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PubMed2026

Interventions with a significant mortality difference in acute respiratory distress syndrome: A systematic review and comparison with Guidelines.

INTRODUCTION: Acute respiratory distress syndrome (ARDS) has a high mortality rate. European Society of Intensive Care Medicine (ESICM) and American Thoracic Society (ATS) Guidelines are the worldwide reference for clinicians in management of ARDS. Mortality represents one of the most important outcomes in intensive care practice and randomized controlled trials (RCTs) the highest level of evidence. We compared Guidelines recommendations with RCT results to highlight differences and find potential new therapeutic opportunities. METHODS: We performed a systematic review of all RCTs reporting a statistically significant mortality difference in ARDS and a subsequent comparison with ESICM and ATS Guidelines recommendations. RESULTS: We identified 33 RCTs and 23 interventions with mortality difference in ARDS patients. Seven interventions relate to invasive ventilation strategies, two to noninvasive ventilation strategies, one to extracorporeal membrane oxygenation (ECMO), 12 to drugs and one to nutritional support. In 25/33 (76%) RCTs the intervention was associated with mortality reduction and in 8/33 with mortality increase (24%). Multicenter studies were 24/33 (73%) while blinding was adopted in 19/33 (58%) studies. Guidelines recommendations supported by RCTs with mortality impact include: the use of low tidal volume ventilation, prone positioning, venovenous ECMO, steroids and the avoidance of high frequency oscillatory ventilation. Eight of the interventions identified were not mentioned by Guidelines but demonstrated reduced mortality, and five further interventions demonstrated increased mortality. CONCLUSIONS: This systematic review highlights potential gaps between RCTs results and Guidelines that could be used to plan future research or highlight topics to be discussed in future Guidelines.

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PubMed2026

Improving survival in Duchenne muscular dystrophy across eras: a systematic review and cumulative meta-analysis.

BACKGROUND: Duchenne muscular dystrophy (DMD) was historically associated with death in the late teens or early twenties, mainly from respiratory failure. Survival has improved substantially with home mechanical ventilation (HMV) and multidisciplinary care, although variability remains. This study evaluated temporal trends in survival in DMD and the impact of HMV. METHODS: A study-level cumulative meta-analysis (PROSPERO CRD420251163011) of studies reporting survival outcomes in patients with DMD was conducted (PubMed 1977 to 13 October 2025). Pooled estimates of median survival were calculated, and random-effects meta-analyses with predefined subgroups (HMV and study period) were performed, alongside meta-regressions. Risk of bias was assessed using the Newcastle-Ottawa Scale. RESULTS: 53 studies (median follow-up 8 years), comprising more than 13,000 patients, of whom 60% received HMV, were included. Median survival differed substantially between ventilated (29 years, 95%CI 27 to 31) and non-ventilated (19 years, 95%CI 18 to 20) patients. Survival improved progressively over time in both groups. Glucocorticoid therapy was not associated with improved survival (p=0.45), whereas treatment with heart failure medications, including renin-angiotensin system inhibitors (p=0.002) and β-blockers (p=0.02), was associated with longer survival. The predominance of mortality shifted from respiratory to cardiac causes, while enhanced cardiac management was associated with a growing contribution of other causes of death. CONCLUSION: Survival in DMD has increased substantially over time, with median survival now approaching the third decade of life among ventilated patients. The growing contribution of cardiac and other non-respiratory causes of death highlights the importance of long-term multidisciplinary and early cardioprotective intervention. STUDY REGISTRATION: The meta-analysis and systematic review have been registered on PROSPERO (CRD420251163011).

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PubMed2026

Anabolic androgen therapy in critically ill adults: A systematic review and meta-analysis.

Critical illness is characterized by a catabolic, proinflammatory state. Anabolic agents, such as testosterone, have therefore been proposed as therapeutic targets. Our objectives were to assess the effects of testosterone in critically ill populations on patient-important outcomes and identify design limitations to inform future studies. We searched for randomized control trials (RCTs) through Medline, Embase, and EBM Reviews databases from inception through February 24, 2026, including English language articles enrolling adults (≥18 years) admitted to ICU where anabolic androgen therapies (AAT) were compared with placebo or standard of care. Studies had to report at least one of: mortality, ICU and hospital lengths of stay, or duration of mechanical ventilation. We extracted data independently using a standardized data extraction tool, and feedback was received from all co-authors to ensure agreement. For each outcome, we performed meta-analyses using a random-effects model with inverse variance weighting in RevMan. We used the GRADE approach to assess certainty in pooled estimates of effect. Of 1325 screened articles, we found 4 that fit our inclusion criteria. Together, we judged risk of bias as 'some concerns' in 3 trials and 'high' in the final trial, and ultimately found that the effects of anabolic-androgen therapy on patient-important outcomes uncertain. With the uncertainty of current evidence for the effects of anabolic-androgen therapy in critically ill adults, there is insufficient support for its routine use. Future randomized evidence is needed to determine whether anabolic-androgen therapy improves clinically-important outcomes and better define its safety profile in critically ill adults.

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PubMed2026

Efficacy and Safety of Mechanical Insufflation-Exsufflation in Invasively Ventilated Critically Ill Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Mechanical insufflation-exsufflation (MI-E) is increasingly used in invasively ventilated adults in the intensive care unit (ICU), yet its therapeutic efficacy and safety remain uncertain due to inconsistent evidence. AIM: To synthesize evidence on the clinical efficacy and safety of MI-E in this population and to examine methodological and clinical heterogeneity underlying reported outcomes. STUDY DESIGN: A systematic review and meta-analysis of randomized studies (including RCTs and randomized crossover trials), conducted following PRISMA guidelines, with risk of bias assessed using the Cochrane risk-of-bias tool. RESULTS: Five randomized controlled trials involving 310 patients were included. Meta-analysis showed that mechanical insufflation-exsufflation (MI-E) significantly increased sputum clearance (SMD = 0.63, 95% CI, 0.32-0.93; p < 0.00011; I2 = 38%) without affecting oxygenation (MD = 0.28, 95% CI, -0.53 to 1.09; p = 0.50; I2 = 9%). Data on respiratory mechanics, ventilation duration and ICU stay could not be pooled. No serious adverse events were reported. CONCLUSIONS: MI-E significantly improves sputum clearance in invasively ventilated critically ill adults, with no severe adverse events reported in the included studies. Its effects on other outcomes remain inconclusive due to limited data and heterogeneity. Standardized protocols and larger trials are needed. RELEVANCE TO CLINICAL PRACTICE: Clinicians may consider MI-E as an adjunct for respiratory secretion management. Application should be guided by structured patient assessment and individualized parameter adjustment. Future research should standardize interventions and target well-defined patient subgroups to inform clear practice guidelines. TRIAL REGISTRATION: The review protocol was registered in the International Prospective Register of Systematic Reviews, with registration number CRD42023403299.

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PubMed2026

Risk factors of venous thromboembolism in ICU patients: a systematic review and meta-analysis.

OBJECTIVE: This study aimed to identify risk factors associated with the development of VTE in patients admitted to the intensive care unit (ICU). METHODS: A systematic literature search was conducted via PubMed, Embase, Web of Science, and Cochrane databases up to 25 April 2025, to identify studies examining the association between risk factors and the occurrence of venous thromboembolism (VTE) in ICU patients. Data were pooled using odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: A total of 2465 relevant studies were identified through the systematic search, of which 30 were included in the meta-analysis. The pooled data showed that the following were significant risk factors for venous thromboembolism (VTE) in ICU patients: central venous catheterization (OR = 2.67, 95% CI: 1.67-4.28; I2 = 28%), invasive mechanical ventilation (OR = 2.08, 95% CI: 1.46-2.96; I2 = 0%), advanced age (OR = 2.06, 95% CI: 1.28-3.31; I2 = 86%), length of ICU stay (OR = 4.24, 95% CI: 1.43-12.57; I2 = 98%), malignancy (OR = 2.30, 95% CI: 1.03-5.12; I2 = 67%), elevated D-dimer levels (OR = 2.46, 95% CI: 1.37-4.40; I2 = 34%), and a history of VTE (OR = 2.84, 95% CI: 1.45-5.55; I2 = 51%). According to the GRADE assessment, the quality of evidence was rated as moderate for invasive mechanical ventilation, low for central venous catheterization and D-dimer levels, and very low for the remaining factors. CONCLUSION: Invasive mechanical ventilation, central venous catheterization, and elevated D-dimer levels are associated with VTE risk, supported by relatively high-quality evidence. These findings may help identify ICU patients at higher risk of VTE, inform the development of risk assessment models for patient stratification, and ultimately contribute to improved prognosis through optimal screening and management strategies.

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PubMed2026

Comparison of VCV and PCV-VG modes on diaphragmatic function in diabetic patients undergoing laparoscopic colorectal surgery: a prospective randomized controlled study.

BACKGROUND: Diabetic patients are prone to induce diaphragmatic weakness, which can lead to postoperative pulmonary complications (PPCs). The optimal mechanical ventilation mode may potentially improve postoperative diaphragmatic function. This study evaluates the effects of two ventilation modes under driving pressure-guided ventilation strategy on diaphragmatic function, as assessed by diaphragm thickening fraction (DTF) and diaphragm excursion (DE), in diabetic patients following laparoscopic colorectal surgery. METHODS: Eighty patients diagnosed with Type II diabetes scheduled for elective laparoscopic colorectal surgery, were randomly allocated to either the pressure-controlled volume-guaranteed ventilation (PCV-VG) group (Group P) or the volume-controlled ventilation (VCV) group (Group V) during surgery. The primary outcome was diaphragmatic function assessed during both tidal breathing and maximal inspiratory effort after surgery. Secondary outcomes included intraoperative mechanical power, PPCs, and other complications. RESULTS: A total of eighty patients were included in the final analysis. The averaged area under the curve (AUC) for mechanical power during ventilation was significantly lower in Group P than in Group V (p = 0.002). PCV-VG significantly improved both DE and DTF within the first two days post-surgery (AUCDEtidal: p = 0.088, AUCDTFtidal: p = 0.004, AUCDEmax: p = 0.029, AUCDTFmax: p = 0.017). Postoperative diaphragmatic weakness was less frequent in Group P than in Group V (p = 0.019). However, there was no difference in the incidence of PPCs between the two groups (p = 0.155). CONCLUSION: PCV-VG mode can reduce intraoperative mechanical power, better preserve postoperative diaphragmatic function. However, these improvements did not translate into clinical benefits, as evidenced by the lack of reduction in the incidence of PPCs.

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PubMed2026

Effects of permissive hypercapnia on intraoperative cerebral oxygenation and early postoperative cognitive function in older patients with fragile brain function during the non-acute phase undergoing laparoscopic colorectal surgery: A randomized controlled trial.

BACKGROUND AND PURPOSE: Older adults with non-acute fragile brain function (NFBF) may be particularly susceptible to perioperative disturbances in cerebral oxygenation and postoperative neurocognitive decline. Permissive hypercapnia (PHC) may enhance cerebral oxygenation, but its effects in this population remain unclear. We examined whether PHC-based ventilation improves intraoperative regional cerebral oxygen saturation (rSO2) and early postoperative cognitive outcomes in older patients with NFBF undergoing elective laparoscopic colorectal surgery. METHODS: In this single-center, single-blind randomized trial, 76 patients were assigned in a 1:1 ratio to PHC-based or conventional ventilation. The primary outcome was the absolute change in rSO2 from baseline (T0) to the end of surgery (T4). Analyses followed the intention-to-treat principle, with prespecified per-protocol sensitivity analysis. Secondary outcomes included intraoperative rSO2 trajectories, cerebral oxygen extraction-related indices, early postoperative cognitive screening, serum neuron-specific enolase and interleukin-6, and safety outcomes. RESULTS: PHC significantly increased rSO2 relative to conventional ventilation (left: adjusted mean difference [aMD] 10.64, 95% CI 8.96-12.33; right: aMD 10.16, 95% CI 8.22-12.11; both P < 0.001), with consistent sensitivity results. Repeated-measures analyses showed persistently higher intraoperative rSO2 in the PHC group. Cerebral oxygen extraction-related indices were generally lower with PHC. However, early postoperative cognitive outcomes and serum biomarkers did not differ between groups. Emergence time was modestly longer with PHC, whereas adverse events were comparable. CONCLUSIONS: PHC-based ventilation favorably modified intraoperative cerebral oxygenation and oxygen-extraction profiles but did not translate into detectable early postoperative cognitive or biomarker benefits in older adults with NFBF.

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PubMed2026

Effect of protective ventilation throughout the intubation period on perioperative oxygenation in patients undergoing MIDCABG: a randomised controlled trial.

INTRODUCTION: Minimally invasive direct coronary artery bypass grafting (MIDCABG) requires prolonged one-lung ventilation (OLV), increasing postoperative pulmonary complications (PPCs) risk. We investigated whether protective lung ventilation (PLV) throughout intubation benefits MIDCABG patients. METHODS: In this single-center randomized study, MIDCABG patients received PLV (low tidal volume of 6-8 mL·kg-1, PEEP of 6 cm H2O, alveolar recruitment maneuvers) or conventional mechanical ventilation (CMV, tidal volume of 8-10 mL·kg-1, without PEEP or maneuvers) from tracheal intubation to extubation. The primary outcome was perioperative oxygenation, assessed by the PaO2/FiO2 ratio. RESULTS: Sixty patients (n = 30 per group) were enrolled. Compared with CMV, PLV improved PaO2/FiO2 ratios (mean difference at OLV60: 34.56 mmHg; 95% CI: 11.78-57.33; p < 0.01), shortened median durations of postoperative mechanical ventilation (median difference: -4.5 h, 95% CI: -8.5 to -0.5; p = 0.013) and hospital stay (median difference: -3.0 days, 95% CI: -5.0 to -1.0; p = 0.019). PLV also reduced driving pressure, airway pressure and intrapulmonary shunt during OLV (all p < 0.05). Desaturation occurred in 23.3% of CMV patients and 13.3% of PLV patients (p = 0.506). Hemodynamic parameters were generally comparable between groups, except for lower MPAP and PVRI in the PLV group during OLV and after ICU admission (p < 0.05). The incidence of PPCs did not differ between groups. CONCLUSIONS: In patients undergoing MIDCABG, PLV applied throughout intubation improved perioperative oxygenation and shortened the duration of postoperative mechanical ventilation and hospital stay, but did not reduce PPCs. CLINICAL TRIAL REGISTRATION: ChiCTR1900022005.

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PubMed2026

Chronic neurological diseases with acute respiratory failure in a real-life cohort: insights into ICU and long-term survival-A retrospective study.

BACKGROUND: Patients with chronic neurological diseases (CND) are at increased risk of pulmonary complications that often require ICU admission. This study aimed to identify clinical factors associated with ICU mortality and long-term survival in patients with CND who developed acute respiratory failure (ARF). METHODS: This retrospective cohort study was conducted in a level III respiratory ICU. Patients with pre-existing CND admitted to the ICU with ARF were included. ICU mortality was analyzed using multivariable logistic regression. Long-term survival after ICU discharge was evaluated using Kaplan-Meier survival analysis and Cox proportional hazards models. Mortality timing was further characterized using hazard function analysis. RESULTS: A total of 220 patients were included; the most common neurological diagnoses were dementia (37.3%), stroke (22.7%), and amyotrophic lateral sclerosis (14.1%). ICU mortality was 33.6%. Higher APACHE II scores were independently associated with increased ICU mortality (OR 1.076 per point increase; 95% CI 1.029-1.126; p < 0.001). Long-term survival differed significantly by post-discharge respiratory support strategy, with Kaplan-Meier analysis demonstrating more favorable survival patterns among patients receiving home non-invasive mechanical ventilation (NIMV) (p = 0.003). In Cox regression analysis, age, home NIMV, and feeding modality at discharge were independently associated with long-term outcomes. Survival analyses revealed an early clustering of deaths within the first months after ICU discharge, particularly among patients with dementia. CONCLUSIONS: In patients with CND, acute physiological severity was the main determinant of ICU mortality, whereas long-term survival after ICU discharge was poor, with deaths clustering within the first months thereafter. Post-discharge respiratory support and nutritional management should be individualized according to the expected clinical trajectory and patient values.

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PubMed2026

Alarms and alarm management with automated versus conventional ventilation in neurocritical care patients.

INTRODUCTION: False or clinically irrelevant alarms are a major driver of ICU alarm fatigue and nursing workload. Ventilator alarms make up a large share, and although automated ventilation modes can reduce manual adjustments, their effect on alarm burden is still unclear. This issue can be particularly relevant in neurocritical care patients, where precise ventilator and alarm management is imperative for patient safety. OBJECTIVES: This explorative post hoc analysis of a randomized clinical trial compared alarm frequency and management between automated ventilation and conventional ventilation in neurocritical care patients. METHODS: Ventilator alarms and manual ventilator changes were captured continuously from the ventilator for up to 24 h per patient. The primary endpoint was a composite of workload-relevant alarms; with alarm management interventions at the ventilator as a key secondary outcome. Additional endpoints included redundant alarms, alarm duration and ventilator management. RESULTS: 13 patients received automated ventilation and 24 received conventional ventilation. No difference was observed in workload-relevant alarm frequency between automated and conventional ventilation (3.28 [2.87 to 4.30] vs 3.73 [1.66 to 7.33] alarms per hour; P = 0.81), while alarm management interventions at the ventilator were lower with automated ventilation (0.14 [0.10 to 0.15] vs 0.21 [0.17 to 0.31] interventions per hour; P = 0.01). Other alarm frequencies, duration of alarms and ventilator management were similar. CONCLUSIONS: In this exploratory post hoc analysis of a randomized clinical trial in neurocritical care patients during the early phase of mechanical ventilation, automated ventilation did not reduce the frequency of total or workload-relevant alarms, nor their duration, but was associated with fewer alarm management interventions compared to conventional ventilation. IMPLICATIONS FOR CLINICAL PRACTICE: Automated ventilation may not reduce alarm frequency in neurocritical care patients, but the observed reduction in alarm-related bedside interventions suggests a potential benefit for nursing workload.

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PubMed2026

The effect of dexmedetomidine in mechanically ventilated patients with sepsis and septic shock: a meta-analysis of randomized controlled trials.

PURPOSE: Dexmedetomidine (DEX) is a central sympatholytic with sedative properties widely used in critically ill patients. However, its effects in patients with sepsis and septic shock remain controversial. This meta-analysis evaluated the efficacy and safety of DEX compared to other sedatives in mechanically ventilated patients with sepsis and septic shock. METHODS: A systematic search was conducted across PubMed, Embase, Scopus, and Cochrane Library from inception through May 1, 2025 for randomized controlled trials comparing DEX with other sedatives or placebo in mechanically ventilated patients with sepsis and septic shock. Primary outcomes included overall mortality and Sequential Organ Failure Assessment (SOFA) scores. Secondary outcomes encompassed duration of mechanical ventilation (MV), length of stay in Intensive Care Unit (ICU), incidence of hypotension and bradycardia. RESULTS: Fifteen studies involving 3,882 patients (1,945 in the DEX group, 1,937 in the control group) were included. DEX was demonstrated no significant differences compared to other sedatives or placebo in overall mortality (Risk Ratio [RR] 0.98, 95% Confidence Interval [CI] 0.90 to 1.07, p = 0.71, I2 = 0%), SOFA scores (Mean Difference [MD] - 0.14, 95% CI -0.81 to 0.52, p = 0.67, I2 = 0%), length of stay in ICU (MD -0.32, 95% CI -1.69 to 1.06, p = 0.65, I2 = 77%), or incidence of hypotension (RR 1.15, 95% CI 0.81 to 1.62, p = 0.44, I2 = 14%). However, DEX significantly reduced the duration of MV (MD -0.54, 95% CI -0.98 to -0.10, p = 0.02, I2 = 25%) but was associated with an increased incidence of bradycardia (RR 1.67, 95% CI 1.22 to 2.28, p = 0.001, I2 = 0%). CONCLUSIONS: In mechanically ventilated patients with sepsis and septic shock, DEX shortened duration of MV but was associated increased bradycardia risk. No mortality or organ dysfunction benefits were observed. These findings suggest DEX is a reasonable therapeutic option to facilitate earlier ventilator weaning in selected patients (particularly those without shock), but careful monitoring for cardiovascular adverse effects is warranted.

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PubMed2026

Integrated Telehealth Rehabilitation and Quality of Life in Mechanically Ventilated Adults: A Randomized Clinical Trial.

IMPORTANCE: Whether integrated rehabilitation strategies spanning intensive care unit (ICU), hospital, and postdischarge phases improve quality of life after acute respiratory failure is uncertain. OBJECTIVE: To evaluate the effect of an integrated multicomponent telehealth-based rehabilitation intervention on health-related quality of life at 90 days after hospital discharge among adults with acute hypoxemic respiratory failure requiring invasive mechanical ventilation. DESIGN, SETTING, AND PARTICIPANTS: This stepped-wedge cluster randomized clinical trial in ICUs of 20 public hospitals in Brazil enrolled adults with acute hypoxemic respiratory failure requiring invasive mechanical ventilation between June 2024 and May 2025, with follow-up through September 2025. INTERVENTIONS: A multicomponent telehealth-based rehabilitation program integrating an ICU telehealth-based rehabilitation intervention focused on ventilator liberation; a ward telehealth-based rehabilitation intervention targeting risk stratification and initiation of individualized rehabilitation plans; and a postdischarge telehealth-based rehabilitation intervention consisting of a 2-month personalized centralized telerehabilitation program. MAIN OUTCOMES AND MEASURES: Health-related quality of life at 90 days after hospital discharge, measured using the EuroQol 5-Dimension 3-Level (EQ-5D-3L) utility score (range, -0.17 [worse than death] to 1 [best health state], with 0 representing death). RESULTS: Among 1916 enrolled patients (mean [SD] age, 60.6 [17.3] years; 43.6% female), 1063 were assigned to the intervention and 853 to usual care per local protocols. At 90 days after hospital discharge, mean (SD) EQ-5D-3L utility scores were higher in the intervention group than in the usual care group (0.16 [0.31] vs 0.12 [0.28]; adjusted difference, 0.049; 95% CI, 0.0002 to 0.098; P = .04) but did not differ among survivors (0.60 [0.32] vs 0.59 [0.32]; adjusted difference, -0.045; 95% CI, -0.138 to 0.045; P = .34). Compared with usual care, the intervention resulted in lower 90-day all-cause mortality (71.8% [676 of 941] vs 78.3% [584 of 746]; adjusted difference, -7.6%; 95% CI, -14.7% to -0.6%; P = .03) and shorter mean (SD) mechanical ventilation duration (9.9 [10.3] vs 15.5 [15.9] days; adjusted difference, -6.2 days; 95% CI, -8.5 to -3.9; P < .001). CONCLUSIONS AND RELEVANCE: In this study, an integrated telehealth-based rehabilitation strategy delivered across ICU, hospital, and postdischarge phases improved 90-day health-related quality of life, potentially influenced by reduced mortality. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT06343545.

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PubMed2026

The effects of nitrate and nitrite supplementation on mitochondrial respiration in permeabilized muscle fibres in young healthy adults.

Nitric oxide (NO) is a direct regulator of mitochondrial respiration. Nitrate (NO3-) and nitrite (NO2-) are good sources of NO, but whether their effects on mitochondrial respiration differ between in vivo and in vitro administration remains unclear. In Study 1, 8 participants consumed NO3- -rich beetroot juice (BR) (∼12.8 mmol NO3-) and NO3- -depleted placebo beetroot juice (PL) (∼0.08 mmol NO3-) acutely and chronically for 2 weeks in a randomised, double-blind, crossover design. A substrate-uncoupler-inhibitor titration (SUIT) protocol was used to assess mitochondrial respiration using high-resolution respirometry (oxygen tension: ∼200-450 μM) in permeabilized muscle fibres. In Study 2, skeletal muscle samples were collected from 11 participants. In a randomised, crossover design, different doses (0, 1.5, and 3.0 μM) of sodium nitrite (NaNO2) were administered to permeabilized muscle fibres. Mitochondrial respiration was measured using the same SUIT protocol under lower oxygen tension (∼50-200 μM). Although muscle NO3- concentration significantly increased after both acute and chronic BR supplementation, mitochondrial respiration and exercise performance did not differ between PL and BR in either condition. Similarly, absolute oxygen flux across different respiratory states were not different between different doses of NaNO2. However, the leak control ratio, reflecting the degree of uncoupling of mitochondrial respiration, was significantly higher with 3.0 μM NaNO2 administration (0.12 ± 0.05) compared to 0 μM NaNO2 administration (0.09 ± 0.04, P = 0.03). These findings, involving both in vivo and in vitro administration approaches, albeit in the presence of relatively high oxygen concentrations, suggest that neither NO3- nor NO2- improves mitochondrial respiration, at least in young healthy adults.

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PubMed2026

Biomass burning contributions to Mexico City's atmospheric CO2 estimated using a multi-isotope approach.

Fossil fuel combustion dominates anthropogenic emissions worldwide; however, special attention should be addressed to biomass burning, since it is an increasingly important contributor under warmer, drier fire-weather conditions exacerbated by climate change. These emissions could impact the atmospheric composition of heavily urbanized environments. To assess the influence of biomass burning, along with fossil fuels combustion and soil and plant respiration on Mexico City's atmospheric composition, we conducted a year-long (December 2023-December 2024) isotopic monitoring of atmospheric CO2, combining radiocarbon (Δ14C), CO2 stable isotopes (δ13C, δ18O), and CO/CO2 ratios. Once defined the isotopic signatures and the characteristic CO/CO2 that describe the sources, we performed Monte Carlo simulations under two tracer modalities (Δ14C + CO/CO2 and Δ14C + CO2 stable isotopes) for source apportionment. Results show that during the dry season, particularly in March-April, atmospheric Δ14C values approached and overlapped background levels despite Mexico City's fossil-fuel dominance, indicating enhanced non-fossil inputs. Moreover, backward HYSPLIT trajectories supported that these elevated Δ14C values coincided with regional wildfire activity. Monte Carlo results attributed up to ∼34 %-60 % of local CO2 to biomass burning in April, followed by March with contributions of ∼31 %-49 %. Since these biomass burning figures contrast with the official emissions inventory of Mexico City metropolitan area, which assigns <1 % of total CO2 emissions to biomass burning, this study could exhibit the emissions inventory underestimation of this source, and thus, the need to reassess and incorporate top-down isotopic constraints in fire-affected urban regions.

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PubMed2026

Impact of real-time respiratory function monitoring on neonatal mask ventilation training: a multicentre simulation-based crossover study.

OBJECTIVE: To evaluate whether visibility of respiratory function monitor (RFM) feedback improves mask ventilation performance and influences subsequent ventilation performance during neonatal resuscitation training. DESIGN: multicentre randomised crossover simulation study. PARTICIPANTS: Healthcare professionals involved in neonatal resuscitation training across participating centres. INTERVENTION: Participants performed positive pressure ventilation (PPV) on both term and premature manikins under two conditions: with visible RFM feedback and with the display masked. The order of feedback visibility was randomised. Each participant completed ventilation assessments in both conditions. MAIN OUTCOME MEASURES: Primary outcomes were expired tidal volume (Vte) and mask leak (%). The proportion of breaths within the target Vte range (4-8 mL/kg) was calculated as a performance indicator. Secondary outcomes included variability in Vte and mask leak to assess ventilation stability between conditions. RESULTS: Visible RFM feedback was associated with lower mask leak and improved ventilation stability in the preterm manikin and with tidal volumes entering the target range in the term manikin. Participants initially ventilated with visible feedback maintained performance after feedback removal, suggesting a carry-over learning effect. CONCLUSION: In this multicentre crossover simulation study, visible RFM feedback was associated with changes in mask ventilation performance and evidence of a carry-over learning effect following feedback removal. Real-time visibility of respiratory parameters may strengthen neonatal resuscitation training.

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PubMed2026

Respiratory effects of recruitment maneuvers according to lung recruitability assessed by electrical impedance tomography in patients with acute respiratory distress syndrome.

Recruitment maneuvers (RM) can improve oxygenation in patients with acute respiratory distress syndrome (ARDS), but their physiological effects depend on lung recruitability. This secondary analysis of a randomized controlled trial (RCT) evaluated oxygenation, respiratory mechanics, regional ventilation, and cardiorespiratory adverse events responses to a RM followed by electrical impedance tomography (EIT)-guided PEEP titration, using EIT to assess lung recruitability. In this study, fifty patients with moderate-to-severe ARDS underwent a stepwise RM followed by individualized PEEP titration guided by EIT. Lung recruitability was determined using the collapse index at PEEP 6 cmH₂O (CLPEEP6), defined as the proportion of collapsed lung at this PEEP level. Patients were classified into high- and low-recruitability groups based on median CLPEEP6 values. Oxygenation (PaO₂/FiO₂), static compliance (Cstat), driving pressure (Pdriv), regional ventilation distribution, and cardiorespiratory adverse events were compared before and after RM, during subsequent individualized EIT-guided PEEP titration. In patients with high recruitability (CLPEEP6 > 12.5), the PaO₂/FiO₂ ratio and Cstat increased significantly after RM (PaO₂/FiO₂: 100.8 ± 30.3 vs. 125.4 ± 38.3 mmHg, p < 0.05; Cstat: 21.5 ± 5.8 vs. 28.0 ± 7.0 mL/cmH₂O, p < 0.001), Pdriv decreased (19.1 ± 3.5 vs. 15.6 ± 3.2 cmH₂O, p < 0.001). EIT demonstrated a posterior redistribution of ventilation after RM. In contrast, patients with low recruitability (CLPEEP6 ≤ 12.5) showed no significant mechanical or oxygenation improvement and transient hypotension, arrhythmia, and desaturation appeared numerically more common in this group. No barotrauma or cardiac arrest occurred, and ICU mortality was similar between groups. A strategy combining a RM with subsequent individualized EIT-guided PEEP titration was associated with improved oxygenation and lung mechanics in patients with high lung recruitability, whereas patients with low recruitability showed limited physiological benefit, with cardiorespiratory adverse events appearing numerically more frequent. The EIT-derived CLPEEP6 index represents a feasible and clinically applicable https://clinicaltrials.gov/study/NCT06733168.

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PubMed2026

Daridorexant in severe obstructive sleep apnea: effects on sleep-disordered breathing and sleep.

STUDY OBJECTIVES: To evaluate the effect of daridorexant on nighttime respiratory function and sleep in adults with severe obstructive sleep apnea (OSA) without insomnia. MATERIALS AND METHODS: This randomized, double-blind, placebo-controlled, two-period, crossover trial was conducted at a single sleep center in 16 adults (≥18 years) with severe OSA without insomnia. In each period, daridorexant 50 mg or placebo was administered every evening for 5 days. Primary and secondary endpoints were the treatment differences (daridorexant-placebo) for apnea/hypopnea index (AHI) and oxygen saturation (SpO2) during total sleep time (TST), respectively, after last dosing. A mean increase in AHI ≥10 events/h and mean decrease in nocturnal SpO2 ≤-2% were the minimum changes considered to be clinically meaningful negative effects. Other endpoints included TST, latency to persistent sleep (LPS), and wake after sleep onset (WASO). RESULTS: Mean baseline AHI was 51.2 events/h (range 30.8, 82.2) and mean SpO2 during TST was 92.1% (range 88.5, 94.3). No clinically meaningful effect of daridorexant on AHI or SpO2 during TST was detected. Treatment differences were -3.7 events/h (one-sided 95% CI ≤ +4.2) and - 0.12 % (one-sided 95% CI ≥ -0.6), respectively. Compared with placebo, daridorexant increased TST by 32.5 min (90% CI: 6.9, 58.2), associated with shorter LPS (-10.3 min [90% CI: -20.6, -0.02]) and a trend towards reduced WASO (-15.2 min [-31.2, 0.9]). Four adverse events were reported (daridorexant n = 3; placebo n = 1), all of mild intensity and none related to respiratory function. CONCLUSION: Short-term treatment with daridorexant does not impair sleep-disordered breathing and may improve sleep in patients with severe OSA. CLINICAL TRIAL: ClinicalTrials.gov, https://clinicaltrials.gov/study/NCT05458193, NCT05458193. Statement of Significance Obstructive sleep apnea (OSA) is highly prevalent and associated, in 30%-50% of cases, with insomnia-related symptoms, yet the safety of insomnia medications in OSA remains unclear. Daridorexant, a dual orexin receptor antagonist for the treatment of adults with insomnia disorder, previously showed no negative effect on sleep-disordered breathing in participants with mild/moderate OSA. This randomized, double-blind, placebo-controlled, crossover trial evaluates daridorexant 50 mg (maximum therapeutic dose) in participants with severe OSA without insomnia. Repeated dosing (5 nights) did not impair nighttime respiratory function, as assessed by apnea/hypopnea index and nocturnal oxygen saturation. Moreover, improvements in sleep characteristics were observed with daridorexant, extending evidence that daridorexant 50 mg is safe and well-tolerated and may improve sleep in adults with severe OSA.

Humans↗

PubMed2026

Antarctic Peninsula soil carbon stock and efflux: A complex interplay of soil properties and heavy metals.

This study establishes a quantitative framework for understanding surface soil carbon dynamics and ecosystem connectivity in Fildes Peninsula and Ardley Island, King George Island, South Shetland Islands, Antarctic Peninsula. The mean soil organic carbon (SOC) stock across all study sites was 1.10 ± 1.93 kg C/m². Restricting net carbon balance analysis to Fildes Peninsula, where soil respiration (Rs) data were available, yielded a site-specific SOC stock of 0.45 ± 0.45 kg C/m². Scaling Rs to a realistic 120-day active season and assuming stable SOC stocks resulted in estimated annual carbon loss of 15 g C/(m2·yr), equivalent to 3.3 % of standing SOC. Comprehensive sensitivity analyses spanning plausible winter respiration (0 %-20 % of summer rates) and annual change in SOC stocks (-1 %-2 %) consistently supported a net carbon sink, with turnover rates constrained to 3.3 %/yr-4.7 %/yr. Principal component analysis showed that ornithogenic processes as the dominant control on SOC, total nitrogen (TN), zinc (Zn), copper (Cu), and cadmium (Cd) provide a clear multivariate signature of marine-derived nutrient, while Pb was decoupled from this gradient and associated instead with fine-particle size controls. These results reveal dual but independent drivers of soil metal enrichment in this region. Despite their limited spatial extent, ornithogenic soils store disproportionately large carbon pools. Overall, this integrated analysis reveals how marine-terrestrial subsidies regulate Antarctic carbon cycling and provides a quantitative and reproducible framework for assessing carbon dynamics under ongoing climate change.

Antarctic Regions↗