Hypoxic Events Research Articles

Integrative physiology-coupled pilot-centered flight simulation

Maintaining the pilot’s physiological performance envelope within the limits of human capabilities may be crucial for avoiding hazardous physiological episodes in fighter aircraft that compromise safety. The main physiological episode of interest is impaired pilot respiration, better known as hypoxia, caused by a high fraction of inspired oxygen (FiO2) at high altitudes and variation in accelerative gravitational forces (g-forces). This research focuses on coupling FlightGear and Pulse Physiology Engine (Pulse) simulations to recreate and understand hypoxic events related to a combination of high g-forces and high-FiO2. By coupling interactive simulations based on FlightGear and Pulse, hypoxia was recreated from two scenarios: simulated accelerative atelectasis, achieved by using high g-forces output from FlightGear with a modified Pulse tension pneumothorax scenario, and the combination of high g-forces and high-FiO2, based on a prototype OBOGS simulation. Each scenario resulted in hypoxic events after executing three consecutive simulations, validated by the ratio mismatch of pulmonary ventilation ([Formula: see text]) and perfusion ([Formula: see text]) rates, [Formula: see text], due to a reduction in ventilation. Eventually, a detailed atelectasis simulation founded on multi-physics finite elements (FE) is planned in future work, where real-time efficiency is feasible through a deep neural network implementation trained on FE experiments. Using neural networks based on biometrics and pre-existing health conditions, if any, will result in the development of a predictive analytics model to determine whether pilots are susceptible to hypoxia prior to flight.

Abstract 4144503: Association of Granular Sleep Health Metrics with Arterial Stiffness in the Community

Introduction: Poor sleep is a risk factor for cardiovascular disease and all-cause mortality; however, the mechanisms underlying this relationship remain poorly understood. Since sleep health is a complex construct extending beyond mere sleep duration, we aimed to examine the relationship between granular sleep health indicators and arterial stiffness. Methods: We analyzed Framingham Offspring cohort (Exam 9) and OMNI cohort 1 (Exam 4) participants with sleep study and applanation tonometry data (n= 847, 56.6% females). Participants wore an M1 device to obtain ECG-derived sleep spectrograms to assess sleep quality and the Nonin WristOx device for oximetry data over two consecutive nights. Sleep variables of interest included total sleep time, duration of stable and unstable NREM, duration of elevated low-frequency coupling (e-LFC), and duration and number of nocturnal hypoxia events. Measures of aortic stiffness and pressure pulsatility included carotid-femoral pulse wave velocity (PWV), and central pulse pressure (CPP). Results: Characteristics of the sample are presented in Table 1. Several sleep measures were associated with PWV in univariable analysis, but significance attenuated after age/sex adjustment (Table 2). After adjusting for cardiovascular risk factors and sociodemographics, duration of e-LFCnb remained associated with CPP (β = 0.036, p = 0.02) Conclusion: Sleep measures associated with aortic stiffness are closely tied to age and sex. Longer duration of e-LFCnb, a hallmark of carotid body-driven elevated sympathetic tone and periodic breathing, is associated with greater pressure pulsatility. Longitudinal studies are needed to fully elucidate the role of e-LFCnb in vascular health

Fipronil exposure alters oxidative stress responses of Nile tilapia (Oreochromis niloticus) to acute moderate hypoxia

Acute hypoxia is known to increase the generation of reactive oxygen species (ROS), leading to modulation in antioxidant defenses. Pollutant exposure can potentiate ROS generation during hypoxic events and impair antioxidant defenses, increasing the susceptibility of hypoxia-tolerant fishes, such as the Nile tilapia (Oreochromis niloticus), to oxidative stress. The purpose of this study was to evaluate oxidative stress responses of O. niloticus to acute (3 and 8 h) moderate hypoxia (dissolved oxygen ≤2 mg/L−1) and how these responses are affected by simultaneous exposure to the insecticide fipronil (0.1 and 0.5 µg L−1). Hypoxia exposure for 3 h caused an increase in glutathione peroxidase (GPx) activity in the gill and also increased catalase (CAT) and glutathione S-transferase (GST) activities in the liver. After 8 h of hypoxia, glutathione reductase (GR) activity increased. DNA damage (comet assay) in erythrocytes was reduced by hypoxia after 3 and 8 h. Fipronil exposure for 3 h decreased CAT activity in the gill, both under normoxia and hypoxia. After 8h, the combination of fipronil and hypoxia increased GR activity in the gill. In the liver, fipronil exposure under hypoxia for 3 h increased CAT and GR activities; after 8 h, CAT was decreased, and GST increased. GR was also increased by fipronil under normoxia for 8 h. All treatments reduced lipid peroxidation levels in the gills, but in the liver, lipid peroxidation was increased by fipronil after 3 h under normoxia. Moreover, fipronil exposure under hypoxia for 3 and 8h increased DNA damage in erythrocytes, while 8 h of fipronil exposure under normoxia decreased it, suggesting the activation of DNA repair mechanisms. Results show that both fipronil and hypoxia exposure significantly modulate the oxidative stress parameters of O. niloticus and that the combination of these factors produces more pronounced effects.

The clinical value of integrated pulmonary index monitoring during an endobronchial ultrasound-guided transbronchial needle aspiration procedure under sedoanalgesia: A prospective study.

To evaluate the clinical relevance of Integrated Pulmonary Index (IPI) monitoring during transbronchial needle aspiration (EBUS-TBNA) under sedation and determine whether it reduces hypoxic events compared to standard monitoring. This prospective observational research was carried out at Dr. Lutfi Kirdar City Hospital, Istanbul, Turkey, between July 2022 and July 2023. A total of 50 patients, aged 18-80 years with American Society of Anesthesiologists scores of I-III, undergoing EBUS-TBNA with deep sedation for diagnostic purposes were included. The IPI values were measured at 6 time points: baseline, induction, 3, 5, 10 minutes, and at the end of the procedure. Patients were categorized based on whether their IPI scores were above 7 (group 1) or below 7 (group 2). A total of 43 patients completed the study. Group 1 had higher end-tidal carbon dioxide and respiratory rate at multiple time points, including induction and at 3, 5, and 10 minutes post-induction (p<0.05). Group 2 experienced a higher rate of apnea at these times (p<0.05). Those with lower IPI scores (namely, IPI=3 and IPI=4) showed significantly higher apnea rates, while those with higher scores (namely, IPI=7 and IPI=8) were less likely to have apneic episodes. The IPI monitoring during EBUS-TBNA under sedation demonstrated improved detection of apnea episodes and enhanced respiratory safety compared to standard monitoring techniques. Additional research involving more varied populations is necessary to confirm these results.

Balance of Antioxidants vs. Oxidants in Perinatal Asphyxia

Perinatal asphyxia refers to an acute event of cerebral ischemia and hypoxia during the perinatal period, leading to various degrees of brain injury. The mechanisms involved in perinatal asphyxia include the production of reactive oxygen species (ROS), accumulation of intracellular calcium, lipid peroxidation, excitatory amino acid receptor overactivation, energy failure, and caspase-mediated cell death. Both primary and secondary neuronal damage are caused by the overproduction of ROS following a hypoxic/ischemic event. ROS can react with nearly any type of molecule, including lipids, proteins, polysaccharides, and DNA. Neonates who suffer from perinatal asphyxia are prone to oxidative stress, which is characterized by a disruption in the oxidant/antioxidant balance, favoring oxidants over the intracellular and extracellular antioxidant scavenging mechanisms. Current research has focused on developing treatment strategies that potentially improve the endogenous antioxidant neuroprotective mechanisms or minimize injury resulting from hypoxia/ischemia. In this narrative review, we aim to present evidence regarding the contribution of oxidant/antioxidant balance to the pathogenesis and progression of perinatal asphyxia. Also, we aim to explore the role of potential antioxidant therapies as promising treatment strategies for perinatal asphyxia, especially as an adjunct to therapeutic hypothermia in infants with perinatal asphyxia. The current literature on antioxidant treatments in newborns is limited; however, allopurinol, melatonin, and erythropoietin have shown some positive effects in clinical trials. Inhibitors of nitric oxide synthase, N-acetylcysteine, and docosahexaenoic acid have shown promising neuroprotective effects in preclinical studies. Finally, nanotherapeutics could potentially modulate oxidative stress in hypoxemic/ischemic brain injury by targeted medication delivery. Future research on neuroprotectants and their processes is warranted to develop innovative treatments for hypoxia/ischemia in clinical practice.

High arousal threshold is associated with metabolic syndrome in patients with obstructive sleep apnea

ObjectiveObstructive sleep apnea (OSA) is associated with metabolic syndrome (MetS). OSA patients with high arousal threshold (ArTH) are less easy to arouse, which leads to more severe hypoxic events. We explored the relationship between high ArTH and MetS in patients with OSA. MethodsWe conducted a cross-sectional study of 112 patients with OSA (mean age 43.50 ± 11.64 years, 89.29 % male). High ArTH was based on an overnight polysomnography, and defined as none or one of the following conditions: apnea-hypopnea index (AHI) < 30 events/hour, minimum oxygen saturation > 82.5 %, or frequency of hypopnea events > 58.3 %. Metabolic syndrome and its components were defined according to the new International Diabetes Federation definition. ResultsAmong the 112 OSA patients, 51 (45.54 %) had MetS and 68 (60.71 %) had high ArTH. Logistic regression, after adjusting for confounders, showed that patients with high ArTH had higher odds for MetS (OR = 4.31, 95 % CI = 1.63–11.42, p = 0.003), central obesity (OR = 5.78, 95 % CI = 1.95–17.16, p = 0.002) and hypertriglyceridemia (OR = 2.84, 95 % CI = 1.11–7.28, p = 0.030) compared to patients with low ArTH. Furthermore, higher ArTH levels were associated with higher values for waist circumference (p-for-trend < 0.001), triglycerides (p-for-trend = 0.042), and systolic blood pressure (p-for-trend = 0.037). Moreover, patients with high ArTH had more apnea events and less hypopnea events. ConclusionsHigh ArTH is associated with MetS in OSA patients. High ArTH is a marker of the severity of cardiometabolic comorbidity in OSA.

Spectrum of delayed post-hypoxic leukoencephalopathy syndrome: A systematic review

BACKGROUND Delayed post hypoxic leukoencephalopathy syndrome (DPHLS), also known as Grinker’s myelinopathy, is a rare but significant neurological condition that manifests days to weeks after a hypoxic event. Characterized by delayed onset of neurological and cognitive deficits, DPHLS presents substantial diagnostic and therapeutic challenges. AIM To consolidate current knowledge on pathophysiology, clinical features, diagnostic approaches, and management strategies for DPHLS, providing a comprehensive overview and highlighting gaps for future research. METHODS Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyzes guidelines, we systematically searched PubMed, ScienceDirect and Hinari databases using terms related to delayed post-hypoxic leukoencephalopathy. Inclusion criteria were original research articles, case reports, and case series involving human subjects with detailed clinical, neuroimaging, or pathological data on DPHLS. Data were extracted on study characteristics, participant demographics, clinical features, neuroimaging findings, pathological findings, treatment, and outcomes. The quality assessment was performed using the Joanna Briggs Institute critical appraisal checklist. RESULTS A total of 73 cases were reviewed. Common comorbidities included schizoaffective disorder, bipolar disorder, hypertension, and substance use disorder. The primary causes of hypoxia were benzodiazepine overdose, opioid overdose, polysubstance overdose, and carbon monoxide (CO) poisoning. Symptoms frequently include decreased level of consciousness, psychomotor agitation, cognitive decline, parkinsonism, and encephalopathy. Neuroimaging commonly revealed diffuse T2 hyperintensities in cerebral white matter, sometimes involving the basal ganglia and the globus pallidus. Magnetic resonance spectroscopy often showed decreased N-acetylaspartate, elevated choline, choline-to-creatinine ratio, and normal or elevated lactate. Treatment is often supportive, including amantadine, an antioxidant cocktail, and steroids. Hyperbaric oxygen therapy may be beneficial in those with CO poisoning. Parkinsonism was often treated with levodopa. Most of the patients had substantial recovery over the course of months and many cases had some residual neurocognitive deficits. CONCLUSION DPHLS remains a complex and multifaceted condition with various etiologies and clinical manifestations. Early recognition and appropriate management are crucial to improving patient outcomes. Future research should focus on standardizing diagnostic criteria, using advanced imaging techniques, and exploring therapeutic interventions to improve understanding and treatment of DPHLS. Conducting prospective cohort studies and developing biomarkers for early diagnosis and monitoring will be essential to advance patient care.

Resistance of Australian fish communities to drought and flood: implications for climate change and adaptations

Climate change‐induced extreme weather and related drought and flood conditions are heterogeneous across space and time. The variability in location, timing, and magnitude of rainfall can alter how species respond to the drought and flood disturbances. To further complicate this matter, when droughts end they are often followed by extreme flooding, which are rarely considered as a disturbance (Humphries et al. 2024), let alone assessed with its own heterogeneity. Consequently, it is difficult to quantify impacts on ecological communities across large spatiotemporal scales without considering flood‐drought disturbance characteristics in sequence (Burton et al. 2020). We hypothesized that native organisms have evolved resistance to withstand repeated cycles of drought‐flood disturbances, and that established non‐native species have adapted to persist in novel conditions. To test this, we fit spatiotemporal models of species occurrence with local rainfall patterns as covariates in the drought and flood impacted Murray‐Darling basin in Australia during the decade long Millenium Drought, and its recovery period. During these drought conditions, river‐floodplain organisms in the Murray‐Darling became localized in refugia that limited longitudinal and lateral connectivity (Bond et al. 2008), and following flooding the same organisms were exposed to dispersal and recruitment opportunities (Humphries et al. 2020), as well as to hypoxic blackwater events that lead to the mortality of aquatic organisms (Small et al. 2014). At the basin‐scale we found that the range size of most native and non‐native fishes were highly resistant to the extreme drought and post‐flood conditions. At local scales, species richness, or detection, actually increased under drought conditions. Both findings highlight the resistance of species to climate change driven extreme weather, which opens new questions on community adaptations.

Ganaxolone Therapy After Preterm Birth Restores Cerebellar Oligodendrocyte Maturation and Myelination in Guinea Pigs.

The postnatal environment is challenging for the preterm neonate with exposure to hypoxic and excitotoxic events, amplified by premature loss of placentally derived neurosteroids. Between preterm birth and term equivalent age (TEA), cerebellar development continues despite these challenges. We hypothesize that neurosteroid replacement therapy during this time will support optimal cerebellar development. Guinea pig sows delivered at term (∼69 days gestation) or were induced to deliver preterm (∼62 days), with preterm pups receiving ganaxolone or vehicle until TEA. Postnatal assessments comprised salivary cortisol (corrected postnatal age [CPA] 0, 7, 38), behavioral analysis (CPA7, 38), and tissue collection (CPA0 and CPA40). Neurodevelopmental markers (MBP, Olig2, and NeuN) were assessed in the cerebellum by immunohistochemistry, whereas RT-PCR was utilized to investigate key inhibitory/excitatory pathways and oligodendrocyte lineage markers. Following preterm birth, there was evidence of a hyperactive phenotype, increased salivary cortisol concentrations, and impaired myelination and oligodendrocyte maturation at the protein level. mRNA expressions of key inhibitory/excitatory pathways and myelin stability were also altered following preterm birth. Importantly, we showed that neurosteroid replacement therapy returns cerebellar development and behavior toward a term-like phenotype. Therefore, ganaxolone may reduce the vulnerability of the cerebellum to postnatal challenges arising from preterm birth.

Hypoxia extreme events in a changing climate: Machine learning methods and deterministic simulations for future scenarios development in the Venice Lagoon

Climate change pressures include the dissolved oxygen decline that in lagoon ecosystems can lead to hypoxia, i.e. low dissolved oxygen concentrations, which have consequences to ecosystem functioning including biogeochemical cycling from mild to severe disruption. The study investigates the potential of machine learning (ML) and deterministic models to predict future hypoxia events. Employing ML models, e.g. Random Forest and AdaBoost, past hypoxia events (2008–2019) in the Venice Lagoon were classified with an F1 score of around 0.83, based on water quality, meteorological, and spatio-temporal factors. Future scenarios (2050, 2100) were estimated by integrating hydrodynamic-biogeochemical and climate projections. Results suggest hypoxia events will increase from 3.5 % to 8.8 % by 2100, particularly in landward lagoon areas. Summer prediction foresee a rise from 118 events to 265 by 2100, with a longer hypoxia-prone season. This model is a valuable tool for developing hypoxia scenarios, aiding in identifying restoration hotspots for climate-threatened lagoons.

Comparison of the ED50 of Ciprofol Combined With or Without Fentanyl for Laryngeal Mask Airway Insertion in Children: A Prospective, Randomized, Open-Label, Dose-Response Trial.

This study aimed to estimate the effect of different doses of fentanyl on the median effective dose (ED50) of ciprofol for attenuating the airway and motor response to laryngeal mask airway (LMA) insertion response in healthy children. 90healthy preschool patients undergoing inguinal hernia repair surgery were randomly assigned to one of three groups: C0 (ciprofol+saline), C1 (ciprofol + fentanyl 1µg/kg), C2 (ciprofol + fentanyl 2µg/kg). Anesthesia was induced with either prepared fentanyl or saline, followed by ciprofol. The dose of ciprofol for each patient was determined using the up-and-down sequential study design. The primary outcome was the ED50 of ciprofol required for smooth LMA insertion in the three groups. Additionally, the time to loss of consciousness and any perioperative adverse events were recorded. Compared with the C0 group, the ED50 (95% confidence interval) of ciprofol in the C1 and C2 groups were significantly lower (1.81 [1.73-1.90]mg/kg versus 0.67 [0.64-0.71]mg/kg and 0.48 [0.42-0.54] mg/kg, respectively; P<0.05). Additionally, the ED50 of ciprofol in the C2 group was lower than that in the C1 group (0.42 [0.42-0.54] mg/kg vs 0.67 [0.64-0.71]mg/kg; P<0.05). Furthermore, the time to loss of consciousness in the C1 and C2 groups decreased by 60% and 53%, respectively, compared to the C0 group. There were no significant differences in the incidence of drug-related hypotension after anesthesia induction among the three groups. No adverse events of hypoxia, bradycardia, or injection pain were observed in any groups. In healthy, non-obese Chinese children undergoing elective inguinal hernia repair surgery, fentanyl 1µg/kg and 2µg/kg before ciprofol injection significantly reduced the ED50 of ciprofol for attenuating LMA response, with minimal occurrence of severe side effects.

Transcriptomic responses to hypoxia in two populations of eastern oyster with differing tolerance

The eastern oyster, Crassostrea virginica, is a keystone species native to the Gulf of Mexico and Atlantic coasts of the United States and Canada. It provides habitat for other marine organisms and makes up the majority of oyster production in the United States. Despite its tolerance to hypoxic conditions, C. virginica is threatened by anthropogenic climate change, which is increasing both average temperature and the frequency and severity of hypoxic events. In this study, we explore the differences in hypoxia-transcriptional response between two populations of eastern oysters with known differences in hypoxia tolerance at three time points over the course of a 5-day hypoxia treatment. We identified sets of genes involved in the hypoxia response and found differences in both the timing and baseline expression of hypoxia-responsive genes between tolerant and sensitive populations, consistent with a scenario of local adaptation. Analysis of differential gene expression between the two populations and conditions revealed two gene modules with higher baseline expression of hypoxia-sensitive genes in the more hypoxia tolerant population. Key GO terms for genes corresponding to differences between populations include DNA repair, ribosome biogenesis, and ribonucleotide binding. Our results imply that differences in hypoxia tolerance between populations could be due to genetic frontloading of hypoxia response pathways in the more tolerant population.

Maternal dietary deficiencies in folic acid or choline reduce primary neuron viability after exposure to hypoxia through increased levels of apoptosis.

Objective: Ischemic stroke is the leading cause of death and disability globally. By addressing modifiable risk factors, particularly nutrition, the prevalence of stroke and its dire consequences can be mitigated. One-carbon (1C) metabolism is a critical biosynthetic process that is involved in neural tube closure, DNA synthesis, plasticity, and cellular proliferation. Folates and choline are two active components of 1C metabolism. We have previously demonstrated that maternal dietary deficiencies during pregnancy and lactation in folic acid or choline result in worse stroke outcomes in offspring. However, there is insufficient data to understand the neuronal mechanisms involved.Methods: Using C57Bl/6J female mice maintained on control, folic acid (0.3 mg/kg) or choline (choline bitrate 300 mg/kg) deficient diets we collected embryonic primary neurons from offspring and exposed them to hypoxic conditions for 6 hours. To determine whether increased levels of either folic acid or choline can rescue reduced neuronal viability, we supplemented cell media with folic acid and choline prior to and after exposure to hypoxia.Results: Our results suggest that maternal dietary deficiencies in either folic acid or choline during pregnancy negatively impacts offspring neuronal viability after hypoxia. Furthermore, increasing levels of folic acid (250 mg/ml) or choline chloride (250 mg/ml) prior to and after hypoxia have a beneficial impact on neuronal viability.Conclusion: The findings contribute to our understanding of the intricate interplay between maternal dietary factors, 1C metabolism, and the outcome of offspring to hypoxic events, emphasizing the potential for nutritional interventions in mitigating adverse outcomes.

Neurological Symptoms and Cause of Death Among Young Children in Low- and Middle-Income Countries

The emergence of acute neurological symptoms in children necessitates immediate intervention. Although low- and middle-income countries (LMICs) bear the highest burden of neurological diseases, there is a scarcity of diagnostic and therapeutic resources. Therefore, current understanding of the etiology of neurological emergencies in LMICs relies mainly on clinical diagnoses and verbal autopsies. To characterize the association of premortem neurological symptoms and their management with postmortem-confirmed cause of death among children aged younger than 5 years in LMICs and to identify current gaps and improve strategies to enhance child survival. This cross-sectional study was conducted between December 3, 2016, and July 22, 2022, at the 7 participating sites in the Child Health and Mortality Prevention Surveillance (CHAMPS) network (Bangladesh, Ethiopia, Kenya, Mali, Mozambique, Sierra Leone, and South Africa). Minimally invasive tissue sampling was performed at the CHAMPS sites with specimens from deceased children aged younger than 5 years. This study included deceased children who underwent a premortem neurological evaluation and had a postmortem-confirmed cause of death. Data analysis was performed between July 22, 2022, and January 15, 2023. Descriptive analysis was performed using neurological evaluations from premortem clinical records and from postmortem determination of cause of death (based on histopathology, microbiological testing, clinical records, and verbal autopsies). Of the 2127 deaths of children codified during the study period, 1330 (62.5%) had neurological evaluations recorded and were included in this analysis. The 1330 children had a median age of 11 (IQR, 2-324) days; 745 (56.0%) were male and 727 (54.7%) presented with neurological symptoms during illness before death. The most common postmortem-confirmed neurological diagnoses related to death were hypoxic events (308 [23.2%]), meningoencephalitis (135 [10.2%]), and cerebral malaria (68 [5.1%]). There were 12 neonates with overlapping hypoxic events and meningoencephalitis, but there were no patients with overlapping meningoencephalitis and cerebral malaria. Neurological symptoms were similar among diagnoses, and no combination of symptoms was accurate in differentiating them without complementary tools. However, only 25 children (18.5%) with meningitis had a lumbar puncture performed before death. Nearly 90% of deaths (442 of 511 [86.5%]) with neurological diagnoses in the chain of events leading to death were considered preventable. In this cross-sectional study of children aged younger than 5 years, neurological symptoms were frequent before death. However, clinical phenotypes were insufficient to differentiate the most common underlying neurological diagnoses. The low rate of lumbar punctures performed was especially worrying, suggesting a challenge in quality of care of children presenting with neurological symptoms. Improved diagnostic management of neurological emergencies is necessary to ultimately reduce mortality in this vulnerable population.

Impact of Slim Linear Echoendoscope on the Practice of EUS.

Standard linear echoendoscopes have a large distal tip and bending radius, which can preclude adequate examination in some patients. We examined the impact of having available slim linear echoendoscopes (SLE) on our endoscopic ultrasound (EUS) practice. As a quality improvement measure, data on the need for the use of SLE were documented in 2000 consecutive procedures performed over a 10-month period from February to November 2022. When examination using a standard size echoendoscope failed due to technical limitations, the procedure was reattempted in the same session using a SLE. The main outcome was the impact of SLE, which was defined as the establishment of a new diagnosis or if findings altered treatment plan. A complete EUS examination failed in 23 of 2000 procedures (1.15%, 95% CI, 0.73-1.72%) performed using standard size echoendoscope (14 male, median age 73y [IQR 66 to 79]). The examination was technically successful when using SLE in 22 of 23 (95.6%) patients. SLE impacted clinical management in all 22 patients (100%) by establishing tissue diagnosis in 19 and/or altering subsequent treatment plan in 5. Adverse event of transient hypoxia was observed in one patient (4.3%). A very experienced EUS team required SLE in 1.1% of consecutive examinations. Our findings suggest that when used, 95% of patients benefitted as it had a significant impact on their clinical management.

Stratification in central Bohai Sea and how it has shaped hypoxic events in summer

Stratification in central Bohai Sea and how it has shaped hypoxic events in summer

Microbiome signature of different stages of hypoxia event in Wonmun Bay

We investigated how microbial communities associated with different hypoxic stages respond to environmental changes across three water depths in Wonmun Bay, South Korea. Analysis of temperature, salinity, dissolved oxygen (DO), and nutrient concentrations revealed prominent seasonal shifts and strong stratification during summer hypoxia. Metabarcoding of prokaryotic 16 S rRNA genes and phototrophic eukaryotic chloroplasts along with quantitative PCR (qPCR) revealed variations in the abundance and composition of these communities. Chloroplast 16 S sequences in May were dominated by land plants (93% of Embryophyta), contrasting with the diverse phytoplankton taxa detected in other months. The water communities in May also had higher total microbial abundance than other months but significantly lower alpha diversity. These results suggest a major influence of freshwater discharge on water communities, pre-conditioning for hypoxia events by promoting organic matter decomposition coupled with DO consumption in bottom water. Subsequently, distinct microbial communities were observed across depths during hypoxia in June and July, while less variability was detected among different depths in September and later months when hypoxia events disappeared. Principal Coordinate analysis (PCoA) demonstrated the distinct patterns of microbial communities in May, June, and July from other months. Both sulfur-oxidizing and sulfate-reducing bacteria (SRB) were prevalent in June while the increase of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) was observed in mid and bottom water in July. This data suggests the intricate interaction between sulfur and nitrogen-cycling microbes during the hypoxia events in Wonmun Bay. In conclusion, this study provides valuable insights into the microbial community responses to the varying environmental conditions at different stages of hypoxia events in eutrophic coastal ecosystems.

Increased risk of respiratory events during endobronchial ultrasound examination in patients with reduced forced expiratory volume: a prospective observational study.

The incidence of adverse events during endobronchial ultrasound is low. Nevertheless, it is unclear, whether patients with impaired pulmonary function have an increased risk of respiratory events during the intervention. A monocentric prospective observational study was performed at the Department of Respiratory Medicine, University Hospital Frankfurt/Main, Germany. Adult patients undergoing an endobronchial ultrasound examination with propofol-sedation were included. Pre-interventional screening included pulmonary function testing, laboratory tests and electrocardiogram. The occurrence of hypercapnia >55 mmHg or reduced oxygen saturation <85% was defined as a respiratory event was recorded and compared between patients with normal and impaired pulmonary function tests. In total, 126 patients were included. Pulmonary function testing revealed a median FEV1 of 2.2 l (range 0.4-6.04l) and a predicted FEV1 of 79.5% (range 20-127.8%) respectively. The median FVC was 3.0 l (range 0.87-7.28l), the median predicted FVC was 82% (range 31.4-128.4%). In 72 examinations (60%) pCO2 levels >55 mmHg were measured. Transient oxygen desaturation <85% occurred in 31 cases (25.8%). The Mann Whitney U-test showed a significantly lower FEV1 (% predicted value) in patients with respiratory events (p = 0.007). ROC analysis identified a predicted FEV1 of 78.5% as the optimal cut-off with a sensitivity of 58% and a specificity of 71%. Using Z-score instead of predicted values, there was no significant association between a lower Z- score of FEV or FVC and hypercapnic or hypoxic events. However, both a lower absolute value of FEV1/FVC and a lower Z-score of the FEV1/FVC index were associated with the occurrence of respiratory events. In binary logistic regression analysis, we could not demonstrate any association with other relevant parameters (age, BMI, sedation dosage, sedation duration, or ASA-score). An impaired forced expiratory volume is associated with the frequency of respiratory events during endobronchial ultrasound examination under propofol-sedation.

Do maternal BMI and gestational weight gain equally affect the risk of infant hypoxic and traumatic events?

Small (SGA) and large (LGA) for gestational age infants have higher risks of infant morbidity when compared to those who are appropriate for gestational age (AGA). Increasing pre-pregnancy maternal BMI and gestational weight gain (GWG) are associated with higher risks of LGA and lower risks of SGA infants; however, their direct effects on infant morbidity are unknown. Therefore, we intended to 1) assess how maternal pre-pregnancy BMI, GWG, and birthweight (categorized as SGA, AGA or LGA) affect infant morbidity and 2) estimate at entry of care the risk of infant morbidity according to pre-pregnancy BMI and possible GWG. we used Consortium on Safe Labor data, a retrospective observational cohort study collecting pregnancy and birth data from 2002 to 2008 in 12 US centers. The association between maternal BMI, GWG and infant morbidity was estimated in singleton gestations delivering ≥ 37 weeks using binomial logistic regression. Hypoxic composite neonatal morbidity was defined as any the following: stillbirth, neonatal death, resuscitation at birth, NICU admission, intracranial hemorrhage, PVH grade III and IV, neonatal seizures, NEC, meconium aspiration, CPAP or mechanical ventilation, RDS, and sepsis. Traumatic composite neonatal morbidity included shoulder dystocia or birth injuries. In this study of 110,594 mother-infant dyads, a total of 8,369 (7.6%) infants experienced hypoxic, while 2,134 (1.9%) developed traumatic morbidity. The risk of hypoxic morbidity among SGA, AGA and LGA infants increased when mothers were overweight (aOR 1.26 [95%CI 1.18-1.34]) or obese (class 1: aOR 1.3 [1.2-1.4]; class 2: aOR 1.7 [1.5-1.9]; class 3: aOR 1.8 [1.6-2]) as opposed to normal weight, and when GWG exceeded (aOR 1.08 [1.02-1.014]) rather than remained within recommendations. The risk of traumatic morbidity increased with maternal obesity (class 1: aOR 1.3 [1.1-1.5]), whilst it dropped with GWG below recommendations (aOR 0.7 [0.6-0.8]). The risk of hypoxic events estimated at entry of care increased with maternal overweight (aOR 1.27 [1.19-1.35]) or obesity (class 1: aOR 1.4 [1.2-1.5]; class 2: aOR 1.7 [1.5-1.9]; class 3: aOR 1.8 [1.6-2.1]), and with possible GWG above (aOR 1.09 [1.03-1.015]) recommendations. The risk of traumatic morbidity increased with overweight (aOR 1.1 [1-1.3]) or obesity (class 1: aOR 1.4 [1.2-1.6]; class 2: aOR 1.3 [1-1.6]), with possible GWG above (aOR 1.2 [1-1.3]), as opposed to below recommendations (aOR 0.7 [0.6-0.8]). While maternal pre-pregnancy BMI and GWG equally affected traumatic morbidity, the former had a greater impact on hypoxic complications. Therefore, weight control prior to pregnancy is at least as effective as avoiding excessive gestational weight gain to prevent neonatal morbidity.

Anatomy of the late Famennian Dasberg event in a deep shelf of southern Euramerica: Oxygenation and productivity in a restricted basin during a progressive long-term cooling

The late Famennian Dasberg event is described as a series of global hypoxic and transgressive events associated with global faunal turnover. The event, recorded on a deep shelf of the Rhenohercynian basin from southern Euramerica, was investigated in the Holy Cross Mountains of Poland using integrated high-resolution geochemical, mineralogical, and palynological studies. The data revealed the progressive restriction of the intrashelf basin resulting from intense regional block tectonics likely connected with the Late Devonian Variscan tectonic activity. This led to weak chemocline ventilation, the development of anoxic conditions, and the deposition of two organic-rich Dasberg black shale (DBS) horizons. The DBS was deposited in an environment characterized by the constant contribution of detrital components from a common source area. A slight change in terrestrial input may have been driven by modest bathymetric changes associated with the tectonics and stronger winds delivering charcoal and terrestrial components (i.e., miospores and phytoclasts). A supply of nutrients from land and delivery of crucial biolimiting elements (i.e., nitrogen and phosphorus) from deeper waters stimulated primary productivity, as recorded in phytoplankton blooms. The δ13Corganic values in the DBS reflect the incorporation of primary biomass from mainly marine photoautotrophs into sedimentary organic matter. Episodic delivery of toxic sulphides to the photic zone was detected by small-sized framboids and biomarkers, which record the appearance of green sulphur bacteria that photosynthesized in euxinic water column. The activity of phototrophic sulphide-oxidizing bacteria could have led to hyper-enrichment of Zn (715–1002 ppm) in the Lower DBS. The diachronous appearance of the DBS horizons in Euramerica and Gondwana, and regionally marked extinction of benthic fauna, suggest that anoxia developed in restricted Black Sea–like basins formed by intensive tectonic activity and continental plate convergence.