Effect of a Ventilatory Assist Device in Addition to Supplemental Oxygen on Exercise Endurance in Subjects With COPD

BACKGROUND

This study assessed the clinical effects of a ventilatory assist (VA) device in addition to supplemental O2 (VA+O2) on exercise endurance in subjects with severe to very severe COPD managed with long-term oxygen therapy (LTOT).

METHODS

This was a crossover clinical feasibility study of the effects of VA+O2 in subjects with severe to very severe COPD managed with LTOT (N = 15). At visit 1, physiologic measures were obtained, and subjects were tested on the cycle ergometer with VA. Peak work rate and flow for continuous supplemental O2/VA+O2 were established. At visit 2, subjects exercised at a constant work rate of 80% peak work rate to maximum endurance after allocation to VA+O2 or O2. Cardiorespiratory variables, work rate, and dyspnea were included to define potential clinical benefits of VA+O2. Data were analyzed using a linear mixed model.

RESULTS

Fifteen subjects with COPD (mean ± SD, age 67.9 ± 9.0 y, FEV1 0.89 ± 0.35 observed) completed the study. Exercise duration in minutes was significantly longer with VA+O2 versus O2 (least squares mean [standard error], 12.0 [2.0] vs 6.2 [2.0], P = .01). VA+O2 versus O2 was also associated with significantly greater isotime improvements in Borg dyspnea scores (3.6 [0.5] vs 5.7 [0.5], P < .001), SpO2 (96.9 [0.9] vs 91.4 [0.9], P < .001), leg fatigue scores (3.8 [0.6] vs 5.2 [0.6], P = .008), and breathing frequency (22.8 [0.9] vs 25.8 [0.9] breaths/min, P = .01). There were no differences in heart rate.

CONCLUSIONS

In symptomatic subjects with severe to very severe COPD, VA+O2 significantly increased exercise time and improved dyspnea, SpO2 , breathing frequency, and leg fatigue versus O2 alone.

Lung-specific interleukin 6 mediated transglutaminase 2 activation and cardiopulmonary fibrogenesis

Pulmonary hypertension (PH) pathogenesis is driven by inflammatory and metabolic derangements as well as glycolytic reprogramming. Induction of both interleukin 6 (IL6) and transglutaminase 2 (TG2) expression participates in human and experimental cardiovascular diseases. However, little is known about the role of TG2 in these pathologic processes. The current study aimed to investigate the molecular interactions between TG2 and IL6 in mediation of tissue remodeling in PH. A lung-specific IL6 over-expressing transgenic mouse strain showed elevated right ventricular (RV) systolic pressure as well as increased wet and dry tissue weights and tissue fibrosis in both lungs and RVs compared to age-matched wild-type littermates. In addition, IL6 over-expression induced the glycolytic and fibrogenic markers, hypoxia-inducible factor 1α, pyruvate kinase M2 (PKM2), and TG2. Consistent with these findings, IL6 induced the expression of both glycolytic and pro-fibrogenic markers in cultured lung fibroblasts. IL6 also induced TG2 activation and the accumulation of TG2 in the extracellular matrix. Pharmacologic inhibition of the glycolytic enzyme, PKM2 significantly attenuated IL6-induced TG2 activity and fibrogenesis. Thus, we conclude that IL6-induced TG2 activity and cardiopulmonary remodeling associated with tissue fibrosis are under regulatory control of the glycolytic enzyme, PKM2.

Extracorporeal Carbon Dioxide Removal to Avoid Invasive Ventilation During Exacerbations of Chronic Obstructive Pulmonary Disease: VENT-AVOID Trial - A Randomized Clinical Trial

Rationale: It is unclear whether extracorporeal CO2 removal (ECCO2R) can reduce the rate of intubation or the total time on invasive mechanical ventilation (IMV) in adults experiencing an exacerbation of chronic obstructive pulmonary disease (COPD). Objectives: To determine whether ECCO2R increases the number of ventilator-free days within the first 5 days postrandomization (VFD-5) in exacerbation of COPD in patients who are either failing noninvasive ventilation (NIV) or who are failing to wean from IMV. Methods: This randomized clinical trial was conducted in 41 U.S. institutions (2018-2022) (ClinicalTrials.gov ID: NCT03255057). Subjects were randomized to receive either standard care with venovenous ECCO2R (NIV stratum: n = 26; IMV stratum: n = 32) or standard care alone (NIV stratum: n = 22; IMV stratum: n = 33). Measurements and Main Results: The trial was stopped early because of slow enrollment and enrolled 113 subjects of the planned sample size of 180. There was no significant difference in the median VFD-5 between the arms controlled by strata (P = 0.36). In the NIV stratum, the median VFD-5 for both arms was 5 days (median shift = 0.0; 95% confidence interval [CI]: 0.0-0.0). In the IMV stratum, the median VFD-5 in the standard care and ECCO2R arms were 0.25 and 2 days, respectively; median shift = 0.00 (95% confidence interval: 0.00-1.25). In the NIV stratum, all-cause in-hospital mortality was significantly higher in the ECCO2R arm (22% vs. 0%, P = 0.02) with no difference in the IMV stratum (17% vs. 15%, P = 0.73). Conclusions: In subjects with exacerbation of COPD, the use of ECCO2R compared with standard care did not improve VFD-5. Clinical trial registered with www.clinicaltrials.gov (NCT03255057).

Health-Related Quality of Life Across the Spectrum of Pulmonary Hypertension

BACKGROUND

Health-related quality of life (HRQOL) is frequently impaired in pulmonary arterial hypertension. However, little is known about HRQOL in other forms of pulmonary hypertension (PH).

RESEARCH QUESTION

Does HRQOL vary across groups of the World Symposium on Pulmonary Hypertension (WSPH) classification system?

STUDY DESIGN AND METHODS

This cross-sectional study included patients with PH from the Pulmonary Vascular Disease Phenomics (PVDOMICS) cohort study. HRQOL was assessed by using emPHasis-10 (e-10), the 36-item Medical Outcomes Survey Short Form survey (physical component score [PCS] and mental component score), and the Minnesota Living with Heart Failure Questionnaire. Pearson correlations between HRQOL and demographic, physiological, and imaging characteristics within each WSPH group were tested. Multivariable linear regressions compared HRQOL across WSPH groups, adjusting for demographic characteristics, disease prevalence, functional class, and hemodynamics. Cox proportional hazards models were used to assess associations between HRQOL and survival across WSPH groups.

RESULTS

Among 691 patients with PH, HRQOL correlated with functional class and 6 min walk distance but not hemodynamics. HRQOL was severely depressed across WSPH groups for all measures except the 36-item Medical Outcomes Survey Short Form survey mental component score. Compared with Group 1 subjects, Group 2 subjects had significantly worse HRQOL (e-10 score, 29 vs 24 [P = .001]; PCS, 32.9 ± 8 vs 38.4 ± 10 [P < .0001]; and Minnesota Living with Heart Failure Questionnaire score, 50 vs 38 [P = .003]). Group 3 subjects similarly had a worse e-10 score (31 vs 24; P < .0001) and PCS (33.3 ± 9 vs 38.4 ± 10; P < .0001) compared with Group 1 subjects, which persisted in multivariable models (P < .05). HRQOL was associated in adjusted models with survival across Groups 1, 2, and 3.

INTERPRETATION

HRQOL was depressed in PH and particularly in Groups 2 and 3 despite less severe hemodynamics. HRQOL is associated with functional capacity, but the severity of hemodynamic disease poorly estimates the impact of PH on patients' lives. Further studies are needed to better identify predictors and treatments to improve HRQOL across the spectrum of PH.

In acute hypoxemic respiratory failure, noninvasive oxygenation methods may reduce death vs. standard oxygen therapy

SOURCE CITATION

Pitre T, Zeraatkar D, Kachkovski GV, et al. Noninvasive oxygenation strategies in adult patients with acute hypoxemic respiratory failure: a systematic review and network meta-analysis. Chest. 2023;164:913-928. 37085046.

Ruminal ergovaline and volatile fatty acid dynamics: Association with poor performance and a key growth regulator in steers grazing toxic tall fescue

Fescue toxicosis (FT) is produced by an ergot alkaloid (i.e., ergovaline [EV])-producing fungus residing in toxic fescue plants. Associations between EV, decreased weight gain and ruminal volatile fatty acids are unclear. Feces, rumen fluid, and blood were collected from 12 steers that grazed non-toxic (NT) or toxic (E +) fescue for 28 days. The E + group exhibited decreased propionate (P), increased acetate (A), and increased ruminal A:P ratio, with similar trends in feces. Plasma GASP-1 (G-Protein-Coupled-Receptor-Associated-Sorting-Protein), a myostatin inhibitor, decreased (day 14) only in E + steers. Ergovaline was present only in E + ruminal fluid and peaked on day 14. The lower ruminal propionate and higher A:P ratio might contribute to FT while reduced GASP-1 might be a new mechanism linked to E + -related weight gain reduction. Day 14 ergovaline zenith likely reflects ruminal adaptations favoring EV breakdown and its presence only in rumen points to local, rather than systemic effects.

Home noninvasive ventilation in severe COPD: in whom does it work and how?

Background

Not all hypercapnic COPD patients benefit from home noninvasive ventilation (NIV), and mechanisms through which NIV improves clinical outcomes remain uncertain. We aimed to identify "responders" to home NIV, denoted by a beneficial effect of NIV on arterial partial pressure of carbon dioxide (PaCO2), health-related quality of life (HRQoL) and survival, and investigated whether NIV achieves its beneficial effect through an improved PaCO2.

Methods

We used individual patient data from previous published trials collated for a systematic review. Linear mixed-effect models were conducted to compare the effect of NIV on PaCO2, HRQoL and survival, within subgroups defined by patient and treatment characteristics. Secondly, we conducted a causal mediation analysis to investigate whether the effect of NIV is mediated by a change in PaCO2.

Findings

Data of 1142 participants from 16 studies were used. Participants treated with lower pressure support (<14 versus ≥14 cmH2O) and with lower adherence (<5 versus ≥5 h·day-1) had less improvement in PaCO2 (mean difference (MD) -0.30 kPa, p<0.001 and -0.29 kPa, p<0.001, respectively) and HRQoL (standardised MD 0.10, p=0.002 and 0.11, p=0.02, respectively), but this effect did not persist to survival. PaCO2 improved more in patients with severe dyspnoea (MD -0.30, p=0.02), and HRQoL improved only in participants with fewer than three exacerbations (standardised MD 0.52, p=0.03). The results of the mediation analysis showed that the effect on HRQoL is mediated partially (23%) by a change in PaCO2.

Interpretation

With greater pressure support and better daily NIV usage, a larger improvement in PaCO2 and HRQoL is achieved. Importantly, we demonstrated that the beneficial effect of home NIV on HRQoL is only partially mediated through a reduction in diurnal PaCO2.

IMPAHCT: A randomized phase 2b/3 study of inhaled imatinib for pulmonary arterial hypertension

AV-101 (imatinib) powder for inhalation, an investigational dry powder inhaled formulation of imatinib designed to target the underlying pathobiology of pulmonary arterial hypertension, was generally well tolerated in healthy adults in a phase 1 single and multiple ascending dose study. Inhaled Imatinib Pulmonary Arterial Hypertension Clinical Trial (IMPAHCT; NCT05036135) is a phase 2b/3, randomized, double-blind, placebo-controlled, dose-ranging, and confirmatory study. IMPAHCT is designed to identify an optimal AV-101 dose (phase 2b primary endpoint: pulmonary vascular resistance) and assess the efficacy (phase 3 primary endpoint: 6-min walk distance), safety, and tolerability of AV-101 dose levels in subjects with pulmonary arterial hypertension using background therapies. The study has an operationally seamless, adaptive design allowing for continuous recruitment. It includes three parts; subjects enrolled in Part 1 (phase 2b dose-response portion) or Part 2 (phase 3 intermediate portion) will be randomized 1:1:1:1 to 10, 35, 70 mg AV-101, or placebo (twice daily), respectively. Subjects enrolled in Part 3 (phase 3 optimal dose portion) will be randomized 1:1 to the optimal dose of AV-101 and placebo (twice daily), respectively. All study parts include a screening period, a 24-week treatment period, and a 30-day safety follow-up period; the total duration is ∼32 weeks. Participation is possible in only one study part. IMPAHCT has the potential to advance therapies for patients with pulmonary arterial hypertension by assessing the efficacy and safety of a novel investigational drug-device combination (AV-101) using an improved study design that has the potential to save 6-12 months of development time. ClinicalTrials.gov Identifier: NCT05036135.

Sleep-Related Hypoxia, Right Ventricular Dysfunction, and Survival in Patients With Group 1 Pulmonary Arterial Hypertension

BACKGROUND

Group 1 pulmonary arterial hypertension (PAH) is a progressive fatal condition characterized by right ventricular (RV) failure with worse outcomes in connective tissue disease (CTD). Obstructive sleep apnea and sleep-related hypoxia may contribute to RV dysfunction, though the relationship remains unclear.

OBJECTIVES

The aim of this study was to prospectively evaluate the association of the apnea-hypopnea index (AHI) and sleep-related hypoxia with RV function and survival.

METHODS

Pulmonary Vascular Disease Phenomics (National Heart, Lung, and Blood Institute) cohort participants (patients with group 1 PAH, comparators, and healthy control participants) with sleep studies were included. Multimodal RV functional measures were examined in association with AHI and percentage of recording time with oxygen saturation <90% (T90) per 10-unit increment. Linear models, adjusted for demographics, oxygen, diffusing capacity of the lungs for carbon monoxide, pulmonary hypertension medications, assessed AHI and T90, and RV measures. Log-rank test/Cox proportional hazards models adjusted for demographics, oxygen, and positive airway pressure were constructed for transplantation-free survival analyses.

RESULTS

Analysis included 186 participants with group 1 PAH with a mean age of 52.6 ± 14.1 years; 71.5% were women, 80.8% were Caucasian, and there were 43 events (transplantation or death). AHI and T90 were associated with decreased RV ejection fraction (on magnetic resonance imaging), by 2.18% (-2.18; 95% CI: -4.00 to -0.36; P = 0.019) and 0.93% (-0.93; 95% CI: -1.47 to -0.40; P < 0.001), respectively. T90 was associated with increased RV systolic pressure (on echocardiography), by 2.52 mm Hg (2.52; 95% CI: 1.61 to 3.43; P < 0.001); increased mean pulmonary artery pressure (on right heart catheterization), by 0.27 mm Hg (0.27; 95% CI: 0.05 to 0.49; P = 0.019); and RV hypertrophy (on electrocardiography), 1.24 mm (1.24; 95% CI: 1.10 to 1.40; P < 0.001). T90, but not AHI, was associated with a 17% increased 5-year risk for transplantation or death (HR: 1.17; 95% CI: 1.07 to 1.28). In non-CTD-associated PAH, T90 was associated with a 21% increased risk for transplantation or death (HR: 1.21; 95% CI: 1.08 to 1.34). In CTD-associated PAH, T90 was associated with RV dysfunction, but not death or transplantation.

CONCLUSIONS

Sleep-related hypoxia was more strongly associated than AHI with measures of RV dysfunction, death, or transplantation overall and in group 1 non-CTD-associated PAH but only with RV dysfunction in CTD-associated PAH. (Pulmonary Vascular Disease Phenomics Program [PVDOMICS]; NCT02980887).

Kynurenine pathway metabolism evolves with development of preclinical and scleroderma-associated pulmonary arterial hypertension

Understanding metabolic evolution underlying pulmonary arterial hypertension (PAH) development may clarify pathobiology and reveal disease-specific biomarkers. Patients with systemic sclerosis (SSc) are regularly surveilled for PAH, presenting an opportunity to examine metabolic change as disease develops in an at-risk cohort. We performed mass spectrometry-based metabolomics on longitudinal serum samples collected before and near SSc-PAH diagnosis, compared with time-matched SSc subjects without PAH, in a SSc surveillance cohort. We validated metabolic differences in a second cohort and determined metabolite-phenotype relationships. In parallel, we performed serial metabolomic and hemodynamic assessments as the disease developed in a preclinical model. For differentially expressed metabolites, we investigated corresponding gene expression in human and rodent PAH lungs. Kynurenine and its ratio to tryptophan (kyn/trp) increased over the surveillance period in patients with SSc who developed PAH. Higher kyn/trp measured two years before diagnostic right heart catheterization increased the odds of SSc-PAH diagnosis (OR 1.57, 95% CI 1.05-2.36, P = 0.028). The slope of kyn/trp rise during SSc surveillance predicted PAH development and mortality. In both clinical and experimental PAH, higher kynurenine pathway metabolites correlated with adverse pulmonary vascular and RV measurements. In human and rodent PAH lungs, expression of TDO2, which encodes tryptophan 2,3 dioxygenase (TDO), a protein that catalyzes tryptophan conversion to kynurenine, was significantly upregulated and tightly correlated with pulmonary hypertensive features. Upregulated kynurenine pathway metabolism occurs early in PAH, localizes to the lung, and may be modulated by TDO2. Kynurenine pathway metabolites may be candidate PAH biomarkers and TDO warrants exploration as a potential novel therapeutic target.NEW & NOTEWORTHY Our study shows an early increase in kynurenine pathway metabolism in at-risk subjects with systemic sclerosis who develop pulmonary arterial hypertension (PAH). We show that kynurenine pathway upregulation precedes clinical diagnosis and that this metabolic shift is associated with increased disease severity and shorter survival times. We also show that gene expression of TDO2, an enzyme that generates kynurenine from tryptophan, rises with PAH development.

Frequency of screening and SBT Technique Trial-North American Weaning Collaboration (FAST-NAWC): an update to the protocol and statistical analysis plan

BACKGROUND

This update summarizes key changes made to the protocol for the Frequency of Screening and Spontaneous Breathing Trial (SBT) Technique Trial-North American Weaning Collaborative (FAST-NAWC) trial since the publication of the original protocol. This multicenter, factorial design randomized controlled trial with concealed allocation, will compare the effect of both screening frequency (once vs. at least twice daily) to identify candidates to undergo a SBT and SBT technique [pressure support + positive end-expiratory pressure vs. T-piece] on the time to successful extubation (primary outcome) in 760 critically ill adults who are invasively ventilated for at least 24 h in 20 North American intensive care units.

METHODS/DESIGN

Protocols for the pilot, factorial design trial and the full trial were previously published in J Clin Trials ( https://doi.org/10.4172/2167-0870.1000284 ) and Trials (https://doi: 10.1186/s13063-019-3641-8). As planned, participants enrolled in the FAST pilot trial will be included in the report of the full FAST-NAWC trial. In response to the onset of the coronavirus disease of 2019 (COVID-19) pandemic when approximately two thirds of enrollment was complete, we revised the protocol and consent form to include critically ill invasively ventilated patients with COVID-19. We also refined the statistical analysis plan (SAP) to reflect inclusion and reporting of participants with and without COVID-19. This update summarizes the changes made and their rationale and provides a refined SAP for the FAST-NAWC trial. These changes have been finalized before completion of trial follow-up and the commencement of data analysis.

TRIAL REGISTRATION

Clinical Trials.gov NCT02399267.

In persistent dyspnea after COVID-19 ARDS, exercise training rehabilitation vs. usual PT reduced dyspnea at 90 d

SOURCE CITATION

Romanet C, Wormser J, Fels A, et al. Effectiveness of exercise training on the dyspnoea of individuals with long COVID: a randomised controlled multicentre trial. Ann Phys Rehabil Med. 2023;66:101765. 37271020.

Classification and Predictors of Right Ventricular Functional Recovery in Pulmonary Arterial Hypertension

BACKGROUND

Normative changes in right ventricular (RV) structure and function have not been characterized in the context of treatment-associated functional recovery (RV functional recovery [RVFnRec]). The aim of this study is to assess the clinical relevance of a proposed RVFnRec definition.

METHODS

We evaluated 63 incident patients with pulmonary arterial hypertension by right heart catheterization and cardiac magnetic resonance imaging at diagnosis and cardiac magnetic resonance imaging and invasive cardiopulmonary exercise testing following treatment (≈11 months). Sex, age, ethnicity matched healthy control subjects (n=62) with 1-time cardiac magnetic resonance imaging and noninvasive cardiopulmonary exercise testing were recruited from the PVDOMICS (Redefining Pulmonary Hypertension through Pulmonary Vascular Disease Phenomics) project. We examined therapeutic cardiac magnetic resonance imaging changes relative to the evidence-based peak oxygen consumption (VO2peak)>15 mL/(kg·min) to define RVFnRec by receiver operating curve analysis. Afterload was measured as mean pulmonary artery pressure, resistance, compliance, and elastance.

RESULTS

A drop in RV end-diastolic volume of -15 mL best defined RVFnRec (area under the curve, 0.87; P=0.0001) and neared upper 95% CI RV end-diastolic volume of controls. This cutoff was met by 22 out of 63 (35%) patients which was reinforced by freedom from clinical worsening, RVFnRec 1 out of 21 (5%) versus no RVFnRec 17 out of 42, 40% (log-rank P=0.006). A therapy-associated increase of 0.8 mL/mm Hg in compliance had the best predictive value of RVFnRec (area under the curve, 0.76; [95% CI, 0.64-0.88]; P=0.001). RVFnRec patients had greater increases in stroke volume, and cardiac output at exercise.

CONCLUSIONS

RVFnRec defined by RV end-diastolic volume therapeutic decrease of -15 mL predicts exercise capacity, freedom from clinical worsening, and nears normalization. A therapeutic improvement of compliance is superior to other measures of afterload in predicting RVFnRec. RVFnRec is also associated with increased RV output reserve at exercise.

Frequency of acute vasodilator response (AVR) in incident and prevalent patients with pulmonary arterial hypertension: Results from the pulmonary vascular disease phenomics study

The prevalence of acute vasodilator response (AVR) to inhaled nitric oxide (iNO) during right heart catheterization (RHC) is 12% in idiopathic pulmonary arterial hypertension (IPAH). AVR, however, is reportedly lower in other disease-associated pulmonary arterial hypertension (PAH), such as connective tissue disease (CTD). The prevalence of AVR in patients on PAH therapy (prevalent cases) is unknown. We sought to determine AVR prevalence in Group 1 PH in the PVDOMICS cohort of incident and prevalent patients undergoing RHC. AVR was measured in response to 100% O2 and O2 plus iNO, with positivity defined as (1) decrease in mean pulmonary artery pressure (mPAP) by ≥10 mmHg to a value ≤40 mmHg, with no change or an increase in cardiac output (definition 1); or (2) decrease in mPAP by ≥12% and pulmonary vascular resistance by ≥30% (definition 2). AVR rates and cumulative survival were compared between incident and prevalent patients. In 338 mainly prevalent (86%) patients, positive AVR to O2-only was <2%, and 5.1% to 16.9%, based on definition 1 and 2 criteria, respectively; following O2 + iNO. IPAH AVR prevalence (4.1%-18.7%) was similar to prior reports. AVR positivity was 7.7% to 15.4% in mostly CTD-PAH prevalent cases, and 2.6% to 11.8% in other PAH groups. Survival was 89% in AVR responders versus 77% in nonresponders from PAH diagnosis, and 91% versus 86% from PVDOMICS enrollment (log-rank test p = 0.04 and p = 0.05, respectively). In conclusion, AVR in IPAH patients is similar to prior studies. AVR in non-IPAH patients was higher than previously reported. The relationship between PAH therapy, AVR response, and survival warrants further investigation.

Iron deficiency in pulmonary vascular disease: pathophysiological and clinical implications

AIMS

Iron deficiency is common in pulmonary hypertension, but its clinical significance and optimal definition remain unclear.

METHODS AND RESULTS

Phenotypic data for 1028 patients enrolled in the Redefining Pulmonary Hypertension through Pulmonary Vascular Disease Phenomics study were analyzed. Iron deficiency was defined using the conventional heart failure definition and also based upon optimal cut-points associated with impaired peak oxygen consumption (peakVO2), 6-min walk test distance, and 36-Item Short Form Survey (SF-36) scores. The relationships between iron deficiency and cardiac and pulmonary vascular function and structure and outcomes were assessed. The heart failure definition of iron deficiency endorsed by pulmonary hypertension guidelines did not identify patients with reduced peakVO2, 6-min walk test, and SF-36 (P > 0.208 for all), but defining iron deficiency as transferrin saturation (TSAT) <21% did. Compared to those with TSAT ≥21%, patients with TSAT <21% demonstrated lower peakVO2 [absolute difference: -1.89 (-2.73 to -1.04) mL/kg/min], 6-min walk test distance [absolute difference: -34 (-51 to -17) m], and SF-36 physical component score [absolute difference: -2.5 (-1.3 to -3.8)] after adjusting for age, sex, and hemoglobin (all P < 0.001). Patients with a TSAT <21% had more right ventricular remodeling on cardiac magnetic resonance but similar pulmonary vascular resistance on catheterization. Transferrin saturation <21% was also associated with increased mortality risk (hazard ratio 1.63, 95% confidence interval 1.13-2.34; P = 0.009) after adjusting for sex, age, hemoglobin, and N-terminal pro-B-type natriuretic peptide.

CONCLUSION

The definition of iron deficiency in the 2022 European Society of Cardiology (ESC)/European Respiratory Society (ERS) pulmonary hypertension guidelines does not identify patients with lower exercise capacity or functional status, while a definition of TSAT <21% identifies patients with lower exercise capacity, worse functional status, right heart remodeling, and adverse clinical outcomes.

Behavioral and Physiological Alterations in Angus Steers Grazing Endophyte-Infected Toxic Fescue during Late Fall

Fescue toxicosis is caused by grazing ergot alkaloid-producing endophyte (Epichloë coenophiala)-infected tall fescue (E+). Summer grazing of E+ leads to decreased productivity, associated impaired thermoregulation, and altered behavior. The goal of this study was to determine the role of E+ grazing-climate interaction on animal behavior and thermoregulation during late fall. Eighteen Angus steers were placed on nontoxic (NT), toxic (E+) and endophyte-free (E-) fescue pastures for 28 days. Physiological parameters, such as rectal temperature (RT), respiration rate (RR), ear and ankle surface temperature (ET, AT), and body weights, were measured. Skin surface temperature (SST) and animal activity were recorded continuously with temperature and behavioral activity sensors, respectively. Environmental conditions were collected using paddocks-placed data loggers. Across the trial, steers on E+ gained about 60% less weight than the other two groups. E+ steers also had higher RT than E- and NT, and lower SST than NT post-pasture placement. Importantly, animals grazing E+ spent more time lying, less time standing, and took more steps. These data suggest that late fall E+ grazing impairs core and surface temperature regulation and increases non-productive lying time, which may be partly responsible for the observed decreased weight gains.

AV-101, a novel inhaled dry-powder formulation of imatinib, in healthy adult participants: a phase 1 single and multiple ascending dose study

Background

Oral imatinib has been shown to be effective, but poorly tolerated, in patients with advanced pulmonary arterial hypertension (PAH). To maintain efficacy while improving tolerability, AV-101, a dry powder inhaled formulation of imatinib, was developed to deliver imatinib directly to the lungs.

Methods

This phase 1, placebo-controlled, randomised single ascending dose (SAD) and multiple ascending dose (MAD) study evaluated the safety/tolerability and pharmacokinetics of AV-101 in healthy adults. The SAD study included five AV-101 cohorts (1 mg, 3 mg, 10 mg, 30 mg, 90 mg) and placebo, and a single-dose oral imatinib 400-mg cohort. The MAD study included three AV-101 cohorts (10 mg, 30 mg, 90 mg) and placebo; dosing occurred twice daily for 7 days.

Results

82 participants (SAD n=48, MAD n=34) were enrolled. For the SAD study, peak plasma concentrations of imatinib occurred within 3 h of dosing with lower systemic exposure compared to oral imatinib (p<0.001). For the MAD study, systemic exposure of imatinib was higher after multiple doses of AV-101 compared to a single dose, but steady-state plasma concentrations were lower for the highest AV-101 cohort (90 mg) compared to simulated steady-state oral imatinib at day 7 (p=0.0002). Across AV-101 MAD dose cohorts, the most common treatment-emergent adverse events were cough (n=7, 27%) and headache (n=4, 15%).

Conclusions

AV-101 was well tolerated in healthy adults, and targeted doses of AV-101 significantly reduced the systemic exposure of imatinib compared with oral imatinib. An ongoing phase 2b/phase 3 study (IMPAHCT; clinicaltrials.gov identifier NCT05036135) will evaluate the safety/tolerability and clinical benefit of AV-101 for PAH.

Classification and Predictors of Right Ventricular Functional Recovery in Pulmonary Arterial Hypertension

Background

Normative changes in right ventricular (RV) structure and function have not been characterized in the context of treatment-associated functional recovery (RVFnRec). The aim of this study is to assess the clinical relevance of a proposed RVFnRec definition.

Methods

We evaluated 63 incident patients with PAH by right heart catheterization and cardiac MRI (CMR) at diagnosis and CMR and invasive cardiopulmonary exercise (CPET) following treatment (∼11 months). Sex, age, race/ethnicity matched healthy control subjects (n=62) with one-time CMR and non-invasive CPET were recruited from the PVDOMICS project. We examined therapeutic CMR changes relative to the evidence-based peak oxygen consumption (VO2 peak )>15mL/kg/min to define RVFnRec by receiver operating curve analysis. Afterload was measured in the as mean pulmonary artery pressure, resistance, compliance, and elastance.

Results

A drop in RV end-diastolic volume of -15 mL best defined RVFnRec (AUC 0.87, P=0.0001) and neared upper 95% CI RVEDV of controls. 22/63 (35%) of subjects met this cutoff which was reinforced by freedom from clinical worsening, RVFnRec 1/21 (5%) versus no RVFnRec 17/42, 40%, (log rank P=0.006). A therapy-associated increase of 0.8 mL/mmHg in compliance had the best predictive value of RVFnRec (AUC 0.76, CI 0.64-0.88, P=0.001). RVFnRec subjects had greater increases in stroke volume, and cardiac output at exercise.

Conclusions

RVFnRec defined by RVEDV therapeutic decrease of -15mL predicts exercise capacity, freedom from clinical worsening, and nears normalization. A therapeutic improvement of compliance is superior to other measures of afterload in predicting RVFnRec. RVFnRec is also associated with increased RV output reserve at exercise.

Clinical Perspective

What is new?: Right ventricular functional recovery (RVFnRec) represents a novel endpoint of therapeutic success in PAH. We define RVFnRec as treatment associated normative RV changes related to function (peak oxygen consumption). Normative RV imaging changes are compared to a well phenotyped age, sex, and race/ethnicity matched healthy control cohort from the PVDOMICS project. Previous studies have focused on RV ejection fraction improvements. However, we show that changes in RVEDV are perhaps more important in that improvements in LV function also occur. Lastly, RVFnRec is best predicted by improvements in pulmonary artery compliance versus pulmonary vascular resistance, a more often cited metric of RV afterload.What are the clinical implications?: RVFnRec represents a potential non-invasive assessment of clinical improvement and therapeutic response. Clinicians with access to cardiac MRI can obtain a limited scan (i.e., ventricular volumes) before and after treatment. Future study should examine echocardiographic correlates of RVFnRec.

Acute vasoreactivity testing during right heart catheterization in chronic thromboembolic pulmonary hypertension: Results from the pulmonary vascular disease phenomics study

Chronic thromboembolic pulmonary hypertension (CTEPH) is believed to involve both vascular obstruction and vasoconstriction; hence, pulmonary vasodilators such as riociguat may be beneficial. Acute vasoreactivity testing (AVT) is seldom performed routinely in CTEPH patients, so there is limited understanding of the frequency and significance of an acute vasodilator response. Systematic vasodilator testing with oxygen (O₂) and oxygen plus inhaled nitric oxide (O₂ + iNO) was performed as part of the Pulmonary Vascular Disease Omics (PVDOMICS) NHLBI project, providing an opportunity to examine AVT responses in CTEPH. Patients with CTEPH enrolled in PVDOMICS (n = 49, 40 with prevalent CTEPH [82%]) underwent right heart catheterization including AVT with O₂ and O₂ + iNO. Hemodynamics were obtained at baseline and with each challenge. Fourteen of 49 patients (29%) had >20% drop in pulmonary vascular resistance (PVR) with O₂. With O₂ + iNO, 30/49 (61%) had >20% drop in PVR, 20% had >20% drop in mean pulmonary artery pressure (mPAP) and PVR, and 8% had >10 mmHg decline in mPAP to mPAP < 40 with normal cardiac output. Patients on riociguat had less response to O₂ + iNO than patients on phosphodiesterase-5 inhibitors. Our findings shed light on the significant variability in vascular tone that is present in CTEPH, confirming that CTEPH represents a combination of mechanical obstruction and vasoconstriction that appears similar to that observed with Group 1 PAH. Additional study regarding whether results of acute vasodilator testing predict response to therapy and relate to prognosis is warranted.

Characterization of SARS-CoV-2 Aerosols Dispersed During Noninvasive Respiratory Support of Patients With COVID-19

BACKGROUND

In the midst of the COVID-19 pandemic, noninvasive respiratory support (NRS) therapies such as high-flow nasal cannula (HFNC) and noninvasive ventilation (NIV) were central to respiratory care. The extent to which these treatments increase the generation and dispersion of infectious respiratory aerosols is not fully understood. The objective of this study was to characterize SARS-CoV-2 aerosol dispersion from subjects with COVID-19 undergoing NRS therapy.

METHODS

Several different aerosol sampling devices were used to collect air samples in the vicinity of 31 subjects with COVID-19, most of whom were receiving NRS therapy, primarily HFNC. Aerosols were collected onto filters and analyzed for the presence of SARS-CoV-2 RNA. Additional measurements were collected in an aerosol chamber with healthy adult subjects using respiratory therapy devices under controlled and reproducible conditions.

RESULTS

Fifty aerosol samples were collected from subjects receiving HFNC or NIV therapy, whereas 6 samples were collected from subjects not receiving NRS. Only 4 of the 56 aerosol samples were positive for SARS-CoV-2 RNA, and all positive samples were collected using a high air flow scavenger mask collection device placed in close proximity to the subject. The chamber measurements with healthy subjects did not show any significant increase in aerosol dispersion caused by the respiratory therapy devices compared to baseline.

CONCLUSIONS

Our findings demonstrate very limited detection of SARS-CoV-2-containing aerosols in the vicinity of subjects with COVID-19 receiving NRS therapies in the clinical setting. These results, combined with controlled chamber measurements showing that HFNC and NIV device usage was not associated with increased aerosol dispersion, suggest that NRS therapies do not result in increased dispersal of aerosols in the clinical setting.

Incidence and Nature of Respiratory Events in Patients Undergoing Bronchoscopy Under Conscious Sedation

BACKGROUND

During diagnostic bronchoscopies, conscious sedation improves patient tolerance, but it can contribute to hypercapnia and hypoxia by various mechanisms including depression of ventilatory drive. This prospective study was undertaken to determine the frequency of respiratory events and associated oxygen desaturations during bronchoscopy with conscious sedation.

PATIENTS AND METHODS

The Nox-T3 monitoring system was placed before starting the bronchoscopy and remained in place for 30 minutes following the procedure. The primary endpoint was the occurrence of obstructive and central apneic events during bronchoscopy under conscious sedation.

RESULTS

Obstructive events (apnea and hypopnea) occurred in 100% of patients (n=31), and central apneas occurred in 58% of patients (n=18) during the procedure with a median of 9 and 2 events per patient, respectively. During recovery, a significant proportion of patients had detectable obstructive (86%) and central (36%) events. Higher body mass index was associated with oxygen desaturation to <90% and with the need for escalation of care. Furthermore, a conscious sedation regimen that included propofol was significantly associated with central apneic events.

CONCLUSION

Respiratory events are common during and immediately postprocedure after conscious sedation for bronchoscopy. Most events are obstructive, and the use of propofol predisposes to central apneas during the procedure. Both types of events are associated with a higher body mass index. Oxygen desaturation to <90% triggers escalation of care. A further prospective study will be required to determine the clinical significance of these apneic events and whether alleviating these events will improve the safety and outcomes of bronchoscopic procedures performed under conscious sedation.

Clinical Characteristics and Transplant-Free Survival Across the Spectrum of Pulmonary Vascular Disease

BACKGROUND

PVDOMICS (Pulmonary Vascular Disease Phenomics) is a precision medicine initiative to characterize pulmonary vascular disease (PVD) using deep phenotyping. PVDOMICS tests the hypothesis that integration of clinical metrics with omic measures will enhance understanding of PVD and facilitate an updated PVD classification.

OBJECTIVES

The purpose of this study was to describe clinical characteristics and transplant-free survival in the PVDOMICS cohort.

METHODS

Subjects with World Symposium Pulmonary Hypertension (WSPH) group 1-5 PH, disease comparators with similar underlying diseases and mild or no PH and healthy control subjects enrolled in a cross-sectional study. PH groups, comparators were compared using standard statistical tests including log-rank tests for comparing time to transplant or death.

RESULTS

A total of 1,193 subjects were included. Multiple WSPH groups were identified in 38.9% of PH subjects. Nocturnal desaturation was more frequently observed in groups 1, 3, and 4 PH vs comparators. A total of 50.2% of group 1 PH subjects had ground glass opacities on chest computed tomography. Diffusing capacity for carbon monoxide was significantly lower in groups 1-3 PH than their respective comparators. Right atrial volume index was higher in WSPH groups 1-4 than comparators. A total of 110 participants had a mean pulmonary artery pressure of 21-24 mm Hg. Transplant-free survival was poorest in group 3 PH.

CONCLUSIONS

PVDOMICS enrolled subjects across the spectrum of PVD, including mild and mixed etiology PH. Novel findings include low diffusing capacity for carbon monoxide and enlarged right atrial volume index as shared features of groups 1-3 and 1-4 PH, respectively; unexpected, frequent presence of ground glass opacities on computed tomography; and sleep alterations in group 1 PH, and poorest survival in group 3 PH. PVDOMICS will facilitate a new understanding of PVD and refine the current PVD classification. (Pulmonary Vascular Disease Phenomics Program PVDOMICS [PVDOMICS]; NCT02980887).

Vascular smooth muscle ROCK1 contributes to hypoxia-induced pulmonary hypertension development in mice

Rho kinase (ROCK) is implicated in the development of pulmonary arterial hypertension (PAH) in which abnormal pulmonary vascular smooth muscle (VSM) contractility and remodeling lead to right heart failure. Pharmacologic ROCK inhibitors block experimental pulmonary hypertension (PH) development in rodents but can have off-target effects and do not distinguish between the two ROCK forms, ROCK1 and ROCK2, encoded by separate genes. An earlier study using gene knock out (KO) in mice indicated that VSM ROCK2 is required for experimental PH development, but the role of ROCK1 is not well understood. Here we investigated the in vivo role of ROCK1 in PH development by generating a VSM-targeted homozygous ROCK1 gene KO mouse strain. Adult control mice exposed to Sugen5416 (Su)/hypoxia treatment to induce PH had significantly increased right ventricular systolic pressures (RVSP) and RV hypertrophy versus normoxic controls. In contrast, Su/hypoxia-exposed VSM ROCK1 KO mice did not exhibit significant RVSP elevation, and RV hypertrophy was blunted. Su/hypoxia-induced pulmonary small vessel muscularization was similarly elevated in both control and VSM ROCK1 KO animals. siRNA-mediated ROCK1 knock-down (KD) in human PAH pulmonary arterial SM cells (PASMC) did not affect cell growth. However, ROCK1 KD led to reduced AKT and MYPT1 signaling in serotonin-treated PAH PASMC. The findings suggest that like VSM ROCK2, VSM ROCK1 actively contributes to PH development, but in distinction acts via nonproliferative pathways to promote hypoxemia, and thus may be a distinct therapeutic target in PH.

Delphi Consensus Recommendation for Optimization of Pulmonary Hypertension Therapy Focusing On Switching from a Phosphodiesterase 5 Inhibitor to Riociguat

Dual combination therapy with a phosphodiesterase‐5 inhibitor (PDE5i) and endothelin receptor antagonist is recommended for most patients with intermediate‐risk pulmonary arterial hypertension (PAH). The RESPITE and REPLACE studies suggest that switching from a PDE5i to a soluble guanylate cyclase (sGC) activator may provide clinical improvement in this situation. The optimal approach to escalation or transition of therapy in this or other scenarios is not well defined. We developed an expert consensus statement on the transition to sGC and other treatment escalations and transitions in PAH using a modified Delphi process. The Delphi process used a panel of 20 physicians with expertise in PAH. Panelists answered three questionnaires on the management of treatment escalations and transitions in PAH. The initial questionnaire included open‐ended questions. Later questionnaires consolidated the responses into statements that panelists rated on a Likert scale from −5 (strongly disagree) to +5 (strongly agree) to determine consensus. The Delphi process produced several consensus recommendations. Escalation should be considered for patients who are at high risk or not achieving treatment goals, by adding an agent from a new class, switching from oral to parenteral prostacyclins, or increasing the dose. Switching to a new class or within a class should be considered if tolerability or other considerations unrelated to efficacy are affecting adherence. Switching from a PDE5i to an SGC activator may benefit patients with intermediate risk who are not improving on their present therapy. These consensus‐based recommendations may be helpful to clinicians and beneficial for patients when evidence‐based guidance is unavailable.

Exploring the Patient Experience with Noninvasive Ventilation: A Human-Centered Design Analysis to Inform Planning for Better Tolerance

BACKGROUND

This study brings a human-centered design (HCD) perspective to understanding the patient experience when using noninvasive ventilation (NIV) with the goal of creating better strategies to improve NIV comfort and tolerance.

METHODS

Using an HCD motivational approach, we created a semi-structured interview to uncover the patients' journey while being treated with NIV. We interviewed 16 patients with chronic obstructive pulmonary disease (COPD) treated with NIV while hospitalized. Patients' experiences were captured in a stepwise narrative creating a journey map as a framework describing the overall experience and highlighting the key processes, tensions, and flows. We broke the journey into phases, steps, emotions, and themes to get a clear picture of the overall experience levers for patients.

RESULTS

The following themes promoted NIV tolerance: trust in the providers, the favorable impression of the facility and staff, understanding why the mask was needed, how NIV works and how long it will be needed, immediate relief of the threatening suffocating sensation, familiarity with similar treatments, use of meditation and mindfulness, and the realization that treatment was useful. The following themes deterred NIV tolerance: physical and psychological discomfort with the mask, impaired control, feeling of loss of control, and being misinformed.

CONCLUSIONS

Understanding the reality of patients with COPD treated with NIV will help refine strategies that can improve their experience and tolerance with NIV. Future research should test ideas with the best potential and generate prototypes and design iterations to be tested with patients.

Update to the study protocol for an implementation-effectiveness trial comparing two education strategies for improving the uptake of noninvasive ventilation in patients with severe COPD exacerbation

BACKGROUND

There is strong evidence that noninvasive ventilation (NIV) improves the outcomes of patients hospitalized with severe COPD exacerbation, and NIV is recommended as the first-line therapy for these patients. Yet, several studies have demonstrated substantial variation in NIV use across hospitals, leading to preventable morbidity and mortality. In addition, prior studies suggested that efforts to increase NIV use in COPD need to account for the complex and interdisciplinary nature of NIV delivery and the need for team coordination. Therefore, our initial project aimed to compare two educational strategies: online education (OLE) and interprofessional education (IPE), which targets complex team-based care in NIV delivery. Due to the impact of the COVID-19 pandemic on recruitment and planned intervention, we had made several changes in the study design, statistical analysis, and implementation strategies delivery as outlined in the methods.

METHODS

We originally proposed a two-arm, pragmatic, cluster, randomized hybrid implementation-effectiveness trial comparing two education strategies to improve NIV uptake in patients with severe COPD exacerbation in 20 hospitals with a low baseline rate of NIV use. Due to logistical constrains and slow recruitment, we changed the study design to an opened cohort stepped-wedge design with three steps which will allow the institutions to enroll when they are ready to participate. Only the IPE strategy will be implemented, and the education will be provided in an online virtual format. Our primary outcome will be the hospital-level risk-standardized NIV proportion for the period post-IPE training, along with the change in rate from the period prior to training. Aim 1 will compare the change over time of NIV use among patients with COPD in the step-wedged design. Aim 2 will explore the mediators' role (respiratory therapist autonomy and team functionality) on the relationship between the implementation strategies and effectiveness. Finally, in Aim 3, through interviews with providers, we will assess the acceptability and feasibility of the educational training.

CONCLUSION

The changes in study design will result in several limitation. Most importantly, the hospitals in the three cohorts are not randomized as they enroll based on their readiness. Second, the delivery of the IPE is virtual, and it is not known if remote education is conducive to team building. However, this study will be among the first to test the impact of IPE in the inpatient setting carefully and may generalize to other interventions directed to seriously ill patients.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04206735 . Registered on December 20, 2019.

Optimal NIV Medicare Access Promotion: Patients With COPD: A Technical Expert Panel Report From the American College of Chest Physicians, the American Association for Respiratory Care, the American Academy of Sleep Medicine, and the American Thoracic Society

This document summarizes the work of the COPD Technical Expert Panel working group. For patients with COPD, the most pressing current coverage barriers identified were onerous diagnostic requirements focused on oxygenation (rather than ventilation) and difficulty obtaining bilevel devices with backup rate capabilities. Because of these difficulties, many patients with COPD were instead sometimes prescribed home mechanical ventilators. Critical evidence supports changes to current policies, including randomized controlled trial evidence suggesting a mortality benefit from bilevel positive airway pressure with backup rate and updated clinical practice guidelines from the American Thoracic Society as well as the European Respiratory Society. To achieve optimal access to noninvasive ventilation for patients with COPD, we make the following key recommendations: (1) removal of the need for overnight oximetry testing; (2) the ability to initiate therapy using bilevel devices with backup rate capability; and (3) increased duration of time to meet adherence criteria (ie, a second 90-day trial period) in those patients actively engaged in their care. Clear guidelines based on medical necessity are also included for patients who require initiation of or switch to a home mechanical ventilator. Adoption of these proposed recommendations would result in the right device, for the right type of patient with COPD, at the right time. Finally, we emphasize the need for adequate clinical support during initiation and maintenance of home noninvasive ventilation in such patients.

Vascular cell-specific roles of mineralocorticoid receptors in pulmonary hypertension

Abnormalities that characterize pulmonary arterial hypertension include impairment in the structure and function of pulmonary vascular endothelial and smooth muscle cells. Aldosterone levels are elevated in human pulmonary arterial hypertension and in experimental pulmonary hypertension, while inhibition of the aldosterone-binding mineralocorticoid receptor attenuates pulmonary hypertension in multiple animal models. We explored the role of mineralocorticoid receptor in endothelial and smooth muscle cells in using cell-specific mineralocorticoid receptor knockout mice exposed to sugen/hypoxia-induced pulmonary hypertension. Treatment with the mineralocorticoid receptor inhibitor spironolactone significantly reduced right ventricular systolic pressure. However, this is not reproduced by selective mineralocorticoid receptor deletion in smooth muscle cells or endothelial cells. Similarly, spironolactone attenuated the increase in right ventricular cardiomyocyte area independent of vascular mineralocorticoid receptor with no effect on right ventricular weight or interstitial fibrosis. Right ventricular perivascular fibrosis was significantly decreased by spironolactone and this was reproduced by specific deletion of mineralocorticoid receptor from endothelial cells. Endothelial cell-mineralocorticoid receptor deletion attenuated the sugen/hypoxia-induced increase in the leukocyte-adhesion molecule, E-selectin, and collagen IIIA1 in the right ventricle. Spironolactone also significantly reduced pulmonary arteriolar muscularization, independent of endothelial cell-mineralocorticoid receptor or smooth muscle cell-mineralocorticoid receptor. Finally, the degree of pulmonary perivascular inflammation was attenuated by mineralocorticoid receptor antagonism and was fully reproduced by smooth muscle cell-specific mineralocorticoid receptor deletion. These studies demonstrate that in the sugen/hypoxia pulmonary hypertension model, systemic-mineralocorticoid receptor blockade significantly attenuates the disease and that mineralocorticoid receptor has cell-specific effects, with endothelial cell-mineralocorticoid receptor contributing to right ventricular perivascular fibrosis and smooth muscle cell-mineralocorticoid receptor participating in pulmonary vascular inflammation. As mineralocorticoid receptor antagonists are being investigated to treat pulmonary arterial hypertension, these findings support novel mechanisms and potential mineralocorticoid receptor targets that mediate therapeutic benefits in patients.

Electrostatically Tuning the Photodissociation of the Irgacure 2959 Photoinitiator in the Gas Phase by Cation Binding

The low-lying electronic states of Irgacure 2959, a Norrish-type I photoinitiator, complexed with a single metal cation are investigated in the gas phase by photodissociation action spectroscopy. Analysis of the band shifts using quantum chemical calculations (TD-DFT and SCS-CC2) reveals the underlying influence of the charge on the key electronic energy levels. Since the cations (H⁺, Li⁺, Na⁺, K⁺, Zn²⁺, Ca²⁺, and Mg²⁺) bind at varying distances, the magnitude of the electric field at the center of the chromophore due to the cation is altered, and this shifts the electronic states by different amounts. Photodissociation action spectra of cation-Irg complexes show that absorption transitions to the first ¹ππ* state are red-shifted with a magnitude proportional to the electric field strength (with red shifts >1 eV), and in most cases, the cation is essentially acting as a point charge. Calculations show that a neighboring ³nπ* state, a key state for the α-cleavage pathway, is destabilized (blue-shifted) by the orientated electric field. As such, if the ¹ππ*-³nπ* energy gap is reduced, increased intersystem crossing rates are expected, resulting in higher yields of the desired radical photoproducts, and this is controlled by the orientated electric field arising from the cation.

A scoring system derived from electronic health records to identify patients at high risk for noninvasive ventilation failure

OBJECTIVE

To develop and validate a clinical risk prediction score for noninvasive ventilation (NIV) failure defined as intubation after a trial of NIV in non-surgical patients.

DESIGN

Retrospective cohort study of a multihospital electronic health record database.

PATIENTS

Non-surgical adult patients receiving NIV as the first method of ventilation within two days of hospitalization.

MEASUREMENT

Primary outcome was intubation after a trial of NIV. We used a non-random split of the cohort based on year of admission for model development and validation. We included subjects admitted in years 2010-2014 to develop a risk prediction model and built a parsimonious risk scoring model using multivariable logistic regression. We validated the model in the cohort of subjects hospitalized in 2015 and 2016.

MAIN RESULTS

Of all the 47,749 patients started on NIV, 11.7% were intubated. Compared with NIV success, those who were intubated had worse mortality (25.2% vs. 8.9%). Strongest independent predictors for intubation were organ failure, principal diagnosis group (substance abuse/psychosis, neurological conditions, pneumonia, and sepsis), use of invasive ventilation in the prior year, low body mass index, and tachypnea. The c-statistic was 0.81, 0.80 and 0.81 respectively, in the derivation, validation and full cohorts. We constructed three risk categories of the scoring system built on the full cohort; the median and interquartile range of risk of intubation was: 2.3% [1.9%-2.8%] for low risk group; 9.3% [6.3%-13.5%] for intermediate risk category; and 35.7% [31.0%-45.8%] for high risk category.

CONCLUSIONS

In patients started on NIV, we found that in addition to factors known to be associated with intubation, neurological, substance abuse, or psychiatric diagnoses were highly predictive for intubation. The prognostic score that we have developed may provide quantitative guidance for decision-making in patients who are started on NIV.

The corona of a surface bubble promotes electrochemical reactions

The evolution of gaseous products is a feature common to several electrochemical processes, often resulting in bubbles adhering to the electrode’s surface. Adherent bubbles reduce the electrode active area, and are therefore generally treated as electrochemically inert entities. Here, we show that this general assumption does not hold for gas bubbles masking anodes operating in water. By means of imaging electrochemiluminescent systems, and by studying the anisotropy of polymer growth around bubbles, we demonstrate that gas cavities adhering to an electrode surface initiate the oxidation of water-soluble species more effectively than electrode areas free of bubbles. The corona of a bubble accumulates hydroxide anions, unbalanced by cations, a phenomenon which causes the oxidation of hydroxide ions to hydroxyl radicals to occur at potentials at least 0.7 V below redox tabled values. The downhill shift of the hydroxide oxidation at the corona of the bubble is likely to be a general mechanism involved in the initiation of heterogeneous electrochemical reactions in water, and could be harnessed in chemical synthesis.

Gas bubbles forming on the surface of an electrode, a phenomenon common to several industrial electrolytic processes, are usually perceived as inert, passivating entities. Here, the authors show that that this general assumption does not hold for gas bubbles masking anodes operating in water.

Pharmacokinetics and tolerability of LIQ861, a novel dry-powder formulation of treprostinil

A dry-powder inhaled formulation of treprostinil (LIQ861) produced using PRINT® technology offers a substantial advantage over current nebulized therapy. Treprostinil is a synthetic prostacyclin analogue that is currently approved for inhalation administration to patients with pulmonary arterial hypertension via nebulized Tyvaso® inhalation solution. LTI-101 was a phase 1, placebo-controlled, double-blind, randomized, single-center study that evaluated the ascending single-dose pharmacokinetics of LIQ861 in healthy subjects. Six sequential, escalating doses (25, 50, 75, 100, 125, and 150 mcg) were studied to investigate treprostinil exposure from LIQ861 inhalation. Subjects (n = 57) were randomly assigned in a 3:1 ratio to receive a single dose of either LIQ861 (n = 43) or placebo (n = 14); 56 subjects completed all protocol-defined assessments. Following single-dose administration, treprostinil exposure from LIQ861 increased proportionally across the dose range studied, and the pharmacokinetics profile of treprostinil administered as LIQ861 was similar to prior reports of inhaled treprostinil. All doses of LIQ861 were generally well-tolerated with no deaths, serious adverse events, or dose-limiting toxicities. The most frequently reported treatment-emergent adverse events related to study drug administration were coughing and throat irritation, which are common to dry-powder formulations. Treatment-related treatment-emergent adverse events were reported more frequently at higher dose levels; however, all were assessed as mild in severity. We conclude that the pharmacokinetics profile of treprostinil using a dry-powder inhaled formulation increased in proportion to dose as anticipated and was similar to earlier reports of inhaled, nebulized treprostinil (Tyvaso®). Based on these results, a phase 3 study (INSPIRE; Clinicaltrials.gov Identifier NCT03399604) evaluating the long-term safety and tolerability of LIQ861 in patients with pulmonary arterial hypertension was initiated.

Rational design of photo-cleavable alkoxyamines for polymerization and synthesis

Theoretical calculations have been performed in order to investigate the impact of different substitution patterns on predicted photoreactivity of alkoxyamines fused to an anthraquinone chromophore. Amino and hydroxy groups (similar to those which have been previously synthesized) are introduced and their effect on excited state energies and charge transfer is assessed. Analogous to formally oxidized alkoxyamines, the charge-separated nNπ* state can undergo mesolytic cleavage or bimolecular or SN2 reactions with nucleophiles, according to the substitution patterns and other reagents present. While homolytic cleavage is in principle promoted by triplet ππ* states, the accessible ππ* triplet states in this system are centered on the chromophore and unreactive. We show that the reactive nNπ* state, which bears a negative charge, is stabilized by hydroxy substitution while amino substitution will destabilize it. After mesolysis to a carbon centred radical, the nitroxide radical re-forms; however, when carbocations are produced the remaining open-shell singlet is stable and unable to undergo coupling with the carbocation.

High-Flow, Noninvasive Ventilation and Awake (Nonintubation) Proning in Patients With Coronavirus Disease 2019 With Respiratory Failure

The coronavirus disease 2019 pandemic will be remembered for the rapidity with which it spread, the morbidity and mortality associated with it, and the paucity of evidence-based management guidelines. One of the major concerns of hospitals was to limit spread of infection to health-care workers. Because the virus is spread mainly by respiratory droplets and aerosolized particles, procedures that may potentially disperse viral particles, the so-called "aerosol-generating procedures" were avoided whenever possible. Included in this category were noninvasive ventilation (NIV), high-flow nasal cannula (HFNC), and awake (nonintubated) proning. Accordingly, at many health-care facilities, patients who had increasing oxygen requirements were emergently intubated and mechanically ventilated to avoid exposure to aerosol-generating procedures. With experience, physicians realized that mortality of invasively ventilated patients was high and it was not easy to extubate many of these patients. This raised the concern that HFNC and NIV were being underutilized to avoid intubation and to facilitate extubation. In this article, we attempt to separate fact from fiction and perception from reality pertaining to the aerosol dispersion with NIV, HFNC, and awake proning. We describe precautions that hospitals and health-care providers must take to mitigate risks with these devices. Finally, we take a practical approach in describing how we use the three techniques, including the common indications, contraindications, and practical aspects of application.

Substituent Effects on Photoinitiation Ability of Monoaminoanthraquinone-Based Photoinitiating Systems for Free Radical Photopolymerization under LEDs

Three monoamino-substituted anthraquinone derivatives (AAQs), that is, 1-aminoanthraquinone (AAQ), 1-(methylamino)anthraquinone (MAAQ), and 1-(benzamido)anthraquinone (BAAQ), incorporated with various additives [e.g., triethanolamine (TEAOH) and phenacyl bromide (PhC(═O)CH₂ Br)] are investigated for their roles as photoinitiating systems of free radical photopolymerization of (meth)acrylate monomers upon the exposure to UV to green LEDs. The AAQs-based photoinitiating systems, AAQ/TEAOH/PhC(═O)CH₂ Br and BAAQ/TEAOH/PhC(═O)CH₂ Br photoinitiators exhibit the highest efficiency for the free radical photopolymerization of DPGDA under the irradiation of blue LED and UV LED, respectively, which is consistent with the extent of overlap between their absorption spectra and the emission spectra of the LEDs. AAQ/TEAOH/PhC(═O)CH₂ Br photoinitiator can also initiate the free radical photopolymerization of different (meth)acrylate monomers, with an efficiency dependent on the chemical structures of these monomers.

Protocol for two-arm pragmatic cluster randomized hybrid implementation-effectiveness trial comparing two education strategies for improving the uptake of noninvasive ventilation in patients with severe COPD exacerbation

Background

COPD is the fourth leading cause of death in the US, and COPD exacerbations result in approximately 700,000 hospitalizations annually. Patients with acute respiratory failure due to severe COPD exacerbation are treated with invasive (IMV) or noninvasive mechanical ventilation (NIV). Although IMV reverses hypercapnia/hypoxia, it causes significant morbidity and mortality. There is strong evidence that patients treated with NIV have better outcomes, and NIV is recommended as first line therapy in these patients. Yet, several studies have demonstrated substantial variation in the use of NIV across hospitals, leading to preventable morbidity and mortality. Through a series of mixed-methods studies, we have found that successful implementation of NIV requires physicians, respiratory therapists (RTs), and nurses to communicate and collaborate effectively, suggesting that efforts to increase the use of NIV in COPD need to account for the complex and interdisciplinary nature of NIV delivery and the need for team coordination. Therefore, we propose to compare two educational strategies: online education (OLE) and interprofessional education (IPE) which targets complex team-based care in NIV delivery.

Methods and design

Twenty hospitals with low baseline rates of NIV use will be randomized to either the OLE or IPE study arm. The primary outcome of the trial is change in the hospital rate of NIV use among patients with COPD requiring ventilatory support. In aim 1, we will compare the uptake change over time of NIV use among patients with COPD in hospitals enrolled in the two arms. In aim 2, we will explore mediators’ role (respiratory therapist autonomy and team functionality) on the relationship between the implementation strategies and implementation effectiveness. Finally, in aim 3, through interviews with providers, we will assess acceptability and feasibility of the educational training.

Discussions

This study will be among the first to carefully test the impact of IPE in the inpatient setting. This work promises to change practice by offering approaches to facilitate greater uptake of NIV and may generalize to other interventions directed to seriously-ill patients.

Trial registration

Name of registry: ClinicalTrials.gov

Trial registration number: NCT04206735

Date of Registration: December 20, 2019

Noninvasive Ventilatory Support for Acute Hypercapnic Respiratory Failure

Noninvasive ventilation is well established as the ventilatory modality of first choice to treat acute or acute-on-chronic hypercapnic respiratory failure in patients with COPD by improving dyspnea and gas exchange, avoiding the need for intubation, and reducing morbidity and mortality rates. Noninvasive ventilation also offers benefit for patients with COPD and with accompanying pneumonia or with hypercapnic respiratory failure in postextubation, postoperative, and do not intubate settings. Noninvasive ventilation, in addition, offers benefit in other forms of acute hypercapnic respiratory failure, including those caused by asthma, cystic fibrosis, and obesity hypoventilation. A newer form of noninvasive ventilatory assistance, high-flow nasal cannula, has emerged in recent years as a technique to not only oxygenate effectively but also to improve ventilatory efficiency and reduce the work of breathing in patients with severe COPD. Results of recent studies indicate that high-flow nasal cannula therapy can benefit some patients with acute hypercapnic respiratory failure, either instead of or in combination with noninvasive ventilation, but more study is needed.

A multifunctional surfactant catalyst inspired by hydrolases

The remarkable power of enzymes to undertake catalysis frequently stems from their grouping of multiple, complementary chemical units within close proximity around the enzyme active site. Motivated by this, we report here a bioinspired surfactant catalyst that incorporates a variety of chemical functionalities common to hydrolytic enzymes. The textbook hydrolase active site, the catalytic triad, is modeled by positioning the three groups of the triad (-OH, -imidazole, and -CO₂H) on a single, trifunctional surfactant molecule. To support this, we recreate the hydrogen bond donating arrangement of the oxyanion hole by imparting surfactant functionality to a guanidinium headgroup. Self-assembly of these amphiphiles in solution drives the collection of functional headgroups into close proximity around a hydrophobic nano-environment, affording hydrolysis of a model ester at rates that challenge α-chymotrypsin. Structural assessment via NMR and XRD, paired with MD simulation and QM calculation, reveals marked similarities of the co-micelle catalyst to native enzymes.

Comprehensive Diagnostic Evaluation of Cardiovascular Physiology in Patients With Pulmonary Vascular Disease: Insights From the PVDOMICS Program

BACKGROUND

Invasive hemodynamic evaluation through right heart catheterization plays an essential role in the diagnosis, categorization, and risk stratification of patients with pulmonary hypertension.

METHODS

Subjects enrolled in the PVDOMICS (Redefining Pulmonary Hypertension through Pulmonary Vascular Disease Phenomics) program undergo an extensive invasive hemodynamic evaluation that includes repeated measurements at rest and during several provocative physiological challenges. It is a National Institutes of Health/National Heart, Lung, and Blood Institute initiative to reclassify pulmonary hypertension groups based on clustered phenotypic and phenomic characteristics. At a subset of centers, participants also undergo an invasive cardiopulmonary exercise test to assess changes in hemodynamics and gas exchange during exercise.

CONCLUSIONS

When coupled with other physiological testing and blood -omic analyses involved in the PVDOMICS study, the comprehensive right heart catheterization protocol described here holds promise to clarify the diagnosis and clustering of pulmonary hypertension patients into cohorts beyond the traditional 5 World Symposium on Pulmonary Hypertension groups. This article will describe the methods applied for invasive hemodynamic characterization in the PVDOMICS program. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02980887.

Toxic tall fescue grazing increases susceptibility of the Angus steer fecal microbiota and plasma/urine metabolome to environmental effects

Impaired thermoregulation and lowered average daily gains (ADG) result when livestock graze toxic endophyte (Epichloë coenophialum)-infected tall fescue (E+) and are hallmark signs of fescue toxicosis (FT), a disease exacerbated by increased temperature and humidity (+temperature-humidity index; +THI). We previously reported FT is associated with metabolic and microbiota perturbations under thermoneutral conditions; here, we assessed the influence of E+ grazing and +THI on the microbiota:metabolome interactions. Using high-resolution metabolomics and 16S rRNA gene sequencing, plasma/urine metabolomes and the fecal microbiota of Angus steers grazing non-toxic or E+ tall fescue were evaluated in the context of +THI. E+ grazing affected the fecal microbiota profile; +THI conditions modulated the microbiota only in E+ steers. E+ also perturbed many metabolic pathways, namely amino acid and inflammation-related metabolism; +THI affected these pathways only in E+ steers. Integrative analyses revealed the E+ microbiota correlated and co-varied with the metabolomes in a THI-dependent manner. Operational taxonomic units in the families Peptococcaceae, Clostridiaceae, and Ruminococcaceae correlated with production parameters (e.g., ADG) and with multiple plasma/urine metabolic features, providing putative FT biomarkers and/or targets for the development of FT therapeutics. Overall, this study suggests that E+ grazing increases Angus steer susceptibility to +THI, and offers possible targets for FT interventions.