High-flow nasal oxygen versus conventional oxygen therapy and noninvasive ventilation in COVID-19 respiratory failure: a systematic review and network meta-analysis of randomised controlled trials

BACKGROUND

Noninvasive methods of respiratory support, including noninvasive ventilation (NIV), continuous positive airway pressure (CPAP), and high-flow nasal oxygen (HFNO), are potential strategies to prevent progression to requirement for invasive mechanical ventilation in acute hypoxaemic respiratory failure. The COVID-19 pandemic provided an opportunity to understand the utility of noninvasive respiratory support among a homogeneous cohort of patients with contemporary management of acute respiratory distress syndrome. We performed a network meta-analysis of studies evaluating the efficacy of NIV (including CPAP) and HFNO, compared with conventional oxygen therapy (COT), in patients with COVID-19.

METHODS

PubMed, Embase, and the Cochrane library were searched in May 2023. Standard random-effects meta-analysis was used first to estimate all direct pairwise associations and the results from all studies were combined using frequentist network meta-analysis. Primary outcome was treatment failure, defined as discontinuation of HFNO, NIV, or COT despite progressive disease. Secondary outcome was mortality.

RESULTS

We included data from eight RCTs with 2302 patients, (756 [33%] assigned to COT, 371 [16%] to NIV, and 1175 [51%] to HFNO). The odds of treatment failure were similar for NIV (P=0.33) and HFNO (P=0.25), and both were similar to that for COT (reference category). The odds of mortality were similar for all three treatments (odds ratio for NIV vs COT: 1.06 [0.46-2.44] and HFNO vs COT: 0.97 [0.57-1.65]).

CONCLUSIONS

Noninvasive ventilation, high-flow nasal oxygen, and conventional oxygen therapy are comparable with regards to treatment failure and mortality in COVID-19-associated acute respiratory failure.

PROSPERO REGISTRATION

CRD42023426495.

Effectiveness of bubble continuous positive airway pressure for treatment of children aged 1-59 months with severe pneumonia and hypoxaemia in Ethiopia: a pragmatic cluster-randomised controlled trial

BACKGROUND

The safety and efficacy of bubble continuous positive airway pressure (bCPAP) for treatment of childhood severe pneumonia outside tertiary care hospitals is uncertain. We did a cluster-randomised effectiveness trial of locally made bCPAP compared with WHO-recommended low-flow oxygen therapy in children with severe pneumonia and hypoxaemia in general hospitals in Ethiopia.

METHODS

This open, cluster-randomised trial was done in 12 general (secondary) hospitals in Ethiopia. We randomly assigned six hospitals to bCPAP as first-line respiratory support for children aged 1-59 months who presented with severe pneumonia and hypoxaemia and six hospitals to standard low-flow oxygen therapy. Cluster (hospital) randomisation was stratified by availability of mechanical ventilation. All children received treatment in paediatric wards (in a dedicated corner in front of a nursing station) with a similar level of facilities (equipment for oxygen therapy and medications) and staffing (overall, one nurse per six patients and one general practitioner per 18 patients) in all hospitals. All children received additional care according to WHO guidelines, supervised by paediatricians and general practitioners. The primary outcome was treatment failure (defined as any of the following: peripheral oxygen saturation <85% at any time after at least 1 h of intervention plus signs of respiratory distress; indication for mechanical ventilation; death during hospital stay or within 72 h of leaving hospital against medical advice; or leaving hospital against medical advice during intervention). The analysis included all children enrolled in the trial. We performed both unadjusted and adjusted analyses of the primary outcome, with the latter adjusted for the stratification variable and for the design effect of cluster randomisation, as well as selected potentially confounding variables, including age. We calculated effectiveness as the relative risk (RR) of the outcomes in the bCPAP group versus low-flow oxygen group. This trial is registered with ClinicalTrial.gov, NCT03870243, and is completed.

FINDINGS

From June 8, 2021, to July 27, 2022, 1240 children were enrolled (620 in hospitals allocated to bCPAP and 620 in hospitals allocated to low-flow oxygen). Cluster sizes ranged from 103 to 104 children. Five (0·8%) of 620 children in the bCPAP group had treatment failure compared with 21 (3·4%) of 620 children in the low-flow oxygen group (unadjusted RR 0·24, 95% CI 0·09-0·63, p=0·0015; adjusted RR 0·24, 0·07-0·87, p=0·030). Six children died during hospital stay, all of whom were in the low-flow oxygen group (p=0·031). No serious adverse events were attributable to bCPAP.

INTERPRETATION

In Ethiopian general hospitals, introduction of locally made bCPAP, supervised by general practitioners and paediatricians, was associated with reduced risk of treatment failure and in-hospital mortality in children with severe pneumonia and hypoxaemia compared with use of standard low-flow oxygen therapy. Implementation research is required in higher mortality settings to consolidate our findings.

FUNDING

SIDA Sweden and Grand Challenges Ethiopia.

Individualized Treatment Effects of Oxygen Targets in Mechanically Ventilated Critically Ill Adults

Importance

Among critically ill adults, randomized trials have not found oxygenation targets to affect outcomes overall. Whether the effects of oxygenation targets differ based on an individual's characteristics is unknown.

Objective

To determine whether an individual's characteristics modify the effect of lower vs higher peripheral oxygenation-saturation (Spo2) targets on mortality.

Design, Setting, and Participants

A machine learning model to predict the effect of treatment with a lower vs higher Spo2 target on mortality for individual patients was derived in the Pragmatic Investigation of Optimal Oxygen Targets (PILOT) trial and externally validated in the Intensive Care Unit Randomized Trial Comparing Two Approaches to Oxygen Therapy (ICU-ROX) trial. Critically ill adults received invasive mechanical ventilation in an intensive care unit (ICU) in the United States between July 2018 and August 2021 for PILOT (n = 1682) and in 21 ICUs in Australia and New Zealand between September 2015 and May 2018 for ICU-ROX (n = 965).

Exposures

Randomization to a lower vs higher Spo2 target group.

Main Outcome and Measure

28-Day mortality.

Results

In the ICU-ROX validation cohort, the predicted effect of treatment with a lower vs higher Spo2 target for individual patients ranged from a 27.2% absolute reduction to a 34.4% absolute increase in 28-day mortality. For example, patients predicted to benefit from a lower Spo2 target had a higher prevalence of acute brain injury, whereas patients predicted to benefit from a higher Spo2 target had a higher prevalence of sepsis and abnormally elevated vital signs. Patients predicted to benefit from a lower Spo2 target experienced lower mortality when randomized to the lower Spo2 group, whereas patients predicted to benefit from a higher Spo2 target experienced lower mortality when randomized to the higher Spo2 group (likelihood ratio test for effect modification P = .02). The use of a Spo2 target predicted to be best for each patient, instead of the randomized Spo2 target, would have reduced the absolute overall mortality by 6.4% (95% CI, 1.9%-10.9%).

Conclusion and relevance

Oxygenation targets that are individualized using machine learning analyses of randomized trials may reduce mortality for critically ill adults. A prospective trial evaluating the use of individualized oxygenation targets is needed.

Enhancing 7-dehydrocholesterol suppresses brain ferroptosis and tissue injury after neonatal hypoxia-ischemia

Neonatal hypoxic-ischemic brain injury (HIBI) results in part from excess reactive oxygen species and iron-dependent lipid peroxidation (i.e. ferroptosis). The vitamin D precursor 7-dehydrocholesterol (7-DHC) may inhibit iron-dependent lipid peroxidation. Primary neurons underwent oxygen and glucose deprivation (OGD) injury and treatment with 7-DHC-elevating medications such as cariprazine (CAR) or vehicle. Postnatal day 9 mice underwent sham surgery or carotid artery ligation and hypoxia and received intraperitoneal CAR. In neurons, CAR administration resulted in significantly increased cell survival compared to vehicle controls, whether administered 48 h prior to or 30 min after OGD, and was associated with increased 7-DHC. In the mouse model, malondialdehyde and infarct area significantly increased after HIBI in the vehicle group, which were attenuated by post-treatment with CAR and were negatively correlated with tissue 7-DHC concentrations. Elevating 7-DHC concentrations with CAR was associated with improved cellular and tissue viability after hypoxic-ischemic injury, suggesting a novel therapeutic avenue.

Pulmonary Complications in Premature Infants Using a Beractant or Poractant for Respiratory Distress Syndrome: A Retrospective Cohort Study

OBJECTIVE

 Premature infants are at the risk of developing respiratory distress syndrome (RDS). Beractants and poractants are two commonly used natural surfactants. This retrospective cohort study aims to compare the incidence of pulmonary complications between beractant and poractant treatment groups.

STUDY DESIGN

 This study evaluated 29 patients treated with beractant and 49 patients treated with poractant. The primary outcome was the incidence of air leak syndrome (ALS) and pulmonary hemorrhage. Secondary outcomes included mortality and pulmonary outcomes, such as mechanical ventilation duration, oxygen dependence duration, fraction of inspired oxygen, and mean airway pressure (MAP) requirement. Logistic regression analyses were conducted to identify independent risk factors for significant primary outcomes.

RESULTS

 No significant difference was found in the demographics between the two groups. A significantly higher incidence of pulmonary hemorrhage was observed in the poractant group (14.3 vs. 0.0%, p = 0.038). The difference in the incidence of ALS between the groups was insignificant (p = 0.536). Logistic regression for the incidence of pulmonary hemorrhage identified coagulopathy as the only significant independent risk factor (odds ratio 39.855, 95% confidence interval [2.912-545.537]; p = 0.006). Secondary outcomes in both treatment groups were similar, except that patients in the poractant group had a higher MAP before surfactant therapy (9 vs. 8 cmH2O, p < 0.001).

CONCLUSION

 This study showed a significantly higher incidence of pulmonary hemorrhage in the poractant group. Coagulopathy was identified as an independent risk factor for pulmonary hemorrhage. Future long-term prospective studies are essential to establish the temporal and causal relationships between coagulopathy and pulmonary hemorrhage in premature infants receiving surfactant therapy for RDS; hence, there is the need for a screening protocol before surfactant administration.

KEY POINTS

· A higher incidence of pulmonary hemorrhage was found in the poractant group.. · Coagulopathy was the only significant risk factor that was related to the incidence of pulmonary hemorrhage.. · A screening protocol might be useful to avoid pulmonary hemorrhage in infants receiving surfactant..

Ozanimod Therapy in Patients With COVID-19 Requiring Oxygen Support: A Randomized Open-Label Pilot Trial

BACKGROUND

Sphingosine-1-phosphate receptor ligands (SRLs) dampen immunopathologic damages in models of viral pneumonia.

RESEARCH QUESTION

Is it feasible to administer an SRL therapy, here ozanimod (OZA), to acutely ill patients infected with SARS-CoV-2?

STUDY DESIGN AND METHODS

The prospective randomized open-label COVID-19 Ozanimod Intervention (COZI) pilot trial was conducted in three Canadian hospitals. Patients admitted for COVID-19 requiring oxygen were eligible. Randomization was stratified for risk factors of poor outcome and oxygen needs at inclusion. Participants were allocated to standard of care or to standard of care plus OZA. OZA (oral, once daily, incremental dosage) was administered for a maximum of 14 days. Primary end point investigated for size effect and variance over time was the assessment of safety and efficacy, evaluated by the daily score on the World Health Organization-adapted six-point ordinal scale for clinical improvement analyzed under the intention-to-treat principle.

RESULTS

Twenty-three patients were randomized to the standard of care arm, and 20 were randomized to the OZA arm from September 2020 to February 2022. Evaluation of efficacy showed nonsignificant reductions of median (interquartile range) duration of respiratory support (6 [3-10] vs 9 [4-12] days; P = .34), median duration of hospitalization (9 [6-12] vs 10 [6-18] days; P = .20), and median time to clinical improvement (4 [3-7] vs 7 [3-11] days; P = .12) for OZA compared with standard of care, respectively. Heart rate was significantly lower with OZA (65 [ 63-67] vs 71 [69-72] beats/min; P < .0001). However, QT and PR intervals were not affected. No severe adverse drug reaction was reported.

INTERPRETATION

To our knowledge, SRL utility in severe pneumonia has never been tested in patients. This study shows for the first time that this new pharmacologic agent may safely be administered to patients hospitalized for viral pneumonia, with potential clinical benefits. Bradycardia was frequent but well tolerated.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT04405102; URL: www.

CLINICALTRIALS

gov.

Critical period of oxygen supplementation and invasive ventilation: implications for severe retinopathy of prematurity

BACKGROUND

Several studies have identified graded oxygen saturation targets to prevent retinopathy of prematurity (ROP), a serious complication in preterm infants. We aimed to analyze the critical period of oxygen supplementation and/or invasive ventilation associated with severe ROP.

METHODS

This retrospective case-control study included neonates with a gestational age (GA) < 29 weeks. Participants were divided into two groups: treated retinopathy and untreated/no retinopathy. Time-weighted average FiO2 (TWAFiO2) and weekly invasive ventilation were compared between groups by postnatal age (PNA) and postmenstrual age (PMA). The association of treated retinopathy with TWAFiO2 and invasive ventilation was analyzed.

RESULTS

Data from 287 neonates were analyzed; 98 were treated for ROP and had lower GAs (25.5 vs. 27.4 weeks, p < 0.01) and lower birthweights (747.6 vs. 1014 g, p < 0.001) than those with untreated/no ROP. TWAFiO2 was higher from PMA 26-34 weeks, except for PMA 31 weeks in treated ROP, and higher in the first nine weeks of life in treated ROP. On multiple logistic regression, TWAFiO2 and invasive ventilation were associated with ROP treatment during the first seven weeks PNA. Invasive ventilation was associated with ROP treatment from PMA 26-31 weeks; no association was found for TWAFiO2 and PMA.

CONCLUSIONS

Amount of oxygen supplementation and/or invasive ventilation during the first 7 weeks of life or up to 31 weeks PMA was associated with development of severe ROP. This period might be candidate timing for strict oxygen supplementation strategies in preterm infants, while concerns of mortality with low oxygen supplementation should be further explored.

Topical oxygen therapy and singlet oxygen in wound healing: A scoping review

The aim of this scoping review was to provide an overview of current research into topical oxygen therapies including the under-researched singlet oxygen for wound healing. A scoping review was undertaken using five databases. After duplicates and ineligible studies were excluded, 49 studies were included for a narrative review. Out of the included 49 studies, 45 (91.8%) were published in the past 10 years (2013-2023) with 32 (65.3%) published in the past 5 years (2018-2023). Eight of the studies were systematic reviews and/or meta-analysis and 18 were RCTs. The search identified zero human RCTs on singlet oxygen, but one human cohort study and five studies in animals. There is evidence that topical oxygen therapy may be useful for the treatment of chronic wounds, mainly diabetic foot ulcers. Singlet oxygen has shown potential, but would need further confirmation in controlled human trials, including more research to understand the bio-properties.

Comparing high-flow nasal oxygen therapy and normobaric oxygen therapy on the treatment of carbon monoxide poisoning

AIM

We aimed to investigate whether there is a difference in the rate of decrease in carboxyhemoglobin (COHB) values between high-flow nasal oxygen (HFNO) and normobaric oxygen (NBO) therapy.

MATERIAL AND METHOD

This retrospective observational study included patients with carbon monoxide poisoning who were treated with HFNO or NBO (control group). All patients were started on NBO therapy with a non-rebreather face mask at a rate of 15 L/min. In the NBO group, NBO treatment was continued until the COHB value fell below 10%. In the HFNO group, as soon as the preparation of the HFNO device was completed, NBO treatment was terminated and HFNO treatment was started and continued until the COHB value fell below 10%. The primary outcome of the study was the difference between HFNO and NBO in terms of COHB half-life rates.

RESULTS

A total of 81 patients were included in the study, 44 in the HFNO group and 37 in the NBO group. The median of COHB t1/2 values between HFNO and the NBO treatment groups were 47.3 (IQR: 25-75%: 31.5-65.4) and 46 (IQR: 25-75%: 32.3-56.2), respectively, but this difference was not statistically significant (p = 0.81).

CONCLUSION

The results of this study suggest that HFNO treatment does not have a significant advantage over NBO treatment in the carbon monoxide elimination rate within the first 60 min of treatment.

Impact of persistent pulmonary hypertension and oxygenation on brain injury in neonates with neonatal encephalopathy treated with therapeutic hypothermia

OBJECTIVE

To investigate the effects of persistent pulmonary hypertension (PPHN) and oxygenation on outcome of neonates with neonatal encephalopathy (NE) treated with therapeutic hypothermia (TH).

STUDY DESIGN

We compared the outcome of neonates with NE treated with TH with or without PPHN.

RESULTS

384 neonates with NE were treated with TH; 24% had PPHN. The fraction of inspired oxygen was higher in the first 4 days of life (p < 0.001) in neonates with PPHN. They had a significantly lower arterial partial pressure of oxygen in the first 4 days of life (p = 0.005) and higher on days 3-4 of life (p < 0.001). They were more often intubated (p < 0.001) and more often had concomitant hypotension (p < 0.001). They had higher mortality (p = 0.009) and more often developed brain injury (p = 0.02).

CONCLUSION

PPHN occurred frequently in neonates with NE treated with TH and was associated with a higher incidence of adverse outcome.

Photocleavable Visible Light-Triggered Anthraquinone-Derived Water-Soluble Block Copolymer for Peroxynitrite Generation in Cancer Therapy

We report a facile stimuli-responsive strategy to generate reactive oxygen and nitrogen species (ROS and RNS) in the biological milieu from a photocleavable water-soluble block copolymer under visible light irradiation (427 nm, 2.25 mW/cm2). An anthraquinone-based water-soluble polymeric nitric oxide (NO) donor (BCPx-NO) is synthesized, which exhibits NO release in the range of 40-65 μM within 10 h of photoirradiation with a half-life of 30-103 min. Additionally, BCPx-NO produces peroxynitrite (ONOO-) and singlet oxygen (1O2) under photoirradiation. To understand the mechanism of NO release and photolysis of the functional group under blue light, we prepared a small-molecule anthraquinone-based N-nitrosamine (NOD). The cellular investigation of the effect of spatiotemporally controlled ONOO- and 1O2 generation from the NO donor polymeric nanoparticles in a triple negative breast adenocarcinoma (MDA-MB-231) under visible light irradiation (white light, 5.83 mW/cm2; total dose 31.5 J/cm2) showed an IC50 of 0.6 mg/mL. The stimuli-responsive strategy using a photolabile water-soluble block copolymer employed to generate ROS and RNS in a biological setting widens the horizon for their potential in cancer therapy.

Hyperoxemia Induced by Oxygen Therapy in Nonsurgical Critically Ill Patients

BACKGROUND

Hyperoxemia, often overlooked in critically ill patients, is common and may have adverse consequences.

OBJECTIVE

To evaluate the incidence of hyperoxemia induced by oxygen therapy in nonsurgical critically ill patients at intensive care unit (ICU) admission and the association of hyperoxemia with hospital mortality.

METHODS

This prospective cohort study included all consecutive admissions of nonsurgical patients aged 18 years or older who received oxygen therapy on admission to the Hospital Santa Luzia Rede D'Or São Luiz adult ICU from July 2018 through June 2021. Patients were categorized into 3 groups according to Pao2 level at ICU admission: hypoxemia (Pao2<60 mm Hg), normoxemia (Pao2= 60-120 mm Hg), and hyperoxemia (Pao2 >120 mm Hg).

RESULTS

Among 3088 patients, hyperoxemia was present in 1174 (38.0%) and was independently associated with hospital mortality (odds ratio [OR], 1.32; 95% CI, 1.04-1.67; P=.02). Age (OR, 1.02; 95% CI, 1.02-1.02; P<.001) and chronic kidney disease (OR, 1.55; 95% CI, 1.02-2.36; P=.04) were associated with a higher rate of hyperoxemia. Factors associated with a lower rate of hyperoxemia were Sequential Organ Failure Assessment score (OR, 0.88; 95% CI, 0.83-0.93; P<.001); late-night admission (OR, 0.80; 95% CI, 0.67-0.96; P=.02); and renal/metabolic (OR, 0.22; 95% CI, 0.13-1.39; P<.001), neurologic (OR, 0.02; 95% CI, 0.01-0.05; P<.001), digestive (OR, 0.23; 95% CI, 0.13-0.41; P<.001), and soft tissue/skin/orthopedic (OR, 0.32; 95% CI, 0.13-0.79; P=.01) primary reasons for hospital admission.

CONCLUSION

Hyperoxemia induced by oxygen therapy was common in critically ill patients and was linked to increased risk of hospital mortality. Health care professionals should be aware of this condition because of its potential risks and unnecessary costs.

Oxygen Therapy in Patients With Intermediate-Risk Acute Pulmonary Embolism: A Randomized Trial

BACKGROUND

The effect of supplemental oxygen therapy in patients with intermediate-risk pulmonary embolism (PE) who do not have hypoxemia at baseline is uncertain.

RESEARCH QUESTION

Does supplemental oxygen improve echocardiographic parameters in nonhypoxemic patients with intermediate-risk PE?

STUDY DESIGN AND METHODS

This pilot trial randomly assigned nonhypoxemic patients with stable PE and echocardiographic right ventricle (RV) enlargement to receive anticoagulation plus supplemental oxygen for the first 48 h vs anticoagulation alone. The primary outcome was normal echocardiographic RV size 48 h after randomization. Secondary efficacy outcomes were the numerical change in the RV to left ventricle (LV) diameter ratio measured 48 h and 7 days after randomization with respect to the baseline ratio measured at inclusion.

RESULTS

The study was stopped prematurely because of the COVID-19 pandemic after recruiting 70 patients (mean ± SD age, 67.3 ± 16.1 years; 36 female [51.4%]) with primary outcome data. Forty-eight h after randomization, normalization of the RV size occurred in 14 of the 33 patients (42.4%) assigned to oxygen and in eight of the 37 patients (21.6%) assigned to ambient air (P = .08). In the oxygen group, the mean RV to LV ratio was reduced from 1.28 ± 0.28 at baseline to 1.01 ± 0.16 at 48 h (P < .001); in the ambient air group, mean RV to LV ratios were 1.21 ± 0.18 at baseline and 1.08 ± 0.19 at 48 h (P < .01). At 90 days, one major bleeding event and one death (both in the ambient air group) had occurred.

INTERPRETATION

In analyses limited by a small number of enrollees, compared with ambient air, supplemental oxygen did not significantly increase the proportion of patients with nonhypoxemic intermediate-risk PE whose RV to LV ratio normalized after 48 h of treatment. This pilot trial showed improvement in some ancillary efficacy outcomes and provides support for a definitive clinical outcomes trial.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT04003116; URL: www.

CLINICALTRIALS

gov.

The effect of high altitude (2500 m) on incremental cycling exercise in patients with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension: a randomised controlled crossover trial

BACKGROUND

Our objective was to investigate the effect of a day-long exposure to high altitude on peak exercise capacity and safety in stable patients with pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH).

METHODS

In a randomised controlled crossover trial, stable patients with PAH or distal CTEPH without resting hypoxaemia at low altitude performed two incremental exercise tests to exhaustion: one after 3-5 h at high altitude (2500 m) and one at low altitude (470 m).

RESULTS

In 27 patients with PAH/CTEPH (44% females, mean±sd age 62±14 years), maximal work rate was 110±64 W at 2500 m and 123±64 W at 470 m (-11%, 95% CI -16- -11%; p<0.001). Oxygen saturation measured by pulse oximetry and arterial oxygen tension at end-exercise were 83±6% versus 91±6% and 6.1±1.9 versus 8.6±1.9 kPa (-8% and -29%; both p<0.001) at 2500 versus 470 m, respectively. Maximal oxygen uptake was 17.8±7.5 L·min-1·kg-1 at high altitude versus 20±7.4 L·min-1·kg-1 at low altitude (-11%; p<0.001). At end-exercise, the ventilatory equivalent for carbon dioxide was 43±9 at 2500 m versus 39±9 at 470 m (9%, 95% CI 2-6%; p=0.002). No adverse events occurred during or after exercise.

CONCLUSIONS

Among predominantly low-risk patients with stable PAH/CTEPH, cycling exercise during the first day at 2500 m was well tolerated, but peak exercise capacity, blood oxygenation and ventilatory efficiency were lower compared with 470 m.

Variability of oxygen requirements in critically ill COVID-19 patients

Background

The global scarcity of medical oxygen has proven to be catastrophic during the surges in COVID-19 cases over the past two years, with the heaviest burden felt in low- and middle-income countries. Despite its criticality, data and analyses of oxygen consumption, even for typical clinical cases, are missing. Consequently, planning oxygen needs, particularly with variable surges in COVID-19 cases, has presented a substantial challenge to policymakers and hospital decision-makers.

Methods

We performed a sub-analysis of the COVID-19 Critical Care Consortium database assessing the oxygen consumption requirements of COVID-19 patients admitted to intensive care units between February 2020 and October 2021. We calculated descriptive statistics for oxygen flow-rates, stratified by oxygen supplementation method, and developed a multi-state model for estimating the frequency, therapy duration, probability of transition, and number of oxygen therapy modes per patient.

Results

Overall, 12 429 patients from 35 countries received oxygen support on at least one day of their hospitalisation. Of the patients with measurable flow rates, 6142 received invasive mechanical ventilation, 838 received high-flow nasal oxygen, and 257 received both modalities. The median flow rate for mechanical ventilation was 3.2 L per minute (interquartile range (IQR) = 2.0-4.9), with a median duration of 12 days (IQR = 6-24), while the median flow rate for high-flow nasal cannula was 40 L per minute (IQR = 15-55), with a median duration of three days (IQR = 2-6).

Conclusions

Oxygen consumption among critical COVID-19 patients varies by mode of delivery (invasive ventilation vs high-flow nasal cannula), across patients, and over treatment duration. Therefore, it is essential that health facilities routinely monitor oxygen utilization to better inform oxygen delivery system design and regular supply planning.

Registration

ClinicalTrials.gov: CTG2021-01 ACTRN12620000421932.

Suppression of cerebral ischemia injury induced blood brain barrier breakdown by dexmedetomidine via promoting CCN1

BACKGROUND

Blood-brain barrier (BBB) could aggravate cerebral ischemia injury. Dexmedetomidine (Dex) has been believed to play a protective role in cerebral ischemia injury-induced BBB injury.

METHODS

Middle cerebral artery occlusion (MCAO) and oxygen-glucose deprivation (OGD) models were established to simulate cerebral ischemia injury. Animal experiments included 4 groups, Sham, MCAO, MCAO+Dex, MCAO+Dex+sh-CCN1. Generally applicable gene set enrichment analysis was performed to analyze gene expression difference. Total collagen content and Evans blue staining were performed to measure infarct ratio and BBB breakdown, respectively. The cell apoptosis, mRNA and protein expression were measured through flow cytometry, PCR, and western blotting, respectively. The levels of IL-1β, TNF-α, and IL-6 in serum were measured with commercial ELISA kits.

RESULTS

Dex greatly promoted the expression level of CCN1. Dex suppressed cerebral ischemia injury, increased tight junction protein expression, improved the memory ability and neurological function of MCAO rats through targeting CCN1. The significant increase of inflammatory factors in the serum of MCAO rats were suppressed by Dex. Dex suppressed OGD induced increase of HRP permeability and promoting tight junction protein expression in vitro through regulating CCN1. The neurological function evaluation was performed with Neurological Severity Score (NSS) and Longa Score Scale.

CONCLUSIONS

Dex could remarkably alleviate cerebral ischemia injury by inhibiting BBB breakdown, inflammatory response, and promoting neurological function and tight junction protein expression via up-regulating CCN1. This study might provide a novel therapeutic target for the prevention and treatment of cerebral ischemia injury-induced BBB.

The therapeutic effect of hyperbaric oxygen therapy in patients with severe to profound idiopathic sudden sensorineural hearing loss

The optimal treatment for sudden sensorineural hearing loss (SSNHL) is unclear. Hyperbaric oxygen therapy (HBOT) has been suggested as a viable option for treatment of SSNHL as it improves vascular dysfunction. In this study, we evaluated the therapeutic effects of HBOT by retrospectively reviewing the records of 2206 patients with SSNHL. 54 who had received HBOT were selected for the HBOT groups, while 59 age-matched controls who had not were selected for the control groups. The HBOT and control groups were divided into subgroups according to intratympanic steroid (ITS) use. Groups A-D had received oral steroids + HBOT, oral steroids only, oral steroids + ITS + HBOT, and oral steroids + ITS, respectively. Of the 113 SSNHL patients, 21 had diabetes mellitus (DM) (2, 0, 9, and 10 patients in Groups A-D, respectively). There was no notable difference in hearing improvement between patients receiving HBOT and those in the control group. However, among diabetic patients, those who underwent HBOT demonstrated a significant improvement in hearing when compared to the control group. The combination of HBOT and steroids could potentially be beneficial for treating severe to profound SSNHL patients with DM.

Effects of cellular radioresponse on therapeutic helium-, carbon-, oxygen-, and neon-ion beams: a simulation study

Objective. Helium, oxygen, and neon ions in addition to carbon ions will be used for hypofractionated multi-ion therapy to maximize the therapeutic effectiveness of charged-particle therapy. To use new ions in cancer treatments based on the dose-fractionation protocols established in carbon-ion therapy, this study examined the cell-line-specific radioresponse to therapeutic helium-, oxygen-, and neon-ion beams within wide dose ranges.Approach. Response of cells to ions was described by the stochastic microdosimetric kinetic model. First, simulations were made for the irradiation of one-field spread-out Bragg peak beams in water with helium, carbon, oxygen, and neon ions to achieve uniform survival fractions at 37%, 10%, and 1% for human salivary gland tumor (HSG) cells, the reference cell line for the Japanese relative biological effectiveness weighted dose system, within the target region defined at depths from 90 to 150 mm. The HSG cells were then replaced by other cell lines with different radioresponses to evaluate differences in the biological dose distributions of each ion beam with respect to those of carbon-ion beams.Main results. For oxygen- and neon-ion beams, the biological dose distributions within the target region were almost equivalent to those of carbon-ion beams, differing by less than 5% in most cases. In contrast, for helium-ion beams, the biological dose distributions within the target region were largely different from those of carbon-ion beams, more than 10% in several cases.Significance.From the standpoint of tumor control evaluated by the clonogenic cell survival, this study suggests that the dose-fractionation protocols established in carbon-ion therapy could be reasonably applied to oxygen- and neon-ion beams while some modifications in dose prescription would be needed when the protocols are applied to helium-ion beams. This study bridges the gap between carbon-ion therapy and hypofractionated multi-ion therapy.

Remote assessment and monitoring with advanced wound therapy to optimise clinical outcomes, access and resources

OBJECTIVE

Patients in rural communities may have limited access to wound care; however, this may be mitigated by using a shared care approach. This study assessed the impact of a remote assessment and monitoring tool in combination with adjunctive continuous topical oxygen therapy (cTOT) in patients with diabetes and hard-to-heal wounds.

METHOD

Patients with hard-to-heal wounds (defined as no visible improvement in the previous four weeks) were enrolled to this 12-week pilot study to validate a shared care approach using an Advanced Digital Wound Care Platform-telehealth (ADWCPt) system (eKare Inc., US) coupled with cTOT. Patient and wound assessments were reviewed by the clinician either remotely, via telehealth calls, or at the clinic, and the number of face-to-face clinic visits was recorded. Patient health status scores were captured before and after the study, along with feedback on usability of the remote platform and cTOT device.

RESULTS

The wounds in all eight patients studied reduced in size over 12 weeks (mean percentage area reduction 92.0%), and two wounds were completely re-epithelialised. Another wound almost healed (99.2% wound area reduction). Clinical interactions consisted of self-assessments (n=80, 50.0%), video assessments with the clinician (n=27, 16.9%), and face-to-face interactions in clinic (n=53, 33.1%). Operational efficiencies encompassed a 54.0% increase in the number of clinical interactions, whereas clinical time was reduced by 25.8%. Health status scores improved across all eight patients and feedback on the shared approach and cTOT device was favourable.

CONCLUSION

A shared care model with ADWCPt coupled with an innovative cTOT device saved time and resources, improving patient access and engagement, along with a marked improvement in the wound healing trajectory.

Effects of Neonatal Hypoxic-Ischemic Injury on Brain Sterol Synthesis and Metabolism

BACKGROUND

 Neonatal hypoxic-ischemic brain injury (HIBI) results from disruptions to blood supply and oxygen in the perinatal brain. The goal of this study was to measure brain sterol metabolites and plasma oxysterols after injury in a neonatal HIBI mouse model to assess for potential therapeutic targets in the brain biochemistry as well as potential circulating diagnostic biomarkers.

METHODS

 Postnatal day 9 CD1-IGS mouse pups were randomized to HIBI induced by carotid artery ligation followed by 30 minutes at 8% oxygen or to sham surgery and normoxia. Brain tissue was collected for sterol analysis by liquid chromatography with tandem mass spectrometry (LC-MS/MS). Plasma was collected for oxysterol analysis by LC-MS/MS.

RESULTS

 There were minimal changes in brain sterol concentrations in the first 72 hours after HIBI. In severely injured brains, there was a significant increase in desmosterol, 7-DHC, 8-DHC, and cholesterol 24 hours after injury in the ipsilateral tissue. Lanosterol, 24-dehydrolathosterol, and 14-dehydrozymostenol decreased in plasma 24 hours after injury. Severe neonatal HIBI was associated with increased cholesterol and sterol precursors in the cortex at 24 hours after injury.

CONCLUSIONS

 Differences in plasma oxysterols were seen at 24 hours but were not present at 30 minutes after injury, suggesting that these sterol intermediates would be of little value as early diagnostic biomarkers.

Understanding Covid-19: Digit ratios and duration of oxygen therapy in hospitalized Covid-19 patients

BACKGROUND

Covid-19 severity shows a sex difference (males>females) and progressive hypoxia among the most seriously affected. Digit ratios are sexually dimorphic and may be negatively-related to prenatal (2nd-to-4th digits' ratio; 2D:4D) and pubertal (3rd-to-5th digits' ratio; 3D:5D) testosterone. Oxygen therapy is important in Covid-19 treatment and low 2D:4D is linked to efficient oxygen metabolism. We consider relationships between digit ratios and duration of oxygen treatment in hospitalized Covid-19 patients.

METHODS

Digit lengths were measured from photographs of the patient's hands. Age, Sex, BMI, vaccination status and number of days of O2 treatment, were recorded.

RESULTS

There were 100 (58 women) patients. Sex differences (males

CONCLUSION

We have found that high (feminized) 2D:4D of males and females is positively related to duration of oxygen therapy. This adds to the evidence for links between severity of Covid-19 and national and individual level variation in foetal androgen (as measured by 2D:4D). We discuss our finding in the light of the "low-androgen-driven COVID-19 pandemic theory".

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Key Words

• COVID-19
• Digit ratio
• Oxygen therapy

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MESH Headings

• Humans
• Male
• Female
• Androgens
• Fingers/anatomy & histology
• Digit Ratios
• COVID-19/therapy
• Pandemics
• COVID-19 Drug Treatment
• Sex Characteristics
• Oxygen/therapeutic use

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Affiliation(s)

Anna Kasielska-Trojan Plastic, Reconstructive and Aesthetic Surgery Clinic, Institute of Surgery, Medical University of Lodz, Lodz, Poland.
Maciej Jabłkowski Department of Infectious and Liver Diseases, Medical University of Lodz, Lodz, Poland
Jolanta Białkowska-Warzecha Department of Infectious and Liver Diseases, Medical University of Lodz, Lodz, Poland
Oliwia Kwaśniewska Medical University of Lodz, Lodz, Poland
Bogusław Antoszewski Plastic, Reconstructive and Aesthetic Surgery Clinic, Institute of Surgery, Medical University of Lodz, Lodz, Poland

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Effects of inhaled low-concentration xenon gas on naltrexone-precipitated withdrawal symptoms in morphine-dependent mice

BACKGROUND

Opioid withdrawal symptoms (OWS) are highly aversive and prompt unprescribed opioid use, which increases morbidity, mortality, and, among individuals being treated for opioid use disorder (OUD), recurrence. OWS are driven by sympathetic nervous system (SNS) hyperactivity that occurs when blood opioid levels wane. We tested whether brief inhalation of xenon gas, which inhibits SNS activity and is used clinically for anesthesia and diagnostic imaging, attenuates naltrexone-precipitated withdrawal-like signs in morphine-dependent mice.

METHODS

Adult CD-1 mice were implanted with morphine sulfate-loaded (60 mg/ml) minipumps and maintained for 6 days to establish morphine dependence. On day 7, mice were given subcutaneous naltrexone (0.3 mg/kg) and placed in a sealed exposure chamber containing either 21% oxygen/balance nitrogen (controls) or 21% oxygen/added xenon peaking at 30%/balance nitrogen. After 10 minutes, mice were transferred to observation chambers and videorecorded for 45 minutes. Videos were scored in a blind manner for morphine withdrawal behaviors. Data were analyzed using 2-way ANOVAs testing for treatment and sex effects.

RESULTS AND CONCLUSIONS

Xenon-exposed mice exhibited fewer jumps (P = 0.010) and jumping suppression was detectible within the first 10-minute video segment, but no sex differences were detected. Brief inhalation of low concentration xenon rapidly and substantially attenuated naltrexone-precipitated jumping in morphine-dependent mice, suggesting that it can inhibit OWS. If xenon effects translate to humans with OUD, xenon inhalation may be effective for reducing OWS, unprescribed opioid use, and for easing OUD treatment initiation, which could help lower excess morbidity and mortality associated with OUD.

Targeting Anaerobic Respiration in Pseudomonas aeruginosa with Chlorate Improves Healing of Chronic Wounds

Objective: Pseudomonas aeruginosa is an opportunistic pathogen that can establish chronic infections and form biofilm in wounds. Because the wound environment is largely devoid of oxygen, P. aeruginosa may rely on anaerobic metabolism, such as nitrate respiration, to survive in wounds. While nitrate reductase (Nar) typically reduces nitrate to nitrite, it can also reduce chlorate to chlorite, which is a toxic oxidizing agent. Therefore, chlorate can act as a prodrug to specifically eradicate hypoxic/anoxic, nitrate-respiring P. aeruginosa populations, which are often tolerant to conventional antibiotic treatments. Approach: Using a diabetic mouse model for chronic wounds, we tested the role that anaerobic nitrate respiration plays in supporting chronic P. aeruginosa infections. Results: P. aeruginosa forms biofilm deep within the wound where the environment is anoxic. Daily treatment of P. aeruginosa-infected wounds with chlorate supported wound healing. Chlorate treatment was as effective as a treatment with ciprofloxacin (a conventional antibiotic that targets both oxic and hypoxic/anoxic P. aeruginosa populations). Chlorate-treated wounds showed markers of good-quality wound healing, including well-formed granulation tissue, reepithelialization and microvessel development. Loss- and gain-of-function experiments showed that P. aeruginosa requires nitrate respiration to establish a chronic wound infection and form biofilms. Innovation: We show that the small molecule chlorate, kills the opportunistic pathogen, P. aeruginosa, by targeting a form of anaerobic metabolism called nitrate respiration. Conclusion: Chlorate holds promise as a treatment to combat diverse bacterial infections where oxygen is limiting and/or where pathogens grow as biofilms because many other pathogens possess Nar and survive using anaerobic metabolism.

In acute hypoxemic respiratory failure, noninvasive oxygenation methods may reduce death vs. standard oxygen therapy

SOURCE CITATION

Pitre T, Zeraatkar D, Kachkovski GV, et al. Noninvasive oxygenation strategies in adult patients with acute hypoxemic respiratory failure: a systematic review and network meta-analysis. Chest. 2023;164:913-928. 37085046.

Family Integrated Care Shortens the Duration of Home Oxygen Therapy in Infants With Bronchopulmonary Dysplasia

BACKGROUND

There have been few reports on whether family integrated care (FIC) can help premature infants with moderate to severe bronchopulmonary dysplasia (BPD) to shorten the duration of home oxygen therapy (HOT).

PURPOSE

To investigate the effect of FIC on the duration of HOT in premature infants with moderate to severe BPD.

METHODS

The subjects were retrospectively selected from premature infants with moderate to severe BPD in our center between June 2019 and December 2021. Patients were divided into the FIC group (n = 47) and the non-FIC group (n = 34). For univariate analysis, t test, Mann-Whitney U test, Pearson χ 2 test, or Fisher exact test was performed to explore the differences between the 2 groups. For multivariate analysis, simple and multiple linear regression was conducted to explore the effect of FIC on the duration of HOT.

RESULTS

(1) The duration of HOT and length of stay after grouping were significantly shorter in the FIC group than in the non-FIC group ( P < .05). (2) The results of linear regression further revealed that FIC could significantly shorten the duration of HOT (simple linear regression, FIC [A] B : -12.709, 95% confidence interval (CI): -21.665 to -3.753; multiple linear regression, FIC [B] B : -11.419, 95% CI: -18.055 to -4.783).

IMPLICATIONS FOR PRACTICE AND RESEARCH

FIC improved the optimal target oxygen saturation ratio before discharge and shortened the duration of HOT in premature infants with moderate and severe BPD. FIC should be promoted in China's neonatal intensive care units, though it puts forward new requirements for nursing education and training.

Efficacy and Safety of Hyperbaric Oxygen Therapy in Fistulizing Crohn's Disease: A Systematic Review and Meta-analysis

BACKGROUND

Hyperbaric oxygen therapy (HBOT) delivers 100% oxygen in a pressurized chamber, increasing tissue oxygen levels and regulating inflammatory pathways. Mounting evidence suggests that HBOT may be effective for inflammatory bowel disease. Our systematic review and meta-analysis aimed to quantify the efficacy and safety of HBOT in fistulizing Crohn's disease (CD).

METHODS

A systematic review was conducted using the EMBASE, Web of Science, Pubmed, and Cochrane Library databases according to the "Preferred Reporting Items for Systematic Reviews and Meta-analyses" criteria. Study bias was assessed using the Cochrane Handbook guidelines.

RESULTS

Sixteen studies with 164 patients were included in the analysis. For all fistula subtypes, the pooled overall clinical response was 87% (95% CI: 0.70-0.95, I2 = 0) and the pooled clinical remission was 59% (95% CI: 0.35-0.80, I2 = 0). The overall clinical response was 89%, 84%, and 29% for perianal, enterocutaneous, and rectovaginal fistulas, respectively. On meta-regression, hours in the chamber and the number of HBOT sessions were not found to correlate with clinical response. The pooled number of adverse events was low at 51.7 per 10,000 HBOT sessions for all fistula types (95% CI: 16.8-159.3, I2 = 0). The risk of bias was observed across all studies.

CONCLUSION

HBOT is a safe and potentially effective treatment option for fistulizing CD. Randomized control trials are needed to substantiate the benefit of HBOT in fistulizing CD.

Conservative versus liberal oxygenation targets in critically ill children (Oxy-PICU): a UK multicentre, open, parallel-group, randomised clinical trial

BACKGROUND

The optimal target for systemic oxygenation in critically ill children is unknown. Liberal oxygenation is widely practiced, but has been associated with harm in paediatric patients. We aimed to evaluate whether conservative oxygenation would reduce duration of organ support or incidence of death compared to standard care.

METHODS

Oxy-PICU was a pragmatic, multicentre, open-label, randomised controlled trial in 15 UK paediatric intensive care units (PICUs). Children admitted as an emergency, who were older than 38 weeks corrected gestational age and younger than 16 years receiving invasive ventilation and supplemental oxygen were randomly allocated in a 1:1 ratio via a concealed, central, web-based randomisation system to conservative peripheral oxygen saturations ([SpO2] 88-92%) or liberal (SpO2 >94%) targets. The primary outcome was the duration of organ support at 30 days following random allocation, a rank-based endpoint with death either on or before day 30 as the worst outcome (a score equating to 31 days of organ support), with survivors assigned a score between 1 and 30 depending on the number of calendar days of organ support received. The primary effect estimate was the probabilistic index, a value greater than 0·5 indicating more than 50% probability that conservative oxygenation is superior to liberal oxygenation for a randomly selected patient. All participants in whom consent was available were included in the intention-to-treat analysis. The completed study was registered with the ISRCTN registry (ISRCTN92103439).

FINDINGS

Between Sept 1, 2020, and May 15, 2022, 2040 children were randomly allocated to conservative or liberal oxygenation groups. Consent was available for 1872 (92%) of 2040 children. The conservative oxygenation group comprised 939 children (528 [57%] of 927 were female and 399 [43%] of 927 were male) and the liberal oxygenation group included 933 children (511 [56%] of 920 were female and 409 [45%] of 920 were male). Duration of organ support or death in the first 30 days was significantly lower in the conservative oxygenation group (probabilistic index 0·53, 95% CI 0·50-0·55; p=0·04 Wilcoxon rank-sum test, adjusted odds ratio 0·84 [95% CI 0·72-0·99]). Prespecified adverse events were reported in 24 (3%) of 939 patients in the conservative oxygenation group and 36 (4%) of 933 patients in the liberal oxygenation group.

INTERPRETATION

Among invasively ventilated children who were admitted as an emergency to a PICU receiving supplemental oxygen, a conservative oxygenation target resulted in a small, but significant, greater probability of a better outcome in terms of duration of organ support at 30 days or death when compared with a liberal oxygenation target. Widespread adoption of a conservative oxygenation saturation target (SpO2 88-92%) could help improve outcomes and reduce costs for the sickest children admitted to PICUs.

FUNDING

UK National Institute for Health and Care Research Health Technology Assessment Programme.

COVID-19 vaccine effectiveness against severe COVID-19 requiring oxygen therapy, invasive mechanical ventilation, and death in Japan: A multicenter case-control study (MOTIVATE study)

INTRODUCTION

Since the SARS-CoV-2 Omicron variant became dominant, assessing COVID-19 vaccine effectiveness (VE) against severe disease using hospitalization as an outcome became more challenging due to incidental infections via admission screening and variable admission criteria, resulting in a wide range of estimates. To address this, the World Health Organization (WHO) guidance recommends the use of outcomes that are more specific to severe pneumonia such as oxygen use and mechanical ventilation.

METHODS

A case-control study was conducted in 24 hospitals in Japan for the Delta-dominant period (August-November 2021; "Delta") and early Omicron (BA.1/BA.2)-dominant period (January-June 2022; "Omicron"). Detailed chart review/interviews were conducted in January-May 2023. VE was measured using various outcomes including disease requiring oxygen therapy, disease requiring invasive mechanical ventilation (IMV), death, outcome restricting to "true" severe COVID-19 (where oxygen requirement is due to COVID-19 rather than another condition(s)), and progression from oxygen use to IMV or death among COVID-19 patients.

RESULTS

The analysis included 2125 individuals with respiratory failure (1608 cases [75.7%]; 99.2% of vaccinees received mRNA vaccines). During Delta, 2 doses provided high protection for up to 6 months (oxygen requirement: 95.2% [95% CI:88.7-98.0%] [restricted to "true" severe COVID-19: 95.5% {89.3-98.1%}]; IMV: 99.6% [97.3-99.9%]; fatal: 98.6% [92.3-99.7%]). During Omicron, 3 doses provided high protection for up to 6 months (oxygen requirement: 85.5% [68.8-93.3%] ["true" severe COVID-19: 88.1% {73.6-94.7%}]; IMV: 97.9% [85.9-99.7%]; fatal: 99.6% [95.2-99.97]). There was a trend towards higher VE for more severe and specific outcomes.

CONCLUSION

Multiple outcomes pointed towards high protection of 2 doses during Delta and 3 doses during Omicron. These results demonstrate the importance of using severe and specific outcomes to accurately measure VE against severe COVID-19, as recommended in WHO guidance in settings of intense transmission as seen during Omicron.

Standard vs. targeted oxygen therapy prehospitally for chronic obstructive pulmonary disease (STOP-COPD): study protocol for a randomised controlled trial

BACKGROUND

A high concentration of inspired supplemental oxygen may possibly cause hypercapnia and acidosis and increase mortality in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Even so, patients with AECOPD are being treated with high oxygen flow rates when receiving inhalation drugs in the prehospital setting. A cluster-randomised controlled trial found that reduced oxygen delivery by titrated treatment reduced mortality-a result supported by observational studies-but the results have never been reproduced. In the STOP-COPD trial, we investigate the effect of titrated oxygen delivery compared with usual care consisting of high flow oxygen delivery in patients with AECOPD in the prehospital setting.

METHODS

In this randomised controlled trial, patients will be blinded to allocation. Patients with suspected AECOPD (n = 1888) attended by the emergency medical service (EMS) and aged > 40 years will be allocated randomly to either standard treatment or titrated oxygen, targeting a blood oxygen saturation of 88-92% during inhalation therapy. The trial will be conducted in the Central Denmark Region and include all ambulance units. The power to detect a 3% 30-day mortality risk difference is 80%. The trial is approved as an emergency trial. Hence, EMS providers will include patients without prior consent.

DISCUSSION

The results will provide evidence on whether titrated oxygen delivery outperforms standard high flow oxygen when used to nebulise inhaled bronchodilators in AECOPD treatment. The trial is designed to ensure unselected inclusion of patients with AECOPD needing nebulised bronchodilators-a group of patients that receives high oxygen fractions when treated in the prehospital setting where the only compressed gas is generally pure oxygen. Conducting this trial, we aim to improve treatment for people with AECOPD while reducing their 30-day mortality.

TRIAL REGISTRATION

European Union Clinical Trials (EUCT) number: 2022-502003-30-00 (authorised 06/12/2022), ClinicalTrials.gov number: NCT05703919 (released 02/02/2023), Universal trial number: U1111-1278-2162.

Machine learning prediction of the failure of high-flow nasal oxygen therapy in patients with acute respiratory failure

Acute respiratory failure (ARF) is a prevalent and serious condition in intensive care unit (ICU), often associated with high mortality rates. High-flow nasal oxygen (HFNO) therapy has gained popularity for treating ARF in recent years. However, there is a limited understanding of the factors that predict HFNO failure in ARF patients. This study aimed to explore early indicators of HFNO failure in ARF patients, utilizing machine learning (ML) algorithms to more accurately pinpoint individuals at elevated risk of HFNO failure. Utilizing ML algorithms, we developed seven predictive models. Their performance was evaluated using various metrics, including the area under the receiver operating characteristic curve, calibration curve, and precision recall curve. The study enrolled 700 patients, with 490 in the training group and 210 in the validation group. The overall HFNO failure rate was 14.1% among the 700 patients. The ML algorithms demonstrated robust performance in our study. This research underscores the potential of ML techniques in creating clinically relevant models for predicting HFNO outcomes in ARF patients. These models could play a pivotal role in enhancing the risk management of HFNO, leading to more patient-centered and personalized care approaches.

A clinical study evaluating the combination of LISA and SNIPPV for the treatment of respiratory distress syndrome in preterm infants

To compare the therapeutic effect of less invasive surfactant administration (LISA) followed by synchronized nasal intermittent positive pressure ventilation (SNIPPV) and traditional intubate-Surfactant-Extubate (InSurE) strategy for the treatment of neonatal respiratory distress syndrome (NRDS). A single-center, non-randomized and single- blinded study Tertiary neonatal intensive care unit 89 infants enrolled were preterm with gestational age < 366/7 weeks and clinically diagnosed with neonatal RDS (NRDS) Interventions: 32 infants were assigned to the LISA + SNIPPV group and 57 infants to the InSurE + nCPAP group. No statistically significant differences were noted in the baseline characteristics of the enrolled infants. A lower proportion of infants developed BPD in the LISA + SNIPPV group compared to the InSurE + CPAP group [10 (31.25%) vs. 21 (36.84%), P > 0.05]; however, there was no statistically significant difference. The number needed to treat (NNT) with LISA + SNIPPV to prevent BPD development is 18. The mortality rate was not significant between our study arms [1 (3.13%) vs 2 (3.51%), P > 0.05]. There were no statistically significant differences in the durations (days) of MV [(12.18 ± 13.89) vs. (11.35 ± 11.61), P > 0.05], oxygen therapy [(35.03 ± 19.13) vs. (39.75 ± 17.91), P > 0.05] and re-intubation rates [(0.19 ± 0.40) vs. (0.21 ± 0.45), P > 0.05] between the two study groups. In terms of complications, the incidence of patent ductus arteriosus (PDA) [24 (75.00%) vs. 27 (47.37%), P < 0.05] was higher and a lower rate of disturbed liver function [1 (3.23%) vs. 19 (33.33%), P < 0.05] were observed in the LISA + SNIPPV group. Acid-base imbalances were reportedly significantly higher in the InSurE group (P < 0.05). No significant differences in other complications were noted. In the interventional group, FiO2 requirements were significantly lower up until the 3rd week of treatment [FiO2 at day 0, (30.75 ± 4.78) vs. (34.66 ± 9.83), P < 0.05; FiO2 at day 21, (25.32 ± 3.74) vs. (29.11 ± 8.17), P < 0.05], as was RSS on days 2 [(0.77 ± 0.38) vs. (1.94 ± 0.75), P < 0.05] and 3 [(0.66 ± 0.33) vs. (1.89 ± 0.82), P < 0.05] after treatment. Additionally, infants in the standard group had a significantly prolonged hospital stay (days) [(45.97 ± 16.93) vs. (54.40 ± 16.26), P < 0.05]. The combination of LISA and SNIPPV for NRDS can potentially lower the rate of BPD, FiO2 demand and shorten the length of hospitalization.

A nitrous oxide/oxygen fixed mixture to reduce pain induced by the hypodermic injection: study protocol for a randomized, controlled trial

BACKGROUND

Patients with hematological malignancies received multiple hypodermic injections of recombinant human granulocyte colony-stimulating factor. Procedural pain is one of the most common iatrogenic causes of pain in patients with hematological malignancies. It is also identified as the most commonly occurring problem in clinical care in the Department of Hematology and Oncology at Shenzhen University General Hospital. However, providing immediate relief from pain induced by hypodermic injection of recombinant human granulocyte colony-stimulating factor remains a major challenge. This trial aims to evaluate the safety and analgesic efficacy of a fixed nitrous oxide/oxygen mixture for patients with hematological malignancies and experiencing procedural pain caused by hypodermic injection of recombinant human granulocyte colony-stimulating factor in the department.

METHODS

The nitrous oxide/oxygen study is a single-center, randomized, double-blind, placebo-controlled trial involving patients with hematological malignancies who require hypodermic injections of recombinant human granulocyte colony-stimulating factor for treatment. This trial was conducted in the Hematology and Oncology Department of Shenzhen University General Hospital. A total of 54 eligible patients were randomly allocated to either the fixed nitrous oxide/oxygen mixture group (n = 36) or the oxygen group (n = 18). Neither the investigators nor the patients known about the randomization list and the nature of the gas mixture in each cylinder. Outcomes were monitored at the baseline (T0), immediately after hypodermic injection of recombinant human granulocyte colony-stimulating factor (T1), and 5 min after hypodermic injection of recombinant human granulocyte colony-stimulating factor (T2) for each group. The primary outcome measure was the score in the numerical rating scale corresponding to the highest level of pain experienced during hypodermic injection of recombinant human granulocyte colony-stimulating factor. Secondary outcomes included the fear of pain, anxiety score, four physiological parameters, adverse effects, total time of gas administration, satisfaction from both patients and nurses, and the acceptance of the patients.

DISCUSSION

This study focused on the safety and analgesic efficacy during hypodermic injection of recombinant human granulocyte colony-stimulating factor procedure. Data on the feasibility and safety of nitrous oxide/oxygen therapy was provided if proven beneficial to patients with hematological malignancies during hypodermic injection of recombinant human granulocyte colony-stimulating factor and widely administered to patients with procedural pain in the department.

TRIAL REGISTRATION

Chinese Clinical Trial Register, ChiCTR2200061507. Registered on June 27, 2022. http://www.chictr.org.cn/edit.aspx?pid=170573&htm=4.

Continuous positive airway pressure or high-flow nasal cannula oxygen therapy for acute hypoxemic respiratory failure unrelated to COVID-19: Another brick in the wall?

See related article

Inhaled recombinant GM-CSF reduces the need for whole lung lavage and improves gas exchange in autoimmune pulmonary alveolar proteinosis patients

RATIONALE

Whole lung lavage (WLL) is a widely accepted palliative treatment for autoimmune pulmonary alveolar proteinosis (aPAP) but does not correct myeloid cell dysfunction or reverse the pathological accumulation of surfactant. In contrast, inhaled recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF) is a promising pharmacological approach that restores alveolar macrophage functions including surfactant clearance. Here, we evaluate WLL followed by inhaled rGM-CSF (sargramostim) as therapy of aPAP.

METHODS

18 patients with moderate-to-severe aPAP were enrolled, received baseline WLL, were randomised into either the rGM-CSF group (receiving inhaled sargramostim) or control group (no scheduled therapy) and followed for 30 months after the baseline WLL. Outcome measures included additional unscheduled "rescue" WLL for disease progression, assessment of arterial blood gases, pulmonary function, computed tomography, health status, biomarkers and adverse events. Patients requiring rescue WLL were considered to have failed their assigned intervention group.

RESULTS

The primary end-point of time to first rescue WLL was longer in rGM-CSF-treated patients than controls (30 versus 18 months, n=9 per group, p=0.0078). Seven control patients (78%) and only one rGM-CSF-treated patient (11%) required rescue WLL, demonstrating a 7-fold increase in relative risk (p=0.015). Compared to controls, rGM-CSF-treated patients also had greater improvement in peripheral arterial oxygen tension, alveolar-arterial oxygen tension difference, diffusing capacity of the lungs for carbon monoxide and aPAP biomarkers. One patient from each group withdrew for personal reasons. No serious adverse events were reported.

CONCLUSIONS

This long-term, prospective, randomised trial demonstrated inhaled sargramostim following WLL reduced the requirement for WLL, improved lung function and was safe in aPAP patients. WLL plus inhaled sargramostim may be useful as combined therapy for aPAP.

Acute Asthma Exacerbations: Management Strategies

Asthma exacerbations, defined as a deterioration in baseline symptoms or lung function, cause significant morbidity and mortality. Asthma action plans help patients triage and manage symptoms at home. In patients 12 years and older, home management includes an inhaled corticosteroid/formoterol combination for those who are not using an inhaled corticosteroid/long-acting beta2 agonist inhaler for maintenance, or a short-acting beta2 agonist for those using an inhaled corticosteroid/long-acting beta2 agonist inhaler that does not include formoterol. In children four to 11 years of age, an inhaled corticosteroid/formoterol inhaler, up to eight puffs daily, can be used to reduce the risk of exacerbations and need for oral corticosteroids. In the office setting, it is important to assess exacerbation severity and begin a short-acting beta2 agonist and oxygen to maintain oxygen saturations, with repeated doses of the short-acting beta2 agonist every 20 minutes for one hour and oral corticosteroids. Patients with severe exacerbations should be transferred to an acute care facility and treated with oxygen, frequent administration of a short-acting beta2 agonist, and corticosteroids. The addition of a short-acting muscarinic antagonist and magnesium sulfate infusion has been associated with fewer hospitalizations. Patients needing admission to the hospital require continued monitoring and systemic therapy similar to treatments used in the emergency department. Improvement in symptoms and forced expiratory volume in one second or peak expiratory flow to 60% to 80% of predicted values helps determine appropriateness for discharge. The addition of inhaled corticosteroids, consideration of stepping up asthma maintenance therapy, close follow-up, and education on asthma action plans are important next steps to prevent future exacerbations.

Clinical Characteristics and Risk of Hypoxemia Development in Women Infected with SARS-CoV-2 during Pregnancy

PURPOSE

There is limited information on the clinical characteristics and prognosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy. The clinical features and risk factors for hypoxemia development were investigated in pregnant women with coronavirus disease-2019 (COVID-19).

MATERIALS AND METHODS

From August 2020 to February 2022, we performed a retrospective cohort study of 410 pregnant women with COVID-19. The clinical characteristics and prognoses were compared between pregnant COVID-19 patients requiring oxygen and those who did not.

RESULTS

Of 410 patients, 100 (24.4%) required oxygen therapy. Among them, fever [163 (52.6%) vs. 81 (81.0%), p<0.001] and cough [172 (56.4%) vs. 73 (73.0%), p=0.003] were more frequently observed than in non-oxygen group. The proportion of unvaccinated women was higher in oxygen group than in non-oxygen group [264 (85.2%) vs. 98 (98.0%), p=0.003]. During the Omicron wave, patients were more likely to have no oxygen requirement [98 (31.6%) vs. 18 (18.0%), p=0.009]. The risk of hypoxemic respiratory difficulty increased if SARS-CoV-2 infection occurred during the third trimester [adjusted odds ratio (aOR) 5.083, 95% confidence interval (CI): 1.095-23.593, p=0.038] and C-reactive protein (CRP) was elevated (≥1.0 mg/dL) at admission (aOR 5.878, 95% CI: 3.099-11.146, p<0.001). The risk was higher in unvaccinated patients (aOR 5.376, 95% CI: 1.193-24.390, p=0.028). However, the risk was lower in patients during the Omicron wave (aOR 0.498, 95% CI: 0.258-0.961, p=0.038).

CONCLUSION

A quarter of SARS-CoV-2-infected women developed hypoxemic respiratory difficulty during pregnancy. SARS-CoV-2 infection during the third trimester, CRP elevation at admission, and no vaccination increased the risk of hypoxemia in pregnant women.

Tofacitinib and pirfenidone as rescue therapies for severe COVID-19 in a patient with previously stable interstitial lung disease associated with Sjögren syndrome

Coronavirus disease 2019 (COVID-19) can lead to pulmonary fibrosis due to the inflammatory process in the lung, resulting in a series of respiratory consequences. Patients with underlying systemic diseases or pre-existing pulmonary diseases are particularly at risk of severe respiratory distress and persistent pulmonary abnormalities. Pirfenidone, a well-known anti-fibrotic agent recognized for its therapeutic effect on idiopathic pulmonary fibrosis, could be a feasible option in severe COVID-19 cases given the similar pathophysiological features shared with interstitial lung diseases. In this paper, we share our experience of early administration of pirfenidone in combination with tofacitinib in a 61-year-old female patient with severe COVID-19 pneumonia. Pirfenidone was initiated because of persistent dependence on high-flow oxygen support and even the requirement for mechanical ventilation due to disease progression after initial standard COVID-19 treatment. The patient was successfully extubated 15 days after the initiation of pirfenidone, and 13 days after extubation, she was completely weaned off supplemental oxygen. A series of chest radiographs and computed tomography scans demonstrated notable improvements in her lung condition. We propose a strategy of using pirfenidone plus tofacitinib as a rescue therapy in the management of patients with severe COVID-19.

Intramuscular paravertebral oxygen-ozone therapy for chronic neck pain and low back pain: evaluation of 6-month clinical outcomes

Spinal pain is recognized as the most common cause of disability, work absenteeism and need of healthcare services worldwide. Although many strategies have been developed for conservative treatment of spinal pain, its increasing prevalence diagnosis highlights the need for new treatments. Oxygen-ozone (O2-O3) therapy is considered to be an alternative therapy due to its analgesic and anti-inflammatory effects. This retrospective study evaluated the effects of O2-O3 intramuscular paravertebral injections in 76 patients with chronic neck pain or low back pain, in terms of pain and disability reduction, quality of life improvement, and analgesic drug intake. Patients were evaluated before, at the end of the treatment, and at 1, 3 and 6 months after the last treatment, using Numeric Rating Scale, Neck Disability Index or Oswestry Disability Index, and Short Form-12 Health Survey. There were significant beneficial effects of O2-O3 therapy in reducing pain and disability reduction and improving quality of life during the 6-month follow-up period. O2-O3 therapy was associated with a reduction in analgesic drug intake at each assessment. Our results allow us not only to support treatment with O2-O3 intramuscular paravertebral injections as a safe and beneficial treatment for chronic low back pain, but also to consider it as a valuable conservative therapy for patients with chronic neck pain.

Nanotechnology-mediated photodynamic therapy: Focus on overcoming tumor hypoxia

The oxygen level in the tumor is a critical marker that determines response to different treatments. Cancerous cells can adapt to hypoxia and low pH conditions within the tumor microenvironment (TME) to regulate tumor metabolism, proliferation, and promote tumor metastasis as well as angiogenesis, consequently leading to treatment failure and recurrence. In recent years, widespread attempts have been made to overcome tumor hypoxia through different methods, such as hyperbaric oxygen therapy (HBOT), hyperthermia, O2 carriers, artificial hemoglobin, oxygen generator hydrogels, and peroxide materials. While oxygen is found to be an essential agent to improve the treatment response of photodynamic therapy (PDT) and other cancer treatment modalities, the development of hypoxia within the tumor is highly associated with PDT failure. Recently, the use of nanoparticles has been a hot topic for researchers and exploited to overcome hypoxia through Oxygen-generating hydrogels, O2 nanocarriers, and O2 -generating nanoparticles. This review aimed to discuss the role of nanotechnology in tumor oxygenation and highlight the challenges, prospective, and recent advances in this area to improve PDT outcomes. This article is categorized under: Nanotechnology Approaches to Biology > Cells at the Nanoscale Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

[Safety Analysis Using Event Tree Analysis for Multi-Ion Therapy]

At the National Institutes for Quantum Science and Technology (QST), a multi-ion therapy using helium, carbon, oxygen, and neon ions has been studied for charged particle therapy with more optimal biological effects. To make multi-ion therapy clinically feasible, a new treatment system was developed to realize the changes of the ion species in each irradiation using the Heavy Ion Medial Accelerator in Chiba (HIMAC). Since radiation therapy is safety-critical, it is necessary to construct a safety system that includes multiple safety barriers in the new treatment system for multi-ion therapy and to perform a safety analysis for the prevention of serious accidents. In this study, we conducted a safety analysis using event tree analysis (ETA) for newly introduced processes in the treatment planning, accelerator, and irradiation system of the multi-ion therapy. ETA is an optimal method to verify multiple safety barriers that are essential for medical safety and to shorten the time for safety analysis by focusing only on the new processes. Through ETA, we clarified the types of malfunctions and human errors that may lead to serious accidents in the new system for multi-ion therapy, and verified whether safety barriers such as interlock systems and human check procedures are sufficient to prevent such malfunctions and human errors. As a result, 6 initial events which may lead to serious accidents were listed in the treatment planning process, 16 initial events were listed in the accelerator system, and 13 initial events were listed in the irradiation system. Among these 35 initial events, 5 cautionary initial events were identified that could lead to serious final events and they had a probability of occurrence higher than 10-4. Meanwhile, the others were all initial events that do not lead to serious accidents, or the initial events that can lead to serious accidents but were considered to have sufficient safety barriers. The safety analysis using ETA successfully identified the system malfunctions and the human errors that can lead to serious accidents, and the multiple safety barriers against them were systematically analyzed. It became clear that the multiple safety barriers were not sufficient for some initial events. We plan to improve the safety barriers for the five cautionary initial events before the start of the clinical trial. Based on these findings, we achieved our objective to conduct a safety analysis for a new treatment system for multi-ion therapy. The safety analysis procedure using ETA proposed by this study will be effective when new systems for radiotherapy are established at QST and other facilities in the future as well.

Safety and Outcome of High-Flow Nasal Oxygen Therapy Outside ICU Setting in Hypoxemic Patients With COVID-19

OBJECTIVE

High-flow nasal oxygen (HFNO) therapy is frequently applied outside ICU setting in hypoxemic patients with COVID-19. However, safety concerns limit more widespread use. We aimed to assess the safety and clinical outcomes of initiation of HFNO therapy in COVID-19 on non-ICU wards.

DESIGN

Prospective observational multicenter pragmatic study.

SETTING

Respiratory wards and ICUs of 10 hospitals in The Netherlands.

PATIENTS

Adult patients treated with HFNO for COVID-19-associated hypoxemia between December 2020 and July 2021 were included. Patients with treatment limitations were excluded from this analysis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Outcomes included intubation and mortality rate, duration of hospital and ICU stay, severity of respiratory failure, and complications. Using propensity-matched analysis, we compared patients who initiated HFNO on the wards versus those in ICU. Six hundred eight patients were included, of whom 379 started HFNO on the ward and 229 in the ICU. The intubation rate in the matched cohort ( n = 214 patients) was 53% and 60% in ward and ICU starters, respectively ( p = 0.41). Mortality rates were comparable between groups (28-d [8% vs 13%], p = 0.28). ICU-free days were significantly higher in ward starters (21 vs 17 d, p < 0.001). No patient died before endotracheal intubation, and the severity of respiratory failure surrounding invasive ventilation and clinical outcomes did not differ between intubated ward and ICU starters (respiratory rate-oxygenation index 3.20 vs 3.38; Pa o2 :F io2 ratio 65 vs 64 mm Hg; prone positioning after intubation 81 vs 78%; mortality rate 17 vs 25% and ventilator-free days at 28 d 15 vs 13 d, all p values > 0.05).

CONCLUSIONS

In this large cohort of hypoxemic patients with COVID-19, initiation of HFNO outside the ICU was safe, and clinical outcomes were similar to initiation in the ICU. Furthermore, the initiation of HFNO on wards saved time in ICU without excess mortality or complicated course. Our results indicate that HFNO initiation outside ICU should be further explored in other hypoxemic diseases and clinical settings aiming to preserve ICU capacity and healthcare costs.

Use of consecutive transcutaneous oxygen measurement when assessing the need for revascularization and association with the outcomes of ischemic diabetic ulcers

This study compared the ankle-brachial index (ABI) with transcutaneous oxygen pressure (TcPO2 ) in assessing peripheral vascular disease (PVD) prevalence in 100 diabetic foot ulcer (DFU) patients. Patients were categorized into vascular or nonvascular reconstruction groups and underwent both ABI and TcPO2 measurements four times over 6 months. Predictive validity for PVD diagnosis was analysed using the area under the receiver-operating characteristic curve (AUC). The study found TcPO2 to be a superior predictor of PVD than ABI. Among the DFU patients, 51 with abnormal TcPO2 values underwent vascular reconstruction. Only TcPO2 values showed significant pretreatment differences between the groups and increased post-reconstruction. These values declined over a 6-month follow-up, whereas ABI values rose. For those with end-stage renal disease (ESRD), TcPO2 values saw a sharp decrease within 3 months. Pre-reconstruction TcPO2 was notably lower in amputation patients versus limb salvage surgery patients. In conclusion, TcPO2 is more effective than ABI for evaluating ischemic limb perfusion and revascularization necessity. It should be prioritized as the primary follow-up tool, especially for ESRD patients.

Penumbral Rescue by normobaric O = O administration in patients with ischemic stroke and target mismatch proFile (PROOF): Study protocol of a phase IIb trial

RATIONALE

Oxygen is essential for cellular energy metabolism. Neurons are particularly vulnerable to hypoxia. Increasing oxygen supply shortly after stroke onset could preserve the ischemic penumbra until revascularization occurs.

AIMS

PROOF investigates the use of normobaric oxygen (NBO) therapy within 6 h of symptom onset/notice for brain-protective bridging until endovascular revascularization of acute intracranial anterior-circulation occlusion.

METHODS AND DESIGN

Randomized (1:1), standard treatment-controlled, open-label, blinded endpoint, multicenter adaptive phase IIb trial.

STUDY OUTCOMES

Primary outcome is ischemic core growth (mL) from baseline to 24 h (intention-to-treat analysis). Secondary efficacy outcomes include change in NIHSS from baseline to 24 h, mRS at 90 days, cognitive and emotional function, and quality of life. Safety outcomes include mortality, intracranial hemorrhage, and respiratory failure. Exploratory analyses of imaging and blood biomarkers will be conducted.

SAMPLE SIZE

Using an adaptive design with interim analysis at 80 patients per arm, up to 456 participants (228 per arm) would be needed for 80% power (one-sided alpha 0.05) to detect a mean reduction of ischemic core growth by 6.68 mL, assuming 21.4 mL standard deviation.

DISCUSSION

By enrolling endovascular thrombectomy candidates in an early time window, the trial replicates insights from preclinical studies in which NBO showed beneficial effects, namely early initiation of near 100% inspired oxygen during short temporary ischemia. Primary outcome assessment at 24 h on follow-up imaging reduces variability due to withdrawal of care and early clinical confounders such as delayed extubation and aspiration pneumonia.

TRIAL REGISTRATIONS

ClinicalTrials.gov: NCT03500939; EudraCT: 2017-001355-31.

Nebulised granulocyte-macrophage colony-stimulating factor (GM-CSF) in autoimmune pulmonary alveolar proteinosis: a systematic review and meta-analysis

BACKGROUND

Autoimmune pulmonary alveolar proteinosis (aPAP) results from impaired macrophage-mediated clearance of alveolar surfactant lipoproteins. Whole lung lavage has been the first-line treatment but recent reports suggest the efficacy of granulocyte-macrophage colony-stimulating factor (GM-CSF). We aimed to review the efficacy and safety of nebulised GM-CSF in aPAP.

METHODS

We conducted a systematic review and meta-analysis searching Embase, CINAHL, MEDLINE and Cochrane Collaborative databases (1946-1 April 2022). Studies included patients aged >18 years with aPAP receiving nebulised GM-CSF treatment and a comparator cohort. Exclusion criteria included secondary or congenital pulmonary alveolar proteinosis, GM-CSF allergy, active infection or other serious medical conditions. The protocol was prospectively registered with PROSPERO (CRD42021231328). Outcomes assessed were St George's Respiratory Questionnaire (SGRQ), 6-min walk test (6MWT), gas exchange (diffusing capacity of the lung for carbon monoxide (D LCO) % predicted) and arterial-alveolar oxygen gradient.

RESULTS

Six studies were identified for review and three for meta-analysis, revealing that SGRQ score (mean difference -8.09, 95% CI -11.88- -4.3, p<0.0001), functional capacity (6MWT) (mean difference 21.72 m, 95% CI -2.76-46.19 m, p=0.08), gas diffusion (D LCO % predicted) (mean difference 5.09%, 95% CI 2.05-8.13%, p=0.001) and arterial-alveolar oxygen gradient (mean difference -4.36 mmHg, 95% CI -7.19- -1.52 mmHg, p=0.003) all significantly improved in GM-CSF-treated patients with minor statistical heterogeneity (I2=0%). No serious trial-related adverse events were reported.

CONCLUSIONS

Patients with aPAP treated with inhaled GM-CSF demonstrated significant improvements in symptoms, dyspnoea scores, lung function, gas exchange and radiology indices after treatment with nebulised GM-CSF of varying duration. There is an important need to review comparative effectiveness and patient choice in key clinical outcomes between the current standard of care, whole lung lavage, with the noninvasive treatment of nebulised GM-CSF in aPAP.

Lack of change in the respiratory quotient during oxygen supply dependence in endotoxemic shock: a subanalysis of an experimental controlled study

OBJECTIVE

To evaluate if the reductions in systemic and renal oxygen consumption are associated with the development of evidence of anaerobic metabolism.

METHODS

This is a subanalysis of a previously published study. In anesthetized and mechanically ventilated sheep, we measured the respiratory quotient by indirect calorimetry and its systemic, renal, and intestinal surrogates (the ratios of the venous-arterial carbon dioxide pressure and content difference to the arterial-venous oxygen content difference. The Endotoxemic Shock Group (n = 12) was measured at baseline, after 60 minutes of endotoxemic shock, and after 60 and 120 minutes of fluid and norepinephrine resuscitation, and the values were compared with those of a Control Group (n = 12) without interventions.

RESULTS

Endotoxemic shock decreased systemic and renal oxygen consumption (6.3 [5.6 - 6.6] versus 7.4 [6.3 - 8.5] mL/minute/kg and 3.7 [3.3 - 4.5] versus 5.4 [4.6 - 9.4] mL/minute/100g; p < 0.05 for both). After 120 minutes of resuscitation, systemic oxygen consumption was normalized, but renal oxygen consumption remained decreased (6.3 [5.9 - 8.2] versus 7.1 [6.1 - 8.6] mL/minute/100g; p = not significance and 3.8 [1.9 - 4.8] versus 5.7 [4.5 - 7.1]; p < 0.05). The respiratory quotient and the systemic, renal and intestinal ratios of the venous-arterial carbon dioxide pressure and content difference to the arterial-venous oxygen content difference did not change throughout the experiments.

CONCLUSION

In this experimental model of septic shock, oxygen supply dependence was not associated with increases in the respiratory quotient or its surrogates. Putative explanations for these findings are the absence of anaerobic metabolism or the poor sensitivity of these variables in detecting this condition.

Pyruvate kinase activators: targeting red cell metabolism in sickle cell disease

Hemoglobin S (HbS) polymerization, red blood cell (RBC) sickling, chronic anemia, and vaso-occlusion are core to sickle cell disease (SCD) pathophysiology. Pyruvate kinase (PK) activators are a novel class of drugs that target RBC metabolism by reducing the buildup of the glycolytic intermediate 2,3-diphosphoglycerate (2,3-DPG) and increasing production of adenosine triphosphate (ATP). Lower 2,3-DPG level is associated with an increase in oxygen affinity and reduction in HbS polymerization, while increased RBC ATP may improve RBC membrane integrity and survival. There are currently 3 PK activators in clinical development for SCD: mitapivat (AG-348), etavopivat (FT-4202), and the second-generation molecule AG-946. Preclinical and clinical data from these 3 molecules demonstrate the ability of PK activators to lower 2,3-DPG levels and increase ATP levels in animal models and patients with SCD, as well as influence a number of potential pathways in SCD, including hemoglobin oxygen affinity, RBC sickling, RBC deformability, RBC hydration, inflammation, oxidative stress, hypercoagulability, and adhesion. Furthermore, early-phase clinical trials of mitapivat and etavopivat have demonstrated the safety and tolerability of PK activators in patients with SCD, and phase 2/3 trials for both drugs are ongoing. Additional considerations for this novel therapeutic approach include the balance between increasing hemoglobin oxygen affinity and tissue oxygen delivery, the cost and accessibility of these drugs, and the potential of multimodal therapy with existing and novel therapies targeting different disease mechanisms in SCD.