Changes In Blood Gases Research Articles

Effect of Chlordiazepoxide or Haloperidol Oral Premedication during Midazolam-Ketamine Anaesthesia on Physiological and Blood Gas Parameters in Adult Male Bonnet Macaques (Macaca radiata)

Capturing wild animals with minimal stress is crucial to reduce morbidity and mortality. Oral premedicants can ease handling and subsequent anaesthetic administration. This study evaluated anaesthetic protocols and physiological changes during vasectomy in 12 adult male Bonnet Macaques. Group I received 10 mg/kg chlordiazepoxide, and Group II received 1 mg/kg haloperidol orally four hours before midazolam-ketamine anaesthesia. Sedation quality, induction, maintenance, and recovery were assessed. Physiological and blood gas changes were monitored at 0, 5, 10, 15, and 20 minutes. Both groups exhibited sedation post-premedication. Induction, maintenance, and anaesthesia depth were similar. Group I had better analgesia, while Group II had superior muscle relaxation. Blood gas analysis indicated mild stress and respiratory acidosis in both groups, with Group II showing more significant hypoxemia and respiratory acidosis. Haloperidol-premedicated animals were easier to handle but exhibited increased stress parameters compared to chlordiazepoxide-premedicated animals. Recovery was better in Group I. Both protocols effectively induced sedation and anaesthesia in Bonnet Macaques.

Shock wave damage from the ventral side in primary blast injury: An experimental study in pigs

Aim/PurposeThis study aimed to apply a shock wave from the ventral side of a pig and examine its effect to use the results for new body armor production for humans. MethodsSeven male hybrid pigs were used. Each pig was placed under general anesthesia on the experimental table in a blast tube to expose the left lateral position from the front chest area, and shock waves generated by compressed air at 3.0 MPa were applied. We examined changes in vital signs and arterial blood gas in the hyper-acute phase and computed tomography (CT) images, and autopsies were performed for organ damage after 3 h of observation. Pathological examination was performed for lung damage, which is considered a characteristic of shock wave injury. ResultsAll seven pigs survived. Respiratory arrest occurred in two pigs; however, spontaneous breathing resumed promptly afterward. Hypotension occurred at a frequency of 4. No bradycardia or cardiac arrest was observed in any pig. In the arterial blood gas analysis before and immediately after shock wave exposure and 1 hour later, PaO2 decreased immediately but tended to improve thereafter. CT revealed pulmonary contusions and multiple bulla-like lesions on the surface of the lungs. An autopsy showed lung injury in all pigs, particularly in five cases with bulla-like lesions of various sizes on the lung surface across all lobes. Pathological findings showed visceral pleural detachment with elastic fibers from the lung parenchyma, and the cavity lesion on the lung surface comprised bullae. The degree of intra-abdominal hemorrhage varied; however, all but one case showed splenic injury. ConclusionNone of the pigs exposed to shock waves from the ventral side died; however, most showed multiple bullae on the lung surface with lung contusion and splenic injury, which may have been greater than those exposed from the dorsal side. This may be due to the direct impact of the shock wave proceeding from the epigastrium and subcostal region, which are not protected by the skeletal structure of the thorax. These characteristics should be considered when producing new body armor for humans to protect the body from shock waves.

The Effect of Opioids and Benzodiazepines on Exacerbation Rate and Overall Survival in Patients with Chronic Obstructive Pulmonary Disease on Long-Term Non-Invasive Ventilation.

Background: There is a growing concern that opioids and benzodiazepines can depress the respiratory drive and could contribute to worsening respiratory failure and higher exacerbation frequency in COPD. However, the relationship between the exacerbation rate and medication taken is poorly understood in patients with chronic respiratory failure due to COPD. Methods: As part of a service evaluation project, we analysed 339 patients with COPD who were established on long-term non-invasive ventilation (LT-NIV) at our tertiary centre. We investigated the relationship between benzodiazepine and opioid prescription and clinical outcomes as well as their impact on the exacerbation rate and overall survival following setup. Results: Before LT-NIV setup, 40 patients took benzodiazepines and 99 patients took opioids. Neither benzodiazepine nor opioid use was associated with changes in daytime blood gases, overnight hypoxia or annual exacerbations before NIV setup, but patients taking opioids were more breathless as assessed by modified Medical Research Council scores (3.91 ± 0.38 vs. 3.65 ± 0.73, p < 0.01). Long-term NIV significantly reduced the number of yearly exacerbations (from 3.0/2.0-5.0/ to 2.8/0.71-4.57/, p < 0.01) in the whole cohort, but the effect was limited in those who took benzodiazepines (from 3.0/2.0-7.0/ to 3.5/1.2-5.5/) or opioids (3.0/2.0-6.0/ to 3.0/0.8-5.5/). Benzodiazepine use was associated with reduced exacerbation-free survival and overall survival (both p < 0.05). However, after adjustment with relevant covariates, the relationship with exacerbation-free survival became insignificant (p = 0.12). Opioids were not associated with adverse outcomes. Conclusions: Benzodiazepines and opiates are commonly taken in this cohort. Whilst they do not seem to contribute to impaired gas exchange pre-setup, they, especially benzodiazepines, may limit the benefits of LT-NIV.

Temperature effects on blood gases in embryonic American alligators (Alligator mississippiensis)

Numerous studies report on the influence of temperature on blood gases in ectothermic vertebrates, but there is merely a cursory understanding of these effects in developing animals. Animals that develop in eggs are at the mercy of environmental temperature and are expected to lack the capacity to regulate gas exchange and may regulate blood gases by means of altered conductance for gas exchange. We, therefore, devised a series of studies to characterize the developmental changes in blood gases when embryonic alligators were exposed to 25, 30 and 35 °C. To determine how blood parameters were impacted by changes in embryonic temperature, blood was sampled from the chorioallantoic membrane artery. The blood in the chorioallantoic membrane artery is a mixture of oxygen-poor and oxygen-rich blood, which based on the embryonic vascular anatomy may reflect blood that perfuses the chemoreceptors of the developing animal. Our findings indicate that following a 48 h exposure to 25 °C or 35 °C, there was a positive relationship between CAM artery blood PO2, PCO2 and glucose. However, blood pH suggests embryonic alligators lack an acute regulatory mechanism for adjusting blood pH.

Changes in blood gas in supine and prone positions in percutaneous stone surgery: does position have any advantage for hemodynamics?

To evaluate whether different positions are advantageous for hemodynamics and respiratory balance in patients undergoing percutaneous nephrolithotomy (PCNL) procedures. Pre- and postoperative arterial blood gas data obtained during spontaneous breathing for 67 prone (Group 1) and 56 supine (Group 2) patients undergoing PCNL were analyzed. Additionally data on all patients' gender, age, body mass index, stone size, access and surgical duration, volume of irrigation fluid, length of hospital stay, requirement for blood transfusion, and residual stones were recorded: There were no differences between the groups in terms of age, stone size, operation time, access time, radiation exposure, transfusion requirements, stone-free rate, and length of hospitalization. A statistically significant pH decrease was observed in both groups in the postoperative period (p = 0.001 and p = 0.001, respectively). There was a statistically significant increase in pCO2 values in both groups in the postoperative period (p = 0.001 and p = 0.024, respectively), and that increase did not differ significantly between the groups (p = 0.624). A statistically significant decrease in pO2 and SpO2 values was observed in both groups in the postoperative period compared to the preoperative period. Again, no statistical difference was observed between the groups for these values. There was a statistically significant decrease in bicarbonate in both groups period (p < 0.001 and p = 0.001, respectively). Hemodynamics and the respiratory balance of the patient are impaired in both prone and supine positions. Neither position is superior to the other in this respect.

Effect of caspase inhibitors on hemodynamics and inflammatory factors in ARDS model rats

To study the effects of caspase inhibitors on hemodynamics and inflammatory factors in acute respiratory distress syndrome (ARDS) model rats. Sixty healthy male Wistar rats were randomly divided into three groups, namely, the control group, ARDS group and ARDS + Caspase inhibitor group, with 20 rats in each group. The control group was intraperitoneally injected with 2 mL/kg saline, and the ARDS model group was established by intraperitoneally injecting 4 mg/kg Lipopolysaccharide (LPS), ARDS + Caspase inhibitor group was adminstered 20 mg/kg caspase inhibitor after intraperitoneal LPS injection. Changes in pulmonary arterial pressure (PAP) and mean arterial pressure (MAP) at 6 and 12 h before and after administration were recorded. Moreover, arterial blood gas was evaluated with a blood gas analyzer and changes in the partial pressure of O2 (PaO2), partial pressure of CO2 (PaCO2), partial pressure of O2/fraction of inspired O2 (PaO2/FiO2) were evaluated. In addition, the lung wet/dry weight (W/D) ratio and inflammatory factor levels in lung tissue were determined. Finally, pathological sections were used to determine the pulmonary artery media thickness (MT), MT percentage (MT%), and the degree of muscle vascularization. The pulmonary arterial pressure of rats was determined at several time points. Compared with the control group, the model group had a significantly increased pulmonary arterial pressure at each time point (P < 0.01), and the mean arterial pressure significantly increased at 6 h (P < 0.05). Compared with that of rats in the model group, the pulmonary arterial pressure of rats in drug administration group was significantly reduced at each time point after administration (P < 0.01), and the mean arterial pressure was significantly reduced at 6 h (P < 0.05). The arterial blood gas analysis showed that compared with those in the control group, PaO2, PaCO2 and PaO2/FiO2 in the model group were significantly reduced (P < 0.01), and PaO2, PaCO2 and PaO2/FiO2 were significantly increased after caspase inhibitor treatment (P < 0.05 or 0.01). The levels of the inflammatory mediators tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) in the model group were significantly higher than those in the control group (P < 0.01), and they were significantly decreased after caspase inhibitor treatment (P < 0.01). In the model group, pulmonary artery MT, MT% and the degree of muscle vascularization were significantly increased (P < 0.05 or 0.01), and pulmonary artery MT and the degree of muscle vascularization were significantly reduced after caspase inhibitor treatment (P < 0.05 or 0.01). Apoptosis Repressor with a Caspase Recuitment Domain (ARC) can alleviate the occurrence and development of pulmonary hypertension (PH) by affecting hemodynamics and reducing inflammation.

Bronchoalveolar Lavage and Oleic Acid Two-hit Model for Inducing Acute Respiratory Distress Syndrome in Swine Models.

Acute respiratory distress syndrome (ARDS) is a widespread and often fatal clinical syndrome marked by the acute onset of pulmonary edema and inflammatory-mediated disruptions in alveolar-capillary permeability resulting in impaired gas exchange and tissue oxygenation with subsequent acute respiratory failure that accounts for 10.4% of all intensive care unit admissions worldwide and boasts a mortality rate of 38.5%. The current treatment for ARDS remains largely supportive. This is largely because of the many challenges of achieving a stable and sustainable animal model that recreates the pathophysiology of ARDS experimentally in a controlled setting to allow research to elucidate potential treatments of ARDS moving forward. The bronchoalveolar lavage and oleic acid models are currently the 2 most frequently used experimental models in inducing ARDS in animal models. This study demonstrated that combining them into a "two-hit model" can produce sustained ARDS in swine models per the Horowitz index (PaO2/FiO2 ratio of ≤300 mmHg). Additionally, expected changes in pH, pCO2, lung compliance, cytokines, and tissue histopathology were observed and add to our confidence and reliability that the "two-hit model" produces symptomatic ARDS in a manner very similar to that observed in humans. In conclusion, we demonstrated a viable animal model of human ARDS that is maintained for a prolonged period, suitable for continuous monitoring of the progression, and evaluation of potential future treatments and procedures to reduce patient morbidity and mortality. To carry out this two-hit model, lung injury was induced through a combination of bronchoalveolar lavage and oleic acid administration and the disease process of ARDS is subsequently tracked through clinically relevant parameters such as respiratory mechanics, cytokine response, aretrial blood gas (ABG) changes, and observation of postmortem histopathologic changes. This promising new model has the capacity to successfully replicate human ARDS which is a well-known and notoriously multifactorial pathogenic process to reproduce experimentally for an extended period of time. The "two-hit model" is a viable and appropriate model for the research of novel treatments for ARDS.

Differential approach to preoperative preparations for diffuse purulent peritonitis in children

BACKGROUND: Diffuse purulent peritonitis is the most severe complication of abdominal surgical pathology accompanied by the development of serious metabolic disorders, and its elimination is a preoperative task.&#x0D; AIM: This study aimed to compare traditional preoperative preparations using a new scheme that provides a differential approach considering the stage of peritonitis, degree of endotoxicosis, child’s age, and succinate administration.&#x0D; MATERIALS AND METHODS: An analysis of the results of treatment of patients aged 1–14 years (average age 7.9 ± 3.9 years) with diffuse purulent peritonitis of various etiologies who were treated from 2006 to 2022 in the children’s surgical department of the V.D. Seredavin Samara Regional Hospital, Samara. The patients were divided into two groups. The main group included 237 patients who underwent preoperative preparation according to the proposed scheme (depending on age, peritonitis stage, and degree of endotoxemia) lasting at least 4–6 h. In addition, for intracorporeal detoxification, the antihypoxant meglumine sodium succinate was used. The control group comprised 102 children who received traditional therapy according to generally accepted approaches and national guidelines for pediatric surgery lasting 2–3 h. Changes in hemodynamic parameters, electrolytes, hematocrit, platelets, and blood gases were comprehensively examined.&#x0D; RESULTS: After preoperative preparation, a statistically significant improvement in hemodynamic parameters was observed in the main group compared with that in the control group; the indicators were close to normal values. The dynamics of hematological parameters indicated more pronounced hemodilution in patients of the main group of all ages, which proves a significant improvement in the rheological properties of blood. Electrolyte and blood gas indicators did not reach the indicators of healthy children in any groups; however, in the main group, they were closer to normal. Complications of varying severity in the main group occurred in 21 children (8.8% ± 1.4%; p 0.001), whereas in the control group, they were diagnosed in 47 patients (46.0% ± 4.6%). A statistically significant reduction in the length of stay of patients in the intensive care unit after surgery was noted in 80% of children in the main group.&#x0D; CONCLUSIONS: The proposed scheme of preoperative preparation based on a differential approach using the antihypoxant meglumine sodium demonstrated greater effectiveness than traditional treatment. The composition, volume, and duration of preoperative preparation are dependent on the state of homeostasis and the age of the patient.

The Outcomes of Preterm Infants with Neonatal Respiratory Distress Syndrome Treated by Minimally Invasive Surfactant Therapy and Non-Invasive Ventilation.

In recent years, the utilization of minimally invasive surfactant therapy (MIST) and Non-invasive ventilation (NIV) as the primary respiratory assistance has become increasingly prevalent among preterm infants with neonatal respiratory distress syndrome (RDS). This study aims to compare the outcomes between MIST administered with nasal continuous positive airway pressure (NCPAP) versus nasal intermittent positive pressure ventilation (NIPPV), with the objective of exploring the respiratory therapeutic benefits of these two approaches. This retrospective study collected data from the neonatal intensive care unit of Kaohsiung Medical University Hospital spanning from January 2016 to June 2021. Infants were divided into two groups based on the type of NIV utilized. The NCPAP group comprised 32 infants, while the NIPPV group comprised 22 infants. Statistical analysis revealed significant differences: the NIPPV group had a smaller gestational age, lower birth weight, higher proportion of female infants, and earlier initiation of MIST. Additionally, the NIPPV group exhibited higher incidence rates of retinopathy of prematurity, longer respiratory support duration, prolonged hospitalization, and mortality. However, upon adjustment, these differences were not statistically significant. Analysis of venous blood gas and respiratory parameter changes indicated that both the NCPAP and NIPPV groups experienced improvements in oxygenation and ventilation following MIST.

Acid-Base Balance in Healthy Adults: Beneficial Effects of Bicarbonate and Sodium-Rich Mineral Water in a Randomized Controlled Trial: The BicarboWater Study.

Noncommunicable diseases (NCDs) are a global health challenge. The complex etiology of NCDs involves genetic, environmental, and lifestyle factors, including dietary habits. Chronic latent metabolic acidosis has been associated with an increased risk of NCDs. Alkalizing diets and mineral water consumption have shown promise in improving acid-base balance and potentially impacting NCDs. In this randomized controlled intervention study, the effect of drinking 1,500-2,000 mL of mineral water daily on acid-base balance was evaluated. Ninety-four healthy participants were divided into two groups: one consumed mineral water with a high bicarbonate and sodium content (HBS, n = 49) and the other consumed mineral water with a low bicarbonate and sodium content (LBS, n = 45). Changes in venous blood gas and urinary acid-base parameters were measured over a short-term (3 days) and long-term (28 days) intervention period. Potential renal acid load (PRAL) and nutrient intake were calculated at baseline and after 28 days. HBS water consumption led to increased urinary pH (24-hour urine and spontaneous urine, both p < 0.001) and bicarbonate levels (p < 0.001), accompanied by reduced titratable acids (p < 0.001) and ammonium (p < 0.001), resulting in a lower renal net acid excretion (p < 0.001). These changes occurred in the short term and persisted until the end of the study. LBS consumption showed no significant effects on urinary pH but led to a slight decrease in bicarbonate (p < 0.001) and NH4 + (p < 0.001), resulting in a slight decrease in NAE (p=0.011). Blood gas changes were modest in both groups. Mineral water consumption in the HBS group altered dietary intake of sodium and chloride, contributing to changes in PRAL values. The study demonstrates that the consumption of mineral water high in bicarbonate and sodium (1,500 mL-2,000 mL/day) can positively influence urinary acid-base parameters and reduce NAE, suggesting potential benefits in maintaining acid-base balance without adverse effects on human health. These findings highlight the importance of mineral water composition in acid-base regulation. This trial is registered with DRKS00025341.

The Vagus Nerve Regulates Immunometabolic Homeostasis in the Ovine Fetus near Term: The Impact on Terminal Ileum.

Glucosensing elements are widely distributed throughout the body and relay information about circulating glucose levels to the brain via the vagus nerve. However, while anatomical wiring has been established, little is known about the physiological role of the vagus nerve in glucosensing. The contribution of the vagus nerve to inflammation in the fetus is poorly understood. Increased glucose levels and inflammation act synergistically when causing organ injury, but their interplay remains incompletely understood. We hypothesized that vagotomy (Vx) will trigger a rise in systemic glucose levels and this will be enhanced during systemic and organ-specific inflammation. Efferent vagus nerve stimulation (VNS) should reverse this phenotype. Near-term fetal sheep (n = 57) were surgically prepared using vascular catheters and ECG electrodes as the control and treatment groups (lipopolysaccharide (LPS), Vx + LPS, Vx + LPS + selective efferent VNS). The experiment was started 72 h postoperatively to allow for post-surgical recovery. Inflammation was induced with LPS bolus intravenously (LPS group, 400 ng/fetus/day for 2 days; n = 23). For the Vx + LPS group (n = 11), a bilateral cervical vagotomy was performed during surgery; of these n = 5 received double the LPS dose, LPS800. The Vx + LPS + efferent VNS group (n = 8) received cervical VNS probes bilaterally distal from Vx in eight animals. Efferent VNS was administered for 20 min on days 1 and 2 +/10 min around the LPS bolus. Fetal arterial blood samples were drawn on each postoperative day of recovery (-72 h, -48 h, and -24 h) as well as at the baseline and seven selected time points (3-54 h) to profile inflammation (ELISA IL-6, pg/mL), insulin (ELISA), blood gas, and metabolism (glucose). At 54 h post-LPS, a necropsy was performed, and the terminal ileum macrophages' CD11c (M1 phenotype) immunofluorescence was quantified to detect inflammation. The results are reported for p < 0.05 and for Spearman R2 > 0.1. The results are presented as the median (IQR). Across the treatment groups, blood gas and cardiovascular changes indicated mild septicemia. At 3 h in the LPS group, IL-6 peaked. That peak was decreased in the Vx + LPS400 group and doubled in the Vx + LPS800 group. The efferent VNS sped up the reduction in the inflammatory response profile over 54 h. The M1 macrophage activity was increased in the LPS and Vx + LPS800 groups only. The glucose and insulin concentrations in the Vx + LPS group were, respectively, 1.3-fold (throughout the experiment) and 2.3-fold higher vs. control (at 3 h). The efferent VNS normalized the glucose concentrations. The complete withdrawal of vagal innervation resulted in a 72-h delayed onset of a sustained increase in glucose for at least 54 h and intermittent hyperinsulinemia. Under the conditions of moderate fetal inflammation, this was related to higher levels of gut inflammation. The efferent VNS reduced the systemic inflammatory response as well as restored both the concentrations of glucose and the degree of terminal ileum inflammation, but not the insulin concentrations. Supporting our hypothesis, these findings revealed a novel regulatory, hormetic, role of the vagus nerve in the immunometabolic response to endotoxin in near-term fetuses.

Physiological and Anesthetic Considerations of Safe and Optimal Pneumoperitoneal Pressures for Laparoscopic Surgeries in Children.

In the era of minimally invasive surgeries, pediatric laparoscopic surgeries are now becoming the standard of care. In this study, we aim to determine the safe and optimal pneumoperitoneal pressures (PPs) for laparoscopic surgery in children aged 1-5 years, along with the technical ease for the surgeon. Prospective, randomized, single-blinded study was conducted at SGPGI Lucknow. Children aged 1-5 years were randomized into Group I (n = 24): PP = 6-8 mmHg and Group II: (PP) = 9-10 mmHg. Hemodynamic, ventilatory, and blood gas changes were measured before CO2 insufflation (T0), 20 min after insufflation (T1), before desufflation (T2), and 10 min after desufflation (T3). Surgeon's technical ease of surgery, postoperative pain, the requirement of rescue analgesia, time to resume feeding, and complications were recorded and analyzed. Paired t-test, Mann-Whitney test, and Wilcoxon signed-rank test were used for nonparametric/parametric data. Chi-square/Fisher's test was used for nominal data. Partial pressure of CO2 (PaCO2) was significantly higher in Group II at T1, T2, and T3, requiring frequent changes in ventilatory settings. Postoperative pain scores were higher in Group II at 1, 6, and 12 h, requiring rescue analgesia. Surgeon's scores and hemodynamics were similar in both groups. Higher PP in Group II caused significant changes in PaCO2, end-tidal CO2, and postoperative pain requiring rescue analgesia, but blood gas changes were clinically insignificant and there were no significant changes in hemodynamic parameters. Since the surgeon's ease of performing surgery was similar in both groups, we recommend that laparoscopy in children aged 1-5 years can be started with lower PPs of 6-8 mmHg, which can be increased if needed based on the surgeon's comfort and the patient's body habitus.

Analysis of therapeutic effects on type II respiratory failure and impact on blood gas changes: high-flow nasal oxygen therapy vs. non-invasive positive pressure ventilation

Analysis of therapeutic effects on type II respiratory failure and impact on blood gas changes: high-flow nasal oxygen therapy vs. non-invasive positive pressure ventilation

Safety of Bioplasma FDP and Hemopure in rhesus macaques after 30% hemorrhage

ObjectivesPrehospital transfusion can be life-saving when transport is delayed but conventional plasma, red cells, and whole blood are often unavailable out of hospital. Shelf-stable products are needed as a temporary...

Loop gain response to increased cerebral blood flow at high altitude.

To compare loop gain (LG) before and during pharmacological increases in cerebral blood flow (CBF) at high altitude (HA). Loop gain (LG) describes stability of a negative-feedback control system; defining the magnitude of response to a disturbance, such as hyperpnea to an apnea in periodic breathing (PB). "Controller-gain" sensitivity from afferent peripheral (PCR) and central-chemoreceptors (CCR) plays a key role in perpetuating PB. Changes in CBF may have a critical role via effects on central chemo-sensitivity during sleep. Polysomnography (PSG) was performed on volunteers after administration of I.V. Acetazolamide (ACZ-10mg/kg) + Dobutamine (DOB-2-5 μg/kg/min) to increase CBF (via Duplex-ultrasound). Central sleep apnea (CSA) was measured from NREM sleep. The duty ratio (DR) was calculated as ventilatory duration (s) divided by cycle duration (s) (hyperpnea/hyperpnea + apnea), LG = 2π/(2πDR-sin2πDR). A total of 11 volunteers were studied. Compared to placebo-control, ACZ/DOB showed a significant increase in the DR (0.79 ± 0.21 vs 0.52 ± 0.03, P = 0.002) and reduction in LG (1.90 ± 0.23 vs 1.29 ± 0.35, P = 0.0004). ACZ/DOB increased cardiac output (CO) (8.19 ± 2.06 vs 6.58 ± 1.56L/min, P = 0.02) and CBF (718 ± 120 vs 526 ± 110ml/min, P < 0.001). There was no significant change in arterial blood gases, minute ventilation (VE), or hypoxic ventilatory response (HVR). However, there was a reduction of hypercapnic ventilatory response (HCVR) by 29% (5.9 ± 2.7 vs 4.2 ± 2.8 L/min, P = 0.1). Pharmacological elevation in CBF significantly reduced LG and severity of CSA. We speculate the effect was on HCVR "controller gain," rather than "plant gain," because PaCO2 and VE were unchanged. An effect via reduced circulation time is unlikely, as the respiratory-cycle length did not change.

Lung Ultrasound Elastography by SWE2D and "Fibrosis-like" Computed Tomography Signs after COVID-19 Pneumonia: A Follow-Up Study.

The aim of this study was to assess the shear wave velocity by LUS elastography (SWE2D) for the evaluation of superficial lung stiffness after COVID-19 pneumonia, according to "fibrosis-like" signs found by Computed Tomography (CT), considering the respiratory function. Seventy-nine adults participated in the study 42 to 353 days from symptom onset. Paired evaluations (SWE2D and CT) were performed along with the assessment of arterial blood gases and spirometry, three times with 100 days in between. During the follow-up and within each evaluation, the SWE2D velocity changed over time (MANOVA, p < 0.05) according to the extent of "fibrosis-like" CT signs by lung lobe (ANOVA, p < 0.05). The variability of the SWE2D velocity was consistently related to the first-second forced expiratory volume and the forced vital capacity (MANCOVA, p < 0.05), which changed over time with no change in blood gases. Covariance was also observed with age and patients' body mass index, the time from symptom onset until hospital admission, and the history of diabetes in those who required intensive care during the acute phase (MANCOVA, p < 0.05). After COVID-19 pneumonia, SWE2D velocity can be related to the extent and regression of "fibrotic-like" involvement of the lung lobes, and it could be a complementary tool in the follow-up after COVID-19 pneumonia.

Blood-pool MRI assessment of myocardial microvascular reactivity.

The ability to non-invasively image myocardial microvascular dilation and constriction is essential to assessing intact function and dysfunction. Yet, conventional measurements based on blood oxygenation are not specific to changes in blood volume. The purpose of this study was to extend to the heart a blood-pool MRI approach for assessing vasomodulation in the presence of blood gas changes and investigate if sex-related differences exist. Animals [five male and five female healthy Sprague Dawley rats (200-500 g)] were intubated, ventilated, and cycled through room air (normoxia) and hypercapnia (10% CO2) in 10-minute cycles after i.v. injection of blood-pool agent Ablavar (0.3 mmol/kg). Pre-contrast T1 maps and T1-weighted 3D CINE were acquired on a 3 Tesla preclinical MRI scanner, followed by repeated 3D CINE every 5 min until the end of the gas regime. Invasive laser Doppler flowmetry of myocardial perfusion was performed to corroborate MRI results. Myocardial microvascular dilation to hypercapnia and constriction to normoxia were readily visualized on T1 maps. Over 10 min of hypercapnia, female myocardial T1 reduced by 20% (vasodilation), while no significant change was observed in the male myocardium. After return to normoxia, myocardial T1 increased (vasoconstriction) in both sexes (18% in females and 16% in males). Laser Doppler perfusion measurements confirmed vasomodulatory responses observed on MRI. Blood-pool MRI is sensitive and specific to vasomodulation in the myocardial microcirculation. Sex-related differences exist in the healthy myocardium in response to mild hypercapnic stimuli.

4 Severity of Retinopathy of Prematurity and Motor Skills Development in Preschoolers

AbstractObjective:Children born preterm are at increased risk of deviation from the typical developmental trajectory. The probability of adverse developmental sequelae is increased in those with history of major perinatal complications. Retinopathy of prematurity (ROP) is a pathological disordered growth of retinal blood vessels occurring in very preterm neonates who require supplemental oxygen. ROP has been linked to intermittent hypoxemic events and blood gas derangements occurring in the Neonatal Intensive Care Unit (NICU), particularly in ventilated infants. Though presence and severity of ROP have been linked to neurodevelopmental impairment, little is known about the relationship between ROP severity and motor development in the preschool age. Because the same hypoxemic events and blood gas changes that lead to severe ROP may also lead to greater developmental deficits in motor control, we hypothesized that ROP severity will be inversely linked to the quality of motor functioning even in NICU graduates without neurological impairments.Participants and Methods:We included 95 preterm (23.6 - 33.6 weeks gestation) preschoolers (49 females, 44 members of twin pairs or triplets). The participants' age ranged from 3.3 - 4.1 years (adjusted for prematurity). ROP screening was conducted during NICU stay and rated from immature retina (0) to grade 4. Motor abilities were assessed with the Peabody Developmental Motor Scales (PDMS-2). Cases with diagnosed perinatal brain pathology (moderate to severe) or cerebral palsy were excluded from analyses.Results:We used linear mixed regression analyses with multiple gestation as a random factor. Severity of ROP was our predictor of interest, whereas socioeconomic status, sex, gestational age, and birth-weight SD served as covariates. Separate analyses were conducted using the PDMS-2 Total Motor, Fine Motor, and Gross Motor Quotients as dependent variables. ROP severity explained a unique portion of the variance in the Total Motor Quotient (F[1, 89] = 5.59, p = .02). Examination of the relationship between ROP severity and motor skill domains yielded a significant association for the Fine Motor Quotient (F[1, 89] = 6.19, p = .015) and a trend for the Gross Motor Quotient (F[1, 89] = 3.64, p = .06).Conclusions:The results of this study reveal that increase in ROP severity is linked to poorer motor skills in preterm-born preschoolers without major disabilities or perinatal diagnosis of moderate to severe brain pathology. This association was evident for both fine and gross motor skills, though only the relationship between ROP severity and the former motor index reached conventional statistical significance. Importantly, ROP severity accounted for a unique portion of the variance in motor performance, over and above the variance explained by other perinatal risk factors. This result is consistent with previous research findings indicating that ROP is linked to the occurrence of multiple, subtle hypoxemic events and 'exposure' to blood gas derangements during NICU stay in very preterm neonates who require respiratory support.

Notoginsenoside R1 protects against hypobaric hypoxia-induced high-altitude pulmonary edema by inhibiting apoptosis via ERK1/2-P90rsk-BAD ignaling pathway

High-altitude pulmonary edema (HAPE) is a potentially fatal disease. Notoginsenoside R1 is a novel phytoestrogen with anti-inflammatory, antioxidant and anti-apoptosis properties. However, its effects and underlying mechanisms in the protection of hypobaric hypoxia-induced HAPE rats remains unclear. This study aimed to explore the protective effects and underlying mechanisms of Notoginsenoside R1 in hypobaric hypoxia-induced HAPE. We found that Notoginsenoside R1 alleviated the lung tissue injury, decreased lung wet/dry ratio, and reduced inflammation and oxidative stress. Additionally, Notoginsenoside R1 ameliorated the changes in arterial blood gas, decreased the total protein concentration in bronchoalveolar lavage fluid, and inhibited the occurrence of apoptosis caused by HAPE. In the process of further exploration of the mechanism, it was found that Notoginsenoside R1 could promote the activation of ERK1/2-P90rsk-BAD signaling pathway, and the effect of Notoginsenoside R1 was attenuated after the use of ERK1/2 inhibitor U0126. Our study indicated that the protective effects of Notoginsenoside R1 against HAPE were mainly related to the inhibition of inflammation, oxidative stress, and apoptosis. Notoginsenoside R1 may be a potential candidate for preventing HAPE.

Obstructive sleep apnea heterogeneity and autonomic function: a role for heart rate variability in therapy selection and efficacy monitoring.

Obstructive sleep apnea is a highly prevalent sleep-related breathing disorder, resulting in a disturbed breathing pattern, changes in blood gases, abnormal autonomic regulation, metabolic fluctuation, poor neurocognitive performance, and increased cardiovascular risk. With broad inter-individual differences recognised in risk factors, clinical symptoms, gene expression, physiological characteristics, and health outcomes, various obstructive sleep apnea subtypes have been identified. Therapeutic efficacy and its impact on outcomes, particularly for cardiovascular consequences, may also vary depending on these features in obstructive sleep apnea. A number of interventions such as positive airway pressure therapies, oral appliance, surgical treatment, and pharmaceutical options are available in clinical practice. Selecting an effective obstructive sleep apnea treatment and therapy is a challenging medical decision due to obstructive sleep apnea heterogeneity and numerous treatment modalities. Thus, an objective marker for clinical evaluation is warranted to estimate the treatment response in patients with obstructive sleep apnea. Currently, while the Apnea-Hypopnea Index is used for severity assessment of obstructive sleep apnea and still considered a major guide to diagnosis and managements of obstructive sleep apnea, the Apnea-Hypopnea Index is not a robust marker of symptoms, function, or outcome improvement. Abnormal cardiac autonomic modulation can provide additional insight to better understand obstructive sleep apnea phenotyping. Heart rate variability is a reliable neurocardiac tool to assess altered autonomic function and can also provide cardiovascular information in obstructive sleep apnea. Beyond the Apnea-Hypopnea Index, this review aims to discuss the role of heart rate variability as an indicator and predictor of therapeutic efficacy to different modalities in order to optimise tailored treatment for obstructive sleep apnea.