Arterial Blood Gas Research Articles

ASIC1a regulates airway epithelial cell pyroptosis in acute lung injury by NLRP3-Caspase1-GSDMD pathway.

Acidosis is the most common complication that seriously affects the prognosis of acute respiratory distress syndrome (ARDS). Acid-sensitive ion channel 1a (ASIC1a) is activated in acidic environments to regulate inflammatory process. However, the role of ASIC1a in ARDS is unclear. In this study, we examined the expression of ASIC1a in airway epithelial cells in an acidic environment. We then investigated whether blocking ASIC1a could inhibit pyroptosis of airway epithelial cells and the molecular mechanism. In the mouse acute lung injury (ALI) model, we observed the changes of lung histopathology, arterial blood gas and pyroptosis related indexes after ASIC1a inhibition. Bronchoalveolar lavage fluid (BALF) from patients with ARDS were collected to explore the expression level of ASIC1a in ARDS patients. Inhibiting ASIC1a can reduce the airway epithelial cell pyroptosis induced by an extracellular acidic environment. ASIC1a can bind to PRKACA, and silencing ASIC1a and PRKACA can inhibit the occurrence of pyroptosis in airway epithelial cells. Compared with control group, arterial blood pH and PaO2 in ALI group were significantly reduced. The inflammation in the lungs is more intense, and the mRNA and protein of NLRP3, Caspase1 and GSDMD were increased, while ASIC1a specific blocker psalmotoxin-1 alleviated this phenomenon. The expression of ASIC1a in BALF of ARDS patients was significantly increased, especially in non-survival group. Acidic micro-environment can induce the increased expression of ASIC1a, and inhibition of ASIC1a can alleviate the inflammation and airway epithelial cell pyroptosis in ARDS. ASIC1a may be a new target for the treatment of ARDS.

Inverse linear association between blood haemoglobin and oxygen saturation accuracy measured by pulse oximetry: a cross-sectional analysis in individuals with COVID-19 infection

BackgroundPulse oximetry measures oxygen saturation non-invasively by using differential absorption of infrared signals which are dependent on the oxyhaemoglobin:deoxyhaemoglobin ratio. We tested the hypothesis that pulse oximetry error in measurements...

Effect of high-frequency oscillatory ventilation with intermittent sigh breaths on carbon dioxide levels in neonates.

High-frequency oscillatory ventilation (HFOV) minimizes ventilator-induced lung injuries. Spontaneous sigh breathing may augment the functional residual capacity, increase lung compliance, and recruit atelectatic alveoli. To evaluate the difference in the partial pressure of carbon dioxide (PaCO2) in neonates receiving invasive HFOV as the primary mode of respiratory support before versus after sigh breaths (Sighs). This prospective study was conducted between January and December 2023. Intubated preterm and term neonates who underwent HFOV with an available arterial line were enrolled in this study after informed parental consent was obtained. Sighs were set at a frequency of 3 breaths/min and pressure of 5 cm H2O above the mean airway pressure for 2 hours. Arterial blood gas was collected before and after Sighs and analyzed using two dependent tests. Thirty neonates with a mean gestational age of 33.6±4.1 weeks and median date of intervention of 1.88 (interquartile range, 0.87-3.79) days were enrolled. The mean PaCO2 level was significantly lower in the HFOV with Sighs group (45.2±6.6 mm Hg) versus the HFOV alone group (48.8±3.1 mm Hg) with a mean difference (MD) of -3.6 mm Hg (95% confidence interval [CI], -6.3 to -0.9; P=0.01). Subgroup analyses indicated the ability of Sighs to reduce the PaCO2 level in neonates with respiratory distress syndrome (n=15; MD [95% CI] = -4.2 [-8.2 to -0.2] mm Hg; P=0.04).

Dyspnea in COVID-associated lung disease

Introduction. Covid-associated lung disease has become one of the leading problems of the COVID-19 pandemic, and early diagnosis of complications is complicated. Assessment of dyspnoea as a significant symptom is important, but its diagnostic ability in this lesion is poorly understood.Aim. To study the features of dyspnoea in COVID-19-associated lung lesions and its diagnostic value.Materials and methods. The study included 134 patients with COVID-19-confirmed pneumonia. Demographic and anthropometric data, subjective condition, dyspnoea severity according to Borg scale, concomitant pathologies, multispiral computed tomography (MSCT) data, arterial blood gas composition, capnometry and spirometry data, as well as disease outcomes (transfer to ICU, support ventilation, fatal outcome) were analysed.Results. Dyspnoea was present in 43.3% of patients. Increased dyspnoea was associated with increased C-reactive protein (CRP), D-dimer, lung tissue damage (MSCT), decreased forced vital capacity (FVC), and increased alveolar-arterial gradient (P(A-a)O2). Dyspnoea correlated with duration of hospitalisation and need for oxygen therapy (OR = 1.307, p = 0.008). 57.4% of patients with hypoxaemia did not complain of dyspnoea, but their outcomes did not differ between patients with dyspnoea and hypoxaemia. 32.2% of patients without hypoxaemia complained of dyspnoea. These patients did not have a significant increase in FGEF by the time of discharge, and it remained lower than in patients without dyspnoea and hypoxaemia.Conclusion. Dyspnoea in COVID-19-associated lung disease is an important symptom correlating with clinical-functional, instrumental and laboratory characteristics of the disease. Comprehensive data analysis is necessary to identify patients requiring further observation.

Abstract Su901: Association of Hemoglobin and Partial Pressure of Oxygen in Arterial Blood on Survival and Neurologic Outcomes in In-Hospital Cardiac Arrest Patients

Background: Lower hemoglobin levels have been associated with poor outcomes in patients with out-of-hospital cardiac arrests. Pre-arrest hemoglobin (within 24 hours) and its association with outcomes and PaO2 in in-hospital cardiac arrest (IHCA) remains unknown. We aimed to evaluate the association of pre-arrest hemoglobin levels with survival and neurologic outcomes, and intra-arrest PaO2 levels in adults with IHCA. Methods: The study population included adults with IHCA undergoing resuscitation at an academic tertiary medical center from 2011-2019. Hemoglobin levels were obtained within 24 hours prior to arrest, and PaO2 levels were obtained intra-arrest via arterial blood gas samples. Patients were classified based upon three pre-arrest hemoglobin (Hgb) levels: Hgb < 8.5, Hgb 8.5-10.5, Hgb > 10.5. Return of spontaneous circulation (ROSC), survival to discharge, favorable neurological outcome (defined as a Glasgow Outcome Score of 4-5), and association with PaO2 served as outcomes of interest. Results: Of the 799 patients studied, 493 patients had pre-arrest hemoglobin data and 164 had intra-arrest PaO2 data. Of those patients that had pre-arrest hemoglobin data, 145 (29.4%) had Hgb < 8.5, 178 (36.1%) had Hgb 8.5-10.5, 170 (34.5%) had Hgb >10.5. Charlson Comorbidity Score was similar across each hemoglobin group. Most patients had PEA/Asystole as the initial rhythm at onset of cardiac arrest, and the number was similar across each hemoglobin group. Mean intra-arrest PaO2 was higher in the Hgb < 8.5 group. Compared to Hgb < 8.5, higher hemoglobin levels were associated with higher rates of ROSC in both univariate (Hgb < 8.5: 46.9% vs. Hgb 8.5-10.5: 59.6% vs. Hgb > 10.5: 62.9%, p = 0.012) and multivariate (Hgb 8.5-10.5: OR 1.51, 95% CI 0.96-2.39; Hgb > 10.5: OR 1.75, 95% CI 1.10-2.79) analyses. Higher hemoglobin levels were associated with higher rates of favorable neurologic outcome in the univariate analysis only (Hgb < 8.5: 10.5% vs. Hgb 8.5-10.5: 11.8% vs. Hgb > 10.5: 19.4%, p = 0.043). There was no significant correlation between pre-arrest hemoglobin and intra-arrest PaO2. Conclusions: In this contemporary registry of adults with IHCA, higher hemoglobin values were associated with higher rates of ROSC. There may be an association between higher hemoglobin levels and favorable neurologic outcome. There was no association between pre-arrest hemoglobin and intra-arrest PaO2.

May the indication for a previous cesarean section affect the outcome at trial of labor in women with induction of labor? Aretrospective cohort study.

Cesarean sections are increasing worldwide and are associated with altered risks of complications for both mother and child. Vaginal birth after cesarean section is associated with lower maternal and neonatal morbidity than in repeat cesarean section. Only a few studies have considered the indication for the previous cesarean section to be of importance for the outcome of subsequent labor. The aim of this study was to evaluate whether the indication for a previous cesarean section affects the outcomes at a subsequent delivery in women with induction of labor. This retrospective cohort study of the four largest delivery units in Stockholm during 2012-2015 included 1150 women with one previous cesarean section with induction of labor. women with induced labor and a previous cesarean section, singleton pregnancy, cephalic presentation, gestational age of ≥34 weeks. The women were grouped by indication for the previous cesarean section. mode of delivery (vaginal birth after previous cesarean section or repeat cesarean section). induction to delivery time, postpartum hemorrhage, uterine rupture. Neonatal outcomes: birth weight, Apgar score <7, arterial umbilical cord blood gas pH <7.0. Our study found that the indication of labor dystocia at the previous cesarean section, increased the risk of repeat cesarean section (aOR 5.35; 95% CI: 1.64-17.50) in women with induction of labor. Other risk factors for repeat cesarean section were birth weight >4000 g, maternal BMI ≥30 or if vaginal prostaglandin was used as the method for induction of labor. A previous vaginal delivery and use of oxytocin increased the chance of a vaginal delivery in this group of women. Our study showed that the indication for the previous cesarean section affects the outcome in the subsequent delivery in women with induction of labor. If the indication for the previous cesarean section was labor dystocia, the risk of repeat cesarean section was increased.

Ginsenoside Rg1 Prevents and Treats Acute Pulmonary Injury Induced by High-Altitude Hypoxia

This study aimed to investigate the protective effects of ginsenoside Rg1 on high-altitude hypoxia-induced acute lung injury (ALI) and elucidated its molecular targets and related pathways, specifically its association with the fluid shear stress pathway. Using a combination of bioinformatics analysis and both in vivo and in vitro experiments, we assessed the role of ginsenoside Rg1 in mitigating physiological and biochemical disturbances induced by hypoxia. In the in vivo experiments, we measured arterial blood gas parameters, levels of inflammatory cells and cytokines, erythrocyte and platelet parameters, and conducted histological analysis in rats. The in vitro experiments utilized human pulmonary microvascular endothelial cells (HPMECs) and A549 cells to examine cell viability, intracellular reactive oxygen species (ROS) and Ca2⁺ levels, and mitochondrial function. The results of the in vivo experiments demonstrate that ginsenoside Rg1 significantly increased arterial blood oxygen partial pressure and saturation, elevated arterial blood glucose levels, and stabilized respiratory and metabolic functions in rats. It also reduced inflammatory cells and cytokines, such as tumor necrosis factor-α and interleukin-6, and improved erythrocyte and platelet abnormalities, supporting its protective role through the regulation of the fluid shear stress pathway. Histological and ultrastructural analyses revealed that Rg1 significantly protected lung tissue structure and organelles. In vitro experiments further confirmed that Rg1 improved cell viability in HPMEC and A549 cells under hypoxic conditions, decreased intracellular ROS and Ca2⁺ levels, and enhanced mitochondrial function. These findings collectively demonstrate that ginsenoside Rg1 exerts significant protective effects against high-altitude hypoxia-induced ALI by enhancing oxygen delivery and utilization, reducing inflammatory responses, and maintaining cellular metabolism and vascular function. Notably, the protective effects of Rg1 are closely associated with the regulation of the fluid shear stress pathway, suggesting its potential for treating high-altitude hypoxia-related diseases.

Predictors of Post-operative ABG Changes to Pre-operative Levels in Kidney Transplant Patients, a Cross-Sectional Study

Background: Kidney transplant is the treatment of choice for chronic renal failure (CRF), significantly improving patient outcomes. Fluid administration during surgery can lead to the accumulation of acid ions and electrolytes, inducing pH changes from the pre-operative to post-operative period, which may compromise transplant success. The impact of acid-base balance changes on transplant outcomes is crucial, yet research on predictors and arterial blood gas (ABG) changes post-kidney transplant is limited. Understanding ABG changes can enhance perioperative management, early detection of complications, and long-term graft function, thereby optimizing patient care and increasing transplant success rates. Objectives: To assess ABG changes before and after kidney transplant and identify predictors of post-operative acidosis in patients with renal failure through cross-sectional studies. Methods: In a retrospective cohort study, we included 97 patients who had undergone kidney transplant. During surgery, patients received crystalloid fluids, with 49 receiving only normal saline and 48 receiving only Ringer's lactate. Data collection involved the insertion of an arterial line after anesthesia induction, and the first ABG sample was obtained as a pre-operative measure. A post-operative measure was taken at the end of the surgery. Ethical considerations were followed throughout the study. Statistical analysis included paired t-test or Wilcoxon signed-rank test to compare pre- and post-operative ABG measures, with a significance level set at a P-value less than 0.05. Results: Total of 97 patients, which 65 (69.4%) were male and 32 (30.6%) were female and mean age was 38.6 ± 12.2. Variables significantly associated with post-op acidosis were fluid administered (OR: 3.25, 95% CI: 1.45 - 4.58), post-op central venous pressure (CVP) (OR: 2.31, 95% CI: 1.23 - 2.62, p &lt; 0.05), post-op base excess (BE) (OR: 2.16, 95% CI: 1.50 - 2.95, P &lt; 0.05). HCO₃ (P = 0.010), BE (P = 0.002), pH (P = 0.023) were significantly lower in the normal saline group compared to the Ringer's group. Post-op pH and BE was also associated with increased post-op CVP. Post-op acidosis and post-op CVP were significantly associated with post-op BE. Conclusions: Post-operative ABG changes, including decreases in pH and HCO3, are key indicators of transplant outcomes, reflecting graft function and patient stability. These findings highlight the critical need for prompt management of ABG abnormalities to optimize transplant success and minimize complications, making vigilant monitoring a vital part of post-transplant care.

TOXIC ALCOHOL POISONING: A CASE REPORT

During the COVID-19 pandemic, toxic alcohol poisoning, notably from methanol, has emerged as a significant concern due to increased consumption of illicit liquor amidst lockdown restrictions. We present a case of a middle-aged man who developed altered consciousness, metabolic acidosis, and shock two days after ingesting hospital spirit. Although initial qualitative tests only detected ethanol, subsequent MRI findings showed classical signs of methanol poisoning, including basal ganglia abnormalities. Prompt management with dialysis, ventilatory support, and adjunctive therapy successfully addressed the acute phase despite the patient remaining delirious for seven days. This case underscores the importance of considering methanol toxicity even in the absence of direct evidence, necessitating comprehensive diagnostic approaches. Awareness and incorporating point-of-care assessments such as arterial blood gas analysis and osmolar gap evaluation in suspected cases are crucial, especially in resource-limited settings. Recognizing unexplained high anion gap metabolic acidosis with a high osmolar gap and characteristic MRI findings can aid in the early diagnosis and management of toxic alcohol poisoning

Impact of intravenous infusion of lidocaine on intrapulmonary shunt and postoperative cognitive function in patients undergoing one-lung ventilation.

Intravenous infusion of lidocaine as an anesthesia adjuvant can improve patient outcomes, but its impact on intrapulmonary shunt during one-lung ventilation (OLV) has not been clarified. To determine the effect of intravenous lidocaine infusion on intrapulmonary shunt during OLV and postoperative cognitive function in video-assisted thoracoscopic surgery (VATS). Sixty patients who underwent OLV for thoracic surgery were randomized to receive intravenous infusion of lidocaine (lidocaine group, n = 30) or normal saline (control group, n = 30) for anesthesia induction. Arterial and venous blood gases were measured during two-lung ventilation and at 15 and 30 min after OLV (OLV + 15 and OLV + 30). The Mini-Mental State Examination was administered before the surgery and at postoperative 12 months to assess patient cognitive function. No significant difference was found in intrapulmonary shunt fraction (Qs/Qt) between the lidocaine group and the control group at OLV + 15 (p = 0.493) and OLV + 30 (p = 0.754). The lidocaine group used significantly lower doses of propofol and remifentanil compared to the control group (both p < 0.001). Furthermore, no significant difference was observed in the incidence of postoperative cognitive dysfunction between the lidocaine group and the control group at 1 year post-operation (3.3% vs 6.7%, p = 0.554). Intravenous lidocaine administered in VATS had no significant impact on intrapulmonary shunt during OLV or postoperative cognitive function. However, it significantly reduced the doses of anesthetics used during the surgery.

An Unusual Case of Alarming Lactic Acidosis: Brain Metabolic Cross-Talk

AbstractA 39-year-old male with a BMI of 30.8 kg/m2 and a normal medical history underwent excision of a left orbito-cavernal hemangioma (4 × 2 × 2 cm) under general anesthesia. Balanced anesthesia and fluid management guided by pulse pressure variation (kept below 12%) were employed. Despite stable hemodynamics and normal blood sugar levels, arterial blood gas (ABG) analysis revealed a progressive rise in lactate levels, reaching 10.6 mmol/L, accompanied by acidemia. Systemic hypoperfusion was ruled out by maintaining mean arterial pressure between 70-80 mm Hg, ensuring a capillary refill time of less than 3 seconds, and confirming a central venous oxygen saturation of 72%. With a total blood loss of 800 mL, one unit of packed red blood cells was transfused due to concerns about decreased microcirculation and tissue hypoxia. After 10 hours of surgery, sodium bicarbonate (NaHCO3) was administered to mitigate metabolic acidosis and its potential impact on intracranial pressure. Postoperatively, lactate levels remained elevated (8-9 mmol/L), but with continued NaHCO3 infusion, lactate reduced to 6.4 mmol/L, allowing extubation. The patient's lactate normalized by the evening, and recovery was uneventful. This case highlights the significant metabolic disturbances, particularly lactic acidosis, that can arise during brain tumor surgery due to prolonged operative times, large tumor size, higher BMI, and stress-induced metabolic derangements. Awareness and prompt management of these disturbances are crucial for successful patient outcomes.

Respiratory Dysfunction and Abnormal Hypoxic Ventilatory Response in Mild to Moderate Parkinson's Disease.

Respiratory dysfunction is an important contributor to morbidity and mortality in advanced Parkinson's disease (PD), but it is unclear what parameters are sensitive to diagnose and monitor respiratory dysfunction across disease phases. We aimed to characterize respiratory dysfunction in mild to moderate PD. In 20 individuals without cardiopulmonary comorbidity, pulmonary and inspiratory muscle function testing were performed ON-medication. Subsequently, the acute ventilatory response to hypoxia (HVR) was assessed by gradually decreasing FIO2 from 0.209 (room air) to 0.127, which was compared to eight age- and sex-matched healthy controls under arterial blood gas monitoring. Lastly, on different days, the same 20 individuals with PD underwent six blinded exposures to 45-min normobaric hypoxia at FiO2 0.163 and 0.127 or placebo OFF-medication to assess breathing responses. At rest, individuals with greatest PD severity had a lower tidal volume (pairwise comparisons: 0.59 vs. 0.74, P = 0.038-0.050) and tended to have a higher breathing frequency (17.7 vs. 14.4, P = 0.076), despite normal pulmonary function. A 45-min exposure to hypoxia induced a significantly lower acute HVR in individuals with PD compared to controls (-0.0489 vs. 0.133 L.min/%, P = 0.0038). Acute HVR was reduced regardless of disease severity. Subacute HVR in individuals with milder disease tended to be higher compared to those with more advanced disease (P = 0.079). Respiratory dysfunction is present in individuals with PD, including those with relatively mild disease severity, and is characterized by altered breathing patterns at rest, as well as a lower HVR, despite normal pulmonary and inspiratory muscle function testing.

Pre-emptive use of glucose 5% as the standard drug solvent reduces hypernatremia in critically ill patients

Abstract Background Hypernatremia presents a common complication in ICU patients, associated with increased mortality and length of stay. This study investigates the effect of sodium chloride 0.9% compared with glucose 5% solution as the standard intravenous drug diluent on the prevalence of hypernatremia in a medical ICU. Methods This is a retrospective before-and-after study comparing two consecutive patient groups before- and after the standard drug solvent was changed from sodium chloride 0.9% to glucose 5% solution for compatible medications. A total of 265 adult COVID-19 patients admitted between October 2020 and March 2021 to the study intensive care unit were included, with 161 patients in the timeframe when sodium chloride 0.9% was employed as the standard drug solvent and 104 patients when glucose 5% was used. Routine sodium measurements from arterial and venous blood gases, along with heparinized lithium plasma, were analyzed. The daily sodium concentrations and the prevalence of severe hypernatremia (&amp;gt;150 mmol/l) were assessed during the first 8 days after ICU admission. Results Baseline characteristics were similar between the two groups. The cumulative volume of intravenous drug diluents was comparable. In the glucose 5% group, about half of the total drug diluent volume was glucose 5% (mean [SD]: 2251.6 [2355.4] mL), compared to 135.0 [746.9] mL (p &amp;lt; 0.001) in the control group. Average sodium concentrations diverged after day two, with the glucose 5% group consistently showing lower sodium levels (mean difference of approximately 2.5 mmol/L). Severe hypernatremia occurred less frequently in the glucose 5% group (6.6% vs. 20%). Conclusion Glucose 5% solution as the standard intravenous drug solvent significantly reduced sodium concentrations and the occurrence of severe hypernatremia. This simple modification in solvent choice may serve as a preventive strategy against hypernatremia in the ICU. Further prospective research is necessary to determine associated clinical outcomes. Trial registration: The trial was registered in the German Clinical Trials Register (DRKS00031877).

Transvenous phrenic nerve stimulation reduces diaphragm injury during controlled mechanical ventilation in a preclinical model of ARDS.

Patients with acute respiratory distress syndrome (ARDS) require periods of deep sedation and mechanical ventilation, leading to diaphragm dysfunction. Our study seeks to determine whether the combination of temporary transvenous diaphragm neurostimulation (TTDN) and mechanical ventilation changes the degree of diaphragm injury and cytokines concentration in a preclinical ARDS model. Moderate ARDS was induced in pigs using oleic acid, followed by ventilation for 12 h post-injury with volume-control at 8 mL/kg, positive end-expiratory pressure (PEEP) 5 cmH2O, respiratory rate and [Formula: see text] set to achieve normal arterial blood gases. Two groups received TTDN: every second breath (MV + TTDN50%, n = 6) or every breath (MV + TTDN100%, n = 6). One group received ventilation only (MV, n = 6). Full-thickness diaphragm and quadricep muscle biopsies were taken at study end. Samples were fixed and stained with hematoxylin and eosin and a point-counting technique was applied to calculate abnormal muscle area fraction. Cytokine concentrations were measured in homogenized tissue using porcine-specific enzyme-linked immunosorbent assay (ELISA) and compared with serum samples. Percentage of abnormal diaphragm tissue was different between MV [8.1% (6.0-8.8)] versus MV + TTDN50% [3.4% (2.1-4.8)], P = 0.010 and MV versus MV + TTDN100% [3.1% (2.5-4.0)], P = 0.005. Percentage of abnormal quadriceps tissue was not different between groups. Cytokine concentration patterns in diaphragm samples were different between all groups (P < 0.001) and the interaction between TTDN application and resultant cytokine concentration pattern was significant (P = 0.025). TTDN, delivered in synchrony with mechanical ventilation, mitigated diaphragm injury, as evidenced by less abnormal tissue in the diaphragm samples, in pigs with oleic acid-induced ARDS and is an exciting tool for lung and diaphragm-protective ventilation.NEW & NOTEWORTHY This study adds to our understanding of applying transvenous diaphragm neurostimulation synchronously with mechanical ventilation by examining its effects on diaphragm muscle injury and cytokine concentration patterns in pigs with acute respiratory distress syndrome (ARDS). We observed that using this therapy for 12 h post lung injury mitigated ventilator-induced diaphragm injury and changed the pattern of cytokine concentration measured in diaphragm tissue. These findings suggest that transvenous diaphragm neurostimulation is an exciting tool for lung and diaphragm protective ventilation.

Arterial blood gases in SCUBA divers at depth

BackgroundCurrent diving physiology postulates that SCUBA divers’ arterial blood gas (ABG) levels vary proportionally to environmental pressure, but, to date, ABGs have only been obtained during simulated dives. Also, recent evidence supports the use of the arterial/alveolar (a:A) partial pressures of oxygen (PO2) ratio to predict the arterial PO2 (PaO2) under hyperbaric conditions from measurements obtained at 1 atmosphere absolute (ATA). This work summarizes ABGs obtained in SCUBA divers in real underwater conditions and aims to validate the a:A ratio in predicting PaO2 in this subset of individuals at depth.MethodsThe study was approved by the local ethics committee. After cannulating the radial artery of the non-dominant limb, ABGs were sampled at the surface before the dive (A), at depth (15 meters of freshwater (mfw) or 42 mfw) before (B) and after (C) pedaling on a submersed bicycle for 10 minutes, and back at surface (D). After calculating the surface alveolar PO2 for each subject, the a:A ratio was obtained and used to predict PaO2 at depth. A linear regression between measured and predicted PaO2 was reported, along with the goodness-of-fit F test.ResultsSix subjects performed the dive at 15 mfw, and four others at 42 mfw. The PaO2 proportionally increased at both depths, remaining stable before and after pedaling. The a:A calculated from the baseline ABG obtained at rest, out of the water, adequately predicted the PaO2 at depth (R2 = 0.97, p&amp;lt;0.001), better at 15 mfw but losing accuracy at 42 mfw.ConclusionsThe ABGs confirmed the proportional rise of PaO2 in SCUBA divers underwater. The a:A ratio could be used to predict the magnitude of PaO2 rise at depth to limit exposure to hyperoxia, especially in repetitive recreational dives and professional divers.

Clinical evaluation of serum miR-513a-3p combined with arterial blood gas analysis parameters and lung ultrasound score in neonatal respiratory distress syndrome

BackgroundNeonatal respiratory distress syndrome (NRDS) is harmful to neonates and the prognosis is variable, ranging from mild to severe forms. This study aims to evaluate the clinical utility of miR-513a-3p in conjunction with arterial blood gas analysis parameters and lung ultrasound (LUS) score in the context of NRDS.MethodsThe study included 169 preterm infants, including 106 newborns with NRDS and 63 newborns without NRDS. The relative expression level of miR-513a-3p was detected by quantitative real time polymerase chain reaction (qRT-PCR). Umbilical artery blood gas parameter values and LUS score were recorded, and the clinical significance of miR-513a-3p, umbilical artery blood gas parameter and LUS score in NRDS were evaluated by Receiver Operating Characteristic (ROC) analysis.ResultsElevated levels of miR-513a-3p were detected in the serum of NRDS, and higher expression of miR-513a-3p was observed in individuals with poor prognosis. Notably, miR-513a-3p exhibited a significant correlation with the parameters of arterial blood gas analysis and LUS score in NRDS patients. Furthermore, miR-513a-3p was one of the risk factors for poor prognosis in NRDS patients. miR-513a-3p levels combined with umbilical artery blood gas parameters and LUS score has diagnostic value for NRDS and is reliable for its prognosis.ConclusionsElevated levels of miR-513a-3p in neonatal serum served as a useful tool in the combined assessment with umbilical artery blood gas analysis and LUS score to diagnosis and prognosis of NRDS. Consequently, miR-513a-3p may be served as a biomarker for diagnosis and prognosis of NRDS.

High-flow nasal cannula oxygen therapy versus noninvasive ventilation for elderly chronic obstructive pulmonary disease patients after extubation: a noninferior randomized controlled trial protocol

IntroductionNoninvasive ventilation (NIV) is widely used for sequential extubation in patients with chronic obstructive pulmonary disease (COPD). However, NIV may cause many adverse events such as claustrophobia, facial skin compression, air leakage, bloating, and even reflux aspiration, resulting in poor patient compliance/tolerance and high failure rate, especially for older adults who are at high risk of communication difficulties and consciousness disorder. High-flow nasal cannula (HFNC) oxygen therapy is a new alternative support to NIV, but whether it can effectively reduce the rate of re-intubation after extubation in elderly patients with COPD remains controversial. The purpose of this study is to explore the safety and efficacy of HFNC versus NIV for elderly COPD patients after extubation.Methods and analysisThis study is an investigator-initiated, single-center, prospective, non-inferior, randomized controlled trial. Elderly patients (age > 65 years) who have received invasive ventilation and was diagnosed with COPD will be randomly assigned to HFNC group or NIV group immediately after extubation with a planned enrollment of 168 patients. The primary outcomes will be reintubation rates at 72 h and 7 days after extubation. Secondary outcomes will include treatment failure, post-extubation vital signs and arterial blood gases, the scores of compliance and comfort of patients, duration of respiratory support after extubation, respiratory support related adverse events, sleep quality scores, usage of sedative and analgesic drugs after extubation, and the incidence of delirium. Additionally, clinical outcomes such as ventilator-free days at 28 days post-randomization, tracheotomy rate, duration of intensive care unit (ICU) and hospital stay, ICU and hospital mortality will be evaluated.Ethics and disseminationThis study has been approved by the Ethics Committee of West China Hospital of Sichuan University (2023–2284). Informed consent is required. It is expected that a follow-up randomized controlled trial will be conducted. The results will be submitted for publication in a peer-reviewed journal and presented at one or more scientific conferences.Trial registrationThe study was retrospectively registered at ClinicalTrials.gov (ChiCTR2400087312).

Association between echocardiographic parameters and abnormal spirometry among chronic heart failure patients

Abstract Background A significant proportion (10-40%) of heart failure (HF) patients have concomitant pulmonary disease which have negative effects on cardiovascular outcome of patients. Because of the similarities in symptoms between HF and pulmonary disease, the prevalence of concomitant pulmonary disease may be underestimated. Early detection manage accordingly may improve outcomes of HF patients. We aimed to study clinical and echocardiographic parameters identifying HF patients with concomitant pulmonary disease. Methods This cross-sectional study included adults (age≥18 years) who were diagnosed with HF. The echocardiogram, arterial blood gas and pulmonary function test (PFT) were performed. The patients were classified into normal and abnormal (obstructive and restrictive) PFT patterns. The primary outcome was the association between echocardiographic parameters and abnormal PFT. The receiver operating characteristic (ROC) curve was performed to evaluate diagnostic performance of echocardiographic parameter in detecting abnormal PFT. Results A total of 57 patients was enrolled, of which 32 patients (56.14%) had normal PFT, 14 patients (24.56%) had obstructive PFT, and 11 patients (19.30%) had restrictive PFT. The clinical characteristics were not different between groups. ROC curve demonstrated that only left atrial volume index (LAVI) and main pulmonary artery (MPA) diameter had significant diagnostic accuracy to predict abnormal PFT with AUC of 0.72 (95%CI 0.57-0.87) and 0.66 (95%CI 0.51-0.80) respectively. Using combination of LAVI (cutoff 40mm2/m2) and MPA diameter (cutoff 22.0 mm) had a sensitivity of 95.7% (95%CI 78.05-99.89%) and specificity of 41.94% (95%CI 24.55-60.92%) in detection patients with abnormal PFT. Conclusion Almost half of HF had concomitant abnormal PFT. The combination of LAVI and MPA diameter can identify patients with abnormal PFT with high negative predictive value and should be considered as screening parameters in HF patients.

Ultrasound-guided versus palpation-guided techniques for vessel catheterization in children undergoing cardiac surgery. A systematic review and meta-analysis of randomized controlled trials

Abstract Background Pediatric heart surgery is the first treatment option for congenital heart disease, which is the leading cause of death in Children. Arterial cannulation (AC) and Central venous catheter (CVC) are required in pediatric cardiac surgery for continuous monitoring of the central venous pressure (CVP), replacement of fluid and blood products, close hemodynamic monitoring, and frequent sampling for arterial blood gases (ABG). Purpose We aim to assess the efficacy and safety of the ultra-sound guided technique compared to the traditional palpation-guided technique for vessel catheterization in children undergoing cardiac surgery. Methods A systematic review and meta-analysis synthesizing evidence from randomized controlled trials (RCTs) studies obtained from PubMed, Embase Cochrane, Scopus, and WOS until February 2024. We used the fixed-effects model to report dichotomous outcomes using risk ratio (RR) and continuous outcomes using mean difference (MD) with a 95% confidence interval (CI). Results Thirteen RCTs with 1060 children were included. Regarding arterial cannulation, ultrasound-guided technique was associated with a statistically significant increase in successful cannulation [RR: 1.31 with 95% CI (1.10, 1.56), P&amp;lt; 0.0001], and first-attempt success [RR: 1.88 with 95% CI (1.35, 2.63), P&amp;lt; 0.0001]; however, it was not associated with any statistically significant difference in venous cannulation in both outcomes with [RR: 1.13 with 95% CI (0.98, 1.30), P= 0.10], [RR: 1.53 with 95% CI (0.86, 2.71), P= 0.15] respectively. Moreover, ultrasound-guided technique was associated with a statistically significant decrease in the number of attempts either in arterial cannulation with [MD: -0.73 with 95% CI (-1.00, -0.46), P&amp;lt; 0.0001] or in venous cannulation with [MD: -1.34 with 95% CI (-2.55, -0.12), P= 0.03], and the time of attempted cannulation also either in arterial cannulation with [MD: -2.27 with 95% CI (-3.38, -1.16), P&amp;lt; 0.0001] or in venous cannulation with [MD: -4.13 with 95% CI (-7.06, -1.19), P&amp;lt; 0.0001]. Finally, ultrasound-guided technique was associated with a statistically significant decrease in the incidence of any complications either in arterial cannulation with [RR: 0.36 with 95% CI (0.18, 0.71), P&amp;lt; 0.001] or in venous cannulation with [RR: 0.30 with 95% CI (0.11, 0.84), P= 0.02]. Conclusion Ultrasound-guided arterial catheterization increases the number of successful catheterizations and first-attempt success rate; however, there was no significant difference in venous cannulation, while both arterial and venous cannulation were associated with decreased number of attempts, reduced overall procedure time, and decreased incidence of complications.

Evaluation of Dexmedetomidine with Tiletamine-Zolazepam for Snow Leopard (Panthera uncia) Immobilization.

This study describes two different doses of dexmedetomidine combined with tiletamine-zolazepam (TZ) for anesthesia in snow leopards (Panthera uncia). A total of 11 adult snow leopards were anesthetized in Xining City, Qinghai Province, China from November 2019 to June 2023. We recorded the onset time, anesthesia duration, head-up time, and walking time. Vital signs were recorded every 5 min during anesthesia. Arterial blood gas analysis was performed approximately 20 min after the onset of anesthesia by collecting blood from the femoral artery. All results were presented as mean±SD. There were no significant differences in onset time, anesthesia duration, head-up time, and walking time between the two anesthesia protocols. Heart rate, respiratory rate, body temperature, and blood pressure had a gradual decreasing trend, and blood oxygen saturation gradually increased. Our results suggest that using dexmedetomidine at doses of 21.25±1.38 μg/kg to 30.95±1.13 μg/kg combined with TZ at 2.07±0.08 mg/kg to 2.13±0.15 mg/kg can provide safe and effective anesthesia for snow leopards.