Dangers of hyperoxia

Effects of hyperoxemia in patients with sepsis - A post-hoc analysis of a multicentre randomized clinical trial

BACKGROUND

Administration of supplemental oxygen is a life-saving treatment in critically ill patients. Still, optimal dosing remains unclear during sepsis. The aim of this post-hoc analysis was to assess the association between hyperoxemia and 90-day mortality in a large cohort of septic patients.

METHODS

This is a post-hoc analysis of the Albumin Italian Outcome Sepsis (ALBIOS) randomized controlled trial (RCT). Patients with sepsis who survived the first 48 h since randomization were included and stratified into two groups according to their average PaO2 levels during the first 48 h (PaO2 0-48 h). The cut-off value was established at 100 mmHg (average PaO2 0-48  h >100 mmHg: hyperoxemia group; PaO2 0-48h≤100: normoxemia group). The primary outcome was 90-day mortality.

RESULTS

1632 patients were included in this analysis (661 patients in the hyperoxemia group, 971 patients in the normoxemia group). Concerning the primary outcome, 344 (35.4%) patients in the hyperoxemia group vs. 236 (35.7%) in the normoxemia group had died within 90 days from randomization (p = 0.909). No association was found after adjusting for confounders (HR 0.87; CI [95%] 0.736-1.028, p = 0.102) or after excluding patients with hypoxemia at enrollment, patients with lung infection or including post-surgical patients only. Conversely, we found an association between lower risk of 90-day mortality and hyperoxemia in the subgroup including patients who had the lung as primary site of infection (HR 0.72; CI [95%] 0.565-0.918). Mortality at 28 days, ICU mortality, incidence of acute kidney injury, use of renal replacement therapy, days to suspension of vasopressor or inotropic agents, and resolution of primary and secondary infections did not differ significantly. Duration of mechanical ventilation and length of stay in ICU were significantly longer in patients with hyperoxemia.

CONCLUSIONS

In a post-hoc analysis of a RCT enrolling septic patients, hyperoxemia as average PaO2>100 mmHg during the first 48 h was not associated with patients' survival.

Intrauterine fetal resuscitation: from maternal repositioning to the latest pharmacological strategies

Intrauterine resuscitation includes different interventions which aim to improve fetal oxygenation when intrapartum fetal hypoxic stress leading to abnormal CTG features is suspected. Based on the etiology of the hypoxic stress, prompt institution of specific conservative measures, aiming to restore fetal oxygenation and normalize the features of the CTG trace, may reduce the incidence of unnecessary operative deliveries. However, there is paucity of evidence supporting the effectiveness of intrauterine resuscitation measures: based on available data, routine administration of fluid boluses is not recommended and should be limited only to volume-depleted patients, in which intravenous hydration has been associated with potential benefits. Similarly, amnioinfusion and maternal oxygen administration cannot be recommended as previous studies on their efficacy reported conflicting results, and some have suggested that these measures may be potentially harmful. On the other hand, changing maternal position seems to be a potentially useful maneuver with no side effects in cases of supine hypotension syndrome or in cases of suspected sustained umbilical cord compression. Administration of tocolytics for ongoing excessive uterine activity is associated with fetal heart rate improvement; within the most used tocolytic drugs, terbutaline (a beta-agonist) is often recommended as the first-choice agent to be administered for intrapartum acute tocolysis due to its efficacy, ease of administration and side effect profile.

Oxygen targets in critically ill patients: from pathophysiology to population enrichment strategies

Oxygen supplementation is widely used to enhance oxygen delivery and to treat or prevent hypoxia; however, it requires careful management to avoid the harmful effects of excessive oxygen exposure. Both hyperoxia (inspiratory oxygen fraction exceeding 0.21) and hyperoxemia (arterial oxygen tension oxygen partial pressure [PaO2] > 100 mmHg) can contribute to lung injury, promote systemic vasoconstriction, and increase the production of reactive oxygen species, which can impair macromolecular and cellular functions. Conversely, in certain situations, hyperoxemia may provide benefits, such as hemodynamic stabilization in hyperdynamic shock, immunomodulation, and bactericidal effects. The literature presents conflicting evidence regarding the impact of different oxygen targets (i.e., PaO2 and/or peripheral saturation of oxygen [SpO2]) on both short- and long-term outcomes in patients with acute critical conditions, such as acute respiratory distress syndrome, sepsis, cardiac arrest, and acute central nervous system injuries. These discrepancies may stem from the small differences between the oxygenation targets used in randomized trials, the physiological limitations of PaO2 and SpO2 targets, which reflect blood oxygen content rather than oxygen delivery, the lack of measurements of microvascular function or oxygen delivery, and the heterogeneity in treatment response. Furthermore, advanced analytical methods (e.g., machine learning) are emerging as promising tools to implement population enrichment strategies. By refining patient sub-group identification, these approaches can significantly optimize precision medicine, enabling more personalized oxygen therapy tailored to individual patient characteristics.

The intelligent podocyte: sensing and responding to a complex microenvironment

Podocytes are key components of the glomerular filtration barrier - a specialized structure that is responsible for the filtration of blood by the kidneys. They therefore exist in a unique microenvironment exposed to mechanical force and the myriad molecules that cross the filtration barrier. To survive and thrive, podocytes must continually sense and respond to their ever-changing microenvironment. Sensing is achieved by interactions with the surrounding extracellular matrix and neighbouring cells, through a variety of pathways, to sense changes in environmental factors such as nutrient levels including glucose and lipids, oxygen levels, pH and pressure. The response mechanisms similarly involve a range of processes, including signalling pathways and the actions of specific organelles that initiate and regulate appropriate responses, including alterations in cell metabolism, immune regulation and changes in podocyte structure and cognate functions. These functions ultimately affect glomerular and kidney health. Imbalances in these processes can lead to inflammation, podocyte loss and glomerular disease.

A long-lasting rat model of hyperoxia-induced acute respiratory distress syndrome: Systematic evaluation and validation

Acute respiratory distress syndrome (ARDS) is an acute diffuse inflammatory lung injury with high morbidity and mortality. Existing animal models fail to replicate all features of human ARDS pathophysiology. This study aimed to establish a standardised protocol for creating a rat model of hyperoxia-induced ARDS, assess the model's compatibility with ARDS criteria, and evaluate its potential as a long-lasting research model. Thirty-six male Sprague-Dawley rats were exposed to a 95 % O2 environment. At 24, 48, and 72 h, physiological function, lung histopathology, alveolar-capillary barrier function, and inflammatory response of the model were assessed. Simultaneously, micro-CT was performed to observe lung injury progression and analyze radiomic features. Finally, assisted ventilation experiments were conducted to confirm the model's properties. After 48 h, the oxygenation index of rats significantly decreased (p < 0.0001), reaching mild-moderate ARDS level defined by Berlin criteria. Obvious histological changes occurred (p < 0.0001), with the formation of hyaline membranes, which are uncommon in small rodents. The permeability of the alveolar-capillary was significantly increased (p < 0.0001). The levels of TNF-α, IL-1β, and IL-6 were markedly elevated (p < 0.0001), indicating a strong inflammatory response. Micro-CT revealed diffuse lung injury, with increasing injury severity over prolonged hyperoxia exposure (p < 0.01). Radiomic features analysis revealed imaging changes analogous to those observed in ARDS patients. After 7 days of assisted ventilation experiments, model rats survived, and hypoxemia in the control group persisted. This study established a long-lasting rat model of hyperoxia-induced ARDS that aligns with the criteria for ARDS. The model is reproducible, controllable in severity, long-term stable, and non-resolution in injury. It is expected to serve as an important bridge connecting basic research and clinical translation, and offers a practicable preclinical platform for evaluating novel ventilatory strategies, anti-inflammatory/anti-fibrotic therapeutics, and other interventions.

The correlation study between post-surgery oxygen partial pressure level and prognosis of patients with sepsis during hospitalization

Sepsis remains a leading cause of mortality and healthcare burden, necessitating improved diagnostic and therapeutic strategies. Observational studies suggest that hyperoxemia may improve postoperative sepsis outcomes, but evidence remains limited. This study aims to explore the optimal range of oxygen partial pressure (PaO2) in postsurgical sepsis patients and its impact on prognosis. Clinical data of adult sepsis patients were extracted from the medical information mart for intensive care-IV database. Patients were categorized into control (PaO2 ≤ 100 mm Hg) and hyperoxemia (PaO2 > 100 mm Hg) groups. Primary outcome was 90-day mortality, while secondary outcomes included 1-year mortality, intensive care unit (ICU)/hospital length of stay, and invasive ventilation duration. Restricted cubic spline analysis stratified postsurgical PaO2 into normal (≤128.7 mm Hg), mild hyperoxemia (128.7-162.1 mm Hg), and severe hyperoxemia (≥162.1 mm Hg). Kaplan-Meier survival analysis and multivariate regression were conducted. Among 1220 patients, hyperoxemia patients were younger, had lower disease severity, and received more aggressive treatment. They had lower rates of acute respiratory failure and acute kidney injury. After cubic spline-based classification, mild hyperoxemia was associated with lower 90-day mortality (OR: 0.54, 95% CI: 0.34-0.86, P = .010), while severe hyperoxemia showed no significant effect (OR: 0.60, 95% CI: 0.30-1.20, P = .147). Kaplan-Meier curves demonstrated significantly improved long-term survival for mild hyperoxemia patients. Mild hyperoxemia in postsurgical sepsis patients is associated with reduced 90-day mortality, suggesting a potential optimal oxygenation range for better outcomes.

OTUD5 enhances activation of multiple cell death pathways and hyperoxia-induced lung injury by stabilizing TRAF4 and activating the p38/JNK pathway

OBJECTIVE

This study aims to elucidate the role of OTUD5 in hyperoxia-induced lung injury and to explore its potential as a therapeutic target for mitigating oxidative stress-related lung damage.

METHODS

AAV9-OTUD5 siRNA was administered via intratracheal injection in a mouse model to silence OTUD5 before exposure to 60 % O2 for 24 h. Lung tissues were analyzed using histological techniques (HE, Masson's, PAS staining) and quantified for collagen deposition and airway epithelial changes. Additionally, qPCR and WB analysisWB analysis assessed OTUD5 and TRAF4 expression levels. Co-immunoprecipitation and dual-immunofluorescence assays evaluated the interaction between OTUD5 and TRAF4. Apoptosis was measured via TUNEL staining and Cleaved-Caspase-3 expression analysis, while ROS levels were assessed using MitoSOX.

RESULTS

Silencing OTUD5 significantly reduced lung injury, evidenced by improved histological architecture and decreased collagen deposition. OTUD5 knockdown attenuated apoptosis markers and ROS production in BEAS-2B cells exposed to hyperoxia. Co-IP assays confirmed that OTUD5 stabilizes TRAF4, linking it to the activation of the p38/JNK signaling pathway. Furthermore, treatment with metformin and berberine chloride diminished the protective effects of OTUD5 knockdown in vivo.

CONCLUSION

OTUD5 plays a critical role in hyperoxia-induced lung injury through the regulation of TRAF4 stability and apoptotic pathways. Targeting OTUD5 may provide a novel therapeutic strategy to mitigate lung damage in conditions characterized by oxidative stress.

Creatine with guanidinoacetic acid improves prefrontal brain oxygenation before, during, and after a cognitive task: A randomized controlled pilot trial

Background: Preliminary studies suggest that creatine and guanidinoacetic acid (GAA) may function as moderate vasodilators, enhancing tissue oxygen saturation. However, the potential effects of this combination on brain oxygenation in humans remain unknown. Aim: The primary objective of this randomized controlled pilot trial was to assess cerebral blood oxygenation indices following a 7-day administration of a mixture containing creatine and GAA in healthy adults. Methods: Nineteen apparently healthy young adults (mean age 21.2 ± 0.4 years; 9 females) were randomly assigned to receive either a mixture (consisting of 2 g of creatine and 2 g of GAA) or a placebo in a crossover design. Oxygen saturation (SpO2) and hemoglobin index (tHb) in the prefrontal cortex were assessed at rest (REST), during meditation that focused on mindful breathing (MED), during a three-component cognitive task (TASK), and during a post-task recovery (REC) before and after 7 days of supplementation. Results: Two-way ANOVA with repeated measures revealed statistically significant differences (treatment vs. time interaction) between interventions for SpO2 during the REST (F = 5.733, P = 0.028), MED (F = 5.897, P = 0.026), and REC phases (F = 6.715, P = 0.018), indicating that the creatine-GAA mixture was more effective than placebo in enhancing oxygen saturation in the prefrontal brain both before, during, and after a cognitive task. Conclusion: These promising findings are of considerable interest for nutritional neuroscience but require validation through well-designed longitudinal trials with larger sample sizes. The study is registered at ClinicalTrials.gov (NCT06371651).

Automated control of inspired oxygen fraction in mechanically ventilated patients: A study protocol for a single-centre randomised controlled trial

BACKGROUND

A novel automated system for the control of the inspired fraction of oxygen, named LeoClac, has been implemented on a mechanical ventilator. The system uses a separate sensor for the measurement of peripheral oxygen saturation which is connected directly to the ventilator. We hypothesise that LeoClac will be superior to manual control in keeping critically ill and mechanically ventilated patients in a SpO2-target range (93-96%).

METHODS

This is a randomised controlled, single-centre superiority study with two parallel groups including 40 patients. Mechanically ventilated patients treated on the intensive care unit (ICU) will be screened for eligibility and included in the study after written informed consent. Patients in the intervention group will be treated with LeoClac. In the control group, FiO2 will be controlled manually by the intensive care team. The primary endpoint of the study is the proportion of time in the target zone for peripheral oxygen saturation within the first 24 hours following randomisation. Secondary endpoints include the analysis of hyperoxia and hypoxia, number of changes in FiO2, number and reasons for self-aborts and manual overrides of the automated system, proportion of time in target zone for peripheral oxygen saturation in the subgroups of patients with hypoxemic respiratory failure and acute hypercapnic respiratory failure. Furthermore, ventilator-free days and ICU mortality at day 28 will be analysed.

ANALYSIS

The precise control of FiO2 with the aim of avoiding both hyperoxia and hypoxia is a fundamental challenge in the highly technical field of mechanical ventilation. Incorporation of patient heterogeneity, the benefits of reduced manual intervention and the potential to optimise treatment outcomes underscore the importance of this research. By addressing the complexities of precise oxygen control in adults, this study contributes to the advancement of critical care practices and may improve patient outcomes.

ETHICS

The study protocol was approved by the ethics committee of the Christian-Albrechts-University Kiel, Germany, on 17 May 2023.

TRIAL REGISTRATION NUMBER

DRKS00032113.

Optimizing Flow-Controlled Ventilation: Impact of I:E Ratios and Oxygen Concentration in a Porcine Model of Total Airway Obstruction

BACKGROUND

Prehospital airway obstruction is a medical emergency requiring immediate intervention. When the insertion of a larger bore tube over an airway catheter is hindered by obstruction, flow-controlled ventilation (FCV) with expiratory ventilation assistance (EVA) may offer a solution by allowing for ventilation through the airway catheter. This method uses a continuous bidirectional flow, necessitating a high-pressure gas source, typically 100% oxygen. However, in prehospital or military settings, oxygen supplies and exact manual control may be limited. Therefore, evaluating FCV/EVA without 100% oxygen, and with variable inspiratory-to-expiratory (I:E) control is essential to ensure its feasibility in such environments. We hypothesized that arterial oxygenation with 21% oxygen would be feasible and would vary between different I:E ratios.

METHODS

In this randomized crossover trial, FCV/EVA with different I:E ratios and fraction of inspired oxygen were compared in total airway obstruction. 15 crossbred male specific pathogen-free swine, mean (standard deviation [SD]) weight 56.6 (2.1) kg were divided into groups; method A (n = 9) and method B (n = 6), anesthetized, muscle relaxed and desaturated <80%. FCV/EVA was performed for 15 minutes through an airway catheter in the obstructed airway.

RESULTS

In I:E 1:1 vs 1:2 with 21% oxygen, the mean difference of Sao2 was 33.8% (95% confidence interval [CI], 16.3-51.4, P =.0020) and Pao2 was 4.7 kPa (95% CI, 1.3-8.1, P =.0127). Paco2 decreased more in 1:1 than 1:1 with a pause and 1:2. Paco2 remained <5 kPa with small variability in 1:1 with 21% oxygen.

CONCLUSIONS

FCV/EVA with 21% oxygen was feasible and maintained oxygenation and ventilation for 15 minutes. An I:E ratio of 1:1 was superior to 1:2. This approach may offer a viable alternative in a totally obstructed airway in resource-limited settings where higher oxygen concentrations are unavailable.

Clinical Disorders in Cystic Fibrosis That Affect Emergency Procedures-A Case Report and Review

Cystic fibrosis (CF) is a multisystemic disease caused by a genetic defect, namely a mutation in the CFTR gene, that results in the production of an abnormal protein that regulates the flow of chloride ions through epithelial cells, leading to the dehydration of secreted mucus and changes in its biological properties. Chronic inflammation and recurrent respiratory infections progressively damage lung tissue, leading to respiratory and cardiorespiratory failure. This study aims to present a clinical case and explore the clinical changes in CF that may influence the provision of pre-hospital first aid. The study presents a case report of a 23-year-old CF patient undergoing evaluation for lung transplantation, infected with Pseudomonas aeruginosa and Staphylococcus aureus with the MSSA phenotype, and in a severe condition due to infectious exacerbation. Despite antibiotic treatment, the patient's condition deteriorated, leading to respiratory failure and cardiac arrest. Emergency measures were taken to maintain airway patency-the patient was sedated, intubated, and connected to a ventilator. CF involves systemic complications that, during exacerbations, may require urgent interventions. Cystic fibrosis is associated with multiple systemic complications, some of which may, during exacerbations, require emergency medical interventions. Providing care to this patient group involves specific procedures addressing the consequences of the underlying disease. Due to increasing survival rates and the emergence of new phenotypes, there is a need for the continuous education of medical personnel, including emergency responders, regarding the management of genetically determined diseases. This study underscores the importance of recognizing CF's complex nature and adapting emergency care accordingly to ensure timely and effective intervention in life-threatening situations.

OPTIMAL PAO 2 IS 130-160 MMHG IN THE FIRST WEEK FOR SEPSIS PATIENTS IN ICU: A RETROSPECTIVE COHORT STUDY BASED ON MIMIC-IV DATABASE

ABSTRACT

Background: The relationship between the partial pressure of oxygen in arterial blood (PaO 2 ) and the prognosis of sepsis patients, and its potential variation over time, remains unclear. The optimal PaO 2 range for sepsis patients has always been a contentious issue, with no consensus. We aimed to explore the association between different levels of PaO 2 exposure over time and the 28-day mortality of sepsis patients, and to identify the optimal PaO 2 range for sepsis patients within a specific time frame. Methods: We retrieved data on adult patients diagnosed with sepsis within 24 h before or after intensive care unit (ICU) admission from the Medical Information Mart for Intensive Care IV (MIMIC-IV, version 2.2) database. We excluded patients who were not admitted to the ICU for the first time, those with ICU stay <24 h, and those without PaO 2 results during their ICU stay. We calculated the time-weighted average (TWA) of PaO 2 and used piece-wise exponential additive mixed models (PAMMs) to estimate the time-dependent changes in the association between TWA-PaO 2 and patient prognosis. Results: A total of 16,880 sepsis patients were included in the MIMIC cohort. Results indicated that patients' TWA-PaO 2 correlates with increased 28-day mortality after ICU admission in sepsis patients, and this association was mainly manifested in the early course of the disease. With a time window of the first 1-7 days after ICU admission, the optimal TWA-PaO 2 range for sepsis patients was ≥130 mmHg and ≤160 mmHg. Increased exposure time, proportion of exposure time, and exposure dose of high-risk PaO 2 outside the range were all associated with an increased risk of 28-day mortality. Conclusion: PaO 2 in sepsis patients should be closely monitored. During the first 1-7 days of ICU admission, PaO 2 should be maintained within the range of ≥130 mmHg and ≤160 mmHg. A dose-dependent relationship exists between high-risk PaO 2 outside the range and patient outcome.

Oxygen Targets for Mechanically Ventilated Adults with Sepsis: Secondary Analysis of the PILOT Trial

Background: Patients with sepsis frequently require invasive mechanical ventilation. How oxygenation during mechanical ventilation affects clinical outcomes for patients with sepsis remains uncertain. Research Question: To evaluate the effects of different oxygen saturation targets on clinical outcomes for patients with sepsis receiving mechanical ventilation. Study Design and Methods: We performed a secondary analysis of the Pragmatic Investigation of optimaL Oxygen Targets (PILOT) trial dataset among patients who met criteria for sepsis by the Sepsis-3 definition at the time of enrollment. We compared patients randomized to a lower oxygen saturation target (90%; range, 88-92%), an intermediate target (94%; range, 92-96%), and a higher target (98%; range, 96-100%) with regard to the outcomes of 28-day in-hospital mortality and ventilator-free days to study day 28. Results: Of 2541 patients in the PILOT dataset, 805 patients with sepsis were included in the current analysis. In-hospital mortality by day 28 did not differ significantly between the lower target group (48%; 95% confidence interval [CI], 42% to 54%), the intermediate target group (50%; 95% CI, 43% to 56%), and the higher target group (51%; 95% CI, 45% to 56%) (P = 0.83). The number of ventilator-free days to day 28 did not significantly differ between the trial groups, with a mean of 9.9 (standard deviation [SD], 11.8) in the lower oxygen saturation target group, 9.5 (SD, 11.2) in the intermediate group, and 9.4 (SD, 11.4) in the higher group (P = 0.65). Interpretation: Among mechanically ventilated patients with sepsis in a large, randomized trial, the incidence of 28-day in-hospital mortality was not statistically significantly different between the use of a lower, intermediate, or higher oxygen target. However, the confidence intervals included treatment effects that would be clinically meaningfully and further randomized trials of oxygen targets in sepsis are required. Referenced trial name Pragmatic Investigation of optimaL Oxygen Targets Trial (PILOT) ClinicalTrials.gov number NCT03537937URL: https://clinicaltrials.gov/study/NCT03537937.

Targeting hypoxia-related pathobiology in Alzheimer's disease: strategies for prevention and treatment

INTRODUCTION

Alzheimer's Disease (AD) is a neurodegenerative condition characterised by cognitive decline and memory impairment. Recent research highlights the important role of hypoxia, a state of insufficient oxygen availability, in exacerbating AD pathogenesis.

MATERIALS AND METHODS

Through the use of a number of different search engines like Scopus, PubMed, Bentham, and Elsevier databases, a literature review was carried out for investigating the role of hypoxia mediated pathobiology in AD. Only peerreviewed articles published in reputable journals in English language were included. Conversely, non-peer-reviewed articles, conference abstracts, and editorials were excluded, along with studies lacking experimental or clinical relevance or those unavailable in full text.

CONCLUSION

Hypoxia exacerbates core pathological features such as oxidative stress, neuroinflammation, mitochondrial dysfunction, amyloid-beta (Aβ) dysregulation, and hyperphosphorylation of tau protein. These interlinked mechanisms establish a self-perpetuating cycle of neuronal damage, accelerating disease progression. Addressing hypoxia as a modifiable risk factor offers potential for both prevention and treatment of AD. Exploring hypoxia and the HIF signalling pathway may help counteract the neuropathological and symptomatic effects of neurodegeneration.

Neurological outcomes and mortality following hyperoxemia in adult patients with acute brain injury: an updated meta-analysis and meta-regression

BACKGROUND

The aim of this study was to evaluate the association of arterial hyperoxemia with neurological outcomes and mortality in adults with acute brain injury (ABI).

METHODS

Six electronic databases, including MEDLINE, Embase and online registers of clinical trials, were systematically searched from inception to June 1 st, 2024. Studies comparing the effects of hyperoxemia versus no hyperoxemia on outcomes of hospitalized adult patients with ABI-related conditions (e.g. traumatic brain injury, post-cardiac arrest, subarachnoid hemorrhage, intracerebral hemorrhage, and ischemic stroke) were included according to PRISMA guidelines. Data were pooled using a random-effects model for unadjusted and covariate-adjusted odds ratios. The primary outcome was poor neurological outcome as defined by each individual study, and the secondary outcome was all-cause mortality. Subgroup analyses were conducted based on principal diagnosis, timing of outcome measures, oxygenation thresholds, among other factors. Meta-regression was applied to identify sources of heterogeneity.

RESULTS

After 7,849 nonduplicated records were screened, 66 studies fulfilled eligibility criteria for systematic review. The meta-analysis including 24 studies (16,635 patients) revealed that patients with hyperoxemia are 1.29 times more likely to develop poor neurological outcomes (unadjusted OR, 1.295; 95% Confidence Interval, CI 1.040-1.616) compared with those with no hyperoxemia, particularly in subarachnoid hemorrhage and ischemic stroke subgroups. The meta-analysis including 35 studies (98,207 patients) revealed that all-cause mortality is 1.13 times more likely (OR 1.13; 95% CI 1.002-1.282) in patients with hyperoxemia compared with no hyperoxemia.

CONCLUSIONS

In our study we found that hyperoxemia is significantly associated with an increased risk of poor neurological outcomes and mortality in patients with acute brain injury compared to those with no hyperoxemia. Our results suggest the importance of carefully adjusting oxygenation strategies in neurocritical ICUs.

Mechanisms of impaired alveolar fluid clearance

Impaired alveolar fluid clearance (AFC) is an important cause of alveolar edema fluid accumulation in patients with acute respiratory distress syndrome (ARDS). Alveolar edema leads to insufficient gas exchange and worse clinical outcomes. Thus, it is important to understand the pathophysiology of impaired AFC in order to develop new therapies for ARDS. Over the last few decades, multiple experimental studies have been done to understand the molecular, cellular, and physiological mechanisms that regulate AFC in the normal and the injured lung. This review provides a review of AFC in the normal lung, focuses on the mechanisms of impaired AFC, and then outlines the regulation of AFC. Finally, we summarize ongoing challenges and possible future research that may offer promising therapies for ARDS.

Recent Advances in Prehospital and In-Hospital Management of Patients with Severe Trauma

Background: Trauma is a major global public health concern. Many countries are working to reduce preventable deaths; however, the mortality rate remains higher than their goal, indicating a need for continuous development in trauma care, including further improvements across the system. This article explores recent developments and updated guidelines for both prehospital emergency care and in-hospital trauma management, emphasizing evidence-based and patient-centered approaches. Current concepts: In the prehospital phase, the primary focus is on early and aggressive hemorrhage control using techniques such as tourniquet application, wound packing, and permissive hypotension as standard practices. Advancements in this field, including intraosseous vascular access and tranexamic acid administration, have improved patient outcomes. The emphasis on structured assessments, particularly "circulation, airway, breathing" (CAB) assessments, underscores the importance of managing life-threatening hemorrhages. During the in-hospital phase, the primary focus is on controlling bleeding. Protocols emphasize the judicious administration of fluids to prevent over-resuscitation and mitigate the risk of exacerbating coagulopathy. Efficient transfusion strategies are implemented to address hypovolemia, while ensuring balanced ratios of blood products. Furthermore, the implementation of advanced interfacility transfer systems and communication tools such as "Situation, Background, Assessment, Recommendation" (SBAR) plays a pivotal role in optimizing patient care and reducing delays in definitive treatment. Discussion and Conclusions: This review highlights the importance of implementing advanced strategies to align with international standards and further decrease the rate of preventable trauma-related deaths. Strengthening education and optimizing resource allocation for both prehospital and hospital-based trauma care are essential steps toward achieving these objectives.

Oxidative stress in trauma patients receiving a restrictive or liberal oxygen strategy - A sub-study of the TRAUMOX2 trial

INTRODUCTION

A liberal supplemental oxygen approach is recommended for all severely injured trauma patients despite limited evidence. Liberal oxygen administration may cause oxidative stress. The aim of this study was to investigate the effect of an early restrictive oxygen strategy versus a liberal oxygen strategy in adult trauma patients on biomarkers of oxidative stress within 48 h of hospital admission.

MATERIALS AND METHODS

This was a single-centre, sub-study of an international, randomised controlled trial TRAUMOX2. In TRAUMOX2, patients were randomised shortly after trauma to a restrictive oxygen strategy (arterial oxygen saturation target of 94 %) or a liberal oxygen strategy (12-15 L of oxygen per minute or fraction of inspired oxygen of 0.6-1.0) for 8 h. Blood samplings were performed at four time points within 48 h after randomisation: upon arrival at the trauma centre, and at eight, 24, and 48 h post-randomisation. The primary outcome was the plasma level of malondialdehyde (MDA) 24 h post-randomisation. Secondary outcomes were numerous, and included the level of MDA at other time points, superoxide dismutase (SOD) at all time points, 30-day mortality, and major respiratory complications.

RESULTS

The sub-study included 90 adult trauma patients. The median MDA levels at 24 h post-randomisation was 60.9 μM (95 % CI 49.5 to 73.4) in the restrictive oxygen group and 56.7 μM (95 % CI 46.9 to 68.2) in the liberal oxygen group, corresponding to a difference of -4.2 μM (95 % CI -19.8 to 10.5; P = 0.35). No significant differences were found in MDA or SOD at the other time points either. Neither did we find a significant difference in 30-day mortality or major respiratory complications.

CONCLUSIONS

In this sub-study of the TRAUMOX2 trial, no significant differences were found in biomarkers of oxidative stress between a restrictive oxygen strategy and liberal oxygen strategy in adult trauma patients.

Lower or Higher Oxygenation Targets in Patients With COVID-19 in the ICU: A Secondary Bayesian Analysis of the Handling Oxygenation Targets in COVID-19 Trial

BACKGROUND

In the Handling Oxygenation Targets in COVID-19 (HOT-COVID) trial, a Pao2 target of 60 mm Hg compared with 90 mm Hg resulted in more days alive without life support at 90 days in adults in the ICU with COVID-19 and hypoxemia. The trial was stopped after enrolling 726 of 780 planned patients because of slow recruitment. Herein, we present the preplanned Bayesian analysis of the HOT-COVID trial.

RESEARCH QUESTION

What are the probabilities of any benefits and of clinically relevant benefits resulting from a Pao2 target of 60 mm Hg vs 90 mm Hg in adult patients with COVID-19 and hypoxemia in the ICU and does heterogeneity of treatment effects (HTE) exist according to selected baseline characteristics?

STUDY DESIGN AND METHODS

We analyzed days alive without life support and 90-day mortality in the HOT-COVID intention-to-treat population (n = 697) using Bayesian general linear models to assess probabilities for benefit or harm, including clinically relevant benefits defined as > 1 day alive without life support and > 2 percentage points lower 90-day mortality. HTE was evaluated based on baseline Sequential Organ Failure Assessment scores, Pao2 to Fio2 ratio, norepinephrine doses, and lactate concentrations.

RESULTS

The mean difference in days alive without life support was 5.7 days (95% credible interval, 0.2-11.2), with a 95.2% probability of clinically relevant benefit and a 98.0% probability of any benefit from the lower Pao2 target. The risk difference in 90-day mortality was -4.6 percentage points (95% credible interval, -11.8 to 2.6 percentage points), with a 76.5% probability of a clinically relevant benefit from the lower target. HTE analyses revealed potential interaction with baseline norepinephrine dose and lactate concentrations for both outcomes.

INTERPRETATION

In patients with COVID-19 and hypoxemia in the ICU, we found a high probability for a clinically relevant benefit of targeting a Pao2 of 60 mm Hg vs 90 mm Hg on number of days alive without life support.

CLINICAL TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT04425031; URL: www.

CLINICALTRIALS

gov.

Effects of high vs. low perioperative inspired oxygen fraction on length of hospital stay and postoperative complications: a systematic review, meta-analysis, and trial sequential analysis

INTRODUCTION

Prolonged length of hospital stay (LOS) and postoperative complications in surgical patients are major public health issues worldwide. Perioperative hyperoxia may increase LOS, and the incidence of cardiac, cerebral, renal, and pulmonary injury; however, the supporting clinical evidence is controversial. Therefore, the current meta-analysis included all relevant randomized controlled trials (RCTs) to investigate the effect of high and low inspired oxygen fraction (FiO2) on LOS, according to postoperative complications.

EVIDENCE ACQUISITION

Standard published RCTs were searched from bibliographic databases to identify all evidence reporting perioperative FiO2 for patients undergoing surgeries. The primary outcome was LOS, and the secondary outcomes were postoperative organ complications, surgical site infection (SSI), and postoperative mortality. The relative risk (RR) and Peto-odds ratio (Peto-OR) for dichotomous outcomes and the mean difference (MD) and standardized mean difference (SMD) for continuous outcomes were estimated using a random-effects model. Trial sequential analysis (TSA) was performed in the meta-analysis to evaluate the required information sizes and assess whether the primary outcome in our meta-analysis was conclusive.

EVIDENCE SYNTHESIS

Thirty-one RCTs with 10506 participants undergoing different surgeries were included. The LOS in the high FiO2 group did not differ significantly from that in the low FiO2 group (MD -0.01, 95% CI -0.10 to 0.08, P=0.81). Moreover, we found no meaningful evidence of subgroup differences in the primary outcome, in comparisons of FiO2, RCT type, surgery type, duration of oxygen inhalation or timing of oxygen inhalation. TSA results further suggested that the number of included studies was sufficient for the primary outcome. There was also no significant difference in postoperative organ complications (cardiac, cerebral, renal, and pulmonary), SSI (rate of SSI, ASEPSIS score, and ASEPSIS score > 20 cases), or postoperative mortality. For postoperative atelectasis, sensitivity analysis showed that after exclusion of one study, "Myles 2007," high FiO2 was associated with increased postoperative atelectasis.

CONCLUSIONS

The use of low FiO2 has no effect on LOS, or the incidence of cardiac, cerebral, and renal injury or postoperative mortality. Compared with low FiO2, high FiO2 did not reduce SSI which was contrary to the guidelines. Meanwhile, high FiO2 may increase postoperative atelectasis in surgical patients.

Perioperative oxygen administration for adults undergoing major noncardiac surgery: a narrative review

Perioperative oxygen administration, a topic under continuous research and debate in anesthesiology, strives to optimize tissue oxygenation while minimizing the risks associated with hyperoxia and hypoxia. This review provides a thorough overview of the current evidence on the application of perioperative oxygen in adult patients undergoing major noncardiac surgery. The review begins by describing the physiological reasoning for supplemental oxygen during the perioperative period and its potential benefits while also focusing on potential hyperoxia risks. This review critically appraises the existing literature on perioperative oxygen administration, encompassing recent clinical trials and meta-analyses, to elucidate its effect on postoperative results. Future research should concentrate on illuminating the optimal oxygen administration strategies to improve patient outcomes and fine-tune perioperative care protocols for adults undergoing major noncardiac surgery. By compiling and analyzing available evidence, this review aims to provide clinicians and researchers with comprehensive knowledge on the role of perioperative oxygen administration in major noncardiac surgery, ultimately guiding clinical practice and future research endeavors.

Heterogeneity of treatment effect: the case for individualising oxygen therapy in critically ill patients

Oxygen therapy is ubiquitous in critical illness but oxygenation targets to guide therapy remain controversial despite several large randomised controlled trials (RCTs). Findings from RCTs evaluating different approaches to oxygen therapy in critical illness present a confused picture for several reasons. Differences in both oxygen target measures (e.g. oxygen saturation or partial pressure) and the numerical thresholds used to define lower and higher targets complicate comparisons between trials. The duration of and adherence to oxygenation targets is also variable with consequent substantial variation in both the dose and the dose separation. Finally, heterogeneity of treatment effects (HTE) may also be a significant factor. HTE is defined as non-random variation in the benefit or harm of a treatment, in which the variation is associated with or attributable to patient characteristics. This narrative review aims to make the case that such heterogeneity is likely in relation to oxygen therapy for critically ill patients and that this has significant implications for the design and interpretation of trials of oxygen therapy in this context. HTE for oxygen therapy amongst critically ill patients may explain the contrasting results from different clinical trials of oxygen therapy. Individualised oxygen therapy may overcome this challenge, and future studies should incorporate ways to evaluate this approach.

The role of NLRP3 inflammasome-mediated pyroptosis in astrocytes during hyperoxia-induced brain injury

BACKGROUND

Hyperoxia-induced brain injury is a severe neurological complication that is often accompanied by adverse long-term prognosis. The pathogenesis of hyperoxia-induced brain injury is highly complex, with neuroinflammation playing a crucial role. The activation of the nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome, which plays a pivotal role in regulating and amplifying the inflammatory response, is the pathological core of hyperoxia-induced brain injury. Additionally, astrocytes actively participate in neuroinflammatory responses. However, there is currently no comprehensive overview summarizing the role of astrocytes in hyperoxia-induced brain injury and the NLRP3 signaling pathways in astrocytes.

OBJECTIVE

This article aims to provide an overview of studies reported in the literature investigating the pathological role of astrocyte involvement during the inflammatory response in hyperoxia-induced brain injury, the mechanisms of hyperoxia activateing the NLRP3 inflammasome to mediate pyroptosis in astrocytes, and the potential therapeutic effects of drugs targeting the NLRP3 inflammasome to alleviate hyperoxia-induced brain injury.

METHOD

We searched major databases (including PubMed, Web of Science, and Google Scholar, etc.) for literature encompassing astrocytes, NLRP3 inflammasome, and pyroptosis during hyperoxia-induced brain injury up to Oct 2024. We combined with studies found in the reference lists of the included studies.

CONCLUSION

In this study, we elucidated the transition of function in astrocytes and activation mechanisms under hyperoxic conditions, and we summarized the potential upstream of the trigger involved in NLRP3 inflammasome activation during hyperoxia-induced brain injury, such as ROS and potassium efflux. Furthermore, we described the signaling pathways of the NLRP3 inflammasome and pyroptosis executed by GSDMD and GSDME in astrocytes under hyperoxic conditions. Finally, we summarized the inhibitors targeting the NLRP3 inflammasome in astrocytes to provide new insights for treating hyperoxia-induced brain injury.

Dose-dependent association of hyperoxia and decreased favorable outcomes in mechanically ventilated patients with traumatic brain injury, a retrospective cohort study

PURPOSE

In patients with traumatic brain injury (TBI), adequate oxygenation is crucial to optimize survival and neurological outcome. However, supranormal oxygen partial pressure (PaO2) only leads to minor increase in cerebral oxygen delivery but can cause numerous pathophysiological disturbances. Therefore, we aimed to study effects of hyperoxia on patient outcome and identify optimum PaO2 ranges.

METHODS

This retrospective, single-center cohort study included TBI patients receiving mechanical ventilation for ≥ 72 h. Time-weighted mean PaO2 and integrals above thresholds of 80, 100, 120, and 150 mmHg were calculated over periods of 1, 3, 7, and 14 days. The effects on in-hospital mortality and favorable functional outcome defined as Glasgow Outcome Scale (GOS) ≥ 4 were explored at discharge and after 3-6 months.

RESULTS

From 01/2013 until 12/2021, 290 patients fulfilled the inclusion criteria. Hyperoxia was dose-dependently associated with a worsened functional outcome 3-6 months post-injury. Regarding the first 24 h, odds ratios were 0.959 (95% confidence intervals: 0.932-0.990; p = 0.009) for time-weighted mean PaO2 and 0.955 (0.923-0.988; p = 0.008), 0.939 (0.897-0.982; p = 0.006), 0.923 (0.871-0.978; p = 0.007) and 0.922 (0.858-0.992; p = 0.029) per mmHg above 80, 100, 120 and 150 mmHg, respectively. For exposure within 72 h, odds ratios were 0.897 (0.819-0.983; p = 0.020), 0.842 (0.738-0.961; p = 0.011) and 0.832 (0.705-0.981; p = 0.029) per mmHg per day over 100, 120 and 150 mmHg, respectively. No significant association could be established between PaO2-exposure and in-hospital mortality, GOS at discharge or the 7- and 14-day periods.

CONCLUSION

In this cohort, hyperoxia within 72 h after admission was dose-dependently associated with an unfavorable neurological outcome after 3-6 months.

Material-independent film formation and autonomous degradation of Cu2+-tetrahydroxy-1,4-benzoquinone metal-organic complexes

Metal-organic complexes (MOCs) have extensively been studied as prominent components in interface engineering. Once the designated missions of MOC films are achieved, or while they are still operational, it is preferred that the films undergo degradation on demand in certain circumstances. Current research on MOC-film degradation predominantly relies on chemical treatment, which can alter the states and conditions of specific systems. This work utilizes tetrahydroxy-1,4-benzoquinone (THBQ), a redox-active organic ligand, for material-independent MOC film formation with Cu2+ ions, achieving automatic, self-adaptive degradation of Cu2+-THBQ MOC films upon exposure to air. The results provide a versatile platform for facilitating the spatiotemporal control of (bio)chemical actions in MOC-encapsulated systems, as well as advancing drug delivery systems and air-responsive sensors where variations in O2 levels are critical.

Hyperoxia and unfavourable outcome in patients with non-traumatic subarachnoid haemorrhage: A systematic review and meta-analysis

BACKGROUND

It is common practice to administer oxygen to neurocritical patients in the Intensive Care Unit (ICU). Consequent hyperoxia has been associated with unfavourable outcomes including in patients with brain injury, after cardiac arrest, sepsis, and traumatic brain injury. The aim of this systematic review was to explore the association between hyperoxia exposure and unfavourable outcome in patients following a non-traumatic subarachnoid haemorrhage (SAH).

METHODS

Systematic searches of Medline, Embase, Emcare, CINAHL and PubMed were performed in February 2024 using key words for SAH and hyperoxia. Non-human studies, articles in languages other than English, studies that did not measure blood oxygenation levels via pulse oximetry or arterial blood gas analyses, and studies exploring traumatic SAH were excluded. The Newcastle-Ottawa Risk of Bias tool (NOS) was used to assess the quality of included manuscripts. The primary outcome was a composite outcome combining mortality or poor functional neurological outcome. Secondary outcomes included mortality, poor functional neurological outcome, and development of delayed cerebral ischaemia (DCI).

RESULTS

The literature search yielded 1,219 non-duplicate articles published after 1 January 2000, of which 21 articles were reviewed as full-texts and nine were included in this review. All included studies were rated good/high quality using the NOS. Hyperoxia exposure was associated with increased risk of adverse composite outcome of death or unfavourable functional neurological outcome (odds ratio (OR) 1.61, 95% confidence interval (CI) 1.19-2.16), poor functional neurological outcome alone (OR 1.79, 95% CI 1.33-2.42) and development of DCI (OR 2.63, 95% CI 1.79-3.85). The association of hyperoxia and hospital mortality alone was not statistically significant (OR 1.42, 95% CI 0.98-2.04).

CONCLUSION

Hyperoxia may contribute to unfavourable outcomes and the development of DCI after an non-traumatic SAH. Trials using restrictive oxygen therapy among patients with SAH are indicated.

Clinicians' attitudes towards supplemental oxygen for trauma patients - A survey

INTRODUCTION

The Advanced Trauma Life Support guidelines (ATLS; 2018, 10th ed.) recommend an early and liberal supplemental oxygen for all severely injured trauma patients to prevent hypoxaemia. As of 2024, these guidelines remain the most current. This may lead to hyperoxaemia, which has been associated with increased mortality and respiratory complications. We aimed to investigate the attitudes among clinicians, defined as physicians and prehospital personnel, towards the use of supplemental oxygen in trauma cases.

MATERIALS AND METHODS

A European, web-based, cross-sectional survey was conducted consisting of 23 questions. The primary outcome was the question: "In your opinion, should all severely injured trauma patients always be given supplemental oxygen, regardless of arterial oxygen saturation measured by pulse oximetry?".

RESULTS

The survey was answered by 707 respondents, which corresponded to a response rate of 52 %. The respondents were predominantly male (76 %), with the largest representation from Denmark (82 %), and primarily educated as physicians (62 %). A majority of respondents (73 % [95 % CI: 70 to 76 %]) did not support that supplemental oxygen should always be provided to all severely injured trauma patients without consideration of their arterial oxygen saturation as measured by pulse oximetry (SpO2), with no significant difference between physicians and non-physicians (p = 0.08). Based on the respondents' preferred dosages, the median initial administered dosage of supplemental oxygen for spontaneously breathing trauma patients with a normal SpO2 in the first few hours after trauma was 0 (interquartile range [IQR] 0-3) litres per minute, with 58 % of respondents opting not to provide any supplemental oxygen. The lowest acceptable SpO2 goal in the first few hours after trauma was 94 % (IQR 92-95). In clinical scenarios with TBI, higher dosage of supplemental oxygen and fraction of inspired oxygen (FiO2) were preferred, as well as targeting partial pressure of oxygen in arterial blood as opposed to adjusting the FiO2 directly, compared to no TBI.

CONCLUSION

Almost three out of four clinicians did not support the administration of supplemental oxygen to all severely injured trauma patients, regardless of SpO2. This corresponds to a more restrictive approach than recommended in the current ATLS (2018, 10th ed.) guidelines.

Effects of Automated Versus Conventional Ventilation on Quality of Oxygenation-A Substudy of a Randomized Crossover Clinical Trial

Background/Objectives: Attaining adequate oxygenation in critically ill patients undergoing invasive ventilation necessitates intense monitoring through pulse oximetry (SpO2) and frequent manual adjustments of ventilator settings like the fraction of inspired oxygen (FiO2) and the level of positive end-expiratory pressure (PEEP). Our aim was to compare the quality of oxygenation with the use of automated ventilation provided by INTELLiVENT-Adaptive Support Ventilation (ASV) vs. ventilation that is not automated, i.e., conventional pressure-controlled or pressure support ventilation. Methods: A substudy within a randomized crossover clinical trial in critically ill patients under invasive ventilation. The primary endpoint was the percentage of breaths in an optimal oxygenation zone, defined by predetermined levels of SpO2, FiO2, and PEEP. Secondary endpoints were the percentage of breaths in acceptable or critical oxygenation zones, the percentage of time spent in optimal, acceptable, and critical oxygenation zones, the number of manual interventions at the ventilator, and the number and duration of ventilator alarms related to oxygenation. Results: Of the 96 patients included in the parent study, 53 were eligible for this current subanalysis. Among them, 31 patients were randomized to start with automated ventilation, while 22 patients began with conventional ventilation. No significant differences were found in the percentage of breaths within the optimal zone between the two ventilation modes (median percentage of breaths during automated ventilation 19.4 [0.1-99.9]% vs. 25.3 [0.0-100.0]%; p = 0.963). Similarly, there were no differences in the percentage of breaths within the acceptable and critical zones, nor in the time spent in the three predefined oxygenation zones. Although the number of manual interventions was lower with automated ventilation, the number and duration of ventilator alarms were fewer with conventional ventilation. Conclusions: The quality of oxygenation with automated ventilation is not different from that with conventional ventilation. However, while automated ventilation comes with fewer manual interventions at the ventilator, it also comes with more ventilator alarms.

CXCL4 deficiency limits M4 macrophage infiltration and attenuates hyperoxia-induced lung injury

BACKGROUND

Bronchopulmonary dysplasia (BPD), a chronic lung disease prevalent among premature infants, significantly impacts lifelong respiratory health. Macrophages, as key components of the innate immune system, play a role in lung tissue inflammation and injury, exhibiting diverse and dynamic functionalities. The M4 macrophage, a distinctive subtype primarily triggered by chemokine (C-X-C motif) ligand 4 (CXCL4), has been implicated in pulmonary inflammatory and fibrotic processes. Nonetheless, its contribution to the pathophysiology of BPD remains uncertain.

OBJECTIVE

This study aimed to elucidate the involvement of CXCL4 in hyperoxia-induced neonatal lung injury and fibrosis, with a particular focus on its influence on M4 macrophages.

METHODS

A BPD model in neonatal mice was established through continuous exposure to 95% O2 for 7 days. Comparative analyses of lung damage and subsequent regeneration were conducted between wild-type (WT) and CXCL4 knockout (KO) mice. Lung tissue inflammation and fibrosis were assessed using histological and immunofluorescence staining, enzyme-linked immunosorbent assay, Western blot, and real-time quantitative polymerase chain reaction. Differentiation of M0 and M4 macrophages was performed in vitro using macrophage colony-stimulating factor and CXCL4, while expressions of S100A8 and MMP7, along with migration assays, were evaluated.

RESULTS

Elevated CXCL4 levels and M4 macrophage activation were identified in the lung tissue of BPD model mice. CXCL4 deficiency conferred protection to alveolar type 2 epithelial cells, reduced sphingosine-1-phosphate metabolic activity, mitigated pulmonary fibrosis, and limited M4 macrophage progression. This deletion further enhanced lung matrix remodeling during recovery. In vitro, CXCL4 promoted M4 macrophage differentiation and increased macrophage migration via chemokine (C-C motif) receptor 1.

CONCLUSION

CXCL4 contributes to hyperoxia-induced lung injury and fibrosis through modulation of cytokine release, alveolar cell proliferation, lipid metabolism, and the regulation of macrophage phenotype and function.

Association Between Arterial Hyperoxia and Mortality in Pediatric and Adult Patients Undergoing Extracorporeal Membrane Oxygenation: A Systematic Review and Meta-Analysis

BACKGROUND

In patients receiving extracorporeal membrane oxygenation (ECMO) support, the association between arterial hyperoxia and outcomes is unclear. We performed a systematic review and meta-analysis to determine the association between arterial Po2 (Pao2) and mortality in patients with ECMO.

METHODS

The meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement and registered in International Prospective Register of Systematic Reviews (PROSPERO; CRD42023467361). We systematically searched PubMed and Embase databases up to September 2023 for randomized trials or observational studies that investigated the association between Pao2 and mortality in pediatric and adult patients receiving venovenous ECMO (VV-ECMO), venoarterial ECMO (VA-ECMO), and extracorporeal cardiopulmonary resuscitation (ECPR). The predefined outcome was 28-day mortality. We synthesized the data using a random-effects model, calculating odds ratios (OR) and corresponding 95% confidence intervals (CI).

RESULTS

Thirteen cohort studies (17,766 participants) were included. All studies used categorical Pao2 cutoff, with varying thresholds ranging from ≥100 mm Hg to ≥300 mm Hg. When compared with patients with normoxia, elevated Pao2 levels at all studied thresholds were consistently associated with increased mortality (≥300 mm Hg: OR 1.56, 95% CI, 1.31-1.85, P < .01; ≥200 mm Hg: OR 1.43, 95% CI, 1.10-1.87, P < .01; ≥150 mm Hg: OR 1.51, 95% CI, 1.15-1.98, P < .01; and ≥100 mm Hg: OR 1.44, 95% CI, 1.03-2.02, P = .03). A sensitivity analysis focusing on studies reporting adjusted OR yielded similar results. We observed this association in both adult and pediatric populations.

CONCLUSIONS

In critically ill patients on VV- or VA-ECMO, increased Pao2 values were associated with increased 28-day mortality in ECMO patients. Our results should be interpreted with caution given observational nature of included studies. Further randomized trials are warranted to validate these results.

The role of responsive MRI probes in the past and the future of molecular imaging

Magnetic resonance imaging (MRI) has become an indispensable tool in biomedical research and clinical radiology today. It enables the tracking of physiological changes noninvasively and allows imaging of specific biological processes at the molecular or cellular level. To this end, bioresponsive MRI probes can greatly contribute to improving the specificity of MRI, as well as significantly expanding the scope of its application. A large number of these sensor probes has been reported in the past two decades. Importantly, their development was done hand in hand with the ongoing advances in MRI, including emerging methodologies such as chemical exchange saturation transfer (CEST) or hyperpolarised MRI. Consequently, several approaches on successfully using these probes in functional imaging studies have been reported recently, giving new momentum to the field of molecular imaging, also the chemistry of MRI probes. This Perspective summarizes the major strategies in the development of bioresponsive MRI probes, highlights the major research directions within an individual group of probes (T 1- and T 2-weighted, CEST, fluorinated, hyperpolarised) and discusses the practical aspects that should be considered in designing the MRI sensors, up to their intended application in vivo.

Association Between Early Hyperoxemia Exposure and Intensive Care Unit Mortality in Intracerebral Hemorrhage: An Observational Cohort Analysis

BACKGROUND

Supraphysiologic levels of oxygen could have potential adverse effects on the brain that may be dose and time dependent in patients with brain injury. We therefore aimed to assess whether exposure to excess supplemental oxygen, measured as time-weighted mean exposure to hyperoxemia, was associated with intensive care unit (ICU) mortality in patients with intracerebral hemorrhage (ICH).

METHODS

In this single-center retrospective cohort study, we included all patients admitted to our ICU with a diagnosis of primary spontaneous ICH. To provide a longitudinal measure of hyperoxemia exposure, we calculated the hyperoxemia dose, defined as the area under the partial pressure of oxygen in arterial blood (PaO2) time curve above the threshold PaO2 value of 100 mm Hg (13.3 kPa) divided by the number of hours of potential exposure. To provide consistent potential exposure windows and limit bias from informative censoring, nested subsets were created with progressively longer exposure periods (0-1 day, 0-2 days, 0-3 days, 0-4 days, 0-5 days, 0-6 days, 0-7 days). We used multivariable Cox regression, with hyperoxemia dose as a time-dependent covariate, to model ICU mortality. Admission ICH and Acute Physiology and Chronic Health Evaluation II scores were included as predictor covariables. A step-function extended Cox model was also fitted.

RESULTS

Between September 2019 and July 2022, 275 patients met the inclusion criteria, with 24,588 arterial blood gas results available for analysis. The mean age was 57.19 years (± 13.99), 59.64% were male, 23.64% had an infratentorial origin of hemorrhage, and ICU mortality was 35.64%. Almost all patients (97.45%) were exposed to hyperoxemia during their ICU admission. Cox regression modeling showed an association between hyperoxemia dose and ICU mortality (hazard ratio 1.15, confidence interval 1.05-1.25, p = 0.003). This association was observed in the 0-1 day subset in the step-function extended Cox model (hazard ratio 1.19, confidence interval 1.06-1.35, p = 0.005) but not in any of the subsequent exposure periods.

CONCLUSIONS

In patients with ICH admitted to the ICU, we observed an association between hyperoxemia dose and ICU mortality. Further prospective study is required to inform guidance on early systemic oxygen targets in ICH.

Ventilation and Oxygenation During and After Adult Cardiopulmonary Resuscitation: Changing Paradigms

Cardiac arrest (CA) remains a major cause of death despite advancements in cardiopulmonary resuscitation (CPR), post-resuscitation care, and international efforts to develop evidence-based guidelines. Effectively managing ventilation and oxygenation during and after CPR is vital for patient survival and neurological outcomes, yet it remains a challenging task. This review examines current strategies for ventilation and oxygenation during and after CPR, focusing on evidence-based guidelines, the balance between ventilation effectiveness and risks, and proposed methods for monitoring ventilation quality. It emphasizes the need to provide adequate ventilation and oxygenation during and after CPR while avoiding hyperventilation and hypoventilation, which can negatively impact resuscitation and post-CA outcomes. The review also explores mechanical ventilation as an alternative to manual methods and the use of feedback devices. The impact of post-CA ventilation and oxygenation on patient outcomes and recommended management strategies are discussed. Finally, the review highlights current gaps in the literature and the need for more well-designed large clinical studies, such as the impact of different ventilation variables (tidal volume and breathing frequency) on the return of spontaneous circulation and long-term outcomes.

Hyperoxia can Induce Lung Injury by Upregulating AECII Autophagy and Apoptosis Via the mTOR Pathway

Oxygen therapy is a crucial medical intervention, but it is undeniable that it can lead to lung damage. The mTOR pathway plays a pivotal role in governing cell survival, including autophagy and apoptosis, two phenomena deeply entwined with the evolution of diseases. However, it is unclarified whether the mTOR pathway is involved in hyperoxic acute lung injury (HALI). The current study aims to clarify the molecular mechanism underlying the pathogenesis of HALI by constructing in vitro and in vivo models using H2O2 and hyperoxia exposure, respectively. To investigate the role of mTOR, the experiment was divided into five groups, including normal group, injury group, mTOR inhibitor group, mTOR activator group, and DMSO control group. Western blotting, Autophagy double labeling, TUNEL staining, and HE staining were applied to evaluate protein expression, autophagy activity, cell apoptosis, and pathological changes in lung tissues. Our data revealed that hyperoxia can induce autophagy and apoptosis in Type II alveolar epithelial cell (AECII) isolated from the treated rats, as well as injuries in the rat lung tissues; also, H2O2 stimulation increased autophagy and apoptosis in MLE-12 cells. Noticeably, the experiments performed in both in vitro and in vivo models proved that the mTOR inhibitor Rapamycin (Rapa) functioned synergistically with hyperoxia or H2O2 to promote AECII autophagy, which led to increased apoptosis and exacerbated lung injury. On the contrary, activation of mTOR with MHY1485 suppressed autophagy activity, consequently resulting in reduced apoptosis and lung injury in H2O2-challenged MLE-12 cells and hyperoxia-exposed rats. In conclusion, hyperoxia caused lung injury via mTOR-mediated AECII autophagy.

Acute respiratory distress syndrome

The understanding of acute respiratory distress syndrome (ARDS) has evolved greatly since it was first described in a 1967 case series, with several subsequent updates to the definition of the syndrome. Basic science advances and clinical trials have provided insight into the mechanisms of lung injury in ARDS and led to reduced mortality through comprehensive critical care interventions. This review summarizes the current understanding of the epidemiology, pathophysiology, and management of ARDS. Key highlights include a recommended new global definition of ARDS and updated guidelines for managing ARDS on a backbone of established interventions such as low tidal volume ventilation, prone positioning, and a conservative fluid strategy. Future priorities for investigation of ARDS are also highlighted.

Hemoglobin-oxygen affinity changes in neonatal blood transfusions: RBC selection insights

BACKGROUND

Despite preterm newborns often requiring blood transfusions, we have an incomplete understanding of the impact of adult packed red blood cell (pRBC) transfusions on fetal red blood cell (RBC) oxygen affinity. We investigated the influence of adult pRBC on oxygen binding in fetal RBCs obtained from the umbilical cord of preterm newborns. This included exploring the influence of the biological age of adult pRBCs on the oxygen affinity of fetal blood.

METHODS

Cord blood samples from preterm infants were titrated with young (Y-RBC) and old (O-RBC) adult pRBCs using an in vitro transfusion model. Parameters, including oxygen affinity (p50), hemoglobin variants, and red blood cell indices, were measured.

RESULTS

The titration of cord blood with adult pRBCs (n = 19) resulted in a concentration-dependent decrease in p50, indicating an increased oxygen affinity. Hemoglobin variant analysis revealed a shift in composition, with a decrease in fetal hemoglobin (HbF) and an increase in adult hemoglobin (HbA) following titration.

CONCLUSION

The impact of biological age was evident, as O-RBCs had a more pronounced effect on p50 values compared to Y-RBCs. Understanding the physiologic implications of transfusing preterm infants with adult pRBCs is important for optimizing transfusion practices in newborns.

IMPACT

In an in vitro model, titrating adult pRBC into fetal blood significantly affects oxygen binding Oxygen affinity of fetal blood is significantly increased after titration of adult pRBC. Compared to older RBC subpopulations of adult pRBC, oxygen-binding properties of younger RBC subpopulations of adult pRBC more closely approximate the oxygen affinity of fetal blood. This work highlights the importance of investigating the influence of adult pRBC transfusion on fetal RBC oxygen binding. This may have implications for morbidities in the newborn period related to oxygen physiology.

Effects of Oxygenation Targets on Mortality in Critically Ill Patients in Intensive Care Units: A Systematic Review and Meta-Analysis

BACKGROUND

The effects of oxygenation targets (partial pressure of arterial oxygen [Pa o2 ], arterial oxygen saturation [Sa o2 ]/peripheral oxygen saturation [Sp o2 ], or inspiratory oxygen concentration [Fi o2 ] on clinical outcomes in critically ill patients remains controversial. We reviewed the existing literature to assess the effects of lower and higher oxygenation targets on the mortality rates of critically ill intensive care unit (ICU) patients.

METHODS

MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Web of Science databases were searched from their dates of inception to December 31, 2022, for randomized controlled trials (RCTs) comparing lower and higher oxygenation targets for critically ill patients ≥18 years of age undergoing mechanical ventilation, nasal cannula, oxygen mask, or high-flow oxygen therapy in the ICU. Data extraction was conducted independently, and RoB 2.0 software was used to evaluate the quality of each RCT. A random-effects model was used for the meta-analysis to calculate the relative risk (RR). We used the I 2 statistic as a measure of statistical heterogeneity. Certainty of evidence was assessed according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines.

RESULTS

We included 12 studies with a total of 7416 patients participating in RCTs. Oxygenation targets were extremely heterogeneous between studies. The meta-analysis found no differences in mortality between lower and higher oxygenation targets for critically ill ICU patients (relative risk [RR], 1.00; 95% confidence interval [CI], 0.93-1.09; moderate certainty). The incidence of serious adverse events (RR, 0.93; 95% CI, 0.85-1.00; high certainty), mechanical ventilation-free days through day 28 (mean difference [MD], -0.05; 95%CI, -1.23 to 1.13; low certainty), the number of patients requiring renal replacement therapy (RRT) (RR, 0.96; 95% CI, 0.84-1.10; low certainty), and ICU length of stay (MD, 1.05; 95% CI, -0.04 to 2.13; very low certainty) also did not differ among patients with lower or higher oxygenation targets.

CONCLUSIONS

Critically ill ICU patients ≥18 years of age managed with lower and higher oxygenation targets did not differ in terms of mortality, RRT need, mechanical ventilation-free days through day 28, or ICU length of stay. However, due to considerable heterogeneity between specific targets in individual studies, no conclusion can be drawn regarding the effect of oxygenation targets on ICU outcomes.

Hyperbaric Treatment Stimulates Chaperone-Mediated Macroautophagy and Autophagy in the Liver Cells of Healthy Female Rats

The role of autophagy goes far beyond the elimination of damaged cellular components and the quality control of proteins. It also cleanses cells from inclusions, including pathogenic viruses, and provides energy-forming components. The liver, which is an organ with increased metabolism, is made up of cells that are particularly vulnerable to damage. Therefore, detoxification of liver cells in the process of autophagy has become a very important issue clinically. The aim of this study was an immunohistochemical evaluation of proteins activated in rat liver cells at different stages of hyperbaric autophagy. The rats used for the study were randomly divided into six equivalent groups-three control groups and three experimental groups. Animals from the experimental groups were subjected to hyperbaric treatment in a hyperbaric chamber, with a pressure of 1.6 ATA for 120 min. They breathed atmospheric air. Rats were decapitated within 5 or 10 days after removal from the chamber. Immunohistochemical reactions with beclin 1, LC3B, RAB7, and HSC73 proteins were carried out on preparations made from liver slices. A three-step labeled streptavidin-biotin detection method of paraffin blocks (LSAB three-step) was used for immunohistochemical research. The results were evaluated using computer programs for morphometric analysis of microscopic images by calculating the mean surface areas occupied by a positive immunohistochemical reaction in individual groups for all antibodies tested. Increased closure of substrates in the autophagosome (beclin 1) induced late endosome transport and accelerated autophagosome maturation process (RAB7). Furthermore, a larger number of autophagosomes (LC3B) was observed in liver cells immediately after the cessation of hyperbaric activity; however, this decreased after 5 days. During this time, chaperone-mediated autophagy (HSC73) was observed on a larger scale. This means that increased macroautophagy induced by hyperbaric treatment weakens with time that has elapsed since the cessation of high pressure, whereas similarly induced chaperone-mediated autophagy intensifies over time.

Closed-loop oxygen usage during invasive mechanical ventilation of pediatric patients (CLOUDIMPP): a randomized controlled cross-over study

Background

The aim of this study is the evaluation of a closed-loop oxygen control system in pediatric patients undergoing invasive mechanical ventilation (IMV).

Methods

Cross-over, multicenter, randomized, single-blind clinical trial. Patients between the ages of 1 month and 18 years who were undergoing IMV therapy for acute hypoxemic respiratory failure (AHRF) were assigned at random to either begin with a 2-hour period of closed-loop oxygen control or manual oxygen titrations. By using closed-loop oxygen control, the patients' SpO2 levels were maintained within a predetermined target range by the automated adjustment of the FiO2. During the manual oxygen titration phase of the trial, healthcare professionals at the bedside made manual changes to the FiO2, while maintaining the same target range for SpO2. Following either period, the patient transitioned to the alternative therapy. The outcomes were the percentage of time spent in predefined SpO2 ranges ±2% (primary), FiO2, total oxygen use, and the number of manual adjustments.

Findings

The median age of included 33 patients was 17 (13-55.5) months. In contrast to manual oxygen titrations, patients spent a greater proportion of time within a predefined optimal SpO2 range when the closed-loop oxygen controller was enabled (95.7% [IQR 92.1-100%] vs. 65.6% [IQR 41.6-82.5%]), mean difference 33.4% [95%-CI 24.5-42%]; P < 0.001). Median FiO2 was lower (32.1% [IQR 23.9-54.1%] vs. 40.6% [IQR 31.1-62.8%]; P < 0.001) similar to total oxygen use (19.8 L/h [IQR 4.6-64.8] vs. 39.4 L/h [IQR 16.8-79]; P < 0.001); however, median SpO2/FiO2 was higher (329.4 [IQR 180-411.1] vs. 246.7 [IQR 151.1-320.5]; P < 0.001) with closed-loop oxygen control. With closed-loop oxygen control, the median number of manual adjustments reduced (0.0 [IQR 0.0-0.0] vs. 1 [IQR 0.0-2.2]; P < 0.001).

Conclusion

Closed-loop oxygen control enhances oxygen therapy in pediatric patients undergoing IMV for AHRF, potentially leading to more efficient utilization of oxygen. This technology also decreases the necessity for manual adjustments, which could reduce the workloads of healthcare providers.

Clinical Trial Registration

This research has been submitted to ClinicalTrials.gov (NCT05714527).

Oxygen therapy in acute hypoxemic respiratory failure: guidelines from the SRLF-SFMU consensus conference

INTRODUCTION

Although largely used, the place of oxygen therapy and its devices in patients with acute hypoxemic respiratory failure (ARF) deserves to be clarified. The French Intensive Care Society (Société de Réanimation de Langue Française, SRLF) and the French Emergency Medicine Society (Société Française de Médecine d'Urgence, SFMU) organized a consensus conference on oxygen therapy in ARF (excluding acute cardiogenic pulmonary oedema and hypercapnic exacerbation of chronic obstructive diseases) in December 2023.

METHODS

A committee without any conflict of interest (CoI) with the subject defined 7 generic questions and drew up a list of sub questions according to the population, intervention, comparison and outcomes (PICO) model. An independent work group reviewed the literature using predefined keywords. The quality of the data was assessed using the GRADE methodology. Fifteen experts in the field from both societies proposed their own answers in a public session and answered questions from the jury (a panel of 16 critical-care and emergency medicine physicians, nurses and physiotherapists without any CoI) and the public. The jury then met alone for 48 h to write its recommendations.

RESULTS

The jury provided 22 statements answering 11 questions: in patients with ARF (1) What are the criteria for initiating oxygen therapy? (2) What are the targets of oxygen saturation? (3) What is the role of blood gas analysis? (4) When should an arterial catheter be inserted? (5) Should standard oxygen therapy, high-flow nasal cannula oxygen therapy (HFNC) or continuous positive airway pressure (CPAP) be preferred? (6) What are the indications for non-invasive ventilation (NIV)? (7) What are the indications for invasive mechanical ventilation? (8) Should awake prone position be used? (9) What is the role of physiotherapy? (10) Which criteria necessarily lead to ICU admission? (11) Which oxygenation device should be preferred for patients for whom a do-not-intubate decision has been made?

CONCLUSION

These recommendations should optimize the use of oxygen during ARF.

Is Obstructive Sleep Apnea Associated with Higher Covid-19 Severity?

Objective  To investigate the associations between obstructive sleep apnea (OSA) and coronavirus disease 2019 (COVID-19) severity. Methods  Twelve individuals hospitalized in a Brazilian tertiary hospital diagnosed with COVID-19 by reverse transcriptase-polymerase chain reaction (RT-PCR) underwent respiratory polygraphy. Results  Polygraphic records identified seven participants without obstructive sleep apnea (OSA) (OSA-) and five with OSA (OSA + ). The OSA+ group presented worse peripheral oxygen saturation (77.6% ± 7.89%) than the OSA- group (84.4% ± 2.57%) ( p  = 0.041). Additionally, the OSA+ group showed greater COVID-19 severity (100%) than the OSA- group (28.57%) ( p  = 0.013) and required longer oxygen therapy ( p  = 0.038), but without difference in the length of hospitalization. The OSA+ group also presented higher rates of platelets ( p  = 0.008) and D-dimer (1,443 ± 897) than the OSA- group (648 ± 263 ng/mL) ( p  = 0.019). Conclusion  Obstructive sleep apnea in individuals hospitalized due to COVID-19 was associated with higher COVID-19 severity, worse peripheral oxygen saturation, longer oxygen therapy time, and higher platelet and D-dimer rates.

Novel gas mixture combined with an auto-transfusion tourniquet enhances cerebral O2 transport and hemodynamic indices in CPR swine. Part B - A pilot experimental study

Objectives

The cognitive outcome of CPR is poor. This study aims to evaluate if enhancing blood flow to the brain and oxygen dissociation from the hemoglobin improve cerebral O2 transport during CPR in cardiac arrest swine.

Methods

Standard swine-CPR model of induced VF and recovery was treated with an auto-transfusion tourniquet (A-TT®; HemaShock® (HS) Oneg HaKarmel Ltd. Israel) and ventilation with a novel mixture of 30% Oxygen, 5% CO2, and 65% Argon (COXAR™). Five swine received the study treatment and 5 controls standard therapy. Animals were anesthetized, ventilated, and instrumented for blood draws and pressure measurements. Five minutes of no-CPR arrest were followed by 10 min of mechanical CPR with and without COXAR-HS™ enhancement followed by defibrillation and 45 min post ROSC follow-up.

Results

All 5 COXAR-HS™ animals were resuscitated successfully as opposed to 3 of the control animals. Systolic (p < 0.05), and diastolic (p < 0.01) blood pressures, and coronary (p < 0.001) and cerebral (p < 0.05) perfusion pressures were higher in the COXAR-HS™ group after ROSC, as well as cerebral flow and O2 provided to the brain (p < 0.05). Blood pressure maintenance after ROSC required much higher doses of norepinephrine in the 3 resuscitated control animals vs. the 5 COXAR-HS™ animals (p < 0.05). jugular vein PO2 and SO2 exceeded 50 mmHg and 50%, respectively with COXAR-HS™.

Conclusions

In this pilot experimental study, COXAR-HS™ was associated with higher diastolic blood pressure and coronary perfusion pressure with lower need of vasopressors after ROSC without significant differences prior to ROSC. The higher PjvO2 and SjvO2 suggest enhanced O2 provision to the brain mitochondria, while limb compression by the HS counteracts the vasodilatory effect of the CO2. Further studies are needed to explore and validate the COXAR-HS™ effects on actual post-ROSC brain functionality.

Hyperoxia in Sepsis and Septic Shock: A Comprehensive Review of Clinical Evidence and Therapeutic Implications

Sepsis and septic shock are leading causes of mortality in intensive care units, characterized by a dysregulated immune response to infection, leading to severe organ dysfunction. Oxygen therapy is a cornerstone of supportive care in sepsis management, aimed at correcting hypoxemia and improving tissue oxygenation. However, the administration of supplemental oxygen must be carefully managed to avoid hyperoxia, which can lead to oxidative stress and additional tissue damage. This review aims to comprehensively analyze the clinical evidence regarding hyperoxia in the context of sepsis and septic shock, evaluating its potential therapeutic benefits and risks and discussing the implications for clinical practice. A thorough literature review included observational studies, randomized controlled trials (RCTs), meta-analyses, and clinical guidelines. The review focuses on the pathophysiology of sepsis, the mechanisms of hyperoxia-induced injury, and the clinical outcomes associated with different oxygenation strategies. The evidence suggests that while oxygen is crucial in managing sepsis, the risk of hyperoxia-related complications is significant. Hyperoxia has been associated with increased mortality and adverse outcomes in septic patients due to mechanisms such as oxidative stress, impaired microcirculation, and potential worsening of organ dysfunction. RCTs and meta-analyses indicate that conservative oxygen therapy may be beneficial in reducing these risks, though optimal oxygenation targets remain under investigation. This review highlights the importance of careful oxygen management in sepsis and septic shock, emphasizing the need for individualized oxygen therapy to avoid the dangers of hyperoxia. Further research is required to refine oxygenation strategies, establish clear clinical guidelines, and optimize outcomes for sepsis and septic shock patients. Balancing adequate oxygenation with the prevention of hyperoxia-induced injury is crucial in improving the prognosis of these critically ill patients.

Airway management and ventilation techniques in resuscitation during advanced life support: an update

For many years, ventilation has been an essential part of advanced life support (ALS) in cardiopulmonary resuscitation (CPR). Nevertheless, there is little evidence about the best method of ventilation during resuscitation for both out-of-hospital cardiac arrest (OHCA) and inhospital cardiac arrest (IHCA) patients. Effective ventilation is one of the two main keys to successful resuscitation. In this context, the question always arises as to which airway management, along with which ventilation mode, constitutes the best strategy. Conventional ventilation modes are not designed for cardiac arrest and show important limitations that must be considered when used in CPR. Manual ventilation without the use of an automated transport ventilator (ATV) could be shown to be uncontrolled in applied volumes and pressures and should be avoided. Mechanical ventilation with an ATV is therefore superior to manual ventilation, but both volume- and pressure-controlled ventilation modes are significantly influenced by chest compressions. With the newly designed chest compression synchronized ventilation (CCSV), a special ventilation mode for resuscitation is available. Further research should be conducted to obtain more evidence of the effect of ventilation during CPR on outcomes following OHCA and not only about how to secure the airway for ventilation during CPR.

Protocol for a systematic review and individual participant data meta-analysis of optimizing oxygen therapy in critically ill patients

Background

Oxygen therapy is a cornerstone treatment of critically ill patients in the intensive care unit (ICU). Whether lower oxygenation therapy brings superior survival outcomes to higher oxygenation therapy is unknown.

Methods

We will search electronic databases: PubMed, Embase, Web of Science, the Cochrane Central Register of Controlled Trials (CENTRAL), International Clinical Trials Registry Platform (ICTRP), and ClinicalTrials.gov from inception to 1 January 2024. Two authors will independently screen for all eligible clinical studies. Emails will be sent for individual participant data. The statistical analyses will be conducted using STATA 15.0 software.

Results

We will evaluate the efficacy of lower oxygenation therapy compared with higher oxygenation therapy based on individual participant data.

Conclusion

This study will offer clinical evidence for oxygen therapy in ICU patients.

FAM134B deletion exacerbates apoptosis and epithelial-to-mesenchymal transition in rat lungs exposed to hyperoxia

Oxygen therapy is widely used in clinical practice; however, prolonged hyperoxia exposure may result in hyperoxic acute lung injury (HALI). In this study, we investigated the role of FAM134B in hyperoxia-induced apoptosis, cell proliferation, and epithelial-to-mesenchymal transition (EMT) using RLE-6TN cells and rat lungs. We also studied the effect of CeO2-NPs on RLE-6TN cells and lungs following hyperoxia exposure. FAM134B was inhibited in RLE-6TN cells and rat lungs following hyperoxia exposure. Overexpressing FAM134B promoted cell proliferation, and reduced EMT and apoptosis following hyperoxia exposure. FAM134B activation increased ER-phagy, decreased apoptosis, improved lung structure damage, and decreased collagen fiber deposition to limit lung injury. These effects could be reversed by PI3K/AKT pathway inhibitor LY294002. Additionally, CeO2-NPs protected RLE-6TN cells and lung damage following hyperoxia exposure by ameliorating impaired ER-phagy. Therefore, FAM134B restoration is a potential therapeutic target for the HALI. Moreover, CeO2-NPs can be used for the treatment of HALI.

POStoperative INTELLiVENT-adaptive support VEntilation in cardiac surgery patients (POSITiVE) II-study protocol of a randomized clinical trial

BACKGROUND

One single-center randomized clinical trial showed that INTELLiVENT-adaptive support ventilation (ASV) is superior to conventional ventilation with respect to the quality of ventilation in post-cardiac surgery patients. Other studies showed that this automated ventilation mode reduces the number of manual interventions at the ventilator in various types of critically ill patients. In this multicenter study in patients post-cardiac surgery, we test the hypothesis that INTELLiVENT-ASV is superior to conventional ventilation with respect to the quality of ventilation.

METHODS

"POStoperative INTELLiVENT-adaptive support VEntilation in cardiac surgery patients II (POSITiVE II)" is an international, multicenter, two-group randomized clinical superiority trial. In total, 328 cardiac surgery patients will be randomized. Investigators screen patients aged > 18 years of age, scheduled for elective cardiac surgery, and expected to receive postoperative ventilation in the ICU for longer than 2 h. Patients either receive automated ventilation by means of INTELLiVENT-ASV or ventilation that is not automated by means of a conventional ventilation mode. The primary endpoint is quality of ventilation, defined as the proportion of postoperative ventilation time characterized by exposure to predefined optimal, acceptable, and critical (injurious) ventilatory parameters in the first two postoperative hours. One major secondary endpoint is ICU team staff workload, captured by the ventilator software collecting manual settings on alarms. Patient-centered endpoints include duration of postoperative ventilation and length of stay in ICU.

DISCUSSION

POSITiVE II is the first international, multicenter, randomized clinical trial designed to confirm that POStoperative INTELLiVENT-ASV is superior to non-automated conventional ventilation and secondary to determine if this closed-loop ventilation mode reduces ICU team staff workload. The results of POSITiVE II will support intensive care teams in their choices regarding the use of automated ventilation in postoperative care of uncomplicated cardiac surgery patients.

TRIAL REGISTRATION

Clinicaltrials.gov NCT06178510 . Registered on December 4, 2023.