Acute Hypoxemic Respiratory Failure

High-flow nasal cannula (HFNC) is a type of oxygen therapy commonly used in adults with breathing problems. While HFNC can help patients avoid breathing tubes and improve oxygen levels, there is no standard method for deciding how and when to reduce and stop this therapy once a patient improves. In many hospitals, these decisions vary from clinician to clinician. This study will compare usual care with a standardized step-by-step plan for reducing HFNC support. Eight hospitals will participate and will switch from usual care to the standardized plan at different time points during the study. The main goal is to determine whether the standardized weaning plan increases the number of patients who can successfully stop HFNC within 5 days. The study will also evaluate how long patients remain on HFNC, whether they need additional breathing support, and how long they stay in the hospital. The results may help develop clearer guidance for safely and efficiently stopping HFNC therapy.

The goal of this observational study is to determine whether metabolomic profiles combined with clinical data can predict high-flow nasal cannula (HFNC) failure and help optimize respiratory support in adult patients with acute hypoxemic respiratory failure (AHRF). The main questions it aims to answer are: Can metabolomic biomarkers identify patients at higher risk of HFNC failure? Does combining metabolomic and clinical data improve the prediction of respiratory support escalation and clinical outcomes? Participants will: Receive standard HFNC treatment according to clinical practice. Undergo collection of clinical, physiological, and laboratory data. Provide blood samples for metabolomic analysis during respiratory support.

The TEMA study (Targeting prEssure-Muscle-index to avoid ventilatory over-Assistance during pressure support ventilation) is a prospective, interventional crossover trial investigating the relationship between pressure support (PS) and tidal volume (Vt) in ICU patients with acute hypoxemic respiratory failure (AHRF) receiving pressure support ventilation (PSV). The study aims to assess whether the Pressure-Muscle Index (PMI)-a marker derived from the difference between plateau and peak inspiratory pressure-can help identify the optimal level of ventilatory assistance, preventing over-assistance and its associated complications such as diaphragm atrophy and patient self-inflicted lung injury (P-SILI). By exploring the sigmoidal relationship between PS and Vt, the study seeks to define a physiological threshold (PMI=0) that may serve as a personalized target for PSV titration.

This observational study will analyze data already collected by the investigators as part of their routine clinical practice from patients with acute respiratory failure (ARF) treated with mechanical ventilation. The study itself does not require any specific intervention. Mechanical ventilation can save the lives of patients with ARF. However, if used improperly, it can exacerbate lung disease and worsen outcomes (Slutsky et al.). Despite decades of animal and clinical research, it remains unclear how to establish the positive end-expiratory pressure (PEEP) during mechanical ventilation to reduce the risk of lung damage. Several methods have been suggested, but none have consistently proven superior to the others (Sahetya et al.). As part of their routine clinical practice, the investigators study the responses to different PEEP levels of patients with ARF undergoing mechanical ventilation by integrating information from various techniques, each examining different aspects of lung morphology and physiology. The methods the investigators use include lung computed tomography (CT) and electrical impedance tomography (EIT). Lung CT is the reference technique for measuring the morphological response to PEEP (Gattinoni et al.). It quantifies the volume of the hyperinflated and non-aerated lung, both of which are related to the risk of mechanical ventilation causing damage (Slutsky et al.). Lung EIT monitors the functional response to PEEP in terms of changes in regional compliance across different PEEP levels. Allegedly, an increase in compliance when PEEP is decreased reveals overdistention, the functional correlate of (worrisome) hyperinflation, at the higher PEEP. A decrease in compliance when PEEP is decreased signals new collapse, the functional correlate of (worrisome) loss of aeration (Franchineau et al.). In the Unit where the investigators work, patients with ARF treated with mechanical ventilation are routinely studied as follows. First, a lung CT with a PEEP of 20 cmH2O and then of 5 cmH2O is obtained. Thereafter, a decremental PEEP test is performed with the EIT, where PEEP is decreased from 20 cmH2O down to 5 cmH2O in steps of 2 or 3 cmH2O. Finally, results are analyzed and compared offline. At the lung CT, decreasing PEEP from 20 to 5 cmH2O is always associated with some decrease in the volume of the hyperinflated lung and some increase in the volume of the non-aerated lung. However, the magnitude of these two effects varies among individuals, and the net response may be defined as the difference between those two competing effects. If the decrease in the volume of the hyperinflated lung is greater than the increase in the volume of the non-aerated lung, the overall response (i.e., less hyperinflation) can be considered positive. PEEP should then be set closer to 5 than to 20 cmH2O. Diversely, if the decrease in the volume of the hyperinflated lung is smaller than the increase in the volume of the non-aerated lung, the overall response (i.e., more loss of aeration) can be considered negative. PEEP should then be set closer to 20 cmH2O (Protti et al.). Similarly, at the lung EIT, decreasing PEEP from 20 to 5 cmH2O is always associated with compliance improvement in some regions (i.e., less overdistension) and worsening in others (i.e., more collapse). Again, the magnitude of these two opposite effects varies among individuals. According to most experts on lung EIT, PEEP should be set at the level where both overdistension and collapse are minimized (the so-called "best" PEEP) (Jonkman et al.). Lung CT requires transfer to the radiology unit, exposure of the patient to radiation, and complex analysis offline. By contrast, lung EIT is virtually risk-free, and analysis can be performed using an automatic algorithm. Nevertheless, lung EIT is less well validated than lung CT. For instance, the assumption that a decrease in compliance in response to a decrease in PEEP is due to new collapse has been questioned (Protti et al., Chiumello et al., Menga et al.). So far, lung CT remains the reference technique for studying individual responses to PEEP, while lung EIT requires further validation. This study aims to verify whether the "best" PEEP identified using lung EIT is strongly associated with the net response assessed using lung CT, when PEEP is decreased from 20 to 5 cmH2O in patients with ARF treated with mechanical ventilation. If so, this would strengthen the rationale for using the lung EIT (which is safer and simpler than the lung CT) to set PEEP.

A multimodal educational intervention to target an oxygen saturation target range (SpO2 90-96%) will reduce ventilator length of stay and reduce occult hypoxemia by increased awareness and adherence to a designated oxygen saturation target range.

Prone positioning has shown beneficial effects in intubated patients with severe respiratory failure and positive effects in awake patients with COVID-19 pneumonia. Conclusive evidence for patients with AHRF without COVID-19 is still missing. The investigators hypothesis that awake prone position in patients with AHRF is superior to standard supine/semi-recumbent position in terms of reducing the rate of tracheal intubation and/or all-cause death within 28 days after randomization.

Acute Hypoxemic Respiratory Failure (AHRF) is one of the prevalent causes of admission around the world and is associated with high mortality in resource-limited settings. Limited access to invasive mechanical ventilation is among the contributing factors to poor outcomes. The Bag CPAP may be useful in reducing the need for intubation and therefore mortality in patients with AHRF but data are lacking. This study aims to determine whether the Bag CPAP compared to standard oxygen care, could reduce the percentage of patients with criteria for intubation in patients with AHRF. This is a prospective randomized, open-label, controlled trial in which patients presenting at the emergency room in Rwanda will be randomly assigned to receive standard oxygen therapy or Bag CPAP. The primary endpoint is the percentage of patients with criteria for intubation at day 7. Secondary endpoints include the tolerance of the Bag CPAP, overall 28-day mortality rate, mortality rate of intubated patients on mechanical ventilation at day 28, percentage of patients intubated at 28 days, ventilator-free days at day 28, interval between the initiation of treatment and the onset of intubation criteria, the interval between the time when criteria for intubation are met and intubation, organ failure-free days at day 7 and length of hospital stay.

Acute hypoxemic respiratory failure may progress to acute respiratory distress syndrome, a life-threatening condition that often requires mechanical ventilation. The optimal ventilation strategy in this patient population remains uncertain. The SVALBARD trial is a feasibility and pilot study designed to compare spontaneous versus controlled mechanical ventilation in patients with acute hypoxemia respiratory failure. The primary objective is to assess the feasibility of the study procedures and interventions, while also collecting descriptive data on key clinical variables to inform the design of a future randomized controlled trial.

Acute hypoxemic respiratory failure (AHRF) happens when the lungs are unable to absorb enough oxygen. The bloodstream is deprived of oxygen which can eventually lead to more severe conditions like multi-organ failure (MOF) and death. AHRF accounts for over 30% of patients to critical care units, thus novel treatments are sorely needed. Research has shown that blood levels of the inflammatory biomarker Interleukin-6 (IL-6) may be a reliable marker for predicting which patients with AHRF will progress into requiring intensive care unit (ICU) admission, MOF, and eventually death. IL-6 levels were shown to reliably peak several days before MOF, ICU admission, and death. Thus, the investigators believe that by identifying patients before the peak of their IL-6 levels, they will be able to administer early treatment to prevent the patient's condition from worsening. The aim of this study is to test the feasibility of a treatment strategy for AHRF based on IL-6 measurement in patients who are admitted to hospital care with AHRF. Patients who are eligible for the study will have their plasma IL-6 levels measured over 2 days. Patients with elevated IL-6 levels will be randomized into 1 of 3 treatment groups: standard of care only, standard of care plus a single IV infusion of Tocilizumab, or standard of care plus treatment with oral Dexamethasone for 10 days. Patients will then be observed till discharge or up to 28 days, and a follow-up phone interview will be conducted 6 months of the end of the observation period.

Acute hypoxemic respiratory failure requires endotracheal intubation and invasive mechanical ventilation in approximately 30-40% of cases, due to severe hypoxemia and/or clinical signs of acute respiratory distress. The primary objectives of invasive mechanical ventilation are to reduce respiratory effort and improve oxygenation. However, this intervention is also associated with both direct and indirect adverse effects, mainly linked to the need for sedation and often neuromuscular blockade. These include hemodynamic compromise, neuromuscular weakness, ventilator-induced lung injury, and infectious complications. An ideal intubation strategy would therefore strike a balance: avoiding the risks of delayed intubation-such as refractory hypoxemia, excessive respiratory effort, and patient self-inflicted lung injury (P-SILI)-while limiting complications associated with invasive mechanical ventilation by withholding it in patients who might otherwise recover without. To date, the optimal strategy for achieving this risk-benefit balance remains uncertain. Clinical practice suggests a broad consensus on the necessity of intubation when so-called safety criteria are met: severe hypoxemia (SaO₂/FiO₂ ratio \< 88), marked respiratory distress (use of accessory muscles, thoracoabdominal paradox, respiratory rate \> 40/min), extra-respiratory manifestations of hypoxia (e.g., altered consciousness), and/or uncontrolled hemodynamic instability. Beyond these safety thresholds, however, debate persists. Some advocate for earlier intubation-a so-called liberal approach-triggered by predefined hypoxemia criteria (e.g., SpO₂/FiO₂ \< 110), with the aim of limiting the deleterious consequences of sustained hypoxemia. In routine practice, the criteria guiding intubation vary widely between clinicians and cannot be attributed to strong scientific evidence. This study therefore seeks to compare, in a randomized interventional design, the two main strategies currently applied across centers: * Liberal intubation strategy: prioritizing the prevention of organ dysfunction related to hypoxemia (notably hypoxic cardiac arrest) and the risk of P-SILI. * Restrictive intubation strategy: prioritizing the reduction of invasive mechanical ventilation use, with the goal of minimizing ventilation-related harm and its associated therapeutic burden.

Sepsis-associated acute respiratory distress syndrome (ARDS) is one of the deadliest and most biologically heterogeneous forms of respiratory failure. Despite uniform diagnostic criteria, patients with septic ARDS show wide variability in inflammatory intensity, alveolar epithelial and endothelial injury, alveolar fluid composition, ventilatory mechanical properties, and clinical evolution. Early identification of these differences may enable better prognostication and more precise treatment. This prospective observational study aims to deeply characterize the earliest phases of septic ARDS by integrating serial bronchoalveolar lavage (BAL) at 0, 24 and 72 hours with parallel plasma biomarker profiling and detailed mechanical ventilation data. This design captures the evolving biological and physiological landscape of septic ARDS during its most dynamic window. The central goal is to identify systemic, alveolar, and hybrid bio-mechano-inflammatory subphenotypes that can inform personalized approaches to support, risk stratification, and future interventional trials.

Rationale: In patients with acute hypoxemic respiratory failure (AHRF), preserving spontaneous breathing during mechanical ventilation offers physiological benefits, but also carries risks. While spontaneous breathing improves gas exchange and limits diaphragm atrophy, strong inspiratory efforts may worsen lung and diaphragm injury. Balancing these factors requires refined and tailored strategies, such as the modulation of PEEP. However, the impact of PEEP on neural respiratory drive and inspiratory effort is very heterogenous, and these two entities have only been studied separately in limited subsets of patients and healthy subjects. Additionally, it remains unclear whether the major determinant of PEEP-induced changes in respiratory drive and effort is represented by variations in diaphragm geometry, lung compliance, or by the presence of expiratory muscles recruitment, which may counteract its effect. Objective: The primary objective is to determine the effect of PEEP on diaphragm neuromechanical efficiency (i.e. an index of neural respiratory drive and inspiratory effort) in patients with acute hypoxemic respiratory failure during invasive assisted mechanical ventilation. The secondary objective is to determine the major physiological contributors to PEEP-mediated changes in diaphragm neuromechanical efficiency. Study design: Prospective, physiological study. Study population: Invasively mechanically ventilated adult patients admitted to the ICU. Intervention: For each patient, six different PEEP levels (15-12-10-8-5-2 cmH2O) will be tested during a decremental PEEP trial. During each step, neural respiratory drive, inspiratory effort, expiratory muscle activity, lung inflation pattern through electrical impedance tomography, respiratory muscle geometry and function through ultrasound and surface EMG, gas exchange and hemodynamics data will be collected. Main study parameters/endpoints: The primary outcome of the study will be the evaluation of PEEP-mediated changes in diaphragm neuromechanical efficiency (NME).

Background: There are no proven therapies specific for pulmonary dysfunction in patients with acute hypoxemic respiratory failure (AHRF) caused by infections (including Covid-19). The full spectrum of AHRF ranges from mild respiratory tract illness to severe pneumonia, acute respiratory distress syndrome (ARDS), multiorgan failure, and death. The efficacy of corticosteroids in AHRF and ARDS caused by infections remains controversial. Methods: This is a multicenter, randomized, controlled, open-label clinical trial testing dexamethasone in mechanically ventilated adult patients with established AHRF (including ARDS) caused by confirmed pulmonary or systemic infections, admitted in a network of Spanish ICUs. Eligible patients will be randomly assigned to receive dexamethasone: either 6 mg/d x 10 days or 20 mg/d x 5 days followed by 10 mg/d x 5 days. The primary outcome is 60-day mortality. The secondary outcome is the number of ventilator-free days at 28 days. All analyses will be done according to the intention-to-treat principle.

We attempt to perform dynamic endotyping of critically ill patients presenting in the emergency department with de novo acute hypoxemic respiratory failure (AHRF). We also attempt to identify what clinical, radiological, physiological and biological variables collected early in the course of AHRF correlate with subsequent mortality and/or persistent severe hypoxemia.

High-flow nasal oxygen therapy (HFNO) is an oxygenation technique frequently used in intensive care. The main objective of our study is to show that the use of a protocol for weaning patients off high-flow nasal oxygen therapy (HFNO) in the intensive care unit increases the probability that patients will be weaned from HFNO at Day 7 post-randomisation. This is a open-label multicentre randomised controlled trial conducted in two parallel groups. The primary endpoint is the success rate at Day 7, with success defined as "definitive" weaning from HFNO, i.e. patients weaned from HFNO for more than 48 hours without recourse to non-invasive ventilation (NIV) or intubation and still alive at Day 7. The weaning protocol will be started as soon as the patient meets all the inclusion criteria, considered to be the prerequisites for initiating weaning from HFNO. Patients will be monitored until Day 28 maximum.

Acute Hypoxemic Respiratory Failure (AHRF) is a condition in which injury to the lungs impairs the ability of the air sacs (alveoli) to ventilate and exchange oxygen. This impairment may be worsened in individuals with elevated body weight, particularly when fat tissue compresses the lungs and promotes alveolar collapse. The impact of body weight on lung function may be greater in individuals with upper-body fat distribution. Two common interventions for AHRF-positive end-expiratory pressure (PEEP) and prone positioning-are used to improve lung ventilation. However, it is unclear whether these therapies are equally effective across different body weight categories and fat distributions. This study will evaluate whether body weight and fat distribution affect patients' lung inflation responses to PEEP and prone positioning. Lung inflation will be assessed using electrical impedance tomography (EIT), a bedside imaging tool that maps lung ventilation, and esophageal manometry, which estimates lung compression through a thin catheter placed in the esophagus. Laboratory tests will also be used to measure markers of inflammation and AHRF severity and find correlations with fat distribution and responses to the tested treatments.. Patients with AHRF requiring mechanical ventilation will be enrolled across a range of body weights. Each participant will undergo combinations of two PEEP levels and two body positions (supine and prone) for 30 minutes each. At the end of the study procedures, clinical care will continue as determined by the treating team.

Pressure support ventilation (PSV) is used to assist the breathing of the intubated patient with some pressure from the ventilator. This support aims at avoiding excessive inspiratory effort, while ensuring a certain degree of training of the patient's inspiratory muscle. Avoiding both minimal and excessive assistance is thus important for the optimal care of the intubated patient ensuring a lung and diaphragm protective ventilation with the goal to liberate the patient from the ventilator as soon as possible. Recently pressure-muscle-index (PMI), an index of inspiratory effort easy to be measured on the ventilator screen, has been proposed to avoid excessive assistance in PSV. This will be the first prospective study testing the effects of setting pressure support based on PMI to avoid excessive assistance on patients recovering from acute lung injury (acute hypoxemic respiratory failure).

This exploratory study aims to investigate the effect of Electrical Impedance Tomography (EIT)-guided ventilator settings on mechanical power in patients with acute hypoxemic respiratory failure (AHRF), including both ARDS and non-ARDS conditions. Mechanical power, a key factor associated with ventilator-induced lung injury (VILI), will be measured before and after EIT-guided PEEP titration. The study will evaluate feasibility and changes in lung mechanics, gas exchange, and EIT parameters. A total of 17 patients requiring invasive mechanical ventilation will be enrolled at Siriraj Hospital, Mahidol University.

While most studies in the medical literature that indicate "music" as an intervention may recognize its impact and capacity to decrease pain perception, anxiety, and/or its role in the regulation of cardiac and respiratory function in ICU patients, no identifiable studies have implemented entrained live music therapy protocols into clinical trials. Music therapy treatment is a non-pharmacological intervention that is individually tailored to the patient's needs and focuses on the assessment and intervention of a specific music application that is provided by a certified music therapist. Entrained music therapy focuses on a dynamic interaction between the patient and music therapist in which the music therapist attempts to promote relaxation and comfort through the patient's identified Song of Kin (SOK). This study measures the effects of live music therapy entrained to the vital signs of adult patients on duration of mechanical ventilation.

The goal of this pilot randomized cross-over study is to compare the effect of a full-face mask with expiratory washout to a conventional full face mask on non-invasive ventilation (NIV) in patients with acute hypercapnic, and acute hypoxemic, respiratory failure. The main questions it aims to answer are: * Does a mask with expiratory washout improve minute ventilation in patients using non-invasive ventilation compared with a conventional single-limb NIV mask * How does a mask with expiratory washout affect respiratory variables compared with a dual-limb NIV mask. Participants already prescribed NIV will undergo 3 arms of the investigation in a randomized order: * Single-limb NIV with investigation mask (with expiratory washout) * Single-limb NIV with conventional mask * Dual-limb NIV with conventional mask

Acute hypoxemic respiratory failure (AHRF) is a common indication for admission to an intensive care unit (ICU), with mortality exceeding 50% in cases where invasive mechanical ventilation is needed. Therefore, assessment of the most adequate oxygen strategy to avoid intubation in patients with AHRF deserves consideration.Previous studies have indicated that non-invasive oxygenation strategies, including high-flow nasal oxygen (HFNO), helmet or face mask noninvasive ventilation (NIV), and continuous positive airway pressure (CPAP), are effective in preventing endotracheal intubation in adult patients with AHRF when compared to the standard oxygen therapy. However, the optimal non-invasive oxygenation strategies remain uncertain. This study aim to determine whether CPAP, compared with HFNC or NIV, increase the intubation-free survival during study period in patients with AHRF.

High flow nasal oxygen therapy (HFNO) is an established modality in the supportive treatment of patients suffering from acute hypoxemic respiratory failure. The high humidified gas flow supports patient's work of breathing, reduces dead space ventilation, and improves functional residual capacity while using an unobtrusive patient's face interface \[Mauri et al, 2017; Möller et al, 2017\]. As hyperoxia is considered not desirable \[Barbateskovic et al, 2019\] during any oxygen therapy, the inspired O2 concentration is usually adapted to a pre-set SpO2 target-range of 92-96% in patients without hypercapnia risk, and of 88-92% if a risk of hypercapnia is present \[O'Driscoll et al, 2017; Beasley et al, 2015\]. In most institutions, the standard of care is to manually adapt the FiO2, although patients frequently have a SpO2 value outside the target range. A new closed loop oxygen controller designed for HFNO was recently developed (Hamilton Medical, Bonaduz, Switzerland). The clinician sets SpO2 targets, and the software option adjusts FiO2 to keep SpO2 within the target ranges. The software option offers some alarms on low and high SpO2 and high FiO2. Given the capability, on the one hand, to quickly increase FiO2 in patients developing sudden and profound hypoxia, and, on the other hand, of automatically preventing hyperoxia in patients improving their oxygenation, such a system could be particularly useful in patients treated with HFNO. A short-term (4 hours vs 4 hours) crossover study indicated that this technique improves the time spent within SpO2 pre-defined target for ICU patients receiving high-flow nasal oxygen therapy \[Roca et al, 2022\]. Due to its simplicity, HFNO is increasingly used outside the ICU during transport and in the Emergency Room (ER). This environment poses specific challenges, as patients may deteriorate very quickly and depending on patient's flow, healthcare providers can easily be overwhelmed. We thus propose to evaluate closed loop controlled HFNO in ER patients. The hypothesis of the study is that closed loop oxygen control increases the time spent within clinically targeted SpO2 ranges and decreases the time spent outside clinical target SpO2 ranges as compared to manual oxygen control in ER patients treated with HFNO.

The goal of this physiological intervention study is to unravel the (patho)physiological mechanisms and potential clinical benefits of a pre-specified early switch from controlled to assisted ventilation in mechanically ventilated adult patients with acute hypoxemic respiratory failure (PaO2/FiO2 ratio \< 200 mmHg). The intervention is that participants will be switched from controlled to assisted ventilation when PaO2/FiO2 ratio \> 200 mmHg. The primary endpoint is the change in regional lung stress (as derived by electrical impedance tomography) when switching from controlled to assisted ventilation and until a successful or failed switch.

Late or delayed intubation in patients with acute hypoxemic respiratory failure (AHRF) treated with nasal high flow (NHF) is associated with increased patient mortality. The ROX index has been designed and validated to predict outcome of NFH therapy by identifying those patients with a high risk of NHF failure and those with a high probability of success. Whether or not the ROX index may improve patient outcome remains to be shown. To do so, a strategy using the ROX index must lead to earlier intubation than commonly-used criteria. The objective of the ROX-1 trial is to assess whether the use of an algorithm incorporating the ROX index to standard of care for the time to intubation in patients with AHRF supported with NHF isassociated with an increase in the proportion of patients who are intubated within the first 12 hours among those patients who fail on NHF.

This study is being conducted to evaluate if wearing a non-invasive breathing support device over the chest/abdomen improves markers of breathing in patients with lung injury requiring high-flow oxygen. The breathing support device consists of a plastic shell that sits over the chest and abdomen and connects to a vacuum that helps the chest expand with breathing. This breathing support is known as continuous negative external pressure (CNEP). Study findings will help determine if this breathing support device might be useful for patients with acute hypoxemic respiratory failure (AHRF).