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Transporting spontaneously ventilating adults with tracheostomies from the operating room (OR) or other anesthetizing locations to the intensive care unit (ICU) or other recovery locations presents significant challenges, as traditional T-pieces may not be readily available. This article describes a novel modification to the Ayre's T-piece, designed to address this gap by using readily available equipment. The modification integrates a 3-mL syringe, a size 7.0 endotracheal tube (ETT) connector, and oxygen tubing from an adult under-the-chin style facemask while adapting the expiratory and inspiratory limbs of the anesthesia circuit., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 International Anesthesia Research Society.)

Electrical impedance tomography (EIT) is an emerging technology for the non-invasive monitoring of regional distribution of ventilation and perfusion, offering real-time and continuous data that can greatly enhance our understanding and management of various respiratory conditions and lung perfusion. Its application may be especially beneficial for critically ill mechanically ventilated patients. Despite its potential, clear evidence of clinical benefits is still lacking, in part due to a lack of standardization and transparent reporting, which is essential for ensuring reproducible research and enhancing the use of EIT for personalized mechanical ventilation. This report is the result of a four-day expert meeting where we aimed to promote the consistent and reliable use of EIT, facilitating its integration into both clinical practice and research, focusing on the adult intensive care patient. We discuss the state-of-the-art regarding EIT acquisition and processing, applications during controlled ventilation and spontaneous breathing, ventilation-perfusion assessment, and novel future directions., Competing Interests: Declarations Ethical approval and consent for participate Not applicable. Consent for publication Not applicable. Competing interests LSM is supported by a fellowship from the European Respiratory Society and a scholarship from Canadian Lung Society. SL has received EIT-related research funding under grant LE 817/40–1 (Project No. 422367304, paid to the institution) from German Research Foundation (DFG). AJ is supported by a personal grant from NWO (ZonMw Veni 2022, 09150162210061, paid to the institution) and has received research funding (paid to the institution) from Pulmotech B.V., Liberate Medical, Netherlands eScience Center and Health ~ Holland. All other authors declared that they have no competing interests., (© 2024. The Author(s).)

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., Competing Interests: Dr Scott discloses relationships with the American Association for Respiratory Care (AARC) and Relias Media. Dr Li discloses relationships with AARC, Fisher & Paykel Healthcare, Aerogen, MEKICS Co, Vincent, the Rice Foundation, and Heyer. Dr Li is a section editor for Respiratory Care. Drs Scott and Li disclose patent applications on a device to monitor and alarm manual ventilation parameters during cardiopulmonary resuscitation (WO2021167870A1; US20230131417A1). Mr Algahtani has disclosed no conflicts of interest., (Copyright © 2024 by Daedalus Enterprises.)

Background: This Population, Intervention, Comparison, and Outcomes-guided systematic review assesses continuous lateral rotation therapy versus conventional position changes in mechanically ventilated critically ill adults, evaluating mortality, ICU length of stay (LOS), and hospital LOS as primary outcomes and respiratory function, mechanical ventilation duration, pulmonary complications, and adverse events as secondary outcomes., Methods: This systematic review follows Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria (International Prospective Register of Systematic Reviews CRD42022384258). Searches spanned databases MEDLINE/PubMed, Embase, Scopus, ScienceDirect, Cochrane, CINAHL, and Web of Science, without language or publication year restrictions. Inclusion criteria involved randomized controlled trials (RCTs) and quasi-randomized trials, comparing continuous lateral rotation therapy (intervention) with conventional position changes (control). Risk of bias and quality of evidence for RCTs were assessed using the Cochrane Collaboration and Grading of Recommendations Assessment, Development, and Evaluation tools. For the quasi-randomized trials, the Risk of Bias in Non-Randomized Studies-of Interventions tool was used., Results: In 18 studies with 1,466 participants (intervention, n = 700, 47.7%; control, n = 766, 52.2%), continuous lateral rotation therapy was predominantly used for prophylactic purposes, with protocols varying from 10-24 h/d. Meta-analysis (16 RCTs) favored continuous lateral rotation therapy for reduced mechanical ventilation duration (standardized mean difference [SMD] -0.17 [CI -0.29 to -0.04] d, P = .008) and lower nosocomial pneumonia incidence (odds ratio 0.39 [CI 0.29-0.52], P < .001). Continuous lateral rotation therapy showed no significant impact on mortality (odds ratio 1.04 [CI 0.80-1.34], P = .77), ICU LOS (SMD -0.11 [CI -0.25 to 0.02] d, P = .11), hospital LOS (SMD -0.10 [CI -0.31 to 0.11] d, P = .33), and incidence of pressure ulcers (odds ratio 0.73 [CI 0.34-1.60], P = .44)., Conclusions: Continuous lateral rotation therapy showed no significant difference in primary outcomes (mortality, ICU and hospital LOS) but revealed significant differences in secondary outcomes (consistently reduced nosocomial pneumonia, with a minor effect on mechanical ventilation duration), supported by moderate certainty. Very low certainty for other outcomes highlights the need for current studies in diverse clinical settings and protocols to assess continuous lateral rotation therapy effectiveness., Competing Interests: The authors have disclosed no conflicts of interest., (Copyright © 2024 by Daedalus Enterprises.)

Background: Adaptive pressure control-continuous mandatory ventilation (APC-CMV) is a frequently utilized ventilator mode in ICU settings. This analysis compared APC-CMV and traditional volume control-continuous mandatory ventilation (VC-CMV) mode, describing factors associated with initiation, maintenance, and changes in settings of each mode., Methods: We analyzed ventilator data from a retrospective electronic health record data set collected as part of a quality improvement project in a single academic ICU. The majority ventilator mode was defined as the mode comprising the highest proportion of mechanical ventilation time. Multivariable logistic regression was used to identify variables associated with initial and majority APC-CMV or VC-CMV modes. Wilcoxon rank-sum tests were used to compare ventilator setting changes/d and sedation as a function of APC-CMV and VC-CMV majority modes., Results: Among 1,213 subjects initiated on mechanical ventilation from January 2013-March 2017, 68% and 24% were initiated on APC-CMV and VC-CMV, respectively, which composed 62% and 21% of the majority ventilator modes. Age, sex, race, and ethnicity were not associated with the initial or majority APC-CMV or VC-CMV modes. Subjects initiated on APC-CMV spent 88% of the mechanical ventilation time on APC-CMV mode. Compared to VC-CMV, subjects with APC-CMV majority mode experienced more ventilator setting changes/d (1.1 vs 0.8, P < .001). There were no significant differences in sedative medications when comparing subjects receiving APC-CMV versus VC-CMV majority modes., Conclusions: APC-CMV was highly utilized in the medical ICU. Subjects on APC-CMV had more ventilator setting changes/d than those on VC-CMV. APC-CMV offered no advantage of reduced setting adjustments or less sedation compared to VC-CMV., Competing Interests: Dr Malhotra discloses relationships with LivaNova, Jazz Zoll, and Eli Lilly. Dr Buhr discloses relationships with Viatris/Theravance Biopharma and DynaMed/American College of Physicians. Dr Martin discloses relationship with the American Academy of Sleep Medicine. The remaining authors have disclosed no conflicts of interest., (Copyright © 2024 by Daedalus Enterprises.)

To improve the management level of general anesthesia during bronchoscopy in the children with diffuse alveolar hemorrhage (DAH). A retrospective study was conducted in the children with DAH who had performed bronchoscopy under general anesthesia with spontaneous respiration by face mask ventilation initially from June 2021 to June 2022 in our hospital. (1) Thirty-four children who had underwent 38 bronchoscopy procedures were included. (2) General anesthesia induction was performed by bolus of propofol intravenous in all the procedures. For maintaining anesthesia, combination use of propofol and remifentanil intravenously infusion were given in 31 procedures (81.6%) and propofol intravenously infusion alone was given in the rest 7 procedures (18.4%). An intravenous bolus of ketamine or propofol was given as an anesthetic adjuvant in 21 procedures (55.3%). Thirty-five procedures (92.1%) were successfully completed under non-tracheal intubation ventilation, whereas the rest 3 procedures (7.9%) needed change to tracheal intubation ventilation. (3) Respiratory depression was found in 7 procedures (18.4%), laryngospasm was found in 2 procedure (2.6%), and bronchospasm was found in 17 procedures (44.7%). Intraoperative hypoxemia occurred in 16 procedures (42.1%). The incidence of intraoperative hypoxemia in the procedures at the active phage of disease was significantly higher compared to those at the remission phage of the disease (P < .05). Intraoperative hypercapnia also occurred in 16 procedures (42.1%). Two procedures (5.3%) were complicated by severe pulmonary hemorrhage. General anesthesia with spontaneous respiration by face mask ventilation is feasible and relatively safe for the children with DAH undergoing bronchoscopy, whereas the anesthetic protocol still needs to be improved., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Ventilator weaning is of great importance for intensive care patients in order to avoid complications caused by prolonged ventilation. However, not all patients succeed in weaning immediately. Their spontaneous breathing may be insufficient, resulting in extubation failure and the subsequent need for reintubation. To identify patients at high risk for weaning failure, a variety of potential predictors has already been examined in individual studies and meta-analyses over the last decades. However, an overview of all the predictors investigated is missing., Aim: To provide an overview of empirically investigated predictors for weaning failure., Methods: A systematic evidence map was developed. To this end, we conducted a systematic search in the Medline, Cochrane, and CINAHL databases in December 2023 and added a citation search and a manual search in June 2024. Studies on predictors for weaning failure in adults ventilated in the intensive care unit were included. Studies on children, outpatients, non-invasive ventilation, or explanatory factors of weaning failure were excluded. Two reviewers performed the screening and data extraction independently. Data synthesis followed an inductive approach in which the predictors were thematically analyzed, sorted, and clustered., Results: Of the 1388 records obtained, 140 studies were included in the analysis. The 112 prospective and 28 retrospective studies investigated a total of 145 predictors. These were assigned to the four central clusters 'Imaging procedures' (n = 22), 'Physiological parameters' (n = 61), 'Scores and indices' (n = 53), and 'Machine learning models' (n = 9). The most frequently investigated predictors are the rapid shallow breathing index, the diaphragm thickening fraction, the respiratory rate, the P/F ratio, and the diaphragm excursion., Conclusion: Predictors for weaning failure are widely researched. To date, 145 predictors have been investigated with varying intensity in 140 studies that are in line with the current weaning definition. It is no longer just individual predictors that are investigated, but more comprehensive assessments, indices and machine learning models in the last decade. Future research should be conducted in line with international weaning definitions and further investigate poorly researched predictors. Registration, Protocol: https://doi.org/10.17605/OSF.IO/2KDYU., Competing Interests: Declarations Ethical approval and consent to participate Not applicable. Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Stress hyperglycaemia is common in critical illness. We have previously observed that increasing severity of respiratory failure in patients with severe COVID-19 is associated with increased insulin demand. Given previously reported direct effects of hypoxia on insulin action, we reasoned that rapid improvements in oxygenation following prone positioning may improve insulin sensitivity and increase risk of hypoglycaemia. A retrospective multi-centre service evaluation comparing blood glucose and insulin administration in patients with COVID-19 pneumonitis receiving prone mechanical ventilation, comparing the 16 h pre-prone and 16 h post-prone time periods. 155 patients were included in this analysis. Oxygenation improved significantly following prone positioning (change in SpO 2 /FIO 2 per hour prone: 3.01 ± 0.14, P < 0.0001). Glycaemic control was similar during the supine and prone study periods, and there were no hypoglycaemic events in the prone study period. Prone positioning was associated with an unexpected modest but significant increase in insulin requirements (mean difference in total insulin dose (IU): 8.32 ± 2.14, P < 0.001) that was robust to several sensitivity analyses, and could not be explained by changes in carbohydrate intake. We did not observe an increased rate of hypoglycaemia during prone ventilation and the adequacy of glycaemic control was comparable during the supine and prone study periods. Unexpectedly, prone ventilation was associated with an increase in insulin requirements despite significant improvement in hypoxaemia. Our findings support the safety of prone ventilation with respect to glycaemic control and identify a novel relationship between ventilation position and insulin requirements in critical illness., Competing Interests: Declarations Competing interests The authors declare no competing interests. Ethics approval and consent to participate This study was approved as a multisite service evaluation at the host institution (Cambridge University Hospitals Service development and Audit Department) and participation of additional centres was confirmed with their respective Audit Departments. The study was exempt from the need for NHS research ethics committee review according to UK Health Research Authority guidance, as it was deemed service evaluation using anonymised data. It was reviewed by the institutional review board (Cambridge University Hospitals) and deemed service evaluation using routinely collected data, with no data collected specifically for this study. All data was anonymised by the direct care team before being analysed centrally. The institutional review board confirmed a consent waiver. The study was registered as a multi-site service evaluation at Cambridge University Hospitals (ref number) and at each individual site., (© 2024. The Author(s).)

Background: The main aim of the study whether changes in central venous-to-arterial CO 2 difference (ΔP(v-a)CO 2 ) and central venous oxygen saturation (ΔScvO 2 ) induced by volume expansion (VE) are reliable parameters to define fluid responsiveness (FR) in sedated and mechanically ventilated septic patients. We also sought to determine whether the degree of FR was related to baseline ScvO 2 and P(v-a)CO 2 levels., Methods: This was a post-hoc analysis of a multicenter prospective study. We included 205 mechanically ventilated patients with acute circulatory failure. Cardiac index (CI), P(v-a)CO 2 , ScvO 2 , and other hemodynamic variables were measured before and after VE. A VE-induced increase in CI > 15% defined fluid responders. Areas under the receiver operating characteristic curves (AUCs) and the gray zones were determined for ΔP(v-a)CO 2 and ΔScvO 2 ., Results: One hundred fifteen patients (56.1%) were classified as fluid responders. The AUCs for ΔP(v-a)CO 2 and ΔScvO 2 to define FR were 0.831 (95% CI 0.772-0.880) (p < 0.001) and 0.801 (95% CI 0.739-0.853) (p < 0.001), respectively. ΔP(v-a)CO 2  ≤ 2.1 mmHg and ΔScvO 2  ≥ 3.4% after VE allowed the categorization between responders and non-responders with positive predictive values of 90% and 86% and negative predictive values of 58% and 64%, respectively. The gray zones for ΔP(v-a)CO 2 (- 2 to 0 mmHg) and ΔScvO 2 (- 1 to 5%) included 22% and 40.5% of patients, respectively. ΔP(v-a)CO 2 and ΔScvO 2 were independently associated with FR in multivariable analysis. No significant relationships were found between pre-infusion ScvO 2 and P(v-a)CO 2 levels and FR., Conclusion: In mechanically critically ill patients, ΔP(v-a)CO 2 and ΔScvO 2 are reliable parameters to define FR and can be used in the absence of CI measurement. The response to VE was independent of baseline ScvO 2 and P(v-a)CO 2 levels. Clinical trial registration The study was registered in the ClinicalTrials.gov registry: NCT03225378, date: July 20, 2017., (© 2024. The Author(s).)

Pressure support ventilation (PSV) is a form of assisted ventilation which has become frequently used, with the aim of partially unloading the patient's inspiratory muscles. Both under- and over-assistance should be avoided to target a lung- and diaphragm- protective ventilation. Herein, we propose a conceptual model, supported by actual data, to describe how patient and ventilator share the generation of tidal volume (Vt) in PSV and how respiratory system compliance (Crs) affects this interaction. We describe the presence of a patient-specific range of PSV levels, within which the inspiratory effort (Pmus) is modulated, keeping Vt relatively steady on a desired value (Vt target ). This range of assistance may be considered the "adequate PSV assistance" required by the patient, while higher and lower levels may result in over- and under-assistance respectively. As we also show, the determinants of over- and under- assistance borders depend on the combination of Crs and the inspiratory effort which the patient is able to sustain over a period of time. These concepts can be applied at the bedside to understand if the level of assistance is adequate to patient's demand, focusing on the variation of relevant parameters (Vt, Pmus and pressure-muscle-index) as patient reaction to a change in the level of assistance., (© 2024. The Author(s).)

Creating multi-level digital-twin models for mechanical ventilation requires a detailed estimation of regional lung volume. An accurate generic map between 2D chest surface motion and 3D regional lung volume could provide improved regionalisation and clinically acceptable estimates localising lung damage. This work investigates the relationship between CT lung volumes and the forced vital capacity (FVC) a surrogate of tidal volume proven linked to 2D chest motion. In particular, a convolutional neural network (CNN) with U-Net architecture is employed to build a lung segmentation model using a benchmark CT scan dataset. An automated thresholding method is proposed for image morphology analysis to improve model performance. Finally, the trained model is applied to an independent CT dataset with FVC measurements for correlation analysis of CT lung volume projection to lung recruitment capacity. Model training results show a clear improvement of lung segmentation performance with the proposed automated thresholding method compared to a typically suggested fixed value selection, achieving accuracy greater than 95% for both training and independent validation sets. The correlation analysis for 160 patients shows a good correlation of R squared value of 0.73 between the proposed 2D volume projection and the FVC value, which indicates a larger and denser projection of lung volume relative to a greater FVC value and lung recruitable capacity. The overall results thus validate the potential of using non-contact, non-invasive 2D measures to enable regionalising lung mechanics models to equivalent 3D models with a generic map based on the good correlation. The clinical impact of improved lung mechanics digital twins due to regionalising the lung mechanics and volume to specific lung regions could be very high in managing mechanical ventilation and diagnosing or locating lung injury or dysfunction based on regular monitoring instead of intermittent and invasive lung imaging modalities., (Creative Commons Attribution license.)

Patients with acute brain injury (ACI) often require mechanical ventilation (MV) and are subject to pulmonary complications, thus justifying the use of Airway Clearance Techniques (ACTs), but their effects on intracranial pressure (ICP) are unknown. This study investigates the neurological and hemodynamics safety of an ACT called ventilator hyperinflation (VHI) in patients with ACI. This was a randomized clinical equivalence trial, which included patients aged ≥ 18 years with a clinical diagnosis of hemorrhagic stroke, with symptom onset within 48 h. The participants were randomly allocated to the Experimental Group (EG, n = 15), which underwent VHI followed by tracheal aspiration (TA), and the Control Group (CG, n = 15), which underwent TA only. Neurological safety was verified by analyzing the morphology of the ICP wave through the non-invasive B4C sensor, which detects bone deformation of the skull, resulting in a P2/P1 ratio and TTP, and hemodynamics through a multi-parameter monitor. Evaluations were recorded during five instances: T1 (baseline/pre-VHI), T2 (post-VHI and before TA), T3 (post-TA), T4 and T5 (monitoring 10 and 20 min after T3). The comparison between groups showed that there was no effect of the technique on the neurological variables with a mean P2/P1 ratio [F (4,112) = 1.871; p = 0.120; np2 = 0.063] and TTP [F (4,112) = 2.252; p = 0.068; np2 = 0.074], and for hemodynamics, heart rate [F (4,112) = 1.920; p = 0.112; np2 = 0.064] and mean arterial pressure [F(2.73, 76.57) = 0.799; p = 0.488; np2 = 0.028]. Our results showed that VHI did not pose a neurological or hemodynamics risk in neurocritical patients after ACI.

Background: Flow-controlled ventilation (FCV) ensures a constant gas flow whereby precise determination of dynamic compliance is feasible. Accordingly, ventilator pressure settings can be adjusted to achieve the highest compliance. This setting will automatically adapt tidal volume to the functionally available lung volume as a personalized approach. This is in contrast to current ventilation settings, where fixed tidal volumes according to predicted body weight (PBW) are recommended. Aim of this subgroup-analysis was to determine whether applied tidal volume differs in male and female patients after compliance guided individualization of ventilation parameters., Methods: A sub-group analysis of 24 patients randomized to receive flow-controlled ventilation in cardiac surgery was performed. Linear mixed-effects model was used in order to investigate sex related differences in respiratory parameters., Results: Compliance guided pressure titration led to comparable pressure settings in male (N.=18) and female (N.=6) patients. In contrast, the applied tidal volume was significantly lower in female patients (8.6 vs. 9.9, 95% CI: -2.3 to -0.2 mL/kg PBW; P=0.029) compared to male individuals, due to a significantly lower compliance (49.3 vs. 70.3, 95% CI: -33.1 to -8.8 mL/cmH2O; P=0.003). Gas exchange parameters were comparable in either sex., Conclusions: Female patients were found to receive lower tidal volumes after compliance guided individualization compared to men during cardiac surgery. This finding may indicate that the functionally available lung volume in women is lower and thus using PBW may not adequately comply with sex related differences, which supports the use of a personalized ventilation strategy.

Background and Objectives: The challenge of identifying preterm infants with bronchopulmonary dysplasia (BPD) that need tracheostomy placement may delay goals of care (GOC) discussions. By identifying infants with a low probability of ventilation liberation, timely GOC discussions may reduce the time to tracheostomy. Our SMART aim was to reduce the postmenstrual age (PMA) of GOC discussions by 20% in infants with BPD and prolonged invasive ventilatory requirement by October 2020., Methods: Our group conducted a quality improvement initiative at the University of Alabama at Birmingham. Infants were included if born at <32 weeks' gestation and exposed to invasive ventilation for ≥2 weeks beyond 36 weeks' PMA. Interventions included (1) consensus of BPD infants at risk for tracheostomy dependence, (2) monthly multidisciplinary tracheostomy meetings, and (3) development and utilization of tracheostomy educational content for families. Statistical process control charts were used for all analyses., Results: A total of 79 infants were included in analyses, of which 44 infants either received a tracheostomy or died. From X-mR control chart analysis, there was special cause variation in the time to GOC discussions, which decreased from 62 to 51 weeks' PMA related to monthly multidisciplinary conferences. The average PMA at tracheostomy decreased from 80 weeks to 63 weeks with no change in the frequency of tracheostomy placement or discordant GOC discussions in which infants survived to hospital discharge without a tracheostomy., Conclusions: In infants with ventilator-dependent BPD, standardization of GOC discussions reduced the PMA of GOC discussions and tracheostomy., (Copyright © 2024 by the American Academy of Pediatrics.)

Objectives: Guillain-Barré syndrome (GBS) and myasthenia gravis (MG) are the most common causes of acute neuromuscular respiratory failure resulting in ICU admission. This synthetic narrative review summarizes the evidence for the prediction and management of acute neuromuscular respiratory failure due to GBS and MG., Data Sources: We searched PubMed for relevant literature and reviewed bibliographies of included articles for additional relevant studies., Study Selection: English-language publications were reviewed., Data Extraction: Data regarding study methodology, patient population, evaluation metrics, respiratory interventions, and clinical outcomes were qualitatively assessed., Data Synthesis: No single tool has sufficient sensitivity and specificity for the prediction of acute neuromuscular respiratory failure requiring mechanical ventilation. Multimodal assessment, integrating history, examination maneuvers (single breath count, neck flexion strength, bulbar weakness, and paradoxical breathing) and pulmonary function testing are ideal for risk stratification. The Erasmus GBS Respiratory Insufficiency Score is a validated tool useful for GBS. Noninvasive ventilation can be effective in MG but may not be safe in early GBS. Airway management considerations are similar across both conditions, but dysautonomia in GBS requires specific attention. Extubation failure is common in MG, and early tracheostomy may be beneficial for MG. Prolonged ventilatory support is common, and good functional outcomes may occur even when prolonged ventilation is required., Conclusions: Multimodal assessments integrating several bedside indicators of bulbar and respiratory muscle function can aid in evidence-based risk stratification for respiratory failure among those with neuromuscular disease. Serial evaluations may help establish a patient's trajectory and to determine timing of respiratory intervention., Competing Interests: Dr. Mobach received funding from Biogen, Amylyx, Mitsubishi Tanabe, and Quralis. Dr. Rabinstein serves on the Clinical Events Classification committee for Boston Scientific and serves on advisory boards for Astra Zeneca, Shionogi, Brainomix, and Chiesi. The remaining authors have disclosed that they do not have any potential conflicts of interest., (Copyright © 2024 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved.)

Introduction: Ventilations are a critical component of cardiopulmonary resuscitation (CPR). There is conflicting evidence, however, on the most appropriate method of ventilation during cardiac arrest management. Recent evidence has suggested that regardless of the optimal ventilation strategy, ventilations are often not delivered compliant with guideline recommendations. Recent technological advancements have allowed for accurate measurement and real-time feedback of ventilation rate and volume during resuscitation. Simulation studies have found significant improvements in ventilations with the use of real-time feedback during simulated cardiac arrest. The use of feedback has not been studied in clinical practice. The objective of this study was to determine whether the use of real-time feedback improves compliance with pre-defined targets for ventilation rate and volume during out-of-hospital cardiac resuscitation., Methods: This was a before-and-after study with four paramedic services in Ontario, Canada. We enrolled adult, out-of-hospital cardiac arrest (OHCA) patients where the ZOLL Accuvent® device was utilized to measure ventilation rate and volume. In the before phase (without feedback), the Accuvent® was used to measure ventilations, however, providers were blinded to the real-time feedback. In the after phase (with feedback), the feedback dashboard was activated and providers used the real-time feedback to guide their ventilations. All other aspects of resuscitation remained consistent throughout the study. The main objective of the study was to compare the proportion of each case that was compliant with pre-defined ventilation targets with real-time feedback and without real-time feedback. We also examined the use of advanced airways on ventilation quality and examined for associations between ventilation parameters and return of circulation., Results: We enrolled 412 patients in the study (191 in the before phase without feedback and 221 in the after phase with feedback). Overall, we found significant improvements in both ventilation rate and volume in the after phase (with real-time feedback) compared to the before phase (without real-time feedback). We did not find any differences in ventilation compliance with or without advanced airways, or intra-arrest or post-cardiac arrest., Conclusion: The use of real-time feedback was associated with an increased proportion of ventilations that were compliant with pre-defined targets during cardiac resuscitation. Further work is required to improve the use of real-time ventilation feedback, and to determine the impact of ventilations on patient outcomes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Rationale: Lung-protective strategies using low Vt and moderate positive end-expiratory pressure (PEEP) are considered best practice in critical care, but interventional trials have never been conducted in patients with acute brain injuries because of concerns about carbon dioxide control and the effect of PEEP on cerebral hemodynamics. Objectives: To test the hypothesis that ventilation with lower VT and higher PEEP compared to conventional ventilation would improve clinical outcomes in patients with acute brain injury. Methods: In this multicenter, open-label, controlled clinical trial, 190 adult patients with acute brain injury were assigned to receive either a lung-protective or a conventional ventilatory strategy. The primary outcome was a composite endpoint of death, ventilator dependency, and acute respiratory distress syndrome (ARDS) at Day 28. Neurological outcome was assessed at ICU discharge by the Oxford Handicap Scale and at 6 months by the Glasgow Outcome Scale. Measurements and Main Results: The two study arms had similar characteristics at baseline. In the lung-protective and conventional strategy groups, using an intention-to-treat approach, the composite outcome at 28 days was 61.5% and 45.3% (relative risk [RR], 1.35; 95% confidence interval [CI], 1.03-1.79; P  = 0.025). Mortality was 28.9% and 15.1% (RR, 1.91; 95% CI, 1.06-3.42; P  = 0.02), ventilator dependency was 42.3% and 27.9% (RR, 1.52; 95% CI, 1.01-2.28; P  = 0.039), and incidence of ARDS was 30.8% and 22.1% (RR, 1.39; 95% CI, 0.85-2.27; P  = 0.179), respectively. The trial was stopped after enrolling 190 subjects because of termination of funding. Conclusions: In patients with acute brain injury without ARDS, a lung-protective ventilatory strategy, as compared with a conventional strategy, did not reduce mortality, percentage of patients weaned from mechanical ventilation, or incidence of ARDS and was not beneficial in terms of neurological outcomes. Because of the early termination, these preliminary results require confirmation in larger trials. Clinical trial registered with www.clinicaltrials.gov (NCT01690819).

Patients with acute respiratory distress syndrome (ARDS) require periods of deep sedation and mechanical ventilation, leading to diaphragm dysfunction. Our study seeks to determine whether the combination of temporary transvenous diaphragm neurostimulation (TTDN) and mechanical ventilation changes the degree of diaphragm injury and cytokines concentration in a preclinical ARDS model. Moderate ARDS was induced in pigs using oleic acid, followed by ventilation for 12 h post-injury with volume-control at 8 mL/kg, positive end-expiratory pressure (PEEP) 5 cmH 2 O, respiratory rate and [Formula: see text] set to achieve normal arterial blood gases. Two groups received TTDN: every second breath (MV + TTDN50%, n = 6) or every breath (MV + TTDN100%, n = 6). One group received ventilation only (MV, n = 6). Full-thickness diaphragm and quadricep muscle biopsies were taken at study end. Samples were fixed and stained with hematoxylin and eosin and a point-counting technique was applied to calculate abnormal muscle area fraction. Cytokine concentrations were measured in homogenized tissue using porcine-specific enzyme-linked immunosorbent assay (ELISA) and compared with serum samples. Percentage of abnormal diaphragm tissue was different between MV [8.1% (6.0-8.8)] versus MV + TTDN50% [3.4% (2.1-4.8)], P = 0.010 and MV versus MV + TTDN100% [3.1% (2.5-4.0)], P = 0.005. Percentage of abnormal quadriceps tissue was not different between groups. Cytokine concentration patterns in diaphragm samples were different between all groups ( P < 0.001) and the interaction between TTDN application and resultant cytokine concentration pattern was significant ( P = 0.025). TTDN, delivered in synchrony with mechanical ventilation, mitigated diaphragm injury, as evidenced by less abnormal tissue in the diaphragm samples, in pigs with oleic acid-induced ARDS and is an exciting tool for lung and diaphragm-protective ventilation. NEW & NOTEWORTHY This study adds to our understanding of applying transvenous diaphragm neurostimulation synchronously with mechanical ventilation by examining its effects on diaphragm muscle injury and cytokine concentration patterns in pigs with acute respiratory distress syndrome (ARDS). We observed that using this therapy for 12 h post lung injury mitigated ventilator-induced diaphragm injury and changed the pattern of cytokine concentration measured in diaphragm tissue. These findings suggest that transvenous diaphragm neurostimulation is an exciting tool for lung and diaphragm protective ventilation.

Purpose: Optimal fluid management in patients with acute respiratory distress syndrome (ARDS) is challenging due to risks associated with both circulatory failure and fluid overload. The performance of dynamic indices to predict fluid responsiveness (FR) in ARDS patients is uncertain., Methods: This post hoc analysis of the HEMOPRED study compared the performance of dynamic indices in mechanically ventilated patients with shock, with and without ARDS, to predict FR, defined as an increase in aortic velocity time integral (VTI)  > 10% after passive leg raising (PLR)., Results: Among 540 patients, 117 (22%) had ARDS and were ventilated with a median tidal volume of 7.6 mL/kg [6.9-8.4] and a median positive end-expiratory pressure of 7 cmH 2 O [5-9]. FR was observed in 45 ARDS patients (39% vs 44% in non-ARDS patients, p = 0.384). Reliability of dynamic indices to predict FR remained consistent in ARDS patients, though with different thresholds. Collapsibility index of the superior vena cava (ΔSVC) showed the best predictive performance in both ARDS (area under the curve [AUC] = 0.763 [0.659-0.868]) and non-ARDS (AUC = 0.750 [0.698-0.802]) patients. A right to left ventricle end-diastolic area ratio  > 0.8 or paradoxical septal motion were strongly linked to the absence of FR (> 80% specificity). FR was not associated with intensive care unit (ICU) mortality (47% vs. 46%, p = 1). However, hypovolemia, defined as an aortic VTI increase  > 32% during PLR (median increase in patients with a partial SVC collapse) was independently associated with ICU mortality (odds ratio [OR] = 1.355 [1.077-1.705], p = 0.011), as well as pulse pressure variation (OR = 1.014 [1.001-1.026], p = 0.034)., Conclusion: Performance of dynamic indices to predict FR appears preserved in ARDS patients, albeit with distinct thresholds. Hypovolemia, indicated by a  > 32% increase in aortic VTI during PLR, rather than FR, was associated with ICU mortality in this population., (© 2024. Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Acute Respiratory Distress Syndrome (ARDS) necessitates personalized treatment strategies due to its heterogeneity, aiming to mitigate Ventilator-Induced Lung Injury (VILI). Advanced monitoring techniques, including imaging, driving pressure, transpulmonary pressure, and mechanical power, present potential avenues for tailored interventions., Objective: To review some of the most important techniques for achieving greater personalization of mechanical ventilation in ARDS patients as evaluated in randomized clinical trials, by analyzing their effect on three clinically relevant aspects: mortality, ventilator-free days, and gas exchange., Methods: Following PRISMA guidelines, we conducted a systematic review and meta-analysis of Randomized Clinical Trials (RCTs) involving adult ARDS patients undergoing personalized ventilation adjustments. Outcomes were mortality (primary end-point), ventilator-free days, and oxygenation improvement., Results: Among 493 identified studies, 13 RCTs (n = 1255) met inclusion criteria. No personalized ventilation strategy demonstrated superior outcomes compared to traditional protocols. Meta-analysis revealed no significant reduction in mortality with image-guided (RR 0.88, 95 % CI 0.70-1.11), driving pressure-guided (RR 0.61, 95 % CI 0.29-1.30), or transpulmonary pressure-guided (RR 0.85, 95 % CI 0.58-1.24) strategies. Ventilator-free days and oxygenation outcomes showed no significant differences., Conclusion: Our study does not support the superiority of personalized ventilation techniques over traditional protocols in ARDS patients. Further research is needed to standardize ventilation strategies and determine their impact on mechanical ventilation outcomes., Competing Interests: Declaration of competing interest The authors declare that they have no financial or personal relationships that could potentially bias their work or influence the interpretation of the results presented in this manuscript., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Inplasy Registration Number: INPLASY202390072., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Venovenous extracorporeal membrane oxygenation (VV ECMO) facilitates the reduction of mechanical ventilation (MV) support in acute respiratory failure. Contrary to increasing evidence regarding its initiation, the optimal timing of VV ECMO weaning in interaction with MV weaning is undetermined. In this retrospective study, 47 patients who received VV ECMO between 2013 and 2021 and survived ≥1 day after ECMO cessation were divided according to their MV status before ECMO removal: 28 patients were classified into an "ECMO weaning during assisted MV/spontaneous breathing" group and 19 into an "ECMO weaning during controlled MV" group. Extracorporeal membrane oxygenation duration was longer in the "assisted MV/spontaneous breathing" group (17 [Interquartile range (IQR) = 11-35] vs. 6 [5-11] days, p < 0.001). These patients had a longer intensive care unit (ICU) stay after ECMO start (48 [29-66] vs. 31 [15-40] days, p = 0.01). No significant differences were found for MV duration after ECMO start (30 [19-45] vs. 19 [12-30] days, p = 0.06) and further ICU survival (86% vs. 89%, p ≥ 0.9). There was a trend toward more patients with mechanical ECMO complications in the "assisted MV/spontaneous breathing" group (57% vs. 32%, p = 0.08). Thus, our results suggest a possible benefit of early ECMO weaning during controlled MV., Competing Interests: Disclosure: The authors have no conflicts of interest to report., (Copyright © ASAIO 2024.)

The use of invasive mechanical ventilation (IMV) is crucial in rescuing patients with respiratory dysfunction. Accurately predicting the demand for IMV is vital for clinical decision-making. However, current techniques are invasive and challenging to implement in pre-hospital and emergency rescue settings. To address this issue, a real-time prediction method utilizing only non-invasive parameters was developed to forecast IMV demand in this study. The model introduced the concept of real-time warning and leveraged the advantages of machine learning and integrated methods, achieving an AUC value of 0.935 (95% CI 0.933-0.937). The AUC value for the multi-center validation using the AmsterdamUMCdb database was 0.727, surpassing the performance of traditional risk adjustment algorithms (OSI(oxygenation saturation index): 0.608, P/F(oxygenation index): 0.558). Feature weight analysis demonstrated that BMI, Gcsverbal, and age significantly contributed to the model's decision-making. These findings highlight the substantial potential of a machine learning real-time dynamic warning model that solely relies on non-invasive parameters to predict IMV demand. Such a model can provide technical support for predicting the need for IMV in pre-hospital and disaster scenarios., (© 2024. International Federation for Medical and Biological Engineering.)

Background: This study aimed to develop and validate a model to predict the risk of prolonged weaning from mechanical ventilation in patients with abdominal trauma., Methods: Patients with abdominal trauma were included and were divided into the training cohort and the validation cohort. The model was constructed using predictive factors identified by univariable and multivariable logistic regressions, and was validated by receiver operating characteristic curve, calibration curve, and decision curve analysis. Clinical outcomes were compared between model-stratified risk groups., Results: In total,190 patients were included, with 133 in the training cohort and 57 in the validation cohort. Six predictive factors, the Acute Physiology and Chronic Health Evaluation II score, Injury Severity Score, Glasgow coma scale, total bilirubin, skeletal muscle index, and abdominal fat index, were identified and were included in the model. The model predicting prolonged weaning owned a good discrimination, had an excellent calibration, and exhibited a favorable net benefit within a reasonable range of threshold probabilities. Significant differences were shown in prolonged weaning and clinical outcomes between the high-risk and low-risk groups (P < .05). Multivariable Cox regression analysis showed that patients in the high-risk group had greater risk of 28-day mortality (P < .05)., Conclusion: This study established a model to predict the risk of prolonged weaning from mechanical ventilation and clinical outcomes in patients with abdominal trauma. Skeletal muscle index was identified as one of independent risk factors of prolonged weaning. The findings offer valuable insights for respiratory management in patients with abdominal trauma., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Introduction: Prone position ventilation (PPV) of patients with adult respiratory distress syndrome (ARDS) supported with veno-venous extracorporeal membrane oxygenation (V-V ECMO) may improve oxygenation and alveolar recruitment and is recommended when extensive dorsal consolidations are present, but only few data regarding adverse events (AE) related to PPV in this group of patients have been published., Methods: Nationwide retrospective analysis of 68 COVID-19 patients admitted from March 2020 - December 2021 with severe ARDS and need of V-V ECMO support. The number of patients treated with PPV, number of PPV-events, timing, the time spent in prone position, number and causes of AE are reported. Causes to stop the PPV regimen and risk factors for AE were explored., Results: 44 out of 68 patients were treated with PPV, and 220 PPV events are evaluated. AE were identified in 99 out of 220 (45%) PPV events and occurred among 31 patients (71%). 1 fatal PPV related AE was registered. Acute supination occurred in 19 events (9%). Causes to stop the PPV regimen were almost equally distributed between effect (weaned from ECMO), no effect, death (of other reasons) and AE. Frequent causes of AE were pressures sores and ulcers, hypoxia, airway related and ECMO circuit related. Most AE occurred during patients first or second PPV event., Conclusions: PPV treatment was found to carry a high incidence of PPV related AE in these patients. Causes and preventive measures to reduce occurrence of PPV related AE during V-V ECMO support need further exploration., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: This study aimed to investigate the impact of optimizing the subglottic suction and aspiration sequence on ventilator-associated pneumonia (VAP) incidence., Methods: A total of 108 patients undergoing transcatheter orotracheal intubation with subglottic secretion drainage (SSD) and mechanical ventilation were selected from the Department of Critical Care Medicine in our hospital between September 2021 and March 2023. The patients were randomly assigned to either the observation group or the control group (54 cases each) using a random number method. In the control group, patients underwent manual airway suction followed by subglottic suction with -100 mmHg pressure. In the observation group, subglottic suction with -100 mmHg pressure was performed first, followed by manual airway suction. The comparative analysis included blood gas parameters, sputum suction effectiveness, VAP occurrence, 28-day morbidity and mortality rates, tracheal secretion culture results, and the workload of nurses., Results: The observation group exhibited significantly shorter tape replacement time, sputum suction time, and number of suctions, along with a longer suction interval compared to the control group (P < 0.05). Post-suctioning, the observation group demonstrated improved blood gas function and a lower incidence of VAP (P < .05). No significant difference in adverse reaction incidence was observed between the two groups (P > .05); however, the Kolcaba score was higher in the observation group (P < .05)., Conclusions: Pre-endotracheal intubation oral and nasal sputum suctioning proves effective in reducing the risk of VAP, lessening the workload of nurses, and enhancing the comfort of sputum suctioning.

Background: Researchers have tried unsuccessfully for many years using randomized controlled trials to show the efficacy of prone ventilation in treating ARDS. These failed attempts were of use in designing the successful PROSEVA trial, published in 2013. However, the evidence provided by meta-analyses in support of prone ventilation for ARDS was too low to be conclusive. The present study shows that meta-analysis is indeed not the best approach for the assessment of evidence as to the efficacy of prone ventilation., Methods: We performed a cumulative meta-analysis to prove that only the PROSEVA trial, due to its strong protective effect, has substantially impacted on the outcome. We also replicated nine published meta-analyses including the PROSEVA trial. We performed leave-one-out analyses, removing one trial at a time from each meta-analysis, measuring p values for effect size, and also the Cochran's Q test for heterogeneity assessment. We represented these analyses in a scatter plot to identify outlier studies influencing heterogeneity or overall effect size. We used interaction tests to formally identify and evaluate differences with the PROSEVA trial., Results: The positive effect of the PROSEVA trial accounted for most of the heterogeneity and for the reduction of overall effect size in the meta-analyses. The interaction tests we conducted on the nine meta-analyses formally confirmed the difference in the effectiveness of prone ventilation between the PROSEVA trial the other studies., Conclusions: The clinical lack of homogeneity between the PROSEVA trial design and the other studies should have discouraged the use of meta-analysis. Statistical considerations support this hypothesis, suggesting that the PROSEVA trial is an independent source of evidence., Competing Interests: Conflict of interest None., (Copyright © 2023 Sociedade Portuguesa de Pneumologia. Published by Elsevier España, S.L.U. All rights reserved.)

Introduction: Preterm infants close to viability commonly require mechanical ventilation (MV) for respiratory distress syndrome. Despite commonly used lung-sparing ventilation techniques, rapid lung expansion during MV induces lung injury, a risk factor for bronchopulmonary dysplasia. This study investigates whether ventilation with optimized lung expansion is feasible and whether it can further minimize lung injury. Therefore, optimized lung expansion ventilation (OLEV) was compared to conventional volume targeted ventilation., Methods: Twenty preterm lambs were surgically delivered after 132 days of gestation. Nine animals were randomized to receive OLEV for 24 h, and seven received standard MV. Four unventilated animals served as controls (NV). Lungs were sampled for histological analysis at the end of the experimental period., Results: Ventilation with OLEV was feasible, resulting in a significantly higher mean ventilation pressure (0.7-1.3 mbar). Temporary differences in oxygenation between OLEV and MV did not reach clinically relevant levels. Ventilation in general tended to result in higher lung injury scores compared to NV, without differences between OLEV and MV. While pro-inflammatory tumor necrosis factor-α messenger RNA (mRNA) levels increased in both ventilation groups compared to NV, only animals in the MV group showed a higher number of CD45-positive cells in the lung. In contrast, mean (standard deviations) surfactant protein-B mRNA levels were significantly lower in OLEV, 0.63 (0.38) compared to NV 1.03 (0.32) (p = .023, one-way analysis of variance)., Conclusion: In conclusion, a small reduction in pulmonary inflammation after 24 h of support with OLEV suggests potential to reduce preterm lung injury., (© 2024 The Author(s). Pediatric Pulmonology published by Wiley Periodicals LLC.)

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., Competing Interests: Competing interests: We have read and understood the BMJ policy on declaration of interests and declare the following interests: LBW and MAM’s institutions receive funding from the National Institutes of Health; MAM’s institution receives funding from the Department of Defense, Roche-Genentech, and Quantum Therapeutics; LBW received funding from Arrowhead, Akebia, Santhera, Global Blood Therapeutics, and Boehringer Ingelheim; she is a stockholder of Virtuoso Surgical, a company that is not related to the topic of this review; MAM received funding from Gilead Pharmaceuticals, Novartis, Johnson and Johnson, Citius Pharmaceuticals, Pliant Therapeutics, Gen1ELifesciences, and Calcimedica., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Introduction: Sedation in mechanically ventilated adults in the intensive care unit (ICU) is commonly achieved with intravenous infusions of propofol, dexmedetomidine or benzodiazepines. Significant limitations associated with each can impact their usage. Inhaled isoflurane has potential benefit for ICU sedation due to its safety record, sedation profile, lack of metabolism and accumulation, and fast wake-up time. Administration in the ICU has historically been restricted by the lack of a safe and effective delivery system for the ICU. The Sedaconda Anaesthetic Conserving Device-S (Sedaconda ACD-S) has enabled the delivery of inhaled volatile anaesthetics for sedation with standard ICU ventilators, but it has not yet been rigorously evaluated in the USA. We aim to evaluate the efficacy and safety of inhaled isoflurane delivered via the Sedaconda ACD-S compared with intravenous propofol for sedation of mechanically ventilated ICU adults in USA hospitals., Methods and Analysis: INhaled Sedation versus Propofol in REspiratory failure in the ICU (INSPiRE-ICU1) is a phase 3, multicentre, randomised, controlled, open-label, assessor-blinded trial that aims to enrol 235 critically ill adults in 14 hospitals across the USA. Eligible patients are randomised in a 1.5:1 ratio for a treatment duration of up to 48 (±6) hours or extubation, whichever occurs first, with primary follow-up period of 30 days and additional follow-up to 6 months. Primary outcome is percentage of time at target sedation range. Key secondary outcomes include use of opioids during treatment, spontaneous breathing efforts during treatment, wake-up time at end of treatment and cognitive recovery after treatment., Ethics and Dissemination: Trial protocol has been approved by US Food and Drug Administration (FDA) and central (Advarra SSU00208265) or local institutional review boards ((IRB), Cleveland Clinic IRB FWA 00005367, Tufts HS IRB 20221969, Houston Methodist IRB PRO00035247, Mayo Clinic IRB Mod22-001084-08, University of Chicago IRB21-1917-AM011 and Intermountain IRB 033175). Results will be presented at scientific conferences, submitted for publication, and provided to the FDA., Trial Registration Number: NCT05312385., Competing Interests: Competing interests: CB, TDG, JK and CH have received consulting fees from Sedana Medical AB as members of their US Trials Steering Committee. JWD has received speaker honoraria from Sedana Medical AB. IS and MF and PVS are employed by Sedana Medical AB., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Capnography, routinely used in operating rooms and intensive care units, reveals essential information on lung ventilation and ventilation-perfusion matching. Mainstream capnography directly measures CO 2 in the breathing circuit for accurate analysis and is considered a reference technique. Sidestream capnography, however, analyzes gas away from the patient leading to potentially less accurate measures. While these methodological differences impact the capnogram indices in mechanically ventilated patients, such assessments during spontaneous breathing are essentially lacking. Accordingly, we aimed to compare mainstream and sidestream capnography in spontaneously breathing subjects, focusing on differences in capnogram shape and dead space indices at various respiratory rates. Simultaneous mainstream and sidestream time and volumetric capnography were performed on spontaneously breathing adults (n = 35). Measurements were performed during controlled low (10/min), medium (12/min), and high (20/min) breathing rates as a challenge. Correlation and Bland-Altman analyses were used to assess trends and agreements between time and volumetric capnography indices obtained by the mainstream and sidestream techniques, including end-tidal CO 2 (ETCO 2 ), shape factors reflecting the slopes of phases 2 and 3, and anatomical and physiological dead space fractions. ETCO 2 and physiological dead space measured by mainstream and sidestream techniques showed excellent correlations (r > 0.90, p < 0.001 for all breathing rates) and agreements. While strong correlations and moderate agreements were evidenced in the parameters reflecting the late phase of expiration (phase 3 slope and exhaled CO 2 volume), these relationships were weaker for indices related to the early phase of expiration (phase 2 slope, anatomical dead space). Changing breathing frequency caused significant alterations in all capnography parameters, which were detectable by both mainstream and sidestream techniques. Sidestream capnography cannot substitute the more accurate mainstream technique for measuring the absolute values of shape factors and ventilation dead space fractions. However, sidestream capnography is also able to detect and track changes in uneven alveolar emptying, ventilation-perfusion matching and ventilation dead space fraction in spontaneously breathing subjects., (© 2024. The Author(s).)

Background: The benefit of Inhaled nitric oxide (iNO) therapy in the setting of COVID-19-related ARDS is obscure. We performed a multicenter retrospective study to evaluate the impact of iNO on patients with COVID-19 who require respiratory support., Methods: This retrospective multicenter study included COVID-19 patients enrolled in the SCCM VIRUS COVID-19 registry who were admitted to different Mayo Clinic sites between March 2020 and June 2022 and required high-flow nasal cannula (HFNC), non-invasive ventilation (NIV), or invasive mechanical ventilation (IMV). Patients were included in the 'spontaneously breathing' group if they remained non-intubated or were initiated on an HFNC (± NIV) before intubation. Patients who got intubated without prior use of an HFNC (± NIV) were included in the 'intubated group.' They were further divided into categories based on their iNO usage. Propensity score matching (PSM) and inverse propensity of treatment weighting (IPTW) were performed to examine outcomes., Results: Among 2767 patients included in our analysis, 1879 belonged to spontaneously breathing (153 received iNO), and 888 belonged to the intubated group (193 received iNO). There was a consistent improvement in FiO2 requirement, P/F ratio, and respiratory rate within 48 h of iNO use among both spontaneously breathing and intubated groups. However, there was no significant difference in intubation risk with iNO use among spontaneously breathing patients (PSM OR 1.08, CI 0.71-1.65; IPTW OR 1.10, CI 0.90-1.33). In a time-to-event analysis using Cox proportional hazard model, spontaneously breathing patients initiated on iNO had a lower hazard ratio of in-hospital mortality (PSM HR 0.49, CI 0.32-0.75, IPTW HR 0.40, 95% CI 0.26-0.62) but intubated patients did not (PSM HR: 0.90; CI 0.66-1.24, IPTW HR 0.98, 95% CI 0.73-1.31). iNO use was associated with longer in-hospital stays, ICU stays, ventilation duration, and a higher incidence of creatinine rise., Conclusions: This retrospective propensity-score matched study showed that spontaneously breathing COVID-19 patients on HFNC/ NIV support had a decreased in-hospital mortality risk with iNO use in a time-to-event analysis. Both intubated and spontaneously breathing patients had improvement in oxygenation parameters with iNO therapy but were associated with longer in-hospital stays, ICU stays, ventilation duration, and higher incidence of creatinine rise., (© 2024. The Author(s).)

Background: Training in mechanical ventilation is a key goal in critical care fellowship education. Web-based simulators offer a cost-effective and readily available alternative to traditional on-site simulators. However, it is unclear how effective they are as teaching tools. In this study, we evaluated the test scores of fellows who underwent mechanical ventilation training by using a web-based simulator compared with fellows who used an on-site simulator during a mechanical ventilation course., Methods: This was a nonrandomized controlled trial conducted as part of a mechanical ventilation course that involved 70 first-year critical care fellows. The course was identical except for the simulation technology used. One group of instructors used a traditional on-site simulator, the ASL 5000 Lung Solution ( n = 39). The second group was instructed in using a web-based simulator, VentSim ( n = 31). Each fellow completed a pre-course test and a post-course test by using a validated, case-based ventilator waveform examination that consisted of 5 questions with a total possible score of 100. The primary outcome was a comparison of the mean scores on the posttest between the 2 groups. The study was designed as a non-inferiority trial with a predetermined margin of 10 points., Results: There was no significant difference in the mean ± SD pretest scores between the web-based and the on-site groups (21.1 ± 12.6 and 26.9 ± 13.6 respectively; P = .11). The mean ± SD posttest scores were 45.6 ± 25.0 for the web-based simulator and 43.4 ± 16.5 for on-site simulator (mean difference 2.2; one-sided 95% CI -7.0 to ∞; P non-inferiority = .02 [non-inferiority confirmed]). Changes in mean ± SD scores (posttest - pretest) were 25.9 ± 20.9 for the web-based simulator and 16.5 ± 15.9 for the on-site simulator (mean difference 9.4, one-sided 95% CI 0.9 to ∞; P non-inferiority < .001 [non-inferiority confirmed])., Conclusions: In the education of first-year critical care fellows on mechanical ventilation waveform analysis, a web-based mechanical ventilation simulator was non-inferior to a traditional on-site mechanical ventilation simulator., Competing Interests: Dr Safadi is the creator of the web-based mechanical ventilation simulator that was used in this study. The remaining authors have reported no conflicts of interest., (Copyright © 2024 by Daedalus Enterprises.)

Backgroud: Lung volume measurements are important for monitoring functional aeration and recruitment and may help guide adjustments in ventilator settings. The expiratory phase of airway pressure release ventilation (APRV) may provide physiologic information about lung volume based on the expiratory flow-time slope, angle, and time to approach a no-flow state (expiratory time [T E ]). We hypothesized that expiratory flow would correlate with estimated lung volume (ELV) as measured using a modified nitrogen washout/washin technique in a large-animal lung injury model., Methods: Eight pigs (35.2 ± 1.0 kg) were mechanically ventilated using an Engström Carescape R860 on the APRV mode. All settings were held constant except the expiratory duration, which was adjusted based on the expiratory flow curve. Abdominal pressure was increased to 15 mm Hg in normal and injured lungs to replicate a combination of pulmonary and extrapulmonary lung injury. ELV was estimated using the Carescape FRC INview tool. The expiratory flow-time slope and T E were measured from the expiratory flow profile., Results: Lung elastance increased with induced lung injury from 29.3 ± 7.3 cm H 2 O/L to 39.9 ± 15.1cm H 2 O/L, and chest wall elastance increased with increasing intra-abdominal pressures (IAPs) from 15.3 ± 4.1 cm H 2 O/L to 25.7 ± 10.0 cm H 2 O/L in the normal lung and 15.8 ± 6.0 cm H 2 O/L to 33.0 ± 6.2 cm H 2 O/L in the injured lung ( P = .39). ELV decreased from 1.90 ± 0.83 L in the injured lung to 0.67 ± 0.10 L by increasing IAP to 15 mm Hg. This had a significant correlation with a T E decrease from 2.3 ± 0.8 s to 1.0 ± 0.1 s in the injured group with increasing insufflation pressures (ρ = 0.95) and with the expiratory flow-time slope, which increased from 0.29 ± 0.06 L/s 2 to 0.63 ± 0.05 L/s 2 (ρ = 0.78)., Conclusions: Changes in ELV over time, and the T E and flow-time slope, could be used to demonstrate evolving lung injury during APRV. Using the slope to infer changes in functional lung volume represents a unique, reproducible, real-time, bedside technique that does not interrupt ventilation and may be used for clinical interpretation., Competing Interests: Dr Kollisch-Singule discloses a relationship with Dräger Medical Systems. Dr Habashi is the founder of ICON, of which Ms Andrews is an employee. Dr Habashi holds patents on a method of initiating, managing, and/or weaning airway pressure release ventilation, as well as controlling a ventilator in accordance with the same. Drs Kaczka and Herrmann are co-founders and shareholders of OscillaVent, and are co-inventors on a patent involving multifrequency oscillatory ventilation. Drs Kaczka and Herrmann disclose a relationship with ZOLL Medical. Dr Kaczka discloses a relationship with Lungpacer Medical. The remaining authors have disclosed no conflicts of interest. The authors maintain that industry had no role in the design and conduct of the study; the collection, management, analysis, or interpretation of the data; nor the preparation, review, or approval of the manuscript., (Copyright © 2024 by Daedalus Enterprises.)

Background: Data describing outcome of extracorporeal membrane oxygenation (ECMO) support in Tuberculosis (Tbc)-associated acute respiratory distress syndrome (ARDS) remain sparce and are mostly confined to singular case reports. The aim of this case series was to analyze intensive care unit (ICU) survival in patients with Tbc-associated ARDS receiving veno-venous (vv-) ECMO support and to compare those to patients not receiving ECMO., Case Presentation: ICU survival was analyzed retrospectively in 14 patients treated for Tbc-associated ARDS at three ECMO-referral university hospitals (Hannover Medical School, University Hospital Bonn (both Germany) and University Hospital Zurich (Switzerland)) during the last 14 years, of which eight patients received additional vv-ECMO support and six standard care only. ICU survival was significantly higher in patients receiving additional vv-ECMO support (62.5%, n = 5/8) compared to those that did not (16.7%, n = 1/6) (p = 0.021). ECMO support was associated with reduced ICU mortality (Hazard ratio adjusted for baseline SOFA score [adj. HR] 0.125 (95% confidence interval (CI): 0.023-0.689), p = 0.017). Median (IQR) time on ECMO and invasive ventilation in the vv-ECMO group were 20 (11-26) and 37 (27-53) days, respectively. Major bleeding defined as transfusion requirement of 4 units of blood or more or surgical and/or radiologic intervention occurred only in one patient, in whom pulmonary bleeding was fatal. Thromboembolic events occurred in none of the vv-ECMO patients., Discussion and Conclusions: This retrospective analysis from three large ECMO centers with similar SOPs suggests vv-ECMO support as a feasible approach in patients with severe Tbc-associated ARDS. Although affiliated with extended runtimes, vv-ECMO might be associated with improved survival in those patients. Vv-ECMO support should thus be considered in Tbc-associated ARDS to enable lung protective strategies during prolonged lung recovery., (© 2024. The Author(s).)

Background: Extubation failure is a crucial issue for acute respiratory distress syndrome (ARDS). Ultrasound of the lung and diaphragm is individually valuable for predicting extubation outcomes. We aimed to determine whether combined lung and diaphragmatic ultrasound could improve the accuracy of predicting the extubation of ARDS patients., Methods: This was a prospective cohort study of ARDS patients who were ready for extubation. The lung ultrasound score (LUS), diaphragmatic displacement (DD), diaphragm thickening fraction (DTF), and diaphragmatic-rapid shallow breathing index (D-RSBI) were measured at the end of the spontaneous breathing trial. The primary outcome was extubation success. Logistic regression was used to combine these indicators, and the predictive performance of the single and combined indicators was evaluated through receiver operating characteristic (ROC) curves, the Hosmer-Lemeshow Ĉ-test, and the Brier score. Multivariate logistic regression was used to determine the association between combined ultrasound indicators and extubation success., Results: This study enrolled 132 eligible patients from January 2019 to December 2022. A total of 71% (94/132) of patients were successfully extubated from mechanical ventilation. The combination of LUS and D-RSBI had the largest area under the ROC curves, the lowest Brier score, and the greatest calibration. After formula transformation, LUS + 2.43 × D-RSBI ≤ 14.273 was significantly associated with extubation success in ARDS patients., Conclusions: In ARDS patients receiving mechanical ventilation, the combination of LUS and D-RSBI was more accurate than a single parameter alone in predicting extubation outcomes. This combined approach could help refine extubation protocols in critical care. Clinical trial registration This study is registered online with the Chinese Clinical Trial Registry (ChiCTR), http://www.chictr.org.cn , ChiCTR1800019340 (Registration time: 2018/11/06)., (© 2024. The Author(s).)

Objective: To compare reintubation rates after planned extubation and unplanned extubation (UE) in patients in neonatal intensive care units (NICUs), to analyse risk factors for reintubation after UE and to compare outcomes in patients with and without UE., Design: Prospective, observational study nested in a randomised controlled trial (SEPREVEN/Study on Epidemiology and PRevention of adverse EVEnts in Neonates). Outcomes were expected to be independent of the intervention tested., Setting: 12 NICUs in France with a 20-month follow-up, starting November 2015., Patients: n=2280 patients with a NICU stay >2 days, postmenstrual age ≤42 weeks on admission., Interventions/exposure: Characteristics of UE (context, timing, sedative administration in the preceding 6 hours, weaning from ventilation at time of UE) and patients., Main Outcome Measures: Healthcare professional-reported UE rates, reintubation/timing after extubation, duration of mechanical ventilation, mortality and bronchopulmonary dysplasia (BPD)., Results: There were 162 episodes of UE (139 patients, median gestational age (IQR) 27.3 (25.6-31.7) weeks). Cumulative reintubation rates within 24 hours and 7 days of UE were, respectively, 50.0% and 57.5%, compared with 5.5% and 12.3% after a planned extubation. Independent risk factors for reintubation within 7 days included absence of weaning at the time of UE (HR, 95% CI) and sedatives in the preceding 6 hours (HR 1.93, 95% CI 1.04 to 3.60). Mortality at discharge did not differ between patients with planned extubation or UE. UE was associated with a higher risk of BPD., Conclusion: In the SEPREVEN trial, reintubation followed UE in 58% of the cases, compared with 12% after planned extubation., Trial Registration Number: NCT02598609., Competing Interests: Competing interests: TD, FC, HY, EA, RL and LS have no conflict of interest to declare. MT declared consulting fees from Pfizer and payments for honoraria and lectures from Gennisium Pharma and Pfizer. LC declares honoraria from Chiesi for lectures unrelated to this topic. CJ declares payment or honoraria for lectures or presentations for Nestlé and Menarini unrelated to this topic. XD declares personal payment for lectures, presentations, speakers bureaus, manuscript writing or educational events from AstraZeneca and from Gennisium Pharma, and support for attending meetings and/or travel (launch congress organisers, launch meeting 2023, European Society for Pediatric Research, Abbott). HY declares support for attending meetings and/or travel from Duomed, Guigoz and Chiesi., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The dynamic regional accuracy of electrical impedance tomography has not yet been validated. We aimed to compare the regional accuracy of electrical impedance tomography with that of four-dimensional computed tomography during dynamic ventilation., Methods: This single-center, prospective, observational study conducted in a general intensive care unit included adult patients receiving mechanical ventilation from July 2021 to February 2024. The patients were mechanically ventilated passively and underwent electrical impedance tomography and four-dimensional computed tomography on the same day., Results: Overall, 45 patients were analyzed. The correlation coefficients in regional dynamic ventilation between four-dimensional computed tomography and electrical impedance tomography in each region were 0.963, 0.963, 0.835 (ventral, central, and dorsal, respectively) in the right lung and 0.947, 0.927, 0.823 (ventral, central, and dorsal, respectively) in the left lung. The correlation coefficient was low when the regional ventilation distribution detected by the electrical impedance tomography was < 2%. After excluding nine patients with a regional ventilation distribution of < 2%, the ventral, central, and dorsal correlation coefficients were 0.963, 0.963, and 0.946 in the right lung and 0.942, 0.924, and 0.951, respectively, in the left lung., Conclusions: Regional ventilation using electrical impedance tomography during dynamic ventilation was highly accurate and consistent with the time phase compared to four-dimensional computed tomography. Given the high correlation between these modalities, they can contribute significantly to further studies on regional ventilation dynamics. Trial registration number ClinicalTrials.gov (No. UMIN00044386)., (© 2024. The Author(s).)

Background: One of the significant changes in intensive care medicine over the past 2 decades is the acknowledgment that improper mechanical ventilation settings substantially contribute to pulmonary injury in critically ill patients. Artificial intelligence (AI) solutions can optimize mechanical ventilation settings in intensive care units (ICUs) and improve patient outcomes. Specifically, machine learning algorithms can be trained on large datasets of patient information and mechanical ventilation settings. These algorithms can then predict patient responses to different ventilation strategies and suggest personalized ventilation settings for individual patients., Objective: In this study, we aimed to design and evaluate an AI solution that could tailor an optimal ventilator strategy for each critically ill patient who requires mechanical ventilation., Methods: We proposed a reinforcement learning-based AI solution using observational data from multiple ICUs in the United States. The primary outcome was hospital mortality. Secondary outcomes were the proportion of optimal oxygen saturation and the proportion of optimal mean arterial blood pressure. We trained our AI agent to recommend low, medium, and high levels of 3 ventilator settings-positive end-expiratory pressure, fraction of inspired oxygen, and ideal body weight-adjusted tidal volume-according to patients' health conditions. We defined a policy as rules guiding ventilator setting changes given specific clinical scenarios. Off-policy evaluation metrics were applied to evaluate the AI policy., Results: We studied 21,595 and 5105 patients' ICU stays from the e-Intensive Care Unit Collaborative Research (eICU) and Medical Information Mart for Intensive Care IV (MIMIC-IV) databases, respectively. Using the learned AI policy, we estimated the hospital mortality rate (eICU 12.1%, SD 3.1%; MIMIC-IV 29.1%, SD 0.9%), the proportion of optimal oxygen saturation (eICU 58.7%, SD 4.7%; MIMIC-IV 49%, SD 1%), and the proportion of optimal mean arterial blood pressure (eICU 31.1%, SD 4.5%; MIMIC-IV 41.2%, SD 1%). Based on multiple quantitative and qualitative evaluation metrics, our proposed AI solution outperformed observed clinical practice., Conclusions: Our study found that customizing ventilation settings for individual patients led to lower estimated hospital mortality rates compared to actual rates. This highlights the potential effectiveness of using reinforcement learning methodology to develop AI models that analyze complex clinical data for optimizing treatment parameters. Additionally, our findings suggest the integration of this model into a clinical decision support system for refining ventilation settings, supporting the need for prospective validation trials., (©Siqi Liu, Qianyi Xu, Zhuoyang Xu, Zhuo Liu, Xingzhi Sun, Guotong Xie, Mengling Feng, Kay Choong See. Originally published in the Journal of Medical Internet Research (https://www.jmir.org), 16.10.2024.)

Sepsis is one of the main causes of acute respiratory distress syndrome (ARDS), which continues to be a common cause of high mortality in intensive care units (ICUs). Despite tremendous advances in basic science and clinical research, the high mortality of ARDS remains a major clinical challenge. Currently, there is a lack of specific and effective therapeutic approaches for ARDS, with treatment primarily focused on supporting organ function. This article provided a comprehensive discussion and summary of respiratory support strategies for sepsis associated with ARDS.

Hyperpolarized (HP) xenon-129 ( 129 Xe) is an inhaled magnetic resonance imaging (MRI) contrast agent with unique spectral and physical properties that can be exploited to quantify pulmonary physiology, including ventilation, restricted diffusion (alveolar-airspace size), and gas exchange. In humans, it has been used to evaluate disease severity and progression in a variety of pulmonary disorders and is approved for clinical use in the United States and United Kingdom. Beyond its clinical applications, the ability of 129 Xe MRI to noninvasively assess pulmonary pathophysiology and provide spatially resolved information is valuable for preclinical research. Among animal models, mice are the most widely used due to the accessibility of genetically modified disease models. Here, 129 Xe MRI is promising as a minimally invasive, radiation-free, and sensitive technique to longitudinally monitor lung disease progression and therapy response (e.g., in drug discovery). This technique can extend to preclinical applications by incorporating an MRI-triggered, free-breathing apparatus or mechanical ventilator to deliver gas. Here, we describe the steps and provide checklists to ensure robust data collection and analysis, including creating a thermally polarized xenon gas phantom for quality control, optimizing polarization, animal handling (sedation, intubation, ventilation, and care for mice), and protocols for ventilation, restricted diffusion, and gas exchange data. While preclinical 129 Xe MRI can be applied in various animal models (e.g., rats, pigs, sheep), this protocol focuses on mice due to the challenges posed by their small anatomy, which are balanced by their affordability and the availability of many disease models.

Background: The aim of this study is to investigate and compare the effects of administering a surfactant through a fine intra-tracheal catheter during spontaneous breathing with the usual INSURE method in premature infants., Materials and Methods: In this clinical trial, premature babies with respiratory distress syndrome who required surfactant administration were randomly assigned to two groups: an intervention group (MIST) and a control group (INSURE). The treatment results were compared in terms of complications related to treatment (desaturation, apnea, bradycardia, and surfactant reflux), respiratory complications (requirement for mechanical ventilation, duration of nCPAP, duration of oxygen requirement, frequency of pneumothorax, and pulmonary hemorrhage), complications related to prematurity (incidence of IVH, NEC, BPD, and PDA), the need for a second dose of surfactant, and the duration of hospitalization., Results: a total of 160 premature babies with a gestational age of 26-34 weeks were randomly divided into two groups. The results showed that the need for mechanical ventilation, the duration of CPAP needed, and the duration of oxygen therapy were significantly lower in the MIST group than in the INSURE group. Additionally, the incidence of BPD was less common in the MIST group compared to the INSURE group. However, surfactant reflux was more common in the MIST group than in the INSURE group. There were no significant differences between the two groups in other outcomes, including the length of hospital stay and complications such as IVH, PDA, NEC, pneumothorax, and pulmonary hemorrhage., Conclusion: The results of this research demonstrate that the less invasive method of surfactant therapy (MIST) is a feasible, effective, and low-risk alternative to the INSURE method.

Background: Extracorporeal membrane oxygenation (ECMO) is increasingly employed to support lung function in patients with acute respiratory failure (ARF). However, the long-term outcomes of the approach have not been encouraging when compared to those of conventional mechanical ventilation. Further, the long-term effects of ECMO on lung function and recovery are unclear. For this review, we examined the long-term lung function outcomes of patients with ARF treated with and without ECMO., Methods: We searched the Embase, CENTRAL, Web of Science, and PubMed sites for studies comparing long-term (≥ 6 months) pulmonary function test results in patients with ARF treated with and without ECMO published until January 2024. We conducted a meta-analysis for percentage predicted values., Results: We included five studies. Our meta-analysis showed similar values of forced vital capacity (FVC%) (MD, 0.47; 95% CI, -3.56-4.50) and forced expiratory flow in the first second % (MD, 1.79; 95% CI, -2.17-5.75) in patients with ARF treated with or without ECMO. The FEV1/FVC % values were slightly higher in patients treated with ECMO than in those without ECMO (MD, 2.03; 95% CI, 0.01-4.04; p-value = 0.05). According to the meta-analysis, the values for total lung capacity % (MD, -3.20; 95% CI, -8.83-2.44) and carbon monoxide diffusion capacity % (MD, -0.72; 95% CI, -3.83-2.39) were also similar between patients undergoing ECMO and those without it., Conclusion: The meta-analysis of a small number of studies with significant selection bias indicates that patients with ARF treated with ECMO may have comparable long-term pulmonary function recovery to those treated with conventional strategies. Further investigations including a larger number of patients and focusing on the long-term impact of ECMO are needed to supplement the current evidence., (© 2024. The Author(s).)

Background: Sleep deprivation is common in intensive care units (ICUs) and may alter respiratory performance. Few studies have assessed the role of sleep disturbances on outcomes in critically ill patients., Objectives: We hypothesized that sleep disturbances may be associated with poor outcomes in ICUs., Methods: Post-hoc analysis pooling three observational studies assessing sleep by complete polysomnography in 131 conscious and non-sedated patients included at different times of their ICU stay. Sleep was assessed early in a group of patients admitted for acute respiratory failure while breathing spontaneously (n = 34), or under mechanical ventilation in patients with weaning difficulties (n = 45), or immediately after extubation (n = 52). Patients admitted for acute respiratory failure who required intubation, those under mechanical ventilation who had prolonged weaning, and those who required reintubation after extubation were considered as having poor clinical outcomes. Durations of deep sleep, rapid eye movement (REM) sleep, and atypical sleep were compared according to the timing of polysomnography and the clinical outcomes., Results: Whereas deep sleep remained preserved in patients admitted for acute respiratory failure, it was markedly reduced under mechanical ventilation and after extubation (p < 0.01). Atypical sleep was significantly more frequent in patients under mechanical ventilation than in those breathing spontaneously (p < 0.01). REM sleep was uncommon at any time of their ICU stay. Patients with complete disappearance of REM sleep (50% of patients) were more likely to have poor clinical outcomes than those with persistent REM sleep (24% vs. 9%, p = 0.03)., Conclusion: Complete disappearance of REM sleep was significantly associated with poor clinical outcomes in critically ill patients., (© 2024. The Author(s).)

Background: Airway pressure release ventilation (APRV) has been shown to be protective against atelectrauma if expirations are brief. We hypothesize that this is protective because epithelial surfaces are not given enough time to come together and adhere during expiration, thereby avoiding their highly damaging forced separation during inspiration., Methods: We investigated this hypothesis in a porcine model of ARDS induced by Tween lavage. Animals were ventilated with APRV in 4 groups based on whether inspiratory pressure was 28 or 40 cmH 2 O, and whether expiration was terminated when end-expiratory flow reached either 75% (a shorter expiration) or 25% (a longer expiration) of its initial peak value. A mathematical model of respiratory system mechanics that included a volume-dependent elastance term characterized by the parameter E 2 was fit to airway pressure-flow data obtained each hour for 6 h post-Tween injury during both expiration and inspiration. We also measured respiratory system impedance between 5 and 19 Hz continuously through inspiration at the same time points from which we derived a time-course for respiratory system resistance ( R rs )., Results: E 2 during both expiration and inspiration was significantly different between the two longer expiration versus the two shorter expiration groups (ANOVA, p < 0.001). We found that E 2 was most depressed during inspiration in the higher-pressure group receiving the longer expiration, suggesting that E 2 reflects a balance between strain stiffening of the lung parenchyma and ongoing recruitment as lung volume increases. We also found in this group that R rs increased progressively during the first 0.5 s of inspiration and then began to decrease again as inspiration continued, which we interpret as corresponding to the point when continuing derecruitment was reversed by progressive lung inflation., Conclusions: These findings support the hypothesis that sufficiently short expiratory durations protect against atelectrauma because they do not give derecruitment enough time to manifest. This suggests a means for the personalized adjustment of mechanical ventilation., (© 2024. The Author(s).)