Effect of Treatment of OSA With CPAP on Glycemic Control in Adults With Type 2 Diabetes: The Diabetes Sleep Treatment Trial (DSTT).

OBJECTIVE: The effect of obstructive sleep apnea (OSA) treatment with continuous positive airway pressure (CPAP) on glycemic measures in patients with type 2 diabetes (T2D) remains unclear. We aimed to determine whether CPAP treatment of OSA improves glycemic measures in patients with T2D. METHODS: This randomized controlled trial (N = 98) examined changes in glycemic measures following 12 weeks of active (n = 49) or sham (n = 49) CPAP and consideried participants' adherence to CPAP therapy (percentage of days with ≥4 hours use and average hours/day of use). RESULTS: Baseline treatment groups were similar. Regarding the efficacy of active vs sham-CPAP over time, at 6 weeks, both groups had similar reductions in fructosamine (mean difference [MD], 95% confidence interval [CI]: CPAP -13.10 [-25.49 to -0.7] vs. sham -7.26 [-20.2 to 5.69]; P = .519) but different in HbA1c (CPAP -0.24 [-0.48 to -0.003] vs sham 0.15 [-0.10 to 0.4]; P = .027). At 12 weeks, reductions in HbA1c values were similar by group (CPAP -0.26 [-0.53 to 0.002] vs sham -0.24 [-0.53 to 0.04]; P = .924). HbA1c reductions were associated with a greater percentage of cumulative days of CPAP usage ≥4 hours per day (b [SE] = 0.006 [0.002]; P = .013) and cumulative hours of CPAP use (b [SE] = 0.08 [0.08]; P = .012). CPAP use of ≥7 hours was associated with a significant reduction in HbA1c (b [SE] 0.54 [0.16]; P = .0012). CONCLUSION: CPAP treatment of OSA did not result in sustained improved glycemic control compared to sham in the intent-to-treat analysis. CPAP adherence was associated with greater improvements in glycemic control.

Metabolic outcomes in adults with type 2 diabetes and sleep disorders.

PURPOSE: Insomnia is frequently co-morbid with obstructive sleep apnea (OSA); the effect of insomnia or co-morbid insomnia and OSA (OSA + I) on associated metabolic outcomes in adults with type 2 diabetes (T2D) remains unclear. This study in adults with T2D compared metabolic outcomes among persons with OSA, insomnia, or OSA + I. METHODS: This study analyzed baseline data from the Diabetes Sleep Treatment Trial of persons recruited for symptoms of OSA or poor sleep quality. Home sleep studies determined OSA presence and severity. Insomnia was evaluated using the Insomnia Severity Index. Height and weight to calculate body mass index (BMI) and blood for laboratory values were obtained. Multivariate general linear models were used to examine the impact of the type of sleep disorder and sociodemographic, lifestyle, and sleep risk factors on metabolic outcomes. RESULTS: Participants (N = 253) were middle-aged (56.3 ± 10.5 years), white (60.5%), obese (mean BMI of 35.3 ± 7.1 kg/m2), and male (51.4%) with poor glucose control (mean HbA1c of 8.0 ± 1.8%). Most participants had OSA + I (42.7%) or insomnia only (41.0%). HbA1c and BMI differed among the sleep disorder groups. In addition, in the adjusted models, having insomnia only, compared to OSA only, was associated on average with higher HbA1c levels (b = 1.08 ± 0.40, p < 0.007) and lower BMI (b = - 7.03 ± 1.43, p < 0.001). CONCLUSIONS: Findings suggest that insomnia frequently co-exists with OSA, is independently associated with metabolic outcomes in adults with T2D, and should be considered in investigations of the effects of OSA in persons with T2D. TRIAL REGISTRATION: Diabetes-Obstructive Sleep Apnea Treatment Trial (NCT01901055), https: Clinicaltrials.gov/ct2/show/NCT01901055; Registration date: July 17, 2013.

Study protocol to assess de-implementation of the initial provider encounter for diagnosis and treatment of obstructive sleep apnea: the DREAM (Direct Referral for Apnea Monitoring) Project.

BACKGROUND: Obstructive sleep apnea (OSA) is a very common and serious health condition which is highly prevalent among U.S. military Veterans. Because the demand for sleep medicine services often overwhelms the availability of such services, it is necessary to streamline diagnosis and treatment protocols. The goals of this study are to, (1) assess the efficacy of de-implementing the initial provider encounter for diagnosis and treatment of OSA; (2) determine the negative predictive value (NPV) of home sleep apnea testing (HSAT); (3) develop HSAT usage recommendations for various at-risk patient populations. METHODS: This is a large, pragmatic study that will take place in 3 VA sleep medicine programs: San Francisco, CA; Portland, OR; and Pittsburgh, PA. All Veterans referred for new sleep apnea evaluations at these sites will be included in this four-year study. Outcomes will include time from referral for OSA to sleep testing and treatment; positive airway pressure (PAP) treatment adherence measures; patient-reported clinical outcomes and measures of satisfaction; determination of the NPV of HSAT; HSAT usage recommendations for at-risk patient populations. DISCUSSION: The DREAM (Direct Referral for Apnea Monitoring) Project will inform sleep medicine providers and clinical organizations regarding strategies to streamline diagnosis and treatment protocols for OSA. Results of this study should have significant impact on clinical practices and professional guidelines. Trial registration The majority of this project is an observational study of clinical procedures. Therefore, clinical trial registration is not required.

Identifying the Demographic and Mental Health Factors That Influence Insomnia Treatment Recommendations Within a Veteran Population.

Objective/Background: Insomnia is a pervasive and costly disorder that is particularly prevalent within the U.S. Veteran population. Although Cognitive Behavioral Therapy for Insomnia (CBT-I) is the recommended first-line treatment for insomnia, high rates of sedative-hypnotic prescribing continue. There is little research investigating the rates and factors impacting insomnia treatment recommendations, both behavioral and pharmacological. Participants: A cohort of 5,254 Veterans referred for either CBT-I or prescribed a sedative-hypnotic medication at a single VA Medical Center composed the group of participants. Methods: The current study evaluated the rates of insomnia treatment recommendations and the extent to which demographic variables, psychiatric disorders, and sleep disorders contributed to referrals for CBT-I or prescriptions for sedative-hypnotic medications within a large administrative data set. Results: Military service-related disability, insomnia diagnosis, and having one or more psychiatric diagnoses were associated with a greater likelihood of receiving a CBT-I referral (alone or in addition to a sedative-hypnotic medication) rather than a sedative-hypnotic prescription alone. A diagnosis of posttraumatic stress disorder was associated with a greater likelihood of receiving a sedative-hypnotic medication alone versus a CBT-I referral. Conclusions: Overall, the findings suggest that sedative-hypnotic medications were overwhelmingly the primary treatment recommendation despite evidence to support CBT-I as the recommended first-line treatment. However, key factors were identified that increased the likelihood of Veterans being referred for CBT-I. Suggestions for better identifying and understanding key factors that impact treatment recommendations are discussed.

Clinical Characterization of Insomnia among Veterans with PTSD: Identifying Risk Factors for Diagnosis and Treatment with Sedative-Hypnotics.

Insomnia is prevalent among Veterans with post-traumatic stress disorder (PTSD), it exacerbates PTSD symptoms, and it contributes to impaired functioning and quality of life. To improve treatment outcomes, it is important to identify risk factors for insomnia and sedative-hypnotic use. Classification and regression trees and logistic regression models were used to identify variables associated with insomnia or sedative-hypnotic use. Key findings include low insomnia diagnosis rates (3.5-5.6%) and high rates of sedative-hypnotics (44.2-49.0%). Younger Veterans and those without a breathing-related sleep disorder (BRSD) were more likely to receive an insomnia diagnosis. Veterans with greater service connection and those with an alcohol/substance use disorder were more likely to be prescribed sedative-hypnotics. Interaction terms may have identified potential groups at risk of being under-diagnosed with insomnia (i.e. non-black Veterans with psychiatric co-morbidity, black Veterans without psychiatric co-morbidity) as well as groups at risk for sedative-hypnotic use (i.e. younger Veterans without BRSD). In sum, Veterans with PTSD have high rates of sedative-hypnotic use despite minimal evidence they are effective. This is counter to recommendations indicating behavioral interventions are the first-line treatment. Policy changes are needed to reduce use of sedative-hypnotics and increase access to behavioral insomnia interventions.

Sleep disorders among rural Veterans: Relative prevalence, comorbidities, and comparisons with urban Veterans.

PURPOSE: To describe and compare demographic characteristics and comorbidities of rural and urban Veterans diagnosed with sleep disorders, and to evaluate whether rurality is a disparity for sleep care among Veterans. METHODS: Numbers of Veterans with sleep disorders and comorbid conditions were determined using the Department of Veterans Affairs (VA's) Corporate Data Warehouse, a database that contains detailed clinical information for all Veterans who receive VA health care. Comparisons between urban and rural Veterans were conducted for fiscal years (FY) 2010-2021. FINDINGS: The prevalence of diagnosed sleep disorders was similar among rural and urban Veterans from FY2010 to 2021 and increased for both groups during this time period. The prevalence of chronic pulmonary disease, congestive heart failure, and diabetes mellitus was higher for rural Veterans with sleep disorders compared to their urban counterparts. From 2012 to 2021, the percentage of rural Veterans who received sleep care at VA facilities was lower than the percentage of urban Veterans who received VA sleep care during the same time span. CONCLUSIONS: Although rural Veterans exhibited a higher prevalence of 3 comorbid conditions associated with sleep disorders, the prevalence of sleep disorder diagnoses was similar between rural and urban Veterans. Therefore, it is possible that sleep disorders are underdiagnosed among rural Veterans. The fact that rural Veterans received VA sleep care at a lower rate compared to urban Veterans indicates that rurality is a disparity in access to care in this population. VA is addressing this disparity through a variety of programs, including telehealth initiatives.

Veterans Health Administration TeleSleep Enterprise-Wide Initiative 2017-2020: bringing sleep care to our nation's veterans.

STUDY OBJECTIVES: The Veterans Health Administration cares for many veterans with sleep disorders who live in rural areas. The Veterans Health Administration's Office of Rural Health funded the TeleSleep Enterprise-Wide Initiative (EWI) to improve access to sleep care for rural veterans through creation of national telehealth networks. METHODS: The TeleSleep EWI consists of (1) virtual synchronous care, (2) home sleep apnea testing, and (3) REVAMP (Remote Veterans Apnea Management Platform), a patient- and provider-facing web application that enabled veterans to actively engage with their sleep care and sleep care team. The TeleSleep EWI was designed as a hub-and-spoke model, where larger sites with established sleep centers care for smaller, rural sites with a shortage of providers. Structured formative evaluation for the TeleSleep EWI is supported by the Veterans Health Administration's Quality Enhancement Research Initiative and was critical in assessing outcomes and effectiveness of the program. RESULTS: The TeleSleep EWI launched with 7 hubs and 34 spokes (2017) and rapidly expanded to 13 hubs and 63 spokes (2020). The TeleSleep EWI resulted in a significant increase in rural veterans accessing sleep care by utilizing home sleep apnea testing to establish a diagnosis of obstructive sleep apnea and virtual care for follow-up. Rates of virtual care utilization were greater in hubs and spokes participating in the TeleSleep EWI compared with non-EWI sleep programs. Additionally, veterans expressed satisfaction with their virtual care TeleSleep experiences. CONCLUSIONS: The TeleSleep EWI successfully increased sleep care access for rural veterans, promoted adoption of virtual care services, and resulted in high patient satisfaction. CITATION: Chun VS, Whooley MA, Williams K, et al. Veterans Health Administration TeleSleep Enterprise-Wide Initiative 2017-2020: bringing sleep care to our nation's veterans. J Clin Sleep Med. 2023;19(5):913-923.

Sustainment of the TeleSleep program for rural veterans.

Background: In fiscal year 2021, the Veterans Health Administration (VHA) provided care for sleep disorders to 599,966 Veterans, including 189,932 rural Veterans. To further improve rural access, the VA Office of Rural Health developed the TeleSleep Enterprise-Wide Initiative (EWI). TeleSleep's telemedicine strategies include tests for sleep apnea at the Veteran's home rather than in a sleep lab; Clinical Video Telehealth applications; and other forms of virtual care. In 2017 and 2020, VHA provided 3-year start-up funding to launch new TeleSleep programs at rural-serving VA medical facilities. Methods: In early 2022, we surveyed leaders of 24 sites that received TeleSleep funding to identify successes, failures, facilitators, and barriers relevant to sustaining TeleSleep implementations upon expiration of startup funding. We tabulated frequencies on the multiple choice questions in the survey, and, using the survey's critical incident framework, summarized the responses to open-ended questions. TeleSleep program leaders discussed the responses and synthesized recommendations for improvement. Results: 18 sites reported sustainment, while six were "on track." Sustainment involved medical centers or regional entities incorporating TeleSleep into their budgets. Facilitators included: demonstrating value; aligning with local priorities; and collaborating with spoke sites serving rural Veterans. Barriers included: misalignment with local priorities; and hiring delays. COVID was a facilitator, as it stimulated adoption of telehealth practices; and also a barrier, as it consumed attention and resources. Recommendations included: longer startup funding; dedicated funding for human resources to accelerate hiring; funders communicating with local facility leaders regarding how TeleSleep aligns with organizational priorities; hiring into job classifications aligned with market pay; and obtaining, from finance departments, projections and outcomes for the return on investment in TeleSleep.

Noninferiority of functional outcome in ambulatory management of obstructive sleep apnea.

RATIONALE: Home portable monitor testing is increasingly being used to diagnose patients with obstructive sleep apnea (OSA) and to initiate them on continuous positive airway pressure (CPAP) treatment. OBJECTIVES: To compare functional outcome and treatment adherence in patients who receive ambulatory versus in-laboratory testing for OSA. METHODS: Veterans with suspected OSA were randomized to either home testing or standard in-laboratory testing. Home testing consisted of a type 3 portable monitor recording followed by at least three nights using an automatically adjusting positive airway pressure apparatus. Participants diagnosed with OSA were treated with CPAP for 3 months. MEASUREMENTS AND MAIN RESULTS: We measured the change in Functional Outcomes of Sleep Questionnaire score, with an a priori noninferiority delta of -1, and the mean daily hours of objectively measured CPAP adherence, with an a priori noninferiority delta of -0.75 hour/day. Of the 296 subjects enrolled, 260 (88%) were diagnosed with OSA, and 213 (75%) were initiated on CPAP. Mean ± SD functional outcome score improved 1.74 ± 2.81 in the home group (P < 0.001) and 1.85 ± 2.46 in the in-laboratory group (P < 0.0001). The lower bound of the one-sided 95% noninferiority confidence interval was -0.54. Mean ± SD hours of daily CPAP adherence were 3.5 ± 2.5 hours/day in the home group and 2.9 ± 2.3 hours/day in the in-laboratory group (P = 0.08). The lower bound of the one-sided 95% noninferiority confidence interval was 0.03. CONCLUSIONS: Functional outcome and treatment adherence in patients evaluated according to a home testing algorithm is not clinically inferior to that in patients receiving standard in-laboratory polysomnography.

Cardiac resynchronization therapy and obstructive sleep-related breathing disorder in patients with congestive heart failure.

OBJECTIVES: To assess the impact of cardiac resynchronization therapy (CRT) with or without atrial overdrive pacing, on sleep-related breathing disorder (SRBD). INTRODUCTION: CRT may have a positive influence on SRBD in patients who qualify for the therapy. Data are inconclusive in patients with obstructive SRBD. METHODS: Consenting patients eligible for CRT underwent a baseline polysomnography (PSG) 2 weeks after implantation during which pacing was withheld. Patients with an apnea hypopnea index (AHI) ≥15 but <50 were enrolled and randomized to atrial overdrive pacing (DDD) versus atrial synchronous pacing (VDD) with biventricular pacing in both arms. Patients underwent two further PSGs 12 weeks apart. RESULTS: Nineteen men with New York Heart Association class III congestive heart failure participated in the study (age 67.2 ± 7.5, Caucasian 78.9%, ischemic 73.7%). The score on Epworth Sleepiness Score was 7.3 ± 4.0, Pittsburgh Sleep Quality Index 7.4 ± 3.1, and Minnesota Living with Heart Failure Questionnaire 36.9 ± 21.9. There were no differences between the groups. At baseline, patients exhibited poor sleep efficiency (65.3 ± 16.6%) with nadir oxygen saturation of 83.5 ± 5.3% and moderate to severe SRBD (AHI 21.5 ± 15.3) that was mainly obstructive (central apnea index 3.3 ± 6.7/hour). On both follow-up assessments, there was no improvement in indices of SRBD (sleep efficiency [68.3 ± 17.9%], nadir oxygen saturation of 82.8 ± 4.6%, and AHI 24.9 ± 21.9). CONCLUSION: In a cohort of elderly male CHF patients receiving CRT, CRT had no impact on obstructive SRBD burden with or without atrial overdrive pacing.

The coordination of breathing and swallowing in chronic obstructive pulmonary disease.

RATIONALE: During deglutition, a strongly preferred exhale-swallow-exhale pattern has been shown in healthy adults. Disruption of this pattern can provoke prandial aspiration. Impaired coordination of breathing and swallowing has been measured in patients with chronic obstructive pulmonary disease (COPD) during the exacerbated state, but no reports describe the coordination of breathing and swallowing in stable patients with COPD during oral intake. OBJECTIVES: To test the hypothesis that persons with moderate to severe COPD would show disordered coordination of breathing and swallowing during oral intake when compared with a matched, healthy control group. METHODS: This study used a prospective, repeated measures design using 25 subjects with COPD and 25 control subjects. Respiratory inductance plethysmography and nasal thermistry were used simultaneously to track respiratory signals. Submental surface EMG was used to mark the presence of each swallow within the respiratory cycle. Data were recorded while participants randomly and spontaneously swallowed solids and semi-solids. MEASUREMENTS AND MAIN RESULTS: Logistic regression showed that participants with COPD swallowed solid food during inhalation more frequently than normal subjects (P = 0.002) and had a significantly higher rate of inhaling after swallowing semi-solid material (P < 0.001). Subjects with COPD also swallowed pudding at low Vt significantly more often than they did the cookie (P = 0.006). Conversely, the control subjects swallowed cookie at low Vt significantly more often than pudding (P = 0.034). Significant differences in deglutitive apnea durations were also found. CONCLUSIONS: Patients with COPD exhibit disrupted coordination of the respiratory cycle with deglutition. Disrupted breathing-swallowing coordination could increase the risk of aspiration in patients with advanced COPD and may contribute to exacerbations.

Reducing aerosol dispersion by high flow therapy in COVID-19: High resolution computational fluid dynamics simulations of particle behavior during high velocity nasal insufflation with a simple surgical mask.

Objective: All respiratory care represents some risk of becoming an aerosol-generating procedure (AGP) during COVID-19 patient management. Personal protective equipment (PPE) and environmental control/engineering is advised. High velocity nasal insufflation (HVNI) and high flow nasal cannula (HFNC) deliver high flow oxygen (HFO) therapy, established as a competent means of supporting oxygenation for acute respiratory distress patients, including that precipitated by COVID-19. Although unlikely to present a disproportionate particle dispersal risk, AGP from HFO continues to be a concern. Previously, we published a preliminary model. Here, we present a subsequent highresolution simulation (higher complexity/reliability) to provide a more accurate and precise particle characterization on the effect of surgical masks on patients during HVNI, low-flow oxygen therapy (LFO2), and tidal breathing. Methods: This in silico modeling study of HVNI, LFO2, and tidal breathing presents ANSYS fluent computational fluid dynamics simulations that evaluate the effect of Type I surgical mask use over patient face on particle/droplet behavior. Results: This in silico modeling simulation study of HVNI (40 L min-1) with a simulated surgical mask suggests 88.8% capture of exhaled particulate mass in the mask, compared to 77.4% in LFO2 (6 L min-1) capture, with particle distribution escaping to the room (> 1 m from face) lower for HVNI+Mask versus LFO2+Mask (8.23% vs 17.2%). The overwhelming proportion of particulate escape was associated with mask-fit designed model gaps. Particle dispersion was associated with lower velocity. Conclusions: These simulations suggest employing a surgical mask over the HVNI interface may be useful in reduction of particulate mass distribution associated with AGPs.

Diabetes sleep treatment trial: Premise, design, and methodology.

The Diabetes Sleep Treatment Trial (DSTT) is a multi-site, double-blinded, randomized, sham-controlled trial. The study objective is to test whether treatment of obstructive sleep apnea (OSA) with continuous positive airway pressure (CPAP) treatment results in improved glycemic control and diabetes self-management behavior compared to participants on a sham-CPAP (sub-therapeutic) device in participants with type 2 diabetes mellitus (T2DM) and co-morbid OSA. The purpose of this paper is to describe the premise for the DSTT, the study design, and the methodology used in this on-going trial. The target enrollment is 210 randomly assigned participants recruited from two sites. The primary outcome for glucose control is HbA1C; additional outcomes for diabetes self-management include objectively measured steps walked and subjectively measured diabetes-related distress, diabetes empowerment, and diabetes knowledge. All participants receive individual diabetes education and counseling for 6 weeks over two individual sessions and three telephone calls. Participants are randomized to receive either sham or active CPAP for 12 weeks, after which, they "guess" their group assignment; this will assist in determining the success of blinding participants to treatment group assignment. Participants revealed to be on active CPAP will be encouraged to continue CPAP for an additional 12 weeks; participants who had been on sham devices will be encouraged to have a repeat CPAP titration study and to crossover to active CPAP treatment for 24 weeks. An intention-to-treat approach will be used for efficacy analyses. The trial is registered with Clinicaltrials.gov (NCT01901055).

National Expansion of Sleep Telemedicine for Veterans: The TeleSleep Program.

STUDY OBJECTIVES: (1) Review the prevalence and comorbidity of sleep disorders among United States military personnel and veterans. (2) Describe the status of sleep care services at Veterans Health Administration (VHA) facilities. (3) Characterize the demand for sleep care among veterans and the availability of sleep care across the VHA. (4) Describe the VA TeleSleep Program that was developed to address this demand. METHODS: PubMed and Medline databases (National Center for Biotechnology Information, United States National Library of Medicine) were searched for terms related to sleep disorders and sleep care in United States military and veteran populations. Information related to the status of sleep care services at VHA facilities was provided by clinical staff members at each location. Additional data were obtained from the VA Corporate Data Warehouse. RESULTS: Among United States military personnel, medical encounters for insomnia increased 372% between 2005-2014; encounters for obstructive sleep apnea (OSA) increased 517% during the same period. The age-adjusted prevalence of sleep disorder diagnoses among veterans increased nearly 6-fold between 2000-2010; the prevalence of OSA more than doubled in this population from 2005-2014. CONCLUSIONS: Most VA sleep programs are understaffed for their workload and have lengthy wait times for appointments. The VA Office of Rural Health determined that the dilemma of limited VHA sleep health care availability and accessibility might be solved, at least in part, by implementing a comprehensive telehealth program in VA medical facilities. The VA TeleSleep Program is an expansion of telemedicine services to address this need, especially for veterans in rural or remote regions. CITATION: Sarmiento KF, Folmer RL, Stepnowsky CJ, Whooley MA, Boudreau EA, Kuna ST, Atwood CW, Smith CJ, Yarbrough WC. National expansion of sleep telemedicine for veterans: the telesleep program. J Clin Sleep Med. 2019;15(9):1355-1364.

Analysis of interaction of acute atrial overdrive pacing with sleep-related breathing disorder.

Dose-related effects of atrial overdrive pacing (AOP) on sleep-related breathing disorder (SRBD) were studied. Fourteen patients with pacemakers with moderate to severe SRBD (mean screening apnea-hypopnea index [AHI] 35.2 +/- 21.9 events/hour) were randomized to 3 levels of pacing (50, 10, and 20 beats/min greater than the mean nocturnal heart rate) and studied by polysomnography, observing for changes in AHI. At the 2 AOP levels, no significant change was observed in the primary end point of reduction in AHI. Additionally, there was no observed impact on secondary end points of the study. Cyclic variation of heart rate was progressively abolished with higher levels of AOP without affecting AHI. Large variations were observed between the screening and control studies in SRBD indexes in a number of patients. In conclusion, AOP demonstrated no benefit to predominantly obstructive SRBD disorder of at least moderate severity.

Impact of Heated Humidified High Flow Air via Nasal Cannula on Respiratory Effort in Patients with Chronic Obstructive Pulmonary Disease.

Background: High flow nasal cannula therapy (HFNC) has been widely adopted for respiratory distress, and evidence suggests that purging dead space of the upper airway improves gas fractions in the lung. This study tests the hypothesis that HFNC with room air could be as effective as low flow oxygen in chronic obstructive pulmonary disease (COPD). Methods: Thirty-two COPD patients prescribed 1 - 2 L/min of oxygen were studied. The conditions tested consisted of a control (CTRL; no therapy), then in random order HFNC and prescribed low flow oxygen (LFO). HFNC was the highest flow tolerated up to 35 L/min without supplemental oxygen. Arterial blood gases (ABGs), respiratory rate (RR), heart rate (HR) and tidal volume (VT) were measured at the end of each condition. Results: Arterial oxygen (PaO2) was greater (p < 0.001) for LFO than both HFNC and CTRL (CTRL=57.4±6.1mmHg, HFNC=58.6±8.3mmHg, LFO=72.6±10.2mmHg). HFNC reduced RR by 11% (p<0.05) from CTRL and LFO (CTRL=20.2±3.8br/min, HFNC=17.9±3.3br/min, LFO=20.2±3.7br/min) with no differences in VT. There were no differences between arterial carbon dioxide (PaCO2) (CTRL=45.5±4.9mmHg, HFNC=45.0±5.3mmHg, LFO=46.0±3.9mmHg). Conclusions: HFNC resulted in a clinically relevant reduction in ventilatory effort with no change in ABG indicating a gas equilibrium effect of purging anatomical dead space. Clinical Trial Registration: ClinicalTrials.gov ID: NCT00990210.

Obstructive sleep apnea is associated with increased readmission in heart failure patients.

BACKGROUND: Heart failure (HF) readmission rates have become an increasingly important quality metric since the advent of the Hospital Readmissions Reduction Program. Despite many well-intentioned efforts to reduce readmissions, clinicians continue to struggle with the problem of high HF readmission rates. HYPOTHESIS: HF patients with obstructive sleep apnea (OSA) will have higher burden of rehospitalization and mortality than HF patients without OSA. METHODS: Our study included 344 patient encounters (among 271 unique patients) with a diagnosis of HF from September 2014 through September 2015. Our primary endpoints were all-cause readmission within 30 and 90 days. Multivariate logistic regression was used to assess the relationship between OSA and readmission when accounting for potential confounders. RESULTS: The patients' were 72 ± 10 years old, and predominantly white (76.2%) and male (99.4%). Among the 344 patient encounters, 247 (71.8%) had diagnosed coronary artery disease, 159 (46.2%) had atrial fibrillation, and 99 (28%) had obstructive sleep apnea (OSA). Notably, patients with OSA had an elevated rate of readmission within 30 days (OSA: 30.3% vs no OSA: 19.6%, P = 0.037) and within 90 days (OSA: 57.6% vs no OSA: 36.3P < 0.01). Patients with OSA had increased risk of readmission within 90 days (odds ratio: 2.38, 95% confidence interval: 1.47-3.83, P < 0.01) even after adjustment for potential confounders of age, race, obesity, diabetes, and chronic obstructive pulmonary disease. CONCLUSIONS: HF patients with OSA have an elevated rate of readmission compared to the general HF population, particularly within the first 90 days after discharge.

The Effects of Hyper- and Hypocapnia on Phonatory Laryngeal Airway Resistance in Women.

PURPOSE: The larynx has a dual role in the regulation of gas flow into and out of the lungs while also establishing resistance required for vocal fold vibration. This study assessed reciprocal relations between phonatory functions-specifically, phonatory laryngeal airway resistance (Rlaw)-and respiratory homeostasis during states of ventilatory gas perturbations. METHOD: Twenty-four healthy women performed phonatory tasks while exposed to induced hypercapnia (high CO2), hypocapnia (low CO2), and normal breathing (eupnea). Effects of gas perturbations on Rlaw were investigated as were the reciprocal effects of Rlaw modulations on respiratory homeostasis. RESULTS: Rlaw remained stable despite manipulations of inspired gas concentrations. In contrast, end-tidal CO2 levels increased significantly during all phonatory tasks. Thus, for the conditions tested, Rlaw did not adjust to accommodate ventilatory needs as predicted. Rather, stable Rlaw was spontaneously accomplished at the cost of those needs. CONCLUSIONS: Findings provide support for a theory of regulation wherein Rlaw may be a control parameter in phonation. Results also provide insight into the influence of phonation on respiration. The work sets the foundation for future studies on laryngeal function during phonation in individuals with lower airway disease and other patient populations.