FiO2 Research Articles

Longitudinal analysis of ARDS variability and biomarker predictive power in burn patients

Acute Respiratory Distress Syndrome (ARDS) is a severe complication in burn patients, characterized by rapid lung inflammation and hypoxemia. Managing ARDS is challenging due to its high mortality rates and the complex interplay of various pathophysiological factors. This study aims to investigate the heterogeneity of ARDS in burn patients admitted to the Intensive Care Unit (ICU) and evaluate the predictive efficacy of biomarkers in comparison to the PaO2/FiO2 (PF) ratio. A retrospective cohort study was conducted at the Burn Intensive Care Unit of Hangang Sacred Heart Hospital in Seoul, Korea, from July 2010 to December 2022, involving 2,318 patients. Longitudinal k-means clustering was employed to identify patient subgroups based on PF ratio trajectories. Biomarkers, including albumin, white blood cell (WBC) count, and lactate, were assessed for their predictive accuracy using multivariable logistic regression, area under the curve (AUC) analysis, net reclassification improvement (NRI), and integrated discrimination improvement (IDI). Four distinct patient clusters were identified. Cluster A exhibited the highest mortality rate at 54.9%, while Cluster D showed the lowest at 7.9%. Albumin demonstrated significantly higher predictive accuracy in Cluster A (AUC: 0.905, NRI: 0.421) and Cluster C (AUC: 0.915, NRI: 0.845), outperforming the PF ratio in both groups. However, in Clusters B and D, biomarkers did not significantly improve upon the predictive power of the PF ratio. Across all clusters, the integration of biomarkers with the PF ratio led to modest improvements but did not consistently outperform the PF ratio as a standalone predictor. This study reveals substantial heterogeneity in ARDS progression among burn patients, with varying mortality rates and biomarker efficacy across clusters. While biomarkers such as albumin showed potential in specific subgroups, their overall contribution to predictive accuracy was limited. Further multicenter, prospective studies are required to validate these findings and develop more refined predictive models. Personalized treatment strategies, based on biomarker profiles and traditional clinical metrics, could enhance ARDS management in burn patients.

Altered cerebral oxygen extraction and metabolism in preterm neonates and the relationship to anemia: A noncontrast MRI study

AbstractObjectiveThe preterm brain is susceptible to structural injuries, which may be related to an imbalance between blood supply and oxygen metabolism. However, the effect of preterm birth on cerebral oxygen metabolism and its underlying mechanism have not been fully elucidated. The present study measured cerebral oxygen extraction and metabolism using noncontrast magnetic resonance imaging (MRI) methods in preterm neonates and examined its relationship with anemia of prematurity.MethodsFifty neonates with a gestational age of 28–42 weeks were enrolled. Cerebral oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) were measured with T2‐relaxation‐under‐spin‐tagging (TRUST) MRI, together with cerebral blood flow (CBF).ResultsWe showed that CBF (p = 0.00021) and CMRO2 (p < 0.0001) increased with gestational age while OEF increased with postnatal age (p = 0.0013). Higher OEF was also associated with a higher Apgar score at birth (p = 0.039). Furthermore, hematocrit significantly mediates the increase of OEF with postnatal age (p < 0.001). Structural equation modeling analysis suggested a bidirectional relationship between CBF and CMRO2; both contributed to the changes in OEF.InterpretationThese findings demonstrated an altered cerebral oxygen metabolism in preterm brain, suggesting a potential role of MRI–based oxygenation measurement in the assessment of transfusion and intervention for preterm neonates.

A Continuous and Noninvasive Method to Estimate Pao2/Fio2 Ratio.

To validate a method for continuously estimating the Pao2/Fio2 (PF) ratio in all critically ill pediatric patients using only standard continuous data monitoring. Retrospective study on a high temporal resolution database. PICU in Montreal, QC, Canada. We included any patients admitted from May 2015 to May 2023 who had an arterial blood gas (ABG) with concurrent continuous pulsed oximetry saturation (Spo2) values. We used our previously validated mathematical model to determine the magnitude of hypoxemia by computing the estimated ePao2/Fio2 (ePF) ratio and comparing it to the Spo2/Fio2 (SF), using PF ratio as the reference standard. None. We analyzed a total of 20,828 ABGs. When Spo2 was below or equal to 97%, the ePF ratio showed a significantly better hypoxemia classification (none, light/moderate, or severe) than the SF ratio (0.80 vs. 0.72; p < 0.001), a lower fixed bias (16.26 vs. -35.24; p < 0.001), a lower mean absolute error (37.92 vs. 63.93; p < 0.001) and a lower proportional bias (slope of 1.01 vs. 0.81; p < 0.001). ePF ratio has also a better limits of agreement difference from Bland-Altman plot (248.10 vs. 292.45; p < 0.001) and coefficient of determination (0.68 vs. 0.59; p < 0.001). When Spo2 was above 97%, the ePF ratio had better classification with Kappa (0.53 vs. 0.43; p < 0.001) and lower fixed bias (-0.63 vs. 65.68; p < 0.001). The PF ratio based on ePF allows for a continuous estimation of hypoxemia severity with a better performance than the SF ratio.

Clinical implications of persistently increased blood urea nitrogen/serum creatinine ratio (PI-BUN/Cr) in severe COVID-19 patients

BackgroundPatients with COVID-19 may experience a persistent increase in the blood urea nitrogen over creatinine ratio (PI-BUN/Cr). Its elevation could reflect multiple underlying pathophysiological processes beyond prerenal injury but also warrants nuanced interpretation due to its complex interplay with various factors, underscoring the importance of investigating its effects on mortality and acute kidney injury in this population.MethodsWe analized a retrospective and longitudinal cohort of patients admitted to a single center in Mexico City for patients with severe COVID-19. Between March 5, 2020 and August 25, 2021, we included patients with confirmed positive diagnosis for SARS-CoV-2, age > 18 years, disease severity was defined by clinical data of respiratory distress syndrome and a ratio of partial oxygen pressure to inspired oxygen fraction < 300 mmHg on admission. We excluded patients with End Stage Kidney Disease. Data was obtained from electronic medical records. PI-BUN/Cr was defined as an increase in the BUN/Cr ratio > 30 in more than 60% of measurements in the hospital. The outcomes included: risk factors to mortality and AKI in-hospital.ResultsThe cohort included 3,007 patients with a median age of 54.6 ± 14.5 years. 35% of patients died; 44.6% developed PI-BUN/Cr ratio and 71.4% AKI. Mortality was associated with older age > 60 years [Hazard ratio (HR)] = 1.45, 95% CI: 1.28–1.65; p < 0.001); male (HR 1.25, 95% CI 1.09–1.44; p = 0.002) and AKI (HR 3.29, 95% CI 2.42–4.46; p < 0.001); PI-BUN/CR & Non-AKI (HR = 2.82, 95% CI: 1.61–4.93; p < 0.001); Non PI-BUN/CR & AKI (HR = 5.47, 95% CI: 3.54–8.44; p < 0.001); and PI-BUN/CR & AKI (HR = 4.26, 95% CI: 2.75–6.62, p < 0.001). Only hiperuricemia was a risk factor for AKI (HR = 1.71, 95% CI: 1.30–2.25, p < 0.001).ConclusionsWhile PI-BUN/Cr alone may not directly associate with mortality, its capacity to sub-phenotype patients according to their AKI status holds significant promise in offering valuable insights into patient prognosis and outcomes. Understanding the nuanced relationship between PI-BUN/Cr and AKI enhances our comprehension of renal function dynamics. It equips healthcare providers with a refined tool for risk stratification and personalized patient management strategies.

Higher protein intake may benefit in patients with prolonged mechanical ventilation

BackgroundPatients with prolonged mechanical ventilation (PMV) is usually associated with muscle wasting and diaphragm weakness, resulting in high medical costs and mortality. Adequate energy and protein intake were beneficial in sarcopenia patients. We aimed to investigate the impact of protein intake in weaning parameters in patients with PMV.Materials and methodsWe enrolled patients with PMV (mechanical ventilation ≥6 h/day for ≥21 days) from a respiratory care center (RCC) of a tertiary medical center from December 2020 to October 2022, and classified them into weaning success and weaning failure groups. The patients’ characteristics, nutrition records, weaning parameters and outcomes were analyzed.ResultsA total of 289 patients were included (mean age 73.5 years). Of the 289 patients, 149 were weaned successfully and 140 were not. The average protein intake was higher in the weaning success group than in the weaning failure group (1.22 ± 0.320 versus 0.99 ± 0.332 g/kg/day, p &amp;lt; 0.001). No significant differences were noted in the average calorie intake and whey protein intake between the two groups. RSBI &amp;lt;90 breaths/min/L (OR = 2.38, p = 0.045), serum albumin at 4th week ≥3 g/dL (OR = 2.89, p = 0.027), daily protein intake ≥1.01 g/kg/day (OR = 8.10, p &amp;lt; 0.001), PaO2/FiO2 (PF) ratio ≥ 300 (OR = 2.56, p = 0.027) were independent predictors for weaning from ventilator. Weak positive correlations were found between average protein intake with PF ratio (r = 0.1576, p = 0.0227) and PaO2 (r = 0.13359, p = 0.0497).ConclusionDaily protein intake had positively correlated with PF ratio and had independently benefit for weaning in patients with PMV.

Preconditioning with Moderate Hypoxia Increases Tolerance to Subsequent Severe Hypoxia in Rats with LPS-Induced Endotoxemia

Hyperproduction of mediators of LPS-induced inflammatory process (endotoxicosis, sepsis) initiates the development of acute respiratory failure (ARF), impaired gas exchange, progressive hypoxemia and hypercapnia, hypotension, respiratory arrest and death. Severe sepsis associated with hypoxemia remains the main cause of death, and therefore the development of methods to increase resistance to acute hypoxia in septic patients is an urgent task. The aim of the work was to study the effectiveness of preconditioning with short-term intermittent moderate hypoxia to increase tolerance to subsequent severe hypoxia in rats with LPS-induced endotoxicosis. The experiments were carried out on anesthetized and tracheostomated male Wistar rats. Endotoxicosis was modeled by administration of a lipopolysaccharide solution (Escherichia coli) in an amount of 7 mg/kg. To assess resistance to severe hypoxia, the rebreathing method of (RM) with a gradual decrease in oxygen in the rebreather from 21% to the onset of apnea was used. Hypoxic preconditioning (hypoxic training, HT) was also created by the method of RM in the mode of 3 cycles: reduction of the oxygen fraction in the rebreather to 12% – 3 min, 5 min – normoxia. 3 groups of animals were studied: I-control-NaCl, II–LPS, III–LPS+HT. The following parameters were recorded: external respiration, mean blood pressure (APm.), saturation (SpO2), fraction of inhaled O2, time of onset of apnea, the amount of spontaneous respiratory recovery (autoresuscitation) in the posthypoxic period. It was shown that the administration of LPS under normoxic conditions was accompanied by hyperventilation, hypoxemia and hypotension. The maximum deterioration in resistance to severe hypoxia was observed in rats with LPS, which was manifested by a decrease in APm, SpO2 and a decrease in the possibility of autoresuscitation after hypoxic apnea. The effect of HT prevented a decrease in blood pressure, SpO2 increased by 1.4 times, survival increased by 2 times, which is comparable to the level of normoxia before the introduction of LPS. It is assumed that the effectiveness of hypoxic preconditioning is due to the inhibition of the inflammatory response.

Evolution of solid residue composition during inert and oxidative biomass torrefaction

Biomass torrefaction is a thermochemical pretreatment that can be used to improve biomass properties, contributing to the energy densification of biomass or increasing its grindability, burning and gasification characteristics, porous structure, etc. While it is typically carried out under inert conditions, oxygen-lean torrefaction of biomass can reduce the process cost and complexity. This work proposes a novel extended 2-step kinetics mechanism capable of accurately predicting the evolution of the chemical composition of torrefied biomass. The model parameters are obtained from data collected from an extensive experimental campaign in which the chemical composition of torrefied biomass was measured at different temperatures, residence times, and oxygen fractions. The carbon mass fraction of the torrefied products was found to increase by up to 50 % under severe inert torrefaction conditions, i.e., high temperatures and long residence times, whereas the hydrogen fraction decreased. In the presence of oxygen during torrefaction, the carbon and hydrogen contents in the solid residue decrease compared with those produced under inert torrefaction. The extended 2-step model can also be used to determine the high heating value and energy densification of the torrefied biomass, with the latter ranging from 1 to 1.4 for the operating conditions tested.

Dynamic shunt flow alterations through patent foramen ovale during off-pump coronary artery bypass grafting induced by airway pressure changes: a case report.

Interatrial right-to-left shunt flow through a patent foramen ovale (PFO) can be caused by changes in heart position for anastomosis during off-pump coronary artery bypass (OPCAB). We herein present a case in which the direction of PFO shunt flow changed with heart position during OPCAB and the ventilation settings after sternal closure. A 66-year-old man with interstitial pneumonia underwent OPCAB. Preoperative transesophageal echocardiography revealed right-to-left shunt flow through a PFO induced by the Valsalva maneuver. During OPCAB, heart displacement resulted in right-to-left shunting and acute hypoxemia, which quickly improved with increase of inspired oxygen fraction. After chest closure, bidirectional shunt flow developed under increased airway pressure. Vigilant intraoperative monitoring with TEE and postoperative airway pressure management are important to address shunt flow and hypoxemia due to PFO.

Do the results of the OXYGEN trial change if analyzed as “as-treated?”: A secondary analysis of the OXYGEN trial

ObjectiveTo determine if the results of the OXYGEN trial changed using an “as-treated” approach instead of the original “intention-to-treat” approach. The multi-center randomized controlled OXYGEN trial aimed to determine the effectiveness of high FiO2 in decreasing infection rates for high-risk tibial plateau, tibial pilon, and calcaneus fractures. MethodsA secondary analysis of a multi-center randomized controlled trial conducted at 29 US trauma centers was performed. A total of 1231 patients aged 18–80 years with tibial plateau, tibial pilon, or calcaneus fractures thought to be at elevated risk of infection were enrolled. Patients were randomly assigned to receive inspired oxygen at a concentration of 80 % FiO2 (treatment) or 30 % FiO2 (control). Adherence was defined using two different criteria. Criterion 1 required at least 80 % of the surgery time ≤40 % FiO2 for the control group or ≥70 % FiO2 for the treatment group. Criterion 2 required at least 80 % of surgery time within 20–40 % (control) or 70–90 % FiO2 (treatment). The primary outcome was surgical site infection (SSI) within 182 days of definitive fracture fixation. Secondary outcomes were deep and superficial surgical site infections within 90, 182, and 365 days of definitive fixation. ResultsUnder Criterion 1, the primary outcome occurred in 7 % (38/523) and 10 % (49/471) of patients in the treatment and control groups, respectively (p = 0.10). Deep infection occurred in 30 (6 %) treatment and 30 (6 %) control patients (p = 0.75). Superficial infection occurred in 9 (2 %) treatment and 20 (4 %) control patients (RR, 0.41; p = 0.03). Using Criterion 2, the primary outcome occurred in 7 % (36/498) of treatment and 10 % (48/468) of control patients (p = 0.12). Deep infection occurred in 28 (6 %) treatment and 29 (6 %) control patients (p = 0.81). Superficial infection occurred in 9 (2 %) treatment and 20 (4.3 %) control patients (RR = 0.43; p = 0.03). ConclusionsWhen re-analyzing based on which patients actually received high or control levels of perioperative oxygen fraction, the results are somewhat consistent with the original “intent-to-treat” analysis. Specifically, high perioperative oxygen lowered the risk of superficial SSI but did not affect deep infections.

Cardiorespiratory Responses to Exercise in Hypobaric versus Normobaric Hypoxia: A Randomized, Single-Blind, Crossover Study.

There is controversy whether there are meaningful physiological differences between hypobaric (HH) and normobaric hypoxia (NH). This study aimed to compare the cardiorespiratory responses to acute HH and NH under strictly controlled conditions. We hypothesized no differences at rest and during submaximal exercise, whereas during maximal exercise, a higher maximal ventilation (V̇Emax), peripheral oxygen saturation (SpO2) and maximal oxygen consumption (V̇O2max) in HH than in NH. In a randomized, single-blind, crossover design, eight young healthy subjects (three females) were studied in an environmental chamber in which either the barometric pressure (HH) or the inspired oxygen fraction (NH) was reduced to the equivalent of ~4000 m altitude. Measurements were taken at rest, during submaximal (moderate and high intensity) and maximal cycling exercise. All resting parameters were similar between HH and NH, except for a lower root mean square of the successive R-R interval differences in HH (p < 0.05). SpO2 was 2% higher in HH at all exercise intensities (p < 0.05). During submaximal exercise, minute ventilation was similar between HH and NH. However, HH yielded a 7% lower tidal volume during moderate-intensity exercise (p < 0.05) and a lower respiratory exchange ratio during high-intensity exercise (p < 0.01). V̇Emax and V̇O2max were 11% and 6% higher in HH, respectively (p < 0.01 for both). SpO2 at maximal exercise was positively correlated with V̇Emax, V̇Emax/V̇O2max and V̇O2max. The higher V̇O2max found in HH than in NH can be attributed to the higher V̇Emax counteracting desaturation at maximal exercise. Conversely, submaximal SpO2 improved in HH through mechanisms other than increased ventilation. These findings are likely due to respiratory muscle unloading in HH, which operated through different mechanisms depending on exercise intensity.

Efficient utilization of enriched oxygen gas in residential PEMFC-CHP system with hydrogen energy storage

The oxygen byproduct generated from water electrolysis can be utilized on-site in residential combined heat and power (CHP) systems to enhance economic efficiency. This study explores solutions for optimizing the use of enriched oxygen gas (EOG) and determining the ideal oxygen fraction to maximize economic viability. A novel EOG supply system is designed to regulate oxygen fraction, oxygen excess ratio (OER), and humidity. A dynamic model of a PEMFC integrated with the EOG supply system is developed using MATLAB/Simulink® software and partially validated. The dual effects of EOG on system efficiency and remaining useful lifetime (RUL) are analyzed using a comprehensive economic optimization algorithm, leading to the identification of optimal oxygen fractions for various hydrogen production modes. Additionally, a feedforward static decoupling controller is designed to independently control the OER and oxygen fraction. The results indicate that, under rated conditions (10 kW), system power increased by 15 %, along with a 10 % improvement in system efficiency, from 48 % to 58 %. In conclusion, the efficient use of enriched oxygen gas demonstrates significant economic feasibility and practical viability, making it highly suitable for distributed power generation applications.

Effects of Pressure, Hypoxia, and Hyperoxia on Neutrophil Granulocytes

Background: The application of normo- and hyperbaric O2 is a common therapy option in various disease patterns. Thereby, the applied O2 affects the whole body, including the blood and its components. This study investigates influences of pressure and oxygen fraction on human blood plasma, nutrient media, and the functions of neutrophil granulocytes (PMNs). Methods: Neutrophil migration, reactive oxygen species (ROS) production, and NETosis were examined by live cell imaging. The treatment of various matrices (Roswell Park Memorial Institute 1640 medium, Dulbecco’s Modified Eagle’s Medium, H2O, human plasma, and isolated PMNs) with hyperbaric oxygen (HBO) was performed. In addition, the expression of different neutrophil surface epitopes (CD11b, CD62L, CD66b) and the oxidative burst were investigated by flow cytometry (FACS). The application of cold atmospheric plasma (CAP) to normoxic and normobaric culture media served as a positive control. Soluble reaction products such as H2O2, reactive nitrogen species (RNS: NO2− and NO3−), and ROS-dependent dihydrorhodamine oxidation were quantified by fluoro- and colorimetric assay kits. Results: Under normobaric normoxia, PMNs migrate slower and shorter in comparison with normobaric hyper- or hypoxic conditions and hyperbaric hyperoxia. The pressure component has less effect on the migration behavior of PMNs than the O2 concentration. Individual PMN cells produce prolonged ROS at normoxic conditions. PMNs showed increased expression of CD11b in normobaric normoxia, lower expression of CD62L in normobaric normoxia, and lower expression of CD66b after HBO and CAP treatment. Treatment with CAP increased the amount of ROS and RNS in common culture media. Conclusions: Hyperbaric and normobaric O2 influences neutrophil functionality and surface epitopes in a measurable way, which may have an impact on disorders with neutrophil involvement. In the context of hyperbaric experiments, especially high amounts of H2O2 in RPMI after hyperbaric oxygen should be taken into account. Therefore, our data support a critical indication for the use of normobaric and hyperbaric oxygen and conscientious and careful handling of oxygen in everyday clinical practice.

Influence of the Clamping Force and the Formation of Liquid Water Along the Channel on the Local Diffusion Processes in PEMFCs

A novel measurement setup, technique, and segmented model are introduced to spatially resolve mass transport losses along the channel in a PEMFC. The newly designed segmented cell enables not only the measurement of local current and voltage data but also the capture of local temperature and compression levels. By extending the commonly used limiting current method, the local mass transport resistance is determined as a function of local operating parameters. The local current and temperature are directly measured, while the operating conditions along the channel such as pressure, oxygen fraction, and relative humidity are obtained empirically from a 1-D differential model. Leveraging both measured and empirically-based simulation results, this comprehensive approach facilitates the characterization of mass transport resistance distribution along the gas channel. The learnings from this study provide valuable insight into the optimization of channel and materials design for enhancing large active area fuel cell performance and durability.

Influence of the Clamping Force and the Formation of Liquid Water Along the Channel on the Local Diffusion Processes in PEMFCs

A novel measurement setup, technique, and segmented model are introduced to spatially resolve mass transport losses along the channel in a PEMFC. The newly designed segmented cell enables not only the measurement of local current and voltage data but also the capture of local temperature and compression levels. By extending the commonly used limiting current method, the local mass transport resistance is determined as a function of local operating parameters. The local current and temperature are directly measured, while the operating conditions along the channel such as pressure, oxygen fraction, and relative humidity are obtained empirically from a 1-D differential model. Leveraging both measured and empirically-based simulation results, this comprehensive approach facilitates the characterization of mass transport resistance distribution along the gas channel. The learnings from this study provide valuable insight into the optimization of channel and materials design for enhancing large active area fuel cell performance and durability.

STABILITY AND COMBUSTION/EMISSION CHARACTERISTICS OF STRATIFIED DUAL-SWIRL OXY-METHANE FLAMES: EFFECTS OF OXYGEN FRACTION

Abstract The stability, combustion, and emission features of stratified oxy-methane (CH4/O2/CO2) flames stabilized over a dual annular counter-rotating swirl (DACRS) burner, developed for gas turbine combustion applications, were investigated experimentally. The experiments were performed at fixed velocity ratio (Vr=Vp/VS=3.0) in both the primary and secondary streams at a constant primary stream velocity, Vp of 5 m/s and at fixed primary stream equivalence ratio, φP=0.9, and over ranges of oxygen fractions (OFP for the primary stream, OFS for the secondary stream) and secondary stream equivalence ratios. Measurements of flame macrostructure, temperature profiles, and exhaust emissions were recorded to characterize the flames and validate future numerical models. The testing findings revealed no flame flashback within the operational ranges of OFP and OFS and up to φs = 1.0. However, the near stoichiometric operation of the primary stream (φp = 0.9) at OFp =0.38, permitted the main secondary flame to tolerate exceptionally lean conditions (φs = 0.397 at OFs =0.34 and φs = 0.223 at OFs =0.39), raising the thresholds for flame blowout. Increasing OFP from 0.21 to 0.38 significantly reduced φS at blowout from 0.537 to 0.223, corresponding to a decrease in the combustor's global equivalence ratio (φg) at blowout from 0.554 to 0.254 at global oxygen fraction (OFg) from 0.38 to 0.39. Lower OFp values caused earlier flame lift-off, indicating the greater influence of OFp on flame macrostructures.

Respiratory effects of prone position in COVID-19 acute respiratory distress syndrome differ according to the recruitment-to-inflation ratio: a prospective observational study

BackgroundImprovements in oxygenation and lung mechanics with prone position (PP) in patients with acute respiratory distress syndrome (ARDS) are inconstant. The objectives of the study were (i) to identify baseline variables, including the recruitment-to-inflation ratio (R/I), associated with a positive response to PP in terms of oxygenation (improvement of the ratio of arterial oxygen partial pressure over the inspired oxygen fraction (PaO2/FiO2) ≥ 20 mmHg) and lung mechanics; (ii) to evaluate whether the response to the previous PP session is associated with the response to the next session.MethodsIn this prospective, observational, single-center study in patients who underwent PP for ARDS due to COVID-19, respiratory variables were assessed just before PP and at the end of the session. Respiratory variables included mechanical ventilation settings and respiratory mechanics variables, including R/I, an estimate of the potential for lung recruitment compared to lung overinflation.ResultsIn 50 patients, 201 PP sessions lasting 19 ± 3 h were evaluated. Neuromuscular blockades were used in 116 (58%) sessions. The PaO2/FiO2 ratio increased from 109 ± 31 mmHg to 165 ± 65 mmHg, with an increase ≥ 20 mmHg in 142 (71%) sessions. In a mixed effect logistic regression, only pre-PP PaO2/FiO2 (OR 1.12 (95% CI [1.01–1.24])/every decrease of 10 mmHg, p = 0.034) in a first model and improvement in oxygenation at the previous PP session (OR 3.69 (95% CI [1.27–10.72]), p = 0.017) in a second model were associated with an improvement in oxygenation with PP. The R/I ratio (n = 156 sessions) was 0.53 (0.30–0.76), separating lower- and higher-recruiters. Whereas PaO2/FiO2 improved to the same level in both subgroups, driving pressure and respiratory system compliance improved only in higher-recruiters (from 14 ± 4 to 12 ± 4 cmH2O, p = 0.027, and from 34 ± 11 to 38 ± 13 mL/cmH2O, respectively, p = 0.014).ConclusionsA lower PaO2/FiO2 at baseline and a positive O2-response at the previous PP session are associated with a PP-induced improvement in oxygenation. In higher-recruiters, lung mechanics improved along with oxygenation. Benefits of PP could thus be greater in these patients.

Effects of Dexmedetomidine in Improving Oxygenation and Reducing Pulmonary Shunt in High-Risk Pediatric Patients Undergoing One-Lung Ventilation for Thoracic Surgery: A Double-Blind Randomized Controlled Trial.

Background and objectives Pediatric thoracic surgery has unique considerations due to the immaturity of the respiratory system anatomically and physiologically, which presents technical and pharmacological considerations, including the very common technique of one-lung ventilation (OLV), which causes serious complications in children. Therefore, we investigated the effects of dexmedetomidine on oxygenation and pulmonary shunt fraction (Qs/Qt) in high-risk pediatric patients undergoing OLV for thoracic surgery. This randomized controlled trial aimed to investigate dexmedetomidine's effect on the partial pressure of arterial oxygen (PaO2) and pulmonary shunt fraction (Qs/Qt). Methods A total of 63 children underwent thoracic surgery with OLV and were divided into two groups. The dexmedetomidine group (group Dex, n = 32) received dexmedetomidine (0.4 μg/kg/hour), and the placebo group (group placebo, n = 31) received normal saline. Two arterial and central venous blood samples were taken for arterial and venous blood gas analysis at four time points: T1 (10 minutes after mechanical ventilation of total lung ventilation), T2 (10 minutes after OLV), T3 (60 minutes after OLV), and T4 (20 minutes after the end of OLV). At these intervals, the following parameters were measured: PaO2, Qs/Qt, mean arterial pressure (MAP), heart rate (HR), and peak inspiratory pressure (PIP). Results The two groups had no significant differences in FEV1/FVC and baseline pulmonary shunt fraction (Qs/Qt). Dexmedetomidine significantly improved PaO2 compared with placebo during OLV (T2 and T3). There was a significant decrease in Qs/Qt compared with placebo during OLV (T2, T3, and T4). There was a decrease in PIP compared with placebo during OLV (T2 and T3). No statistically significant differences in MAP or HR were observed between the groups. Conclusion Infusion of dexmedetomidine during OLV in high-risk pediatric thoracic surgery reduces shunt and pulmonary shunt fraction Qs/Qt, improves PaO2 and body oxygenation, reduces PIP and pressure load, and maintains hemodynamic stability (MAP, HR).

Chronic intermittent hypoxia triggers cardiac fibrosis: Role of epididymal white adipose tissue senescent remodeling?

Obstructive sleep apnea (OSA) is a growing health problem affecting nearly 1 billion people worldwide. The landmark feature of OSA is chronic intermittent hypoxia (CIH), accounting for multiple organ damage, including heart disease. CIH profoundly alters both visceral white adipose tissue (WAT) and heart structure and function, but little is known regarding inter-organ interaction in the context of CIH. We recently showed that visceral WAT senescence drives myocardial alterations in aged mice without CIH. Here, we aimed at investigating whether CIH induces a premature visceral WAT senescent phenotype, triggering subsequent cardiac remodeling. In a first experiment, 10-week-old C57bl6J male mice (n = 10/group) were exposed to 14 days of CIH (8 h daily, 5%-21% cyclic inspired oxygen fraction, 60 s per cycle). In a second series, mice were submitted to either epididymal WAT surgical lipectomy or sham surgery before CIH exposure. Finally, we used p53 deficient mice or Wild-type (WT) littermates, also exposed to the same CIH protocol. Epididymal WAT was assessed for fibrosis, DNA damages, oxidative stress, markers of senescence (p16, p21, and p53), and inflammation by RT-qPCR and histology, and myocardium was assessed for fibrosis and cardiomyocyte hypertrophy. CIH-induced epididymal WAT remodeling characterized by increased fibrosis, oxidative stress, DNA damage response, inflammation, and increased expression of senescent markers. CIH-induced epididymal WAT remodeling was associated with subtle and early myocardial interstitial fibrosis. Both epididymal WAT surgical lipectomy and p53 deletion prevented CIH-induced myocardial fibrosis. Short-term exposure to CIH induces epididymal WAT senescent remodeling and cardiac interstitial fibrosis, the latter being prevented by lipectomy. This finding strongly suggests visceral WAT senescence as a new target to mitigate OSA-related cardiac disorders.

The Effect of Hemoadsorption with CytoSorb on Severe COVID-19 Complications

The aim of the study was to assess the effect of hemoadsorption with CytoSorb on the inflammatory response, respiratory failure, and mortality in patients with severe novel coronavirus infection.Materials and methods. A retrospective single-center cohort comparative study of hemoadsorbtion using the CytoSorb therapy included data from 124 COVID-19 ICU patients. Patients were divided into two groups: the study arm with hemoadsorption (group 1, N=93) and the control arm without hemoadsorption (group 2, N=31). Patients in group 1 had more severe respiratory failure at baseline, but were otherwise comparable to patients in group 2 in terms of clinical and demographic parameters.Results. After hemoadsorption, group 1 patients showed significant improvement in 9 of 13 monitored clinical, instrumental, and laboratory parameters: fever (P=0.005), lactate dehydrogenase (LDH) (P&lt;0.001), C-reactive protein (CRP) (P&lt;0.001), and IL-6 (P&lt;0.001) levels, as well as an increase in SpO₂/FiO₂ ratio (P=0.041), leukocyte count (P&lt;0.001) and lymphocyte count (P=0.003), as well as no significant changes in SOFA score (P=0.068). The only improvement seen in group 2 patients was a reduction in fever (P=0.003). Other significant changes in group 2 were unfavorable, such as a decrease in SpO₂/FiO₂ ratio (P=0.002), an increase in inspiratory oxygen fraction FiO₂ (P=0.001), leukocyte count (P&lt;0.05), LDH (P=0.038), procalcitonin (P&lt;0.001), and IL-6 (P=0.005), as well as an increase in SOFA score from 3.0 to 7.0 (95%CI, 3.0–9.0) (P=0.001). The all-cause hospital mortality rate was 37,63% in group 1 and 74.20% in group 2.Conclusion. The use of hemoadsorption with CytoSorb as a pathogenetic therapy targeting the hyperinflammatory response in the management algorithm of ICU patients with severe COVID-19 complications resulted in resolution of the inflammatory response and respiratory failure, as well as a significant reduction in mortality.

H1N1pdm09 infection in children: A case report of reemerging disease in COVID-19 pandemic

An outbreak of H1N1 infection was first declared by the World Health Organization in 2009 and confirmed in the post-pandemic phase in 2010. Amid the COVID-19 pandemic, we found a confirmed case of H1N1pdm09 in Bunda Women and Children Hospital Jakarta. A 13-year-old boy was referred to our hospital after four days of hospitalization due to worsening tachypnea following a productive cough and fever. The patient had severe dyspnea with inspiratory effort and oxygen desaturation to 80%, therefore admitted to our pediatric intensive care unit. On physical examination, the patient had increased work of breathing, looked irritable, had a respiratory rate of about 40x/minute with non-rebreathing mask support, and crackles were heard in both lungs. Chest x-ray showed right bronchopneumonia. There was a history of a generalized seizure for less than 1 minute, which stopped spontaneously in previous hospital care. The patient was diagnosed with mucopolysaccharidosis at age six years old and has never received enzyme replacement therapy. Laboratory results revealed thrombocytopenia, leukopenia, neutrophilia, monocytosis, high c-reactive protein and procalcitonin, and elevated liver enzymes. The investigation of etiology was performed using the respiratory panel test and showed a positive real-time polymerase chain reaction for H1N1pdm09 and Influenza A. The patient was given oxygen therapy with a high-flow nasal cannula with an oxygen fraction of 40% and a flow of 20 liters per minute, fluid maintenance while fasting, antibiotics, inhaled beta-2 agonists, and a neuraminidase inhibitor (oseltamivir). The patient's clinical and laboratory markers improved on the third day of treatment, and he was discharged two days later.