Changes In Ventilation Research Articles

Lung function and quality of life one year after severe COVID-19 in Brazil.

To evaluate symptoms, lung function, and quality of life of a cohort of patients hospitalized for severe COVID-19 12 months after hospital admission. This was a cross-sectional study. We included severe COVID-19 survivors hospitalized in one of three tertiary referral hospitals for COVID-19 in the city of Belo Horizonte, Brazil. Participants were submitted to lung function and six-minute walk tests and completed the EQ-5D-3L questionnaire. The whole sample comprised 189 COVID-19 survivors (mean age = 59.6 ± 13.4 years) who had been admitted to a ward only (n = 96; 50.8%) or to an ICU (n = 93; 49.2%). At 12 months of follow-up, 43% of patients presented with dyspnea, 27% of whom had a restrictive ventilatory disorder and 18% of whom presented with impaired DLCO. There were no significant differences in FVC, FEV1, and TLC between the survivors with or without dyspnea. However, those who still had dyspnea had significantly more impaired DLCO (14.9% vs. 22.4%; p < 0.020) and poorer quality of life. After one year, survivors of severe COVID-19 in a middle-income country still present with high symptom burden, restrictive ventilatory changes, and loss of quality of life. Ongoing follow-up is needed to characterize long COVID-19 and identify strategies to mitigate its consequences.

P477 How the use of nocturnal non-invasive ventilation and oxygen therapy changes in patients with cystic fibrosis using elexacaftor/tezacaftor/ivacaftor

P477 How the use of nocturnal non-invasive ventilation and oxygen therapy changes in patients with cystic fibrosis using elexacaftor/tezacaftor/ivacaftor

Ventilatory response of peripheral chemoreceptors to hypercapnia during exercise above the respiratory compensation point.

Peripheral hypercapnic chemosensitivity (PHC) is assessed as the change in ventilation in response to a rapid change in carbon dioxide pressures (PCO2). The increase in chemoresponse from rest to sub-respiratory compensation point (RCP) exercise intensities is well-defined but less clear at intensities above the RCP when changes in known ventilatory stimulants occur. Twenty healthy subjects (n=10 females) completed a maximal exercise test on one day and on a subsequent day, transient hypercapnia was used to test PHC at multiple exercise stages. The transient hypercapnia involved two breaths of 10% CO2 repeated five times during each of the following: sitting at rest on the cycle ergometer, cycling at 40% Wmax, cycling at 85% Wmax, at rest on the cycle ergometer immediately following the 85% stage, and cycling at 40% Wmax again following the post-exercise rest. The PHC was not different across exercise intensities (0.98±0.37 vs. 0.91±0.39 vs. 0.92±0.42 L min-1 mmHg-1 for 1st 40% Wmax, 85% Wmax, and 2nd 40% Wmax, respectively (p=0.45). There were no differences in PHC between pre-supra-RCP exercise rest and post-supra-RCP exercise rest (0.52±0.23 vs. 0.53±0.24 L min-1 mmHg-1, p=0.8003). Using a repeated measures correlation to account for within participants changes, there was a significant relationship between the end-tidal PCO2 and PHC for the 85% intensity (r=0.5, p<0.0001) when end-tidal PCO2 was dynamic between the trials. We conclude that the physiological changes (e.g. metabolic milieu, temperature, etc) produced with supra-RCP exercise do not further augment PHC, and that the pre-stimulus end-tidal PCO2 modulates the PHC.

Pulmonary function assessment among conventional and organic cotton farmers exposed to pesticides in the Central-West region of Burkina Faso.

Respiratory diseases have been associated with the exposure of populations to some environmental pollutants such as pesticides. To assess effects of pesticides on farmers' respiratory health, this study aimed to evaluate the pulmonary function of cotton farmers exposed to synthetic and natural pesticides in the Central-West region of Burkina Faso. A cross-sectional study was conducted from June to July 2022 among 281 conventional and 189 organic cotton farmers. After collecting information on pesticide use conditions, pulmonary function tests (PFTs) were performed on each farmer according to the American Thoracic Society/European Respiratory Society guidelines, in order to assess chronic respiratory effects among cotton producers. Binary logistic regression was used to assess factors associated with the occurrence of ventilatory changes. Both conventional and organic cotton farmers reported similar chronic respiratory symptoms in different proportions. The main reported were rhinitis (54.45% conventional vs. 34.92% organic), chest pains (41.28% conventional vs. 23.81% organic), cough (33.45% conventional, 24.34% organic), breathlessness (31.67% conventional, 4.23% organic) (p<0.05). 16.18% and 27.50% of conventional male and female cotton farmers, respectively, had a restrictive defect. Among organic cotton farmers, 15.85% and 18.69%, respectively, of males and females had a restrictive defect. Furthermore, a significant increase in the predicted average percentage of FEV1/FVC ratio was observed among organic cotton farmers after salbutamol's use (p = 0.039). The type of cultivated cotton was not associated with ventilatory changes neither in the univariate analysis, nor in the multivariate analysis. Other factors such as farmers' age, BMI and insecticides use frequency per year were also important. Farmers who used insecticides more than 6 times per season had an increased risk of developing an obstructive defect (OR = 1.603; 95%CI: 0.484-5.309) compared to those who used them 6 times or less. Chronic respiratory signs and ventilatory impairments were found among conventional and, to our knowledge, for the first time among organic cotton producers. However, these health effects were more prevalent among conventional cotton farmers than organic ones.

Ventilation performance evaluation of an operating room with temperature-controlled airflow system in contaminant control: A numerical study

This article investigates the efficacy of temperature-controlled airflow systems in modern operating rooms for contaminant control, a critical factor in preventing surgical site infections. We have conducted experimental measurements in an operating room equipped with temperature-controlled ventilation to map the airflow field and contaminant dispersion (airborne particles with diameters ranging from 0.5 to 1 μm). The results were used to validate the computational fluid dynamics code, which was then employed to simulate and examine different conditions, including contaminant release locations and air supply rates. Realizable k-epsilon and passive scalar models were utilized to simulate airflow and airborne particle phases. We assessed the airflow distribution and contaminant dispersion, utilizing indices such as ventilation and air change efficiency scales. The analysis provided quantitative insights into the distribution and removal of contaminants, as well as the speed at which the room air was replaced. Contamination was found to be effectively reduced when contaminants were released near exhaust outlets or under central unidirectional inlets. The presence of the operating table caused a big distortion of the central downward airflow, forming a horizontal air barrier at the periphery. Under this unique interior configuration, an appropriate air supply ratio between central and periphery zones was required to achieve optimal overall ventilation performance.

Recovery of Ventilatory and Metabolic Responses to Hypoxia after Chronic Hypoxia in Neonatal Rats

Chronic hypoxia (CH) from birth blunts the hypoxic ventilatory response (HVR) in newborn rats, but there is conflicting evidence as to whether (or how quickly) the HVR recovers after these rats are returned to room air. In this study, Sprague-Dawley rats were exposed to either 21% O2 (Control) or 12% O2 (CH) for the first 3 postnatal days. Breathing and metabolism were studied using head-body plethysmography and respirometry immediately after the 3 days of CH (i.e., at P3) or after 1, 4-5, or 7 days of recovery in room air (i.e., at P4, P7-8, or P10). The early phase of the HVR was blunted in CH rats at P3 (13.7± 2.3 vs. 30.6±3.4 % increase from baseline during 12% O2), and the HVR was more biphasic in CH rats after 1 day of recovery. However, no significant differences in the HVR were observed between treatment groups after 3-4 or 7 days of recovery. Males and females showed similar patterns. Changes in ventilation during hypoxia were strongly biphasic in the younger age groups: ventilation increased initially, but this was followed by a gradual decline in ventilation towards or below baseline levels. However, when accounting for metabolic depression, all age groups continued to hyperventilate during the late phase of the HVR [i.e., the ratio of ventilation to CO2 production (CO2 convection requirement) remained elevated relative to baseline values]. The CO2 convection requirement response to hypoxia did not differ between treatment groups during the late phase of the HVR at any age, but metabolism and CO2 convection requirement could not be determined during the early phase of the HVR due to non-steady state conditions. In conclusion, 3 days of CH produces only a transient blunting of the HVR in newborn rats. Longer CH exposures may be required to elicit persistent changes in the HVR or, alternatively, this plasticity may not be revealed until after puberty. Supported by NIH grant P20 GM-103423 (Maine INBRE). 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.

Consumption of probiotic SLAB51 enhances ventilatory acclimatization to high altitude

Ventilatory acclimatization to hypoxia (VAH) is crucial for adjusting to physiologically stressful high-altitude environments. Increased ventilatory and cardiac responses to low-oxygen (O2) may partially mitigate deleterious effects at high altitude. Previous studies show that administration of the probiotic SLAB51 (O2booster; Hecto, Seoul, South Korea) improves O2 saturation in patients suffering from COVID-19 and O2-treated prematurely born babies. Since changes in ventilation may contribute to increase O2 saturation, we hypothesize that acute administration of SLAB51 to sojourners traveling to high altitude will increase respiratory responses to hypoxia. We measured minute ventilation (VI) and heart rate (HR) during normoxia and acute isocapnic hypoxia in 17 healthy participants (9 males, 8 females) of Latino ancestry with residence at sea level in San Diego and surrounding areas. We performed control experiments at sea level and then the participants were taken to White Mountain Barcroft Station (12,470ft / 3,800m) to repeat the measurements. At high altitude, the participants underwent a double-blind, placebo-controlled study with administration of placebo (n=8) or SLAB51 probiotic (n=9) up to three times per day for up to four days. Recordings of physiological parameters were obtained during steady-state at different gas mixtures with continuous monitoring of O2 saturation to target 10% desaturation during the acute hypoxia stimulus. We measured hypoxic ventilatory and heart rate responses (HVR and HHRR, respectively) and compared results between placebo and probiotic groups (mean ± SEM). As expected, high altitude increased VI and HR values compared to sea-level measurements in all participants. However, at high altitude, we found a significant increase of VI (p&lt;0.02) in participants consuming SLAB51 (0.275+0.015 L/min per Kg) when compared to those administered with placebo (0.207±0.025 L/min per Kg) during exposure to acute hypoxia. Administration of SLAB51 did not produce differences in HR responses at high altitude, and HVR and HHRR were not significantly different with SLAB51 treatment. Our results show that consumption of the probiotic SLAB51 increases ventilatory responses to hypoxia at high altitude without affecting hypoxia-induced changes in HR, suggesting that SLAB51 probiotic intervention may contribute to ventilatory acclimatization to hypoxia, although future studies are required to determine the mechanisms underlying this potential response. 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.

Changes in preBötzinger Complex neuron discharge associated with changes in PCO2 in decerebrate rabbits

Background: Maskrey and Nicol reported a strong increase in minute ventilation with increase in PCO2 (J Physiol 1980, 301: 49-58). We investigated a) whether there was a ceiling to this effect at high CO2 levels and b) whether the change in ventilation was associated with specific changes in respiratory neurons in the preBötzinger complex (preBC). Methods: The study was approved by the local Animal Care Committee and conformed to NIH standards. Adult New Zealand White rabbits (3-4 kg) were anesthetized, tracheotomized, ventilated, decerebrated and vagotomized. Phrenic nerve activity was recorded from the C5 rootlet, time averaged and used to calculate inspiratory (TI) and expiratory durations (TE) and peak phrenic activity (PPA). PPA was normalized to the value at PCO2 50mmHg. Individual neurons were recorded in the functionally identified preBC using multichannel electrodes at increasing CO2 levels. Statistical analysis used the Wilcoxon signed-rank test to determine changes in respiratory parameters between CO2 levels and Friedman RM-ANOVA to determine changes in neuronal discharge frequency (Fn). A generalized linear mixed model was used to determine associations between CO2-dependent changes in TI, TE, PPA, and changes in Fn for different neuron types. p&lt;0.05 indicated a significant difference. Results: In 34 animals, the increase in minute ventilation with increasing PCO2 was due mostly to the change in PPA. The increase in respiratory rate was due mostly to a decrease in TE. There was little increase in respiratory output at PCO2 &gt; 50 mmHg. In 209 neurons, increasing PCO2 increased Fn in inspiratory augmenting (I aug, n= 70, p&lt;0.0001 for CO2 30 vs 40 and 40 vs 50mmHg), I parabolic (I para, n=43, p&lt;0.0001 for CO2 40 vs 50 mmHg), pre-inspiratory (pre-I, n=35, p&lt;0.01 for CO2 30 vs 40 mmHg), and expiratory decrementing (E dec, n=44, p&lt;0.01 for CO2 40 vs 50 mmHg) neurons, but not in I dec (n=8) and non-respiratory modulated (NRM, n=9) neurons. The strongest correlation was found between the changes in phase timing and PPA and Fn in I aug and pre-I neurons. Conclusion: We found a ceiling effect to the increase in respiratory output at PCO2 levels &gt; 50 mmHg. Inspiratory preBC neuron subtypes were more affected by the changes in PCO2. NIH R01HL159546. 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.

Ozone exposure limits cardiorespiratory function during maximal cycling exercise in endurance athletes.

Ground-level ozone (O3) is a potent air pollutant well recognized to acutely induce adverse respiratory symptoms and impairments in pulmonary function. However, it is unclear how the hyperpnea of exercise may modulate these effects, and the subsequent consequences on exercise performance. We tested the hypothesis that pulmonary function and exercise capability would be diminished, and symptom development would be increased during peak real-world levels of O3 exposure compared with room air. Twenty aerobically trained participants [13 M, 7 F; maximal O2 uptake (V̇o2max), 64.1 ± 7.0 mL·kg-1·min-1] completed a three-visit double-blinded, randomized crossover trial. Following a screening visit, participants were exposed to 170 ppb O3 or room air (<10 ppb O3) on separate visits during exercise trials, consisting of a 25-min moderate-intensity warmup, 30-min heavy-intensity bout, and a subsequent time-to-exhaustion (TTE) performance test. No differences in O2 uptake or ventilation were observed during submaximal exercise between conditions. During the TTE test, we observed significantly lower end-exercise O2 uptake (-3.2 ± 4.3%, P = 0.004), minute ventilation (-3.2 ± 6.5%, P = 0.043), tidal volume (-3.6 ± 5.1%, P = 0.008), and a trend toward lower exercise duration in O3 compared with room air (-10.8 ± 26.5%, P = 0.092). As decreases in O2 uptake and alterations in respiratory pattern were also present at matched time segments between conditions, a limitation of oxygen transport seems likely during maximal exercise. A more comprehensive understanding of the direct mechanisms that limit oxygen transport during exercise in high-pollutant concentrations is key for mitigating performance changes.NEW & NOTEWORTHY We demonstrate that in highly trained endurance athletes, exposure to peak real-world levels of O3 air pollution (170 ppb) significantly diminishes O2 uptake along with corresponding changes in ventilation during maximal exercise. As no differences were observed during extended submaximal exercise, a combined effect of effective dose of pollution and exercise intensity on severity of responses seems likely.

Cardiorespiratory Responses to Acute Intermittent Hypoxia in Humans With Chronic Spinal Cord Injury.

Brief exposure to repeated episodes of low inspired oxygen, or acute intermittent hypoxia (AIH), is a promising therapeutic modality to improve motor function after chronic, incomplete spinal cord injury (SCI). Although therapeutic AIH is under extensive investigation in persons with SCI, limited data are available concerning cardiorespiratory responses during and after AIH exposure despite implications for AIH safety and tolerability. Thus, we recorded immediate (during treatment) and enduring (up to 30 min post-treatment) cardiorespiratory responses to AIH in 19 participants with chronic SCI (>1 year post-injury; injury levels C1 to T6; American Spinal Injury Association Impairment Scale A to D; mean age = 33.8 ± 14.1 years; 18 males). Participants completed a single AIH (15, 60-sec episodes, inspired O2 ≈ 10%; 90-sec intervals breathing room air) and Sham (inspired O2 ≈ 21%) treatment, in random order. During hypoxic episodes: (1) arterial oxyhemoglobin saturation decreased to 82.1 ± 2.9% (p < 0.001); (2) minute ventilation increased 3.83 ± 2.29 L/min (p = 0.008); and (3) heart rate increased 4.77 ± 6.82 bpm (p = 0.010). Considerable variability in cardiorespiratory responses was found among subjects; some individuals exhibited large hypoxic ventilatory responses (≥0.20 L/min/%, n = 11), whereas others responded minimally (<0.20 L/min/%, n = 8). Apneas occurred frequently during AIH and/or Sham protocols in multiple participants. All participants completed AIH treatment without difficulty. No significant changes in ventilation, heart rate, or arterial blood pressure were found 30 min post-AIH p > 0.05). In conclusion, therapeutic AIH is well tolerated, elicits variable chemoreflex activation, and does not cause persistent changes in cardiorespiratory control/function 30 min post-treatment in persons with chronic SCI.

Physics-based in silico modelling of microvascular pulmonary perfusion in COVID-19.

Due to its ability to induce heterogenous, patient-specific damage in pulmonary alveoli and capillaries, COVID-19 poses challenges in defining a uniform profile to elucidate infection across all patients. Computational models that integrate changes in ventilation and perfusion with heterogeneous damage profiles offer valuable insights into the impact of COVID-19 on pulmonary health. This study aims to develop an in silico hypothesis-testing platform specifically focused on studying microvascular pulmonary perfusion in COVID-19-infected lungs. Through this platform, we explore the effects of various acinar-level pulmonary perfusion abnormalities on global lung function. Our modelling approach simulates changes in pulmonary perfusion and the resulting mismatch of ventilation and perfusion in COVID-19-afflicted lungs. Using this coupled modelling platform, we conducted multiple simulations to assess different scenarios of perfusion abnormalities in COVID-19-infected lungs. The simulation results showed an overall decrease in ventilation-perfusion (V/Q) ratio with inclusion of various types of perfusion abnormalities such as hypoperfusion with and without microangiopathy. This model serves as a foundation for comprehending and comparing the spectrum of findings associated with COVID-19 in the lung, paving the way for patient-specific modelling of microscale lung damage in emerging pulmonary pathologies like COVID-19.

Rehabilitation Nursing Care for a patient undergoing corrective surgery for scoliosis: case report

Introduction: Scoliosis is characterized by three-dimensional changes in the spine, mainly in the thoracic and/or lumbar region, leading to musculoskeletal and pulmonary changes and changes in the person's functionality. After corrective spinal surgical intervention, the intervention of a rehabilitation nurse becomes essential, in order to guide and optimize the person's training and empowerment, in this phase of health-disease transition.Clinical Case Report: Clinical case study, inherent to the situation of a person undergoing corrective surgery for scoliosis. The nursing process was carried out, through data collection, evaluation, diagnosis survey, rehabilitation nursing interventions, and the respective results assessment. The numerical pain scale, the body balance assessment, the Barthel Index, the Functional Independence Measure and the Timed Up and Go test were used as assessment instruments. Based on the International Classification for Nursing Practice and the Rehabilitation Nurse Specialist standard of care document.Discussion: The rehabilitation nursing plan implemented for the person undergoing corrective surgery for scoliosis contributed beneficially to the improvement of the ventilation pattern, muscle strength, mobility, gait, independence in carrying out self-care and increased functionality. There was an increase in knowledge and training in techniques to adapt to their situation, favoring a safe transition to home after hospital discharge.Conclusion: In view of musculoskeletal and ventilatory changes, a Motor Functional Reeducation and Respiratory Functional Reeducation plan is extremely important, in association with the person's teaching and training plan.

Analysis of haemodynamics surrounding blood transfusions after the arterial switch operation: a pilot study utilising real-time telemetry high-frequency data capture.

Packed red blood cell transfusions occur frequently after congenital heart surgery to augment haemodynamics, with limited understanding of efficacy. The goal of this study was to analyse the hemodynamic response to packed red blood cell transfusions in a single cohort, as "proof-of-concept" utilising high-frequency data capture of real-time telemetry monitoring. Retrospective review of patients after the arterial switch operation receiving packed red blood cell transfusions from 15 July 2020 to 15 July 2021. Hemodynamic parameters were collected from a high-frequency data capture system (SickbayTM) continuously recording vital signs from bedside monitors and analysed in 5-minute intervals up to 6 hours before, 4 hours during, and 6 hours after packed red blood cell transfusions-up to 57,600 vital signs per packed red blood cell transfusions. Variables related to oxygen balance included blood gas co-oximetry, lactate levels, near-infrared spectroscopy, and ventilator settings. Analgesic, sedative, and vasoactive infusions were also collected. Six patients, at 8.5[IQR:5-22] days old and weighing 3.1[IQR:2.8-3.2]kg, received transfusions following the arterial switch operation. There were 10 packed red blood cell transfusions administered with a median dose of 10[IQR:10-15]mL/kg over 169[IQR:110-190]min; at median post-operative hour 36[IQR:10-40]. Significant increases in systolic and mean arterial blood pressures by 5-12.5% at 3 hours after packed red blood cell transfusions were observed, while renal near-infrared spectroscopy increased by 6.2% post-transfusion. No significant changes in ventilation, vasoactive support, or laboratory values related to oxygen balance were observed. Packed red blood cell transfusions given after the arterial switch operation increased arterial blood pressure by 5-12.5% for 3 hours and renal near-infrared spectroscopy by 6.2%. High-frequency data capture systems can be leveraged to provide novel insights into the hemodynamic response to commonly used therapies such as packed red blood cell transfusions after paediatric cardiac surgery.

Linking northeastern North Pacific oxygen changes to upstream surface outcrop variations

Abstract. Understanding the response of the ocean to global warming, including the renewal of ocean waters from the surface (ventilation), is important for future climate predictions. Oxygen distributions in the ocean thermocline have proven an effective way to infer changes in ventilation because physical processes (ventilation and circulation) that supply oxygen are thought to be primarily responsible for changes in interior oxygen concentrations. Here, the focus is on the North Pacific thermocline, where some of the world's oceans' largest oxygen variations have been observed. These variations, described as bi-decadal cycles on top of a small declining trend, are strongest on subsurface isopycnals that outcrop into the mixed layer of the northwestern North Pacific in late winter. In this study, surface density time series are reconstructed in this area using observational data only and focusing on the time period from 1982, the first full year of the satellite sea surface temperature record, to 2020. It is found that changes in the annual maximum outcrop area of the densest isopycnals outcropping in the northwestern North Pacific are correlated with interannual oxygen variability observed at Ocean Station P (OSP) downstream at about a 10-year lag. The hypothesis is that ocean ventilation and uptake of oxygen is greatly reduced when the outcrop areas are small and that this signal travels within the North Pacific Current to OSP, with 10 years being at the higher end of transit times reported in other studies. It is also found that sea surface salinity (SSS) dominates over sea surface temperature (SST) in driving interannual fluctuations in annual maximum surface density in the northwestern North Pacific, highlighting the role that salinity may play in altering ocean ventilation. In contrast, SSS and SST contribute about equally to the long-term declining surface density trends that are superimposed on the interannual cycles.

LIVER ENZYME ALTERATIONS AFTER LAPAROSCOPIC CHOLECYSTECTOMY IN A TERTIARY CARE CENTER

Objective: Cholelithiasis is a prevalent global health concern, with laparoscopic cholecystectomy (LC) emerging as the preferred surgical intervention. While LC offers an advantage such as shorter hospital stays, it poses potential risks, including cardiovascular impediments because of hemodynamic and ventilatory changes. The current research study was done to assess the impact of LC on hematological parameters, comparing pre-operative and post-operative levels. Methods: The study comprised 51 subjects undertaking LC, and preoperative and postoperative blood samples were analyzed for various hematological parameters. Parameters investigated included hemoglobin (Hb), mean corpuscular volume, mean corpuscular Hb, mean corpuscular Hb concentration, hematocrit, platelet count, mean platelet volume (MPV), and liver function tests such as alanine transaminase and alkaline phosphatase. Results: Preliminary findings demonstrated significant alterations in hematological parameters post-LC. Changes in MPV, leukocytes, neutrophils, neutrophil–lymphocyte ratio, platelet–lymphocyte ratio, and coagulation factors were observed. Moreover, there was a notable proliferation in thromboembolic measures connected with pneumoperitoneum pressure and surgery duration. Conclusion: LC induces substantial changes in hematological parameters, potentially contributing to postoperative complications. Understanding these alterations is crucial for implementing appropriate pre-, peri-, and post-operative measures to minimize morbidity, mortality, and overall health-care costs. Further investigations are required in interpreting the principal mechanisms and refine strategies for optimizing patient outcomes in LC.

Quantifying Regional Radiation-Induced Lung Injury in Patients Using Hyperpolarized 129Xe Gas Exchange Magnetic Resonance Imaging

PurposeRadiation-induced lung injury (RILI) has been shown to alter regional ventilation and perfusion in the lung. However, changes in regional pulmonary gas exchange have not previously been measured. MethodsTen patients receiving conventional radiation therapy (RT) for lung cancer underwent pre-RT and 3-month post-RT MRI using an established hyperpolarized-129Xe gas exchange technique to map lung function. Four patients underwent an additional 8-month post-RT MRI. The MR signal from inhaled xenon is measured in three pulmonary compartments: the lung airspaces, the alveolar membrane tissue, and the pulmonary capillaries (interacting with red blood cells, RBCs). Thoracic 1H MRI scans were acquired, and deformable registration was used to transfer 129Xe functional maps to the RT planning CT. The RT-associated changes in ventilation, membrane uptake, and RBC transfer, were computed as a function of regional lung dose (equivalent dose in 2-Gy fractions, EQD2). Pearson correlation and t-tests were used to determine statistical significance, and weighted sum of squares linear regression subsequently characterized the dose-dependence of each functional component. Pulmonary function testing (PFT) metrics forced vital capacity (FVC) and diffusing capacity for carbon monoxide (DLCO) were also acquired at each timepoint. ResultsCompared to pre-RT baseline, 3-month post-RT ventilation decreased by an average of -0.24±0.05 %/Gy (ρ=-0.88; P<.001), membrane uptake increased by 0.69±0.14 %/Gy (ρ=0.94; P<.001), and RBC transfer decreased by -0.41±0.06 %/Gy (ρ=-0.92; P<.001). Membrane uptake maintained a strong positive correlation with regional dose at 8 months post-RT, demonstrating an increase of 0.73±0.11 %/Gy (ρ=0.92; P=.006). Changes in membrane uptake and RBC transfer appeared greater in magnitude (%/Gy) for subjects with low heterogeneity in their baseline lung function. An increase in whole-lung membrane uptake showed moderate correlation with decreases in FVC (ρ=-0.50; P=0.17) and DLCO (ρ=-0.44; P=0.23), with neither correlation reaching statistical significance. ConclusionHyperpolarized-129Xe MRI measured and quantified regional, RT-associated, dose-dependent changes in pulmonary gas exchange. This tool could enable future work to improve our understanding and management of RILI.

Subjective and objective comparative analysis of nasal ventilation function before and after nasal septoplasty

Objective:To investigate the changes of nasal ventilation before and after septoplasty by using NOSE scoring scale and nasal function examination, and to explore the correlation between subjective nasal obstruction and nasal function examination and its clinical application value. Methods:A total of 129 cases of nasal septum deviation from December 2021 to April 2023 in our hospital were selected for study. All patients underwent septoplasty. Nasal obstruction symptom evaluation（NOSE） was performed in all patients before surgery and 3 months after surgery. nasal minimal cross-sectional area（MCA） and nasal cavity volume（NCV） were recorded by nasal acoustic reflex, nasal resistance meter and nasal respiration apparatus, nasal resistance（NR）, distance between the nostril to minimum cross-sectional area,（the distance between the nostril to minimum cross-sectional area, MD）, nasal inspiratory volume（IV）, nasal expiratory volume（EV）, the nasal partitioning ratio, NPR includes objective indicators such as inspiratory volume difference ratio（NPRi） and expiratory volume difference ratio（NPRe）. Paired test was used to compare and analyze the changes of various indicators before and after surgery, and the difference（P<0.05） was statistically significant, and Pearson correlation linear analysis was used to analyze the correlation between subjective and objective indicators. Results:There were statistically significant differences in NOSE score, NCV, NR, MD, EV, IV, NPRe and NPRi of 129 patients before and after surgery（P<0.05）, while there was no statistically significant difference between MCA before and after surgery（P>0.05）. Preoperative NOSE score was correlated with NR, NCV, EV, IV, NPRe and NPRi（P<0.05）, but not with MD and MCA（P>0.05）. There was correlation between NOSE score and NR, MCA, NCV, EV, IV, NPRe and NPRi（P<0.05）, but no correlation between nose score and MD（P>0.05）. Conclusion:The subjective NOSE scale combined with nasal function test has certain clinical reference value in evaluating the surgical effect of patients with deviated nasal septum.

SOMNOLOGIC SCREENING AND MONITORING IN PATIENTS IN THE ACUTE PERIOD OF ISCHEMIC STROKE

Summary. Cerebral stroke – is one of the leading causes of morbidity and mortality, the frequency of which is constantly increasing and is about 1 million people per year in Europe; and from 13 to 35% of these patients die within the first 30 days of treatment, and 20-40% of patients who survived, are dependent on the external physical assistance and only about 10% return to a full-quality life. A significant part of patients with ischemic stroke has obstructive sleep breathing disorders, which are often the cause of the stroke development and significantly complicate its course, primarily due to the impaired airway patency, numerous episodes of apnea/hypopnea and hypoxemia, hypercapnia, etc. A comprehensive study of the frequency of the obstructive sleep apnea syndrome development and its degree of severity, its inherent ventilation and oxygenation disorders against the background of standard treatment and in combination with noninvasive respiratory support in patients with ischemic stroke, can play an important positive role on the way to the improvement of the results of treatment and rehabilitation. Objective. To study changes in ventilation and oxygenation in patients in the acute period of ischemic stroke, depending on the method of intensive therapy. Methods. Ischemic patients were performed a questionnaire survey and screening monitoring to find sleep breathing disorders («SomnoChek micro», Weinman, Germany), based on the results of which there were formed two groups: traditional stroke treatment and in combination with auto-CPAP support, which was performed with the help of «ResMed Air Sence-i» (Australia). To control the effectiveness of respiratory support, «SomnoChek micro» (Weinman, Germany) and «Masimo SafetyNet» (Masimo, USA) were used, the obtained somnological indices were processed statistically. Results. The frequency of detection of obstructive sleep apnea syndrome in patients with ischemic stroke in the acute period is 44%. The initial values of the apnea/hypopnea index (AHI) did not statistically significantly differ from each other and were 51.38±20.31/hour in the patients of the experimental group, and 51.21±20.27/hour in patients of the control group. During the 7th day, the AHI values in patients of the experimental group, whose traditional treatment of ischemic stroke was supplemented with sessions of CPAP-therapy at night, statistically significantly decreased at 89.2% compared to the initial data and were 5.54±1.98/hour, which are normal values and indicate the rapid and high efficiency of CPAP-support and its good tolerability by patients. In patients of the control group receiving only traditional treatment, the AHI values remained high, within pathological values and were 46.73±20.21/hour. When comparing reliable AHI intervals in observation groups, their 8.4-fold difference was determined. Against the background of CPAP-therapy, during the 7th day of observation, a statistically significant decrease in hypercapnia was determined in the patients of the experimental group, namely a decrease in the average PnCO2 at 23% compared to the initial level up to the limit of 37.57±1.04 mm Hg. Against the background of the use of CPAPtherapy in patients of the experimental group during the 7th day of observation, there was found a decrease (p&lt;0.001) of snoring at 92.1% (12.6-fold), compared to the initial level up to the limit of 2.43±2.22%, which indicates a stable restoration and maintenance of free patency of the upper respiratory tract under the influence of CPAP-support. Conclusion. Manifestations of obstructive sleep apnea syndrome in patients with ischemic stroke in the acute period were found in 88 people (44%), of which 68% had a moderate and severe form of nocturnal breathing disorders that required respiratory correction. Standardized medicinal therapy and early rehabilitation of patients with ischemic stroke does not affect the course and severity of the accompanying syndrome of obstructive sleep apnea and needs to be supplemented with methods of non-invasive respiratory support. In patients with ischemic stroke against the background of auto CPAP-therapy, positive dynamics was recorded in terms of correction of obstructive sleep apnea syndrome: a steady tendency or normalization of somnologic indices, ventilation, oxygenation, cessation of snoring. A clinical problem remains the low patients’ adherence to the use of CPAP-support and its tolerability, despite the absolute indications for its use.

A Phase 2 Randomized Clinical Trial Evaluating 4-Dimensional Computed Tomography Ventilation-Based Functional Lung Avoidance Radiation Therapy for Non-Small Cell Lung Cancer

PurposeTo determine whether 4-dimensional computed tomography (4DCT) ventilation-based functional lung avoidance radiotherapy preserves pulmonary function compared with standard radiotherapy for non-small cell lung cancer (NSCLC). Material and MethodsThis single center, randomized, phase 2 trial enrolled patients with NSCLC receiving curative intent radiotherapy with either stereotactic body radiotherapy or conventionally fractionated radiotherapy between 2016 and 2022. Patients were randomized 1:1 to standard of care radiotherapy or functional lung avoidance radiotherapy. The primary endpoint was the change in Jacobian-based ventilation as measured on 4DCT from baseline to three months post-radiation. Secondary endpoints included changes in volume of high- and low-ventilating lung, pulmonary toxicity, and changes in pulmonary function tests (PFTs). ResultsA total of 122 patients were randomized and 116 were available for analysis. Median follow up was 29.9 months. Functional avoidance plans significantly (P<.05) reduced dose to high-functioning lung without compromising target coverage or organs at risk constraints. When analyzing all patients, there was no difference in the amount of lung showing a reduction in ventilation from baseline to 3 months between the two arms (1.91% vs 1.87%; P=.90). Overall grade ≥2 and grade ≥3 pulmonary toxicities for all patients were 24.1% and 8.6%, respectively. There was no significant difference in pulmonary toxicity or changes in PFTs between the two study arms. In the conventionally fractionated cohort, there was a lower rate of grade ≥2 pneumonitis (8.2% vs 32.3%; P=.049) and less of a decline in change in FEV1 (-3 vs -5; P=.042) and FVC (1.5 vs -6; P=.005) at 3 months, favoring the functional avoidance arm. ConclusionsThere was no difference in post-treatment ventilation as measured by 4DCT between the arms. In the cohort of patients treated with conventionally fractionated radiotherapy with functional lung avoidance, there was reduced pulmonary toxicity, and less decline in PFTs suggesting a clinical benefit in patients with locally advanced NSCLC. Trial RegistrationClinicalTrials.gov Identifier: NCTXXXX Anonymized for Review XXXX

Retrospective Validation of a Computerized Physiologic Equation to Predict Minute Ventilation Needs in Critically Ill Children.

Mechanical ventilation (MV) is pervasive among critically ill children. We sought to validate a computerized physiologic equation to predict minute ventilation requirements in children and test its performance against clinician actions in an in silico trial. Retrospective, electronic medical record linkage, cohort study. Quaternary PICU. Patients undergoing invasive MV, serial arterial blood gas (ABG) analysis within 1-6 hours, and pharmacologic neuromuscular blockade (NMB). ABG values were filtered to those occurring during periods of NMB. Simultaneous ABG and minute ventilation data were linked to predict serial Pa co2 and pH values using previously published physiologic equations. There were 15,121 included ABGs across 500 encounters among 484 patients, with a median (interquartile range [IQR]) of 20 (10-43) ABGs per encounter at a duration of 3.6 (2.1-4.2) hours. The median (IQR) Pa co2 prediction error was 0.00 (-3.07 to 3.00) mm Hg. In Bland-Altman analysis, the mean error was -0.10 mm Hg (95% CI, -0.21 to 0.01 mm Hg). A nested, in silico trial of ABGs meeting criteria for weaning (respiratory alkalosis) or escalation (respiratory acidosis), compared the performance of recommended ventilator changes versus clinician decisions. There were 1,499 of 15,121 ABGs (9.9%) among 278 of 644 (43.2%) encounters included in the trial. Calculated predictions were favorable to clinician actions in 1124 of 1499 ABGs (75.0%), equivalent to clinician choices in 26 of 1499 ABGs (1.7%), and worse than clinician decisions in 349 of 1499 ABGs (23.3%). Calculated recommendations were favorable to clinician decisions in sensitivity analyses limiting respiratory rate, analyzing only when clinicians made changes, excluding asthma, and excluding acute respiratory distress syndrome. A computerized equation to predict minute ventilation requirements outperformed clinicians' ventilator adjustments in 75% of ABGs from critically ill children in this retrospective analysis. Prospective validation studies are needed.