort measured by diaphragm thickening fraction (DTF) in healthy volunteers. Methods: DTF was measured in spontaneously breathing, healthy volunteers during 4 phases: (I) without connection to a ventilator, (II) on a ventilator without any applied pressures, (III) with a CPAP of 5 cmH₂O, and (IV) with an additional inspiratory support pressure of 5 cmH₂O. Results: Twenty-nine individuals agreed to participate. DTF was similar during the first two phases (32 ± 13% and 35 ± 22%). A considerable increase in DTF to 51 ± 21% was noted in phase III. The introduction of inspiratory support pressure during phase IV led to a reduction in DTF back to 36 ± 23% (p < 0.001). Tidal volume and minute ventilation were both slightly higher in phase IV compared to phase III. Conclusion: CPAP without inspiratory support pressure increases respiratory effort measured by DTF in healthy subjects. Further research is required to investigate this phenomenon in a clinical setting.

Ferroptosis-related genes are considered as potential targets for CPAP treatment of obstructive sleep apnea.

Obstructive sleep apnea (OSA) is a common syndrome characterized by upper airway dysfunction during sleep. Continuous positive airway pressure (CPAP) is the most frequently utilized non-surgical treatment for OSA. Ferroptosis play a crucial role in the physiological diseases caused by chronic intermittent hypoxia, but its involvement in the development of OSA and the exact mechanisms have incompletely elucidated. GSE75097 microarray dataset was used to identify differentially expressed genes between OSA patients and CPAP-treated OSA patients. Subsequently, Gene Ontology (GO) annotation, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, STRING database, and FerrDb database were conducted to analyze the biological functions of differentially expressed genes and screen ferroptosis-related genes. Finally, GSE135917 dataset employed for validation. There were 1,540 differentially expressed genes between OSA patients and CPAP-treated OSA patients. These differentially expressed genes were significantly enriched in the regulation of interleukin-1-mediated signaling pathway and ferroptosis-related signaling pathway. Subsequently, 13 ferroptosis-related genes (DRD5, TSC22D3, TFAP2A, STMN1, DDIT3, MYCN, ELAVL1, JUN, DUSP1, MIB1, PSAT1, LCE2C, and MIR27A) were identified from the interaction between differentially expressed genes and FerrDb database, which are regarded as the potential targets of CPAP-treated OSA. These ferroptosis-related genes were mainly involved in cell proliferation and apoptosis and MAPK signaling pathway. Furthermore, DRD5 and TFAP2A were downregulated in OSA patients, which showed good diagnostic properties for OSA, but these abnormal signatures are not reversed with short-term effective CPAP therapy. In summary, the identification of 13 ferroptosis-related genes as potential targets for the CPAP treatment of OSA provides valuable insights into the development of novel, reliable, and accurate therapeutic options.

Acute Effect of Positive Airway Pressure on Heart Rate Variability in Obstructive Sleep Apnea.

Autonomic dysregulation is associated with cardiovascular consequences in obstructive sleep apnea (OSA). This study aimed to investigate the effect of acute continuous positive airway pressure (CPAP) treatment on autonomic activity and to identify factors contributing to heart rate variability (HRV) changes in OSA. Frequency domain HRV parameters were calculated and compared between the baseline polysomnography and during the CPAP titration in 402 patients with moderate to severe OSA. There were significant reductions in total power, very low-frequency band power, low-frequency band power, and high-frequency band power during the CPAP titration as compared to the baseline polysomnography. This tendency was pronounced in male patients with severe OSA. Multivariate analysis found that changes in the apnea-hypopnea index and oxygen saturation were significantly associated with changes in sympathetic and parasympathetic activity, respectively. This study demonstrated that HRV parameters significantly changed during the CPAP titration, indicating a beneficial effect of CPAP in the restoration of sympathetic and parasympathetic hyperactivity in OSA. Prospective longitudinal studies should determine whether long-term CPAP treatment aids in maintaining the long-lasting improvement of the autonomic functions, thereby contributing to the prevention of cardiovascular and cerebrovascular diseases in patients with OSA.

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

BackgroundNoninvasive 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 resultsWe 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. ConclusionsCPAP 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.

Estimation of antihypertensive effect after initiating continuous positive airway pressure treatment in Japanese patients with sleep disordered breathing

Abstract Introduction It is true that patients with cardiovascular diseases including hypertension have already suffered from sleep disordered breathing (SDB). Furthermore, Continuous Positive Airway Pressure (CPAP) treatment shows antihypertensive effect by improving sympathetic nervous activity. On the other hand, we reported that CPAP treatment had a beneficial effect on hypertension, but 70% patients still remain inadequately treated. As a result, we need the strict blood pressure follow up for patient with SDB after initiating CPAP treatment at ESC congress 2022. Purpose Our aim in this study is to estimate the antihypertensive effect after initiating CPAP treatment, also estimate the differences of CPAP effect by focusing on Japanese non-obese body. Methods All patients were conducted full night polysomnography. One-hundred eighty patients showed obstructive SDB {apnea hypopnea index (AHI) &amp;gt;20/hour}, and CPAP treatment were initiated. We divided into three groups by using body mass index (BMI). Group A showed BMI &amp;lt; 25 kg/m2 (n = 59). Group B showed 25 ≦BMI &amp;lt; 30 kg/m2 (n = 68), and Group C showed 30 ≦ BMI kg/m2 (n = 53). If patients had already taken blood pressure-lowering agents, they had to continue blood pressure-lowering agents without changing other agents or dose intensification. According to Japanese society of hypertension guidelines for the managements of hypertension 2019 (JSH2019), we estimated the improvement of blood pressure to assess effectiveness of CPAP treatment after six-month follow up. Results The study group consisted of 180 SDB patients (152 males, 28 females). The mean age was 53 ± 12 years. Figure 1 showed polysomnographic data before initiating CPAP treatment. Group A was significantly lower apnea hypopnea index (AHI) than in Group B and C (p &amp;lt; 0.0001). Figure 2 showed the changes of blood pressure after initiating CPAP treatment (six-month). There was no significant difference respect to changes of systolic blood pressure (ΔSBP), but Group A showed the tendency for worsening SBP compared with other groups. Conclusions We could estimate that CPAP treatment had only limited effects in antihypertensive effect for Japanese patients, who especially had non-obese body and lower AHI level. We need the strict blood pressure follow up for patient with SDB after initiating CPAP treatment.Figure