Acute Hypoxemic Respiratory Failure Research Articles

Early physiologic changes after awake prone positioning predict clinical outcomes in patients with acute hypoxemic respiratory failure.

The optimal physiologic parameters to monitor after a session of awake prone positioning in patients with acute respiratory failure are not well understood. This study aimed to identify which early physiologic changes after the first session of awake prone positioning are linked to the need for invasive mechanical ventilation or death in patients with acute respiratory failure. We performed a secondary analysis of a prospective cohort study of adult patients with acute respiratory failure related to coronavirus disease 2019 (COVID-19) treated with awake prone positioning. We assessed the association between relative changes in physiological variables (oxygenation, respiratory rate, pCO2 and respiratory rate-oxygenation [ROX] index) within the first 6h of the first awake prone positioning session with treatment failure, defined as endotracheal intubation and/or death within 7days. 244 patients [70 female (29%), mean age 60 (standard deviation [SD] 13) years] were included. Seventy-one (29%) patients experienced awake prone positioning failure. ROX index was the main physiologic predictor. Patients with treatment failure had lower mean [SD] ROX index at baseline [5 (1.4) versus 6.6 (2.2), p < 0.0001] and within 6h of prone positioning [5.6 (1.7) versus 8.7 (2.8), p < 0.0001]. After adjusting for baseline characteristics and severity, a relative increase of the ROX index compared to baseline was associated with lower odds of failure [odds ratio (OR) 0.37; 95% confidence interval (CI) 0.25-0.54 every 25% increase]. Relative changes in the ROX index within 6h of the first awake prone positioning session along with other known predictive factors are associated with intubation and mortality at day 7.

ELMO-CPAP: an effective approach in the management of patients with acute hypoxemic respiratory failure

ELMO-CPAP: an effective approach in the management of patients with acute hypoxemic respiratory failure

Efficacy of high-flow nasal oxygen therapy in cancer patients with concurrent acute hypoxemic respiratory failure: a retrospective propensity score study.

Acute respiratory failure is the leading cause of intensive care unit (ICU) admission of cancer patients. Studies of the efficacy of high-flow nasal cannula (HFNC) therapy were rarely conducted in cancer populations. We here compared the clinical effects of HFNC therapy and conventional oxygen therapy (COT) in cancer patients with concurrent acute hypoxemic respiratory failure (AHRF). In this single-center retrospective study, cancer patients with concurrent acute hypoxic respiratory failure either received initial oxygen therapy via HFNC (HFNC group, 68 patients) or received initial oxygen therapy via a nasal cannula, simple mask, or mask with reservoir bag (COT group, 133 patients). Groups were propensity score matched. Differences in respiratory rate (RR), heart rate (HR), and PaO2/FiO2 ratio before and after treatment in the two groups were compared using a mixed-effects model. The 28-day mortality risk was explored using a Cox proportional hazards model. The 24-h and 48-h PaO2/FIO2 ratios were significantly higher in the HFNC than in the COT group (210.5mmHg vs. 178.5mmHg; P < 0.01; 217.1mm Hg vs. 181.6mm Hg; P < 0.01, respectively). Differences in RR and HR between the groups at each time point were nonsignificant. The 28-day mortality rate was 17.4% vs. 38.1% for the HFNC and COT groups, respectively (P < 0.01). Hazard ratio was significantly higher for COT group (HR 2.6, 95% confidence interval 1.3, 5.3). Compared with COT, HFNC use for initial oxygen therapy can improve PaO2/FIO2 ratio and survival rate in cancer patients with AHRF.

Systematic review and network meta-analysis of non-invasive respiratory support in paediatric patients with acute hypoxaemic respiratory failure: a protocol

IntroductionAcute hypoxic respiratory failure (AHRF) is one of the most common causes of admission to paediatric intensive care units (PICUs) around the world, posing a serious health concern for the...

Baicalein suppresses inflammation and attenuates acute lung injury by inhibiting glycolysis via HIF‑1α signaling.

Baicalein, a flavonoid monomer compound isolated from the dried root of the traditional Chinese herb Scutellaria baicalensis, has several pharmacological activities, such as anti‑inflammatory, anti‑angiogenic, antitumor, antimicrobial and antiviral properties. Acute lung injury (ALI) is characterized by injury of the alveolar epithelium and capillary endothelium, which results in decreased lung volume, decreased lung compliance, ventilation/perfusion mismatch, intrapulmonary edema, alveolar edema and even acute hypoxemic respiratory failure. The present study aimed to investigate the effects of baicalein on lung injury and inflammation. Bioinformatics analysis using network pharmacology predicted that the hypoxia inducible factor‑1α (HIF‑1α) and glycolysis signaling pathways were involved in the mechanism underlying the therapeutic effects of baicalein. Further in vitro and in vivo experiments, such as immunohistochemistry, immunofluorescence and PCR, verified that baicalein could inhibit HIF‑1α signaling, thus suppressing glycolysis, and improving inflammatory responses and ALI. Taken together, the results of the present study suggested that the anti‑inflammatory effects of baicalein on treating ALI were associated with its ability to suppress glycolysis via the HIF‑1α signaling pathway.

Respiratory Oscillometry in Patients With Acute Hypoxemic Respiratory Failure: A Feasibility Study.

Assessing respiratory mechanics in patients with acute hypoxemic respiratory failure who are not intubated could provide useful information about illness trajectory. Oscillometry is a respiratory function test used to measure total respiratory impedance during tidal breathing, which reveals resistive and elastic properties of the lung. This study assessed the feasibility of oscillometry in patients with acute hypoxemic respiratory failure and described their respiratory mechanics. Adult participants with acute hypoxemic respiratory failure who were receiving noninvasive respiratory support with [Formula: see text] ≥0.4 and flow ≥6 L/min underwent oscillometry at baseline and after resolution of acute hypoxemic respiratory failure. The primary end point was the number of participants who completed the baseline measurement. The feasibility criterion was in obtaining baseline oscillometry measurements in ≥80% of enrolled participants. Of 183 patients screened between July 2022 and August 2023, 29% were unable to cooperate due to altered mental state, 20% with extreme hypoxemia were excluded because of clinical instability, and 12% declined participation. Of the 10 participants (5.4%) recruited, all tolerated oscillometry measurements. At baseline, the median (minimum, maximum) [Formula: see text] was 0.8 (0.4, 0.8), median oxygen saturation of 94% dropped to a nadir of 82% at the end of oscillometry and recovered within 2 min. Lung reactance was increased, with a reactance area of 25 (15-32) cm H2O/L. Hypoxemia resolved in 9 participants. After resolution of acute hypoxemic respiratory failure in 8 (6-16) d, the median reactance area dropped to 15 (14-19) cm H2O/L. Respiratory mechanics in the participants with acute hypoxemic respiratory failure who were not intubated could be assessed by oscillometry in carefully selected cases.

Predicting High-Flow Nasal Cannula Oxygen Therapy Failure in Patients With Acute Hypoxaemic Respiratory Failure Using Machine Learning: Model Development and External Validation.

To develop and validate a prediction model for high-flow nasal cannula (HFNC) failure in patients with acute hypoxaemic respiratory failure (AHRF). AHRF accounts for a major proportion of intensive care unit (ICU) admissions and is associated with high mortality. HFNC is a non-invasive respiratory support technique that can improve patient oxygenation. However, HFNC failure, defined as the need for escalation to invasive mechanical ventilation, can lead to delayed intubation, prolonged mechanical ventilation and increased risk of mortality. Timely and accurate prediction of HFNC failure has important clinical implications. Machine learning (ML) can improve clinical prediction. Multicentre observational study. This study analysed 581 patients from an academic medical centre in Boston and 180 patients from Guangzhou, China treated with HFNC for AHRF. The Boston dataset was randomly divided into a training set (90%, n = 522) and an internal validation set (10%, n = 59), and the model was externally validated using the Guangzhou dataset (n = 180). A random forest (RF)-based feature selection method was used to identify predictive factors. Nine machine learning algorithms were selected to build the predictive model. The area under the receiver operating characteristic curve (AUC) and performance evaluation parameters were used to evaluate the models. The final model included 38 features selected using the RF method, with additional input from clinical specialists. Models based on ensemble learning outperformed other models (internal validation AUC: 0.83; external validation AUC: 0.75). Important predictors of HFNC failure include Glasgow Coma Scale scores and Sequential Organ Failure Assessment scores, albumin levels measured during HFNC treatment, ROX index at ICU admission and sepsis. This study developed an interpretable ML model that accurately predicts the risk of HFNC failure in patients with AHRF. Clinicians and nurses can use ML models for early risk assessment and decision support in AHRF patients receiving HFNC. TRIPOD checklist for prediction model studies was followed in this study. Patients were involved in the sample of the study.

Factors associated with the effectiveness of high-flow therapy in patients with acute hypoxemic respiratory failure: An observational study

BackwardThe COVID-19 pandemic has severely tested global health systems. Non-invasive respiratory support, especially combining high-flow nasal cannula (HFNC) and continuous positive airway pressure, has effectively treated COVID-19 induced Acute Hypoxemic Respiratory Failure and reduced mortality. However, HFNC alone is more comfortable, better tolerated, and less costly than non-invasive ventilation. Understanding which patients benefit from HFNC monotherapy versus combined therapies is essential. MethodsThis observational study included patients admitted to the intermediate respiratory care unit of a COVID-19 hospital between December 2020 and September 2021. All patients treated with HFNC were included (n = 1301). HFNC failure was defined as the need for escalated therapy (non-invasive ventilation, intubation) or death. Epidemiological, clinical, non-invasive respiratory support parameters, and laboratory data were collected, and a multivariable analysis identified key determinants. ResultsHFNC was successful in 39.9 % of patients. (n = 511) Risk factors for HFNC failure included increased age, male gender, obesity, obstructive sleep apnea, higher respiratory rate, initial SpO2/FiO2 ≤ 148, and initial PaO2/FiO2 ≤ 100. An increase in the ROX Index at 24 h and slower disease progression were associated with successful treatment. These findings led to the developmet of an index to identify patients who benefit most from HFNC monotherapy. ConclusionsHFNC monotherapy can be effective for a specific profile of patients with Acute Hypoxemic Respiratory Failure due to COVID-19. This tool may help manage these patients more appropriately. Further studies are needed to determine if these findings can be applied to Acute Hypoxemic Respiratory Failure caused by other pathologies. Implications for Clinical PracticeThis study underscores the importance of early identification and management of patients at risk of HFNC failure in intermediate respiratory care units. By recognizing factors such as age, comorbidities, and respiratory indices, healthcare providers can implement targeted strategies to enhance HFNC success. These strategies may include more stringent monitoring, tailored respiratory support, and timely escalation to more intensive therapies if needed. Our findings highlight the need for a comprehensive approach to managing severe respiratory failure in critical care settings, ultimately improving patient outcomes and reducing the burden on healthcare systems.

Respiratory rate-oxygenation index on the 3rd day is the best predictor of treatment failure in COVID-19 patients.

Predictors of outcomes are essential to identifying severe COVID-19 cases and optimizing treatment and care settings. The respiratory rate-oxygenation (ROX) index, originally introduced for predicting the failure of non-invasive support in acute hypoxemic respiratory failure (AHRF), has not been extensively studied over time during hospitalization. This multicenter prospective observational study analyzed COVID-19-related AHRF patients admitted to eight Italian hospitals during the second pandemic wave. The study assessed the ROX index using receiver operator characteristic curves and areas under the curve with 95% confidence intervals to predict treatment failure, defined as endotracheal intubation (ETI) or death. A total of 227 patients (69.2% males) were enrolled, with a median arterial partial pressure of oxygen (PaO2)/fraction of inspired oxygen (FiO2) ratio at admission of 248 (interquartile range: 170-295). Nearly one-third (29.5%) required ETI or died during hospitalization. Those who experienced treatment failure were older (median age 70 versus 61 years, p<0.001), more likely to be current or former smokers (8.5% versus 6.4% and 42.4% versus 25.5%, p=0.039), had a higher prevalence of cardiovascular diseases (74.6% versus 46.3%, p<0.001), and had a lower PaO2/FiO2 ratio at presentation (median 229 versus 254, p=0.014). Gender, body mass index, and other comorbidities showed no significant differences. In patients who failed treatment, the ROX index was higher at presentation and worsened sharply by days 3 and 4. Conversely, in patients who survived without requiring ETI, the ROX index remained stable and reduced after 5-6 days. The ROX index's predictive ability improved notably by the third day of hospitalization, with the best cut-off value identified at 8.53 (sensitivity 75%, specificity 68%). Kaplan-Meier curves indicated that a ROX index of 8.53 or lower on days 1, 2, or 3 was associated with a higher risk of treatment failure. Thus, a single ROX index assessment on day 3 is more informative than its variability over time, with values of 8.53 or lower predicting non-invasive respiratory support failure in hospitalized COVID-19 patients.

Inter-lung asymmetrical airway closure cause insufflation delay between lungs in acute hypoxemic respiratory failure

BackgroundElectrical Impedance Tomography (EIT) can quantify ventilation in the two lungs and be used to measure the airway opening pressure (AOP) of each lung. Asymmetrical AOPs can cause inter-lung insufflation delay.ObjectivesTo assess the relation between AOP asymmetry and inter-lung insufflation delay at different PEEP levels.MethodsPatients with acute hypoxemic respiratory failure and airway closure were included. Low-flow pressure-volume curves and EIT signal were recorded during controlled ventilation and for some patients in pressure support ventilation.Results23 patients were studied, 22 patients had ARDS, 9 patients had asymmetrical airway closure with an AOP of 10 [6–13] cmH20 in the sicker lung (AOPsicker) vs. 5 [3–9, ] cmH20 in the healthier lung. During a low flow inflation, the inter-lung inflation delay was 0 [0-112]ms vs. 1450 [375–2400]ms in patients without or with asymmetrical AOPs, p < 0.0001. This delay was correlated to the difference of AOP between the 2 lungs, Spearman R2 = 0.800, p < 0.0001. During tidal ventilation, median delay was 0 [0–62] ms vs. 150 [50–355] ms in patients without vs. with asymmetry, p = 0.019. Setting PEEP at the crossing point of a decremental EIT-based PEEP trial decreased the inter-lung insufflation delay. During pressure support insufflation delay could still be measured and was reduced by increasing PEEP from 5 to 10 cmH2O in patient with asymmetrical lung injury.ConclusionIn asymmetrical airway closure, titrating PEEP can minimize inter-lung insufflation delay and can be monitored by EIT. Reducing the delay and reducing ventilation asymmetry is also feasible during pressure support ventilation when low flow inflation curves cannot be performed.

Effect of high-flow nasal cannula oxygen versus standard oxygen on mortality in patients with acute hypoxaemic respiratory failure: protocol for a multicentre, randomised controlled trial (SOHO)

IntroductionFirst-line oxygenation strategy in patients with acute hypoxaemic respiratory failure consists in standard oxygen or high-flow nasal oxygen therapy. Clinical practice guidelines suggest the use of high-flow nasal oxygen rather...

Management of adult mechanically ventilated patients: A UK-wide survey.

Mechanical ventilation is a common and often lifesaving intervention that is utilised in intensive care. However, the practices can vary between centres. Through this national survey we aim to gain more information about different strategies adopted across the UK. All adult intensive care units in the UK were approached to participate. The questionnaire was developed with an electronic survey engine and conducted between 09/11/2023 and 01/04/2024 (Survey Monkey®). The survey included questions on ventilator modes, settings, protocols/pathways, rescue strategies, immediate post-extubation period and follow-up. There were 196 responses from 104 hospitals. The most widely adopted start-up ventilation mode was pressure-regulated volume-controlled mode. For acute hypoxaemic respiratory failure (AHRF), most of respondents reported full (39.8%) or partial compliance (58.1%) with the ARDSnet protocol, with PEEP settings being the commonest deviation. Prone positioning (99.0%), followed by recruitment manoeuvres (91.3%) were commonly used rescue measures during AHRF. APRV (55.7%), inhaled (51.3%) and systemic pulmonary vasodilators (44.1%) were also commonly used. Conservative oxygen targets (SaO2 of 88%-92%) were commonly adopted (70.6%). As a care bundle, intermittent ETT cuff pressure monitoring was more common (65.5%) than continuous cuff pressure monitoring (20.0%). Propofol and alfentanil were the most common initial sedative and analgesia (99.5% and 56.9%) respectively. Routine volatile anaesthetic use was rare. Our survey has shown significant variation of practice in common but crucial elements of management of patients receiving mechanical ventilation. We hope the results in our survey highlight potential future areas of research. South-coast Peri-operative Audit and Research Collaborative (SPARC)Severn Trainee Anaesthetic and Critical Care Research group (STAR)Collaborative research in Anaesthesia in the Northeast (CRANE).

Options for optimizing noninvasive respiratory support in the development of hypoxemic acute respiratory failure

Introduction. Acute respiratory failure (ARF) remains one of the most relevant problems of modern medicine and intensive care, and respiratory support (RS) remains the indispensable method of temporary external respiratory function replacement. Despite of widespread use of non-invasive ventilation (NIV) in clinical practice, at present systematic scientific data about possibilities for optimizing the use of these methods of RS in patients with hypoxemic ARF development is absent. It can be assumed that the combination of mask NIV and high-flow oxygen therapy (HFOT) at the stage of ARF development can improve results of treatment in this group of patients.The objective was to improve the results of treatment in patients with hypoxemic ARF through the combined use of mask NIV and HFOT.Materials and methods. The prospective cohort study included 77 patients aged 46.8 ± 11.8 years. Patients were randomized into three groups: in group A, RS was performed by using NIV and traditional low-flow oxygen therapy, in group B – by using HFOT, in group C – by sequential combination of NIV sessions and HFOT. The groups compared gas exchange rates, RS duration, intubation rate and nosocomial pneumonia (NP) incidence, length of treatment in the intensive care unit (ICU) and hospitalizations, overall mortality, and prognostic factors for tracheal intubation were also studied.Results. The combination of mask NIV and HFOT was found to be more clinically effective compared to their separate use. Combination of mask NIV and HFOT had the best effect on gas exchange rates in the long term period, reduced RS duration, intubation rate and pneumonia incidence, ICU treatment duration. Risk factors for tracheal intubation were revealed: RS duration more than 4.5 days, intra-abdominal pressure (IAP) more than 18 cm of water.Conclusions. The combination of mask NIV and HFOT increases the therapeutic potential of each of these RS methods and improves the results of treatment in patients with hypoxemic ARF development.

Disseminated Toxoplasma Gondii Infection in a Deceased Donor Kidney Transplant Recipient: A Fatal Case Report

Abstract Introduction/Objective Post-transplant immunosuppression predisposes patients to severe complications from opportunistic infections, including Toxoplasma gondii. Typically asymptomatic and self-limited in immunocompetent individuals, Toxoplasma gondii can cause life-threatening disseminated disease in immunocompromised patients like solid organ transplant recipients. The challenge in diagnosing Toxoplasmosis is further exacerbated in patients receiving prophylactic therapy with agents such as Atovaquone, which may mask clinical suspicion. This case report describes a fatal presentation of disseminated Toxoplasmosis in a kidney transplant recipient. Methods/Case Report A 44-year-old male with a history of deceased donor kidney transplant presented to the emergency department two months post-transplant with symptoms of malaise, shortness of breath, hypoxemia, and hypotension. Despite medical interventions, the patient deteriorated rapidly, developing acute hypoxemic respiratory failure and septic shock requiring intubation. Subsequently, he succumbed to multisystem organ failure five days after admission. The autopsy revealed disseminated Toxoplasma gondii infection, with tachyzoites/bradyzoites identified in multiple organs, including the brain, bone marrow, and lymph nodes. Positive Toxoplasma immunohistochemical staining and PCR confirmed the diagnosis. Results (if a Case Study enter NA) NA Conclusion Toxoplasma infection in post-transplant patients can manifest as a severe and potentially fatal complication. Dissemination can arise from the reactivation of latent infection, donor transmission, or new acquisition. In this case, the infection likely resulted from the reactivation of latent infection in the donor, compounded by immunosuppression in the recipient. Notably, the patient received Atovaquone prophylaxis due to a sulfa allergy. Nonetheless, the case highlights the potential for delayed diagnosis due to atypical presentations in immunocompromised patients. Clinicians should maintain a high index of suspicion for Toxoplasma infection in post- transplant patients, particularly in those with unexplained clinical deterioration. This case emphasizes the importance of maintaining a high index of suspicion for T. gondii infection in post-transplant patients, even in those receiving prophylaxis.

Heterogeneous impact of Sighs on mortality in patients with acute hypoxemic respiratory failure: insights from the PROTECTION study.

Sigh breaths may impact outcomes in acute hypoxemic respiratory failure (AHRF) during assisted mechanical ventilation. We investigated whether sigh breaths may impact mortality in predefined subgroups of patients enrolled in the PROTECTION multicenter clinical trial according to: 1.the physiological response in oxygenation to Sigh (responders versus non-responders) and 2.the set levels of positive end-expiratory pressure (PEEP) (High vs. Low-PEEP). If mortality differed between Sigh and No Sigh, we explored physiological daily differences at 7-days. Patients were randomized to pressure support ventilation (PSV) with Sigh (Sigh group) versus PSV with no sigh (No Sigh group). (1) Sighs were not associated with differences in 28-day mortality in responders to baseline sigh-test. Contrarily-in non-responders-56 patients were randomized to Sigh (55%) and 28-day mortality was lower with sighs (17%vs.36%, log-rank p = 0.031). (2) In patients with PEEP > 8cmH2O no difference in mortality was observed with sighs. With Low-PEEP, 54 patients were randomized to Sigh (48%). Mortality at 28-day was reduced in patients randomised to sighs (13%vs.31%, log-rank p = 0.021). These findings were robust to multivariable adjustments. Tidal volume, respiratory rate and ventilatory ratio decreased with Sigh as compared with No Sigh at 7-days. Ventilatory ratio was associated with mortality and successful extubation in both non-responders and Low-PEEP. Addition of Sigh to PSV could reduce mortality in AHRF non-responder to Sigh and exposed to Low-PEEP. Results in non-responders were not expected. Findings in the low PEEP group may indicate that insufficient PEEP was used or that Low PEEP may be used with Sigh. Sigh may reduce mortality by decreasing physiologic dead space and ventilation intensity and/or optimizing ventilation/perfusion mismatch. ClinicalTrials.gov; Identifier: NCT03201263.

8281 Continuous Low-Dose Etomidate Infusion For The Management Of Severe Hypercortisolism In Metastatic Adrenocortical Carcinoma

Abstract Disclosure: A. Jamil: None. N. Mohammad: None. S. Narayana: None. Background: Adrenocortical carcinoma (ACC) is a rare endocrine malignancy of the adrenal glands with a poor prognosis that often presents with excess hormone secretion. Approximately, 45% of cases present with hypercortisolism.1 A key component of management is achieving control of hypercortisolism. Though there are multiple enteral therapies that can inhibit cortisol production, few treatment options are available for use in critically ill patients who are not surgical candidates and cannot take oral medications. Though primarily known as a short-acting intravenous anesthetic agent used for sedation, etomidate also inhibits 11-β-hydroxylase, a key enzyme involved in corticosteroid biosynthesis.2 Clinical Case: A 28-year-old woman with metastatic adrenocortical carcinoma with associated hypercortisolism was initially admitted for anemia and thrombocytopenia, with an initial cortisol on admission of 29.3 μg/dl (normal range: 2.3-19.4 ug/dl). Due to her large tumor burden with metastasis to the liver and invasion into the inferior vena cava, she was deemed a poor surgical candidate with a poor overall prognosis. Her hospital course was complicated by acute hypoxemic respiratory failure requiring intubation, and thus her enteral steroidogenesis inhibitors (mitotane, ketoconazole, and metyrapone) were discontinued as none were administrable via nasogastric tube. Consequently, her hypercortisolism worsened rapidly with a cortisol level of 351.3 μg/dl , prompting initiation of continuous low-dose etomidate infusion, which resulted in significant improvements in her cortisol levels. After eight days of etomidate treatment, her cortisol levels reached a goal value of 25.0 μg/dl. However, she then suffered an ischemic cerebrovascular event and multiorgan failure, and was subsequently transitioned to hospice care. Conclusion: Low-dose etomidate infusion is an effective therapeutic agent for hypercortisolism in patients with ACC that are unable to take oral medications.

Awake prone positioning and ventilation distribution as assessed by electric impedance tomography in patients with non-COVID-19 acute respiratory failure: A prospective physiology study

BackgroundAwake prone positioning (APP) can reportedly reduce the need for intubation and help to improve the prognosis of patients with acute hypoxemic respiratory failure (AHRF) infected with COVID-19. However, its physiological mechanism remains unknown. In this study, we evaluated the effect of APP on lung ventilation in patients with moderate-to-severe AHRF in an attempt to better understand the effects on ventilation distribution and to prevent intubation in non-intubated patients. MethodsThe prospective study was performed in the Department of Critical Care Medicine at Shanghai General Hospital, China, from January 2021 to November 2022. The study included patients with AHRF (partial pressure of oxygen [PaO2]/inspired oxygen concentration [FiO2] <200 mmHg or oxygen saturation [SpO2]/FiO2 <235) treated with high-flow nasal oxygen. Electrical impedance tomography (EIT) measurements including center of ventilation (COV), global inhomogeneity (GI) index, and regional ventilation delay (RVD) index were performed in the supine position (T0), 30 min after the start of APP (T1), and at 30 min returning to supine position after the APP (T2). Clinical parameters like SpO2, respiratory rate (RR), FiO2, heart rate (HR), and ROX (the ratio of SpO2 as measured by pulse oximetry/FiO2 to RR) were also recorded simultaneously at T0, T1, and T2. To evaluate the effect of the time points on the variables, Mauchly's test was performed for sphericity and repeated measures analysis of variance was applied with Bonferroni's post hoc multiple comparisons. ResultsTen patients were enrolled. The PaO2/FiO2 ratio was (111.4±33.4) mmHg at the time of recruitment. ROX showed a significant increase after initiation of APP {median (interquartile range [IQR]): T0: 7.5 (6.0–10.1) vs. T1: 7.6 (6.4–9.3) vs. T2: 8.3 (7.2–11.0), P=0.043}. RR (P=0.409), HR (P=0.249), and SpO2/FiO2 (P=0.103) did not change significantly during prone positioning (PP). The COV moved from the ventral area to the dorsal area (T0: [48.8±6.2] % vs. T1: [54.8±6.8] % vs. T2: [50.3±6.1] %, P=0.03) after APP. The GI decreased significantly after APP (T0: median=42.7 %, [IQR: 38.3–47.5] % vs. T1: median=38.2 %, [IQR: 34.6–50.7] % vs. T2: median=37.4 %, [IQR: 34.2–41.4] %, P=0.049). RVD (P=0.794) did not change after APP. ConclusionsAPP can improve ventilation distribution and homogeneity of lung ventilation as assessed by EIT in non-intubated patients with AHRF.Trail Registration Chinese Clinical Trial Registry Identifier: ChiCTR2000035895.

Statistical Power and Performance of Strategies to Analyze Composites of Survival and Duration of Ventilation in Clinical Trials.

Patients with acute hypoxemic respiratory failure are at high risk of death and prolonged time on the ventilator. Interventions often aim to reduce both mortality and time on the ventilator. Many methods have been proposed for analyzing these endpoints as a single composite outcome (days alive and free of ventilation), but it is unclear which analytical method provides the best performance. Thus, we aimed to determine the analysis method with the highest statistical power for use in clinical trials. Using statistical simulation, we compared multiple methods for analyzing days alive and free of ventilation: the t, Wilcoxon rank-sum, and Kryger Jensen and Lange tests, as well as the proportional odds, hurdle-Poisson, and competing risk models. We compared 14 scenarios relating to: 1) varying baseline distributions of mortality and duration of ventilation, which were based on data from a registry of patients with acute hypoxemic respiratory failure and 2) the varying effects of treatment on mortality and duration of ventilation. All methods have good control of type 1 error rates (i.e., avoid false positive findings). When data are simulated using a proportional odds model, the t test and ordinal models have the highest relative power (92% and 90%, respectively), followed by competing risk models. When the data are simulated using survival models, the competing risk models have the highest power (100% and 92%), followed by the t test and a ten-category ordinal model. All models struggled to detect the effect of the intervention when the treatment only affected one of mortality and duration of ventilation. Overall, the best performing analytical strategy depends on the respective effects of treatment on survival and duration of ventilation and the underlying distribution of the outcomes. The evaluated models each provide a different interpretation for the treatment effect, which must be considered alongside the statistical power when selecting analysis models.

Comparison of high flow and standard oxygen therapy in patients with acute hypoxemic respiratory failure in emergency department. A randomized controlled cross over superiority trial

Comparison of high flow and standard oxygen therapy in patients with acute hypoxemic respiratory failure in emergency department. A randomized controlled cross over superiority trial

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

The aim of this study is the evaluation of a closed-loop oxygen control system in pediatric patients undergoing invasive mechanical ventilation (IMV). Cross-over, multicenter, randomized, single-blind clinical trial. Patients between the ages of 1 month and 18 years who were undergoing IMV therapy for acute hypoxemic respiratory failure (AHRF) were assigned at random to either begin with a 2-hour period of closed-loop oxygen control or manual oxygen titrations. By using closed-loop oxygen control, the patients' SpO2 levels were maintained within a predetermined target range by the automated adjustment of the FiO2. During the manual oxygen titration phase of the trial, healthcare professionals at the bedside made manual changes to the FiO2, while maintaining the same target range for SpO2. Following either period, the patient transitioned to the alternative therapy. The outcomes were the percentage of time spent in predefined SpO2 ranges ±2% (primary), FiO2, total oxygen use, and the number of manual adjustments. The median age of included 33 patients was 17 (13-55.5) months. In contrast to manual oxygen titrations, patients spent a greater proportion of time within a predefined optimal SpO2 range when the closed-loop oxygen controller was enabled (95.7% [IQR 92.1-100%] vs. 65.6% [IQR 41.6-82.5%]), mean difference 33.4% [95%-CI 24.5-42%]; P < 0.001). Median FiO2 was lower (32.1% [IQR 23.9-54.1%] vs. 40.6% [IQR 31.1-62.8%]; P < 0.001) similar to total oxygen use (19.8 L/h [IQR 4.6-64.8] vs. 39.4 L/h [IQR 16.8-79]; P < 0.001); however, median SpO2/FiO2 was higher (329.4 [IQR 180-411.1] vs. 246.7 [IQR 151.1-320.5]; P < 0.001) with closed-loop oxygen control. With closed-loop oxygen control, the median number of manual adjustments reduced (0.0 [IQR 0.0-0.0] vs. 1 [IQR 0.0-2.2]; P < 0.001). Closed-loop oxygen control enhances oxygen therapy in pediatric patients undergoing IMV for AHRF, potentially leading to more efficient utilization of oxygen. This technology also decreases the necessity for manual adjustments, which could reduce the workloads of healthcare providers. This research has been submitted to ClinicalTrials.gov (NCT05714527).