Decrease In Oxygen Saturation Research Articles

Relationship among muscle strength, muscle endurance, and skeletal muscle oxygenation dynamics during ramp incremental cycle exercise.

Peak oxygen uptake (VO2), evaluated as exercise tolerance, is a strong predictor of life prognosis regardless of health condition. Several previous studies have reported that peak VO2 is higher in those with a greater decrease in muscle oxygen saturation (SmO2) in the active muscles during incremental exercise. However, the skeletal muscle characteristics of individuals exhibiting a greater decrease in SmO2 during active muscle engagement in incremental exercise remain unclear. This study aimed to clarify the relationship among muscle strength, muscle endurance, and skeletal muscle oxygenation dynamics in active leg muscles during incremental exercise. Twenty-four healthy young men were included and categorized into the non-moderate-to-high muscular strength and endurance group (those with low leg muscle strength, endurance, or both; n = 11) and the moderate-to-high muscular strength and endurance group (those with both moderate-to-high leg muscle strength and endurance; n = 13). All participants underwent cardiopulmonary exercise testing combined with near-infrared spectroscopy to assess whole-body peak VO2 and the change in SmO2 at the lateral vastus lateralis from rest to each exercise stage as skeletal muscle oxygenation dynamics. A linear mixed-effects model, with the change in SmO2 from rest to each stage as the dependent variable, individual participants as random effects, and group and exercise load as fixed effects, revealed significant main effects for both group (P = 0.001) and exercise load (P < 0.001) as well as a significant interaction between the two factors (P < 0.001). Furthermore, multiple-comparison test results showed that the change in SmO2 from rest to 40%-100% peak VO2 was significantly higher in the moderate-to-high muscular strength and endurance group than in the non-moderate-to-high muscular strength and endurance group. Maintaining both muscle strength and endurance at moderate or higher levels contributes to high skeletal muscle oxygenation dynamics (i.e., greater decrease in SmO2) during moderate- or high-intensity exercise.

Unsophisticated assessment of the cardiopulmonary function in patients with pectus excavatum using the six minute walk test

Background We explored whether the maximum predicted walking distance, assessed with six-minute walk test (6MWT) and reflecting submaximal functional exercise capacity, is decreased among patients with pectus excavatum (PEX). Methods This study comprised a retrospective analysis of patients with PEX who underwent a 6MWT for the assessment of functional capacity. The maximum distance walked was recorded and compared to reference values established for different populations, including a young and healthy South American population. Results We included 43 patients with PEX who underwent 6MWT. The mean age was 17.8 ± 6.7 years. The mean maximum distance walked was significantly lower than the predicted distance (600.8 ± 67.6 metres vs. 729.8 ± 67.5 metres, p < 0.0001). Using the Enright reference equation including an older reference population, the mean negative difference was higher (PEX patients walked 190.4 ± 78.4 metres less than predicted, p < 0.0001). We also applied the Li et al. reference equation accounting for sex among other variables, detecting a decreased walked distance compared to the gender-adjusted predicted distance (PEX patients walked a mean 222.4 ± 87.4 metres less than predicted, p < 0.0001). Using the Ulrich et al. equation, PEX patients walked a mean 114.2 ± 85.1 metres less than predicted (p < 0.0001). Although of uncertain clinical relevance, there was a significant decrease in the mean oxygen saturation after exercise (baseline 97.4 ± 1.2%, vs. final 96.4 ± 2.1%, p = 0.006). Conclusions In this study, we identified a significant reduction in the maximum walked distance among patients with PEX compared to the predicted distance, thus potentially emerging as an unsophisticated means to evaluate and quantify functional exercise capacity.

The association between six-minute walk test and one minute sit to stand test in patients with acute exacerbations of COPD

ABSTRACT Aim: Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are a major complication of COPD and a leading cause of hospitalization, detrimentally affecting functional exercise capacity. The 6-minute walk test (6MWT) is a reliable measure of exercise capacity in chronic lung diseases. Conversely, the 1-minute sit-to-stand test (1STST) offers a simpler assessment of physical function. The aim was to demonstrate the association of functional exercise capacity assessed by 1STST and 6MWT in COPD patients with acute exacerbation. Materials and Methods: In this study, 37 hospitalized patients with acute exacerbation COPD (mean age:66 years) underwent assessments including pulmonary function testing, 6MWT, 1STST and modified Medical Research Council (MMRC). Parameters such as heart rate, oxygen saturation, and perceived dyspnea (via the modified Borg scale) were monitored during tests. Results: The results showed a significant correlation between 6MWT and 1STST performance (r=0.656, p&amp;lt;0.001). Notably, end-tidal oxygen saturation differed between tests, with the 6MWT showing higher end-tidal dyspnea scores. During recovery, 1STST induced increased heart rate and decreased oxygen saturation. Both 6MWT and 1STST were negatively associated with age and MMRC. Positive correlations were observed between 6MWT and FEV1(L) and PEF(L). Conclusions: Similar to the 6MWT, the 1STS test may be used to evaluate how well patients with AECOPD perform during functional exercise. We propose that the 1STST is a suitable alternative to the 6MWT for the assessment of functional exercise performance during hospitalization in AECOPD patients.

Toxicological Effects of Commonly Used Mosquito Coil Smoke on Liver and Lung Function in Rats

The utilization of mosquito coils as a household-level strategy for mosquito control is widely practiced in malaria-endemic regions spanning Africa, Asia, and South America. However, the continuous application of mosquito coils has prompted significant apprehensions concerning environmental and health implications. This research aims to evaluate the potential hepatic and pulmonary toxicities associated with the inhalation of mosquito coil smoke in rat subjects over both sub-chronic and chronic durations. A questionnaire was used to make inquiries regarding the prevalent types and brands of mosquito coils employed, the manner in which they are used, the durations for which they are utilized. A total of twenty-four albino rats were categorized into three distinct groups: the control group and two exposed groups. These groups were subjected to distinct brands of mosquito coil smoke across two distinct exposure regimens – a sub-chronic exposure lasting 4 weeks and a chronic exposure spanning 12 weeks. Following the exposure periods, blood samples were collected for the analysis of serum-based and biochemical markers, including serum aspartate aminotransferase (AST), alanine aminotransferase (AST), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), bilirubin, serum bicarbonate, and Lactate dehydrogenase (LDH), oxygen saturation, C-reactive protein, total protein, and microscopic analysis of lung tissue and liver tissue. The histopathological analysis of lung tissue was appropriately included. However, the analysis of liver tissue was omitted. The results demonstrated a significant elevation in the levels of these biochemical markers among the exposed rats in comparison to the control group. Concurrently, a decrease in blood oxygen saturation was noted in the exposed rats when contrasted with the control group. Conversely, the serum concentrations of high-sensitivity C-reactive protein, total protein, and alanine aminotransferase (ALT) did not exhibit notable differences in relation to the control group. Additionally, microscopic analysis of lung tissue indicated the presence of histopathological lesions in the exposed rats, suggesting a detrimental impact of mosquito coil smoke exposure in a time-dependent progression.

Oral bacteriotherapy is associated with decreased blood lactate concentration during exercise at high altitude

Exposure to high altitude leads to decreased oxygen saturation (SpO2) and, in some individuals, the development of adverse outcomes such as acute high-altitude sickness. A further decrease in oxygen availability during exercise at altitude leads to greater anaerobic metabolism and increased lactate production. Previous studies show that ingestion of the probiotic SLAB51 (O2BOOSTER; Hecto, Seoul, South Korea) improved SpO2 in individuals exercising in a hypobaric chamber (simulated altitude 16,732 ft (~5100 m) above sea level) compared to individuals who did not ingest the probiotic. However, the use of SLAB51 during exercise at high terrestrial altitude has yet to be studied. We hypothesized that individuals who ingest SLAB51, relative to those given a placebo, will exhibit less of a difference in lactate production during sub-maximal exercise when paired high-altitude and sea-level values pre- and post-exercise are compared. We recruited 17 participants of Latino ancestry, ages 19-63 years, for studies at sea level (University of California, San Diego) and at high altitude (University of California White Mountain Barcroft Research Station, 3801 m). At sea level and on the third or fourth day at high altitude, we measured SpO2 and heart rate (HR) via pulse oximetry (forehead probe) before and during the last 30 seconds of a 10-minute submaximal (1 watt/kg) bout of exercise on a cycle ergometer (n = 5 for each group). Blood lactate concentration was measured before and after exercise from fingertip capillary blood samples. The respective differences between SpO2 and HR pre-exercise and during the final 30 seconds of exercise (the ΔSpO2 and ΔHR) were calculated for all individuals. The Δlactate blood concentration was calculated by the difference between lactate pre- and post-exercise. ΔSpO2, ΔHR, and Δlactate values were computed for sea level and high altitude. The difference between the respective sea-level Δ and the high-altitude Δ values were quantified for each measurement and compared between the groups who received either SLAB51 or the placebo upon arrival, and the same treatment for three days at high altitude. As expected, exercise increased HR and blood lactate concentration at sea level and high altitude and decreased SpO2 at high altitude. The difference of Δlactate between sea level and high altitude was lower (p = 0.023) in the SLAB51 (n = 4, 0.93 ± 0.18 mmol/L) versus placebo (n = 4, 1.63 ± 0.13 mmol/L) group. However, there were no significant differences of ΔSpO2 and ΔHR between groups. Our findings show that taking SLAB51 could lower the production of lactate during submaximal exercise at high altitude. This means that anaerobic glycolysis may play a smaller role in energy production when the probiotic is taken compared to the placebo. To further understand the influence of SLAB51 as a supplement on exercise performance at altitude, more research with a bigger sample size is necessary. Supported by LEA Altitude Performance Fund. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Intraoperative Hypoxemia in the Right Lateral Decubitus Position: A Case Report

Platypnea-Orthodeoxia syndrome (POS), an exceptionally uncommon condition, is characterized by decreased oxygen saturation in an upright posture with corresponding improvement in the supine position. Recently, an 85-year-old female patient presented for surgery due to a left femoral neck fracture. Following successful tracheal intubation and anesthesia induction, the ventilator indicated an airway pressure of 15mmHg. While in the right lateral decubitus position, the patient developed hypoxia despite normal arterial blood pressure and symmetrical breath sounds. Attempts to alleviate the hypoxia through pure oxygen ventilation, tympanic lung ventilation, and high-frequency ventilation were unsuccessful. Subsequently, there was a notable decrease in both blood pressure and heart rate, prompting an immediate halt to the surgery and repositioning the patient to the supine position. This resulted in the normalization of the patient&amp;apos;s heart rate, oxygen saturation, and blood pressure. To investigate the etiology, a TEE probe was inserted, revealing the presence of a patent foramen ovale (PFO) and a significant right-to-left shunt while the patient was in the lateral position. The procedure was performed in a specific right lateral decubitus position. This case may represent a unique manifestation of POS syndrome, expanding the differential diagnosis for intraoperative position-related hypoxemia. Given the severe hypoxemia observed with intraoperative positional changes, a strong suspicion of POS syndrome is warranted.

Anesthetic challenges in patients with multicompartmental lymphatic failure after Fontan palliation undergoing transcatheter thoracic duct decompression.

Lymphatic flow abnormalities are central to the development of protein losing enteropathy, plastic bronchitis, ascites and pleural effusions in patients palliated to the Fontan circulation. These complications can occur in isolation or multicompartmental (two or more). The treatment of multicompartmental lymphatic failure aims at improving thoracic duct drainage. Re-routing the innominate vein to the pulmonary venous atrium decompresses the thoracic duct, as atrial pressure is lower than systemic venous pressure in Fontan circulation. Transcatheter thoracic duct decompression is a new minimally invasive procedure that involves placing covered stents from the innominate vein to the atrium. Patients undergoing this procedure require multiple general anesthetics, presenting challenges in managing the sequelae of disordered lymphatic flow superimposed on Fontan physiology. We reviewed the first 20 patients at the Center for Lymphatic Imaging and Intervention at a tertiary care children's hospital presenting for transcatheter thoracic duct decompression between March 2018 and February 2023. The patients ranged in age from 3 to 26 years. The majority had failed prior catheter-based lymphatic intervention, including selective embolization of abnormal lympho-intestinal and lympho-bronchial connections to treat lymphatic failure in a single compartment. Fourteen had failure in three lymphatic compartments. Patients were functionally impaired (ASA 3-5) with significant comorbidities. Concurrent with thoracic duct decompression, three patients required fenestration closure for the resultant decrease in oxygen saturation. Ten patients had improvement in symptoms, seven had no changes and three have limited follow up. Five (25%) of these patients were deceased as of January 2024 due to non-lymphatic complications from Fontan failure.

Conditional deficiency of Rho-associated kinases disrupts endothelial cell junctions and impairs respiratory function in adult mice.

The Ras homology (Rho) family of GTPases serves various functions, including promotion of cell migration, adhesion, and transcription, through activation of effector molecule targets. One such pair of effectors, the Rho-associated coiled-coil kinases (ROCK1 and ROCK2), induce reorganization of actin cytoskeleton and focal adhesion through substrate phosphorylation. Studies on ROCK knockout mice have confirmed that ROCK proteins are essential for embryonic development, but their physiological functions in adult mice remain unknown. In this study, we aimed to examine the roles of ROCK1 and ROCK2 proteins in normal adultmice. Tamoxifen (TAM)-inducible ROCK1 and ROCK2 single and double knockout mice (ROCK1flox/flox and/or ROCK2flox/flox;Ubc-CreERT2) were generated and administered a 5-day course of TAM. No deaths occurred in either of the single knockout strains, whereas all of the ROCK1/ROCK2 double conditional knockout mice (DcKO) had died by Day 11 following the TAM course. DcKO mice exhibited increased lung tissue vascular permeability, thickening of alveolar walls, and a decrease in percutaneous oxygen saturation compared with noninducible ROCK1/ROCK2 double-floxed control mice. On Day 3 post-TAM, there was a decrease in phalloidin staining in the lungs in DcKO mice. On Day 5 post-TAM, immunohistochemical analysis also revealed reduced staining for vascular endothelial (VE)-cadherin, β-catenin, and p120-catenin at cell-cell contact sites in vascular endothelial cells in DcKO mice. Additionally, VE-cadherin/β-catenin complexes were decreased in DcKO mice, indicating that ROCK proteins play a crucial role in maintaining lung function by regulating cell-cell adhesion.

The time course of hypoxia effects using an aviation survival trainer

IntroductionReduced environmental oxygen levels at high altitudes can result in hypoxic hypoxia, which remains a primary threat in tactical aviation. Hypoxia broadly impairs cognition and can degrade a pilot's ability to safely operate the aircraft. Current hypoxia countermeasures include aircraft life support systems that deliver supplemental oxygen and using controlled hypoxia exposures to train aviators to recognize symptoms. To maximize the effectiveness of these countermeasures, it is critical to understand how hypoxia impacts performance and associated neurocognitive outcomes. We previously showed that a neural marker that indexes sensory processing integrity is sensitive to hypoxia impairment.MethodsHere, we extend this line of research closer to the training environment by using hypoxia simulation equipment currently standard in aviation survival training. In a single-blind, repeated-measures, counterbalanced design, we exposed 34 healthy participants to either normoxic air (ground level) or normobaric hypoxia (altitude equivalent gradually increasing from 10 to 25k') for 20 min after a 10 min baseline at ground level. During the exposure, participants completed a cognitive assessment battery while passively elicited neural responses to auditory tones were recorded using electroencephalography (EEG). Participants reported their hypoxia symptoms throughout and upon completion of their exposures.ResultsWe found that the hypoxia exposure rapidly elicited the predicted physiological responses in peripheral oxygen saturation (decrease) and heart rate (increase) within 2–3 minutes of exposure onset. On average, participants reported hypoxia symptoms in a delayed manner, ~8 min following the exposure onset. Performance on the cognitive tasks was relatively unaffected by hypoxia for basic tasks including Stroop, fine motor tracking, color vision and arithmetic, but was significantly degraded by hypoxia for more advanced tasks that combined a visual search component with Stroop and a working memory task. EEG activity associated with pre-attentive auditory processing was impaired on average shortly after the first symptom report, ~10 min from exposure start.DiscussionTogether, these results move hypoxia research closer to conditions encountered in aviation survival training and support the use of training devices for future hypoxia research.

Early “Red Flags” in hospitalized patients with COVID-19

Relevance. Among the studies during the COVID-19 pandemic, a special role is played by studies examining the prognostic value of clinical, laboratory and instrumental markers in patients. Biomarkers with absolute sensitivity and specificity for predicting the outcome of a new coronavirus infection have not been identified yet.Aim: To identify early clinical and laboratory predictors of severity and mortality in hospitalized patients with COVID-19 and to evaluate the effectiveness of the pharmacotherapy in outpatient and early hospital settings.Methodology and research methods. A retrospective, comparative study was carried out. Medical data from 745 adult patients with COVID-19, hospitalized in the respiratory hospital of the Siberian State Medical University (Tomsk) from 05/16/2020 to 09/30/2020 were included. The main group consists of patients who were discharged from the hospital. The comparison group included patients with a fatal outcome of the disease.Results. The group of deceased patients was characterized by older age and a greater number of comorbid diseases (р &lt; 0.0001), the presence of pneumonia during the year preceding COVID-19 (р &lt; 0.0001) and risk factors for the development of Pseudomonas aeruginosa infection (р &lt; 0.005). Early admission to the hospital (р = 0.0110), severe dyspnea (р &lt; 0.0001) with a decrease in oxygen saturation below reference values (р &lt; 0.0001) are also associated with the risk of a fatal outcome. Anosmia was significantly more common in the group of surviving patients.The number of platelets, the absolute number of lymphocytes, amounts of total protein, albumin (р &lt; 0.0001), sodium (р = 0.0013) in the first 48 hours of hospitalization in the main group were significantly higher. The number of leukocytes (p = 0.0078), neutrophils (p &lt; 0.0001), neutrophil-lymphocyte ratio (p &lt; 0.0001), concentrations of glucose, aspartate aminotransferase, urea, creatinine, C-reactive protein and lactate dehydrogenase were significantly lower in the main group. Serum procalcitonin levels &gt; 0.5 ng/ml were 5 times higher in deceased patients during early period of hospitalization.Conclusion. Clinical, anamnestic and laboratory factors were identified through this study. These factors may be useful in the early period of hospitalization for accurate assessment of risks of severe ill, effective disease management and reduction of mortality in hospitalized patients with COVID-19.

The effects of acute normobaric hypoxia on standing balance while dual-tasking with and without visual input.

To investigate the influence of acute normobaric hypoxia on standing balance under single and dual-task conditions, both with and without visual input. 20 participants (7 female, 20-31years old) stood on a force plate for 16, 90-s trials across four balance conditions: single-task (quiet stance) or dual-task (auditory Stroop test), with eyes open or closed. Trials were divided into four oxygen conditions where the fraction of inspired oxygen (FIO2) was manipulated (normoxia: 0.21 and normobaric hypoxia: 0.16, 0.145 and 0.13 FIO2) to simulate altitudes of 1100, 3,400, 4300, and 5200m. Participants breathed each FIO2 for ~ 3min before testing, which lasted an additional 7-8min per oxygen condition. Cardiorespiratory measures included heart rate, peripheral blood oxygen saturation, and pressure of end tidal (PET) CO2 and O2. Center of pressure measures included total path length, 95% ellipse area, and anteroposterior and mediolateral velocity. Auditory Stroop test performance was measured as response accuracy and latency. Significant decreases in oxygen saturation and PETO2, and increased heart rate were observed between normoxia and normobaric hypoxia (P < 0.0001). Total path length was higher at 0.13 compared to 0.21 FIO2 for the eyes closed no Stoop test condition (P = 0.0197). No other significant differences were observed. These findings suggest that acute normobaric hypoxia has a minimal impact on standing balance and does not influence auditory Stroop test or dual-task performance. Further investigation with longer exposure is required to understand the impact and time course of normobaric hypoxia on standing balance.

ПРОГНОЗИРОВАНИЕ ПРОГРЕССИРОВАНИЯ ИНТЕРСТИЦИАЛЬНОГО ЗАБОЛЕВАНИЯ ЛЁГКИХ У ПАЦИЕНТОВ С СИСТЕМНОЙ СКЛЕРОДЕРМИЕЙ: АНАЛИЗ ДАННЫХ КОГОРТНОГО ИССЛЕДОВАНИЯ

Introduction. Systemic sclerosis (scleroderma) is an autoimmune disease that often causes inflammatory fibrosing lesions of the pulmonary interstitial tissue, referred to as interstitial lung disease. It is associated with a significant reduction in survival and is the leading immediate cause of the systemic scleroderma patients’ death. Progression rate of interstitial lung disease varies greatly. Since the specific immunosuppressive and antifibrotic treatment is only justified in case of progressive lesions, predicting the interstitial lung disease progression is of great practical importance. Aim: To develop approaches to predicting the progression of interstitial lung disease in systemic scleroderma patients. Materials and Methods. Our analysis included the data of patients observed in the Registry of Myositis, Systemic Scleroderma and Mixed Diseases (REMISSiZ). Inclusion criteria: Age 18+ years, the proven case of systemic scleroderma, eligibility for ACR/EULAR (2013), and the repeated high-resolution computed tomography of lungs with an interval of at least 1 year. All patients underwent 6-minute walking tests. Results and Discussion. The study included 44 patients (43 women) aged 62.9 ± 11.5 years in average. The average follow-up duration was 530 ± 231 days. Radiological progression was associated with younger age, p=0.03, severity of Raynaud’s phenomenon, p=0.032, shorter disease duration, p=0.038, and shorter distance covered in the 6-minute walk test, p=0.05. The progression of functional impairment, determined by the dynamics of the distance covered in the 6-minute walk test, was associated with a decrease in blood oxygen saturation at rest (p=0.003), the severity of breath shortness according to the Borg scale (p=0.006), the initial distance of the 6-minute walk test (p &lt;0.001), the presence of topoisomerase I antibodies (anti-Scl-70, p=0.034), and complaints of breath shortness (p=0.043) and dysphagia (p=0.034). As a result of reverse stepwise selection of variables, three independent significant predictors were selected from the above indicators: Dysphagia, anti-Scl-70, and the initial walking distance in the 6-minute walk test. Based on these indicators, a regression formula is presented for predicting the progression of functional impairment in systemic scleroderma patients. Conclusions. X-ray-detected progression of interstitial lung disease in systemic sclerosis patients is associated with younger age and Raynaud’s phenomenon severity. To predict the decline in the systemic sclerosis patients’ functionality, it is advisable to consider the presence of dysphagia and topoisomerase I antibodies (anti-Scl-70).

Infective Endocarditis due to Unusual Pathogens Complicated with Pulmonary Thromboembolism: A Rare Occurrence in a Premature Infant

Background: Survival of low birth weight preterm neonates has increased with the availability of better neonatal care, however, the use of central lines for longer duration increases the risk of bacterial and fungal sepsis. Neonatal infective endocarditis (IE) is a rare presentation of neonatal sepsis and is often associated with complications and high mortality. Clinical Description: A 36 weeker, premature baby, hospitalized for early onset sepsis, was transferred to our hospital on day 15 of life, with an umbilical catheter in situ, with fever, respiratory distress, and persistent thrombocytopenia. Clinical examination revealed decreased oxygen saturation, crepitations in the right lung field, systolic murmur, and hepatomegaly. Management and Outcome: Baseline investigations revealed positive septic screen with thrombocytopenia with meningitis, neonatal cholestasis, and right sided consolidation on chest X ray. A two dimensional echocardiography (ECHO) revealed vegetation on the tricuspid valve, and blood culture from two sites revealed growth of Candida tropicalis and Serratia marcescens. Colistin, tigecycline, and amphotericin B therapy were initiated as per sensitivity along with low molecular weight heparin for prevention of embolization. The baby developed acute worsening in respiratory distress after 4 weeks of therapy. Repeat ECHO revealed increased size of cardiac vegetation and computed tomography of thorax with pulmonary angiography revealed pulmonary thromboembolism. Unfortunately, the baby succumbed to complications of IE. Conclusion: Invasive instrumentations such as umbilical catheterization and prolonged hospitalizations of premature newborns predispose them to develop IE, especially with unusual organisms. Such infections have a complicated course and may be fatal.

Effects of obstructive sleep apnea syndrome on clinical and instrumental indicators in obese patients

Due to the high prevalence of obstructive sleep apnea syndrome (OSAS), its diagnosis and treatment remains one of the urgent problems of medicine. Hypodiagnosis of OSAS is observed in everyday clinical practice. The early OSAS diagnosis and treatment, including the use of non‑invasive assisted ventilation of the lungs with constant positive pressure during sleep, could prevent the development and progression of cardiovascular diseases, and significantly improve the quality of life of a person.&#x0D; Objective — to assess OSAS impact on the clinical and instrumental indicators in obese patients, to establish correlation between the characteristics of cardiorespiratory sleep monitoring and indicators of carbohydrate and lipid metabolism in obese patients.&#x0D; Materials and methods. Observations involved 78 patients with I ‑ II degree obesity. According to the results of cardiorespiratory monitoring (CRM) of sleep, three groups of obese patients were formed. The first group included 26 patients with an apnea‑hypopnea index &lt;30 episodes per hour (mild OSAS degree). The second group was consisted of 26 patients with apnea/hypopnea index (AHI) over 30 episodes per hour (severe OSAS degree). The groups matched by percentage of men and women, the mean age and body mass index.&#x0D; Results. An increase in body weight and body mass index (BMI) in obese patients was associated with an increase in the number and total duration of episodes of apnea/hypopnea, AHI, as well as a decrease in blood oxygen saturation (SpO2). Parameters of waist circumference (WC), hip circumference (HC), WC/HC positively correlated with the number and duration of episodes of apnea/hypopnea, AHI, and negatively correlated with SpO2. Positive values of the Spearman r coefficient ranged from 0.23 to 0.57, negative values — from –0.26 to –0.48 (р &lt;0.05).&#x0D; Conclusions. In obese patients with OSAS, the parameters of cardiorespiratory sleep monitoring — apnea‑hypopnea index, total duration of apnea episodes, directly correlated with body mass index, waist circumference, blood pressure level, total cholesterol, blood triglycerides. An inverse correlation was found between oxygen saturation and fasting glycemia and the level of glycated hemoglobin.

Analysis of the factors of heart rate variability affected after a hypoxia tolerance test as a function of gender

Heart rate variability (HRV), the variation of time intervals between heartbeats, reflects the result of the interaction between the autonomic nervous system and the cardiovascular system. Hypoxia is a stressor that causes changes in HRV and a decrease in arterial oxygen saturation (SaO2). The aim of our study is to analyse if the time and frequency domains of HRV are affected after a hypoxia tolerance test in healthy participants as a function of gender. Material and methods: 23 healthy volunteers (11 women and 12 men) with a mean age of 23.08±2.99 performed a hypoxia tolerance test (11%, 5050 m) with the iAltitude simulator. Heart rate and SaO2 were monitored during the test and HRV frequency domain (FD) and time domain (TD) data were obtained. We analysed the five minutes before and after each session. Outcomes: Simulated altitude-induced hypoxia can cause changes in HRV in a group of healthy individuals. Statistically significant differences were also found between before and after the normobaric hypoxia test in the time-domain variables RRm, SDNN, HRm, HR STD, pNN50. In addition, in women statistically significant differences were found in RMSSD, and in the frequency-domain variables HF and LF/HF. While in males, statistically significant differences were found in SDNN. In both men and women, significant differences were observed in RRm, HRm and pNN50. Conclusion: The differences found in HRV after the hypoxia tolerance test indicate that females show a greater activation of the parasympathetic nervous system compared to males. While males showed greater sympathetic activation. Keywords: Heart rate variability, normobaric hypoxia, stress, autonomic nervous system.

Local Anesthetics with Vasoconstrictors in Hypertensive Patients Undergoing Dental Extraction Procedures: A Serial Case Report

Background: Systemic absorption of vasoconstrictors and adverse cardiac effects are reasons for not using vasoconstrictors in hypertensive patients. However, several recent studies reported that the use of local anesthetics with vasoconstrictors in hypertensive patients doesn’t cause a statistically significant increase in blood pressure and heart rate. The objective of the study is to evaluate the preoperative, intraoperative and postoperative blood pressure, heart rate and peripheral oxygen saturation in hypertensive patient who undergoing dental extraction procedures with local anesthetics with vasoconstrictors. Case presentation: We reported three serial cases of male patients (40, 45, 47 years old) undergoing radixes lower posterior tooth extracted, with blood pressures 143/88mmHg, 140/86mmHg and 142/86 mmHg. The patient underwent extraction under infiltration local anesthetics with vasoconstrictors (epinephrine). All patient’s blood pressure increased 1-3 points intraoperative and decreased again postoperative. The patient's heart rate also increased 10-25 times per minute intraoperative. The decrease in oxygen saturation (2%) only occurred in one patient, intraoperative. Conclusion: The slight hemodynamic changes in these three patients indicate that the use of local anesthetics with vasoconstrictors in hypertensive patients undergoing dental extraction procedures is relatively safe.

Two-lung ventilation with artificial pneumothorax on cerebral desaturation and early postoperative cognitive outcome: a randomized controlled trial.

The effect of two lung ventilation (TLV) with carbon dioxide artificial pneumothorax on cerebral desaturation and postoperative neurocognitive changes in elderly patients undergoing elective minimally invasive esophagectomy (MIE) is unclear. The first aim of this study was to compare the effect of TLV and one lung ventilation (OLV) on cerebral desaturation. The second aim was to assess changes in early postoperative cognitive outcomes of two ventilation methods. This prospective, randomized, controlled trial enrolled patients 65 and older scheduled for MIE. Patients were randomly assigned (1:1) to TLV group or OLV group. The primary outcome was the incidence of cerebral desaturation events (CDE). Secondary outcomes were the cumulative area under the curve of desaturation for decreases in regional cerebral oxygen saturation (rSO2) values below 20% relative to the baseline value (AUC.20) and the incidence of delayed neurocognitive recovery. Fifty-six patients were recruited between November 2019 and August 2020. TLV group had a lower incidence of CDE than OLV group [3 (10.71%) vs. 13 (48.14%), P = 0.002]. TLV group had a lower AUC.20 [0 (0-35.86) % min vs. 0 (0-0) % min, P = 0.007], and the incidence of delayed neurocognitive recovery [2 (7.4%) vs. 11 (40.7%), P = 0.009] than OLV group. Predictors of delayed neurocognitive recovery on postoperative day 7 were age (OR 1.676, 95% CI 1.122 to 2.505, P = 0.006) and AUC.20 (OR 1.059, 95% CI 1.025 to 1.094, P < 0.001). Compared to OLV, TLV had a lower incidence of CDE and delayed neurocognitive recovery in elderly patients undergoing MIE. The method of TLV combined with carbon dioxide artificial pneumothorax may be an option for these elderly patients. Chinese Clinical Trial Registry (identifier: ChiCTR1900027454).

Abstract 4164: Hybrid photoacoustic imaging and fast ultrasound localization microscopy to probe the tumor microenvironment

Abstract Photoacoustic (PA) imaging can map the physiological conditions of tissues and track the biodistribution of contrast agents. Ultrasound localization microscopy (ULM) with microbubbles provides deep-tissue super-resolution blood vessel images and blood velocity maps. The integration of these techniques offers a potential tool for oncological applications, such as visualizing tumor hypoxia and vasculature. Additionally, because PA imaging and ULM can share the same ultrasound detector and data-acquisition system, PA images can seamlessly fuse with ULM images without requiring post co-registration processing. However, the acquisition time of ULM is considerably longer (several minutes per frame) compared to PA imaging (10 milliseconds to 100 milliseconds per frame), limiting the simultaneous acquisition of the two imaging modalities. To address this issue, we developed a deep learning model based on U-Net to accelerate the frame rate of ULM using information from sparse microbubble locations and power Doppler images. By enabling fast ULM acquisition, we developed an interleaved PA/fast ULM imaging technique to simultaneously capture photoacoustic and ULM images. Our experiments demonstrated up to a 16 times improvement in acquisition speed with U-Net, utilizing in vivo mouse brain and skin tumor data. The hybrid imaging sequence achieved super-resolution vascular and tissue oxygenation imaging with less than 2 seconds of acquisition time per frame in vivo. The implementation of this rapid dual imaging scheme enables the longitudinal monitoring of 3D tumor microvasculature and hypoxia conditions using a common linear ultrasound transducer. We monitored tumor growth of epidermoid carcinoma (A431) in a mouse model from Day 7 to Day 17 of tumor implantation, and the results reveal a significant decrease in tumor vasculature density and oxygen saturation as the tumor grew larger over time. The results indicate a positive relationship between oxygen saturation and vessel density. Our findings showcase the potential of this innovative technique for advancing deep tissue, high-resolution, multi-biological parameters imaging in oncological research. Citation Format: Shensheng Zhao, Sayantani Basu, Roy H. Campbell, Yang Zhao, Yun-Sheng Chen. Hybrid photoacoustic imaging and fast ultrasound localization microscopy to probe the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4164.

Substantiation of the possibility of using bronchoalveolar lavage with perfluorocarbon fluids for the treatment of the alveolar stage of toxic pulmonary edema

Introduction. Toxic pulmonary edema is an acute syndrome characterized by the accumulation of fluid in the extravascular spaces of the lungs, impaired gas exchange, the formation of tissue hypoxia and acidosis, which can occur in acute inhalation poisoning with pulmonary toxicants at work. Existing methods of drug and respiratory therapy are ineffective in the development of alveolar pulmonary edema (end-stage acute respiratory distress syndrome; ARDS). In this regard, the search for new approaches to the treatment of this condition, which is characterized by almost 100 % mortality, is of great practical importance. One of such approaches is the use of perfluorocarbon (PFC) fluids, which, due to their unique physical and chemical properties, are able not only to ensure the evacuation of edematous fluid from the alveoli and respiratory tract, but also to restore gas exchange in the parts of the lungs filled with them. This article will present an experimental evaluation of the use of PFC fluids in a model of the alveolar stage of toxic pulmonary edema.&#x0D; The goal of the study is to determine the effect of bronchoalveolar lavage (BAL) using perfluorocarbons on the indicators of acute respiratory failure and the outcome of the alveolar stage of toxic pulmonary edema.&#x0D; Materials and methods. The study was carried out on male Wistar rats aged 4 months, weighing 180–230 g. Toxic pulmonary edema was initiated by endotracheal injection of 0.1 M HCl solution. Anesthetized rats were intubated with a cannula, then intratracheally injected with 0.1 M HCl solution at a dose of 2 ml/kg and connected to a ventilator. After that, the animals were randomized by weight into groups of 6 individuals each. Animals of the experimental group with a decrease in saturation below 80%, 2–6 procedures of bronchoalveolar lavage (BAL) with PFC-oxygenated liquid in a single dose of 2.0 ml/kg were performed. Heart rate, oxygen saturation, duration of survival, and overall survival by group were recorded.&#x0D; The resalts. In all rats, there was a decrease in oxygen saturation (SpO2) and heart rate (HR) after HCl administration, which was restored to the lower limits of normal within 5 minutes. However, after 25 to 30 minutes, the animals experienced a rapid decrease in SpO2, an increase in heart rate, the appearance of wet wheezing in the lungs, and the discharge of foamy fluid from the catheter. Against this background, there was a rapid death of animals, At the same time, the average duration of survival was 30.6±3.3 min. In turn, in the animals of the experimental group, after each BAL procedure, an increase in saturation was noted, it was possible to evacuate a total of 9.1±0.8 ml/kg of edematous fluid from the lungs. It was also noted that the average duration of survival of rats in the experimental group was 1.69 times and amounted to 51.6±3.8 minutes.&#x0D; Conclusions. The use of BAL with PFC fluids in the alveolar stage of toxic pulmonary edema makes it possible to evacuate a significant amount of edematous fluid from the lower parts of the lungs due to its displacement by a perfluorocarbon with a higher density; to short-term reduce the severity of manifestations of acute respiratory failure after instillation of oxygenated PFC liquid; to increase the duration of survival of animals by ensuring gas exchange in previously uninvolved parts of the lungs.&#x0D; Ethics. The study was conducted in accordance with the ethical principles of the Declaration of Helsinki. The Clinical Study Protocol was reviewed at a meeting of the local Ethics Committee FSBSI IRIOH. Protocol No. 4 of May 25, 2022.

COVID-19 vaccines breakthrough infection and adverse reactions in medical students: a nationwide survey in Iran.

There are different types of COVID-19 vaccines approved worldwide. Since no national studies focus on vaccine-related adverse reactions and breakthrough cases, this study aimed to investigate the rate of adverse events and COVID-19 infection in medical students in Iran. This retrospective cohort study included Iranian medical students who received two doses of COVID-19 vaccines. The medical team gathered the demographic characteristics, comorbidities, type of vaccine, adverse events following vaccination, and history of COVID-19 infection data through a phone interview. The frequency of adverse events and breakthrough infection was stratified by vaccine type (ChAdOx1-S, Gam-COVID-Vac, and BIBP-CorV). A total of 3,591 medical students enrolled in this study, of which 57.02% were females, with a mean age of 23.31 + 4.87. A PCR-confirmed and suspicious-for-COVID-19 breakthrough infection rate of 4.51 and 7.02% was detected, respectively. There was no significant relation between breakthrough infection and gender, BMI, blood groups, and comorbidities. However, there was a significant difference in breakthrough infection rate among different types of vaccines (p = 0.001) and history of COVID-19 infection (p = 0.001). A total of 16 participants were hospitalized due to COVID-19 infection after vaccination for reasons such as dyspnea, abnormal imaging, or decreased oxygen saturation. No severe infection or death was observed in the studied population. Vaccination prevented severe COVID-19 infection, although a high breakthrough infection rate was evident among Iranian medical students during the Delta variant's peak. Vaccine effectiveness may be fragile during emerging new variants and in high-exposure settings. Moreover, adverse events are rare, and the benefits of vaccination outweigh the side effects. However, many limitations challenged this study, and the results should be cautious.