Pulmonary Ventilation Research Articles

Demonstration of Membrane Transport of Histidine using Goat Intestinal Inverted Sacs: An Experiential Pedagogical Tool for Undergraduates.

Histidine is an essential amino acid that is also a precursor for metabolites implicated in the immune system, pulmonary ventilation, and vascular circulation. Absorption of dietary histidine relies largely on the sodium-coupled neutral amino acid transport by the Broad neutral amino acid transporter (B0AT) present on the apical membrane of the enterocyte. Here, we demonstrate the absorption of histidine by the intestinal villus enterocytes from the lumen using goat jejunal inverted sacs. The jejunal sacs exposed to varying concentrations of sodium and histidine were assayed to determine the concentration of histidine inside the sacs as a function of time. The results show active histidine absorption. Increasing the concentration of salt resulted in higher absorption of histidine, suggesting a symport of sodium and histidine absorption in goat intestinal inverted sacs. This protocol may be applied to visualize the intestinal mobility of amino acids or other metabolites with appropriate modifications. We propose this experiment as an experiential pedagogical tool that can help undergraduate students comprehend the concept of membrane transport.

The airway smooth muscle and the pipe dream of better bronchodilators.

Research on airway smooth muscle has traditionally focused on its putative detrimental role in asthma, emphasizing on how its shortening narrows the airway lumen, without much consideration about its potential role in subserving the function of the entire respiratory system. New experimental evidence on mice suggests that not only the smooth muscle is required to sustain life postnatally, but its stiffening effect on the lung tissue also protects against excessive airway narrowing and, most importantly, against small airway narrowing heterogeneity and closure. These results suggest that the smooth muscle plays an vital role in the lung periphery, essentially safeguarding alveolar ventilation by preventing small airway closure. These results also shed light on perplexing clinical observations, such as the long-standing doubts about the safety of bronchodilators. Since there seems to be an optimal level of smooth muscle contraction, at least in small airways, the therapeutic goal of maximizing the relaxation of the smooth muscle in asthma needs to be revisited. A bronchodilator with an excessive potency for inhibiting smooth muscle contraction, and that is still potent at concentrations reaching the lung periphery, may foster airway closure and air trapping, resulting in no net gain or even a decline in lung function.

“Distribution of pulmonary ventilation in the lateral decubitus position of healthy adults under Non-Invasive Mechanical Ventilation: a pilot study”

ObjectiveIn the lateral decubitus position, the largest percentage of pulmonary ventilation in non-sedated subjects is distributed mainly in the dependent lung. MethodsWe aimed to investigate, via impedance tomography, the distribution of pulmonary ventilation in the lateral position under the effect of different Continuous Positive Airway Pressure (CPAP) levels (0, 5, 10 cm H2O) in healthy subjects. The volunteers were noninvasively ventilated in both lateral positions and supine positions at the beginning and end of the process. ResultsA statistically significant difference between the percentage distribution of lung ventilation in different CPAP levels in the right and left lateral decubitus body positions was observed. ConclusionWe concluded that in the lateral position, as positive pressure increases, ventilation of the dependent lung increases, while, conversely, pulmonary ventilation of the non-dependent lung decreases.

Management and Outcomes of Pulmonary Embolism in the Oldest-Old.

Treatment for pulmonary embolism has expanded to include Direct Oral Anticoagulants (DOACs). The incidence of pulmonary-embolism (PE) in "oldest-old" age group (≥85 years) is rapidly increasing, but there is limited research on its management and clinical outcomes. To examine the differences in management and outcomes in those aged ≥85 years compared to other age groups. We performed a retrospective cohort-study of 373 consecutive patients with pulmonary embolism confirmed on imaging by Computed Tomography Pulmonary Angiogram (CTPA) or Ventilation Perfusion (VQ) Scan at a principal referral hospital in Sydney, Australia. Data collected include clinical and demographic data, Charlson comorbidity index, treatment type and outcomes including complications, recurrent venous thromboembolism, and mortality. Across the age groups, DOACS were prescribed to 53.4% (n=199) of patients. In oldest-old patients with PE, LMWH bridging to warfarin was the most frequently prescribed treatment, used in 46.2% (n=18, 95% CI: 30.8%-61.5%, p=0.003) of these patients. The mortality rate for patients on LMWH was 13.9% (n=5, 95% CI: 4.2%-37.5%, p=0.553). Overall, major bleeding incidents were rare, occurring in just 1.7% (n=4, 95% CI: 0.4%-3.3%) of patients, with no significant differences in outcomes across age groups. DOACs are increasingly used as the treatment modality of choice in atrial fibrillation but are less well studied in pulmonary embolism, particularly in oldest-old patients. We found that the safety and efficacy profile of DOACs in pulmonary embolism treatment is similar across the age groups. Our study does not support any change in treatment protocols of PE in the oldest old, but further studies are required to confirm our findings.

Interevaluator reliability of a tool for measuring body height in adult intensive care patients

BackgroundThe calculation of body height in the intensive care unit is essential for obtaining the ideal body weight, which is used to program the tidal volume and establish objective and effective pulmonary ventilation. The objective of the study was to determine the interrater reliability of a tool for measuring body height in adult patients in an intensive care unit (ICU) in southwestern Colombia. MethodsThis cross-sectional observational study was conducted between January and May 2021, following the recommendations of the COSMIN protocol. Two physiotherapists in the roles of observer/evaluator measured the heights of 106 patients upon admission to the ICU with a previously designed. The sample size was calculated based on Pearson's correlation coefficient. For interrater reliability, the intraclass correlation coefficient (ICC) was used, and Bland–Altman analysis was used to assess concordance. The 95% confidence interval was established, and a P value <0.05 indicated statistical significance. ResultsA total of 106 individuals with a mean age of 59.3 years were included; the mean body height was 158.5 cm for women. The interrater reliability of the measurement of height was excellent (global ICC of 0.99, P = 0.000), and an almost perfect positive correlation was obtained between the raters for both women and men (R = 0.99). ConclusionsExcellent interrater/interobserver reliability was obtained for the measurement of body height in the ICU. This research highlights the importance of protocolizing the measurement of height in critical patients with valid and reliable instruments.

Effective Ventilation Mode in Early Neonatal Sepsis, Bilateral Pneumonia, and Pulmonary Hypertension in a Very Low Birth Weight Newborn (Case Report)

The aim was to demonstrate an alternative approach to respiratory therapy in respiratory failure complicated by pulmonary hypertension when conventional ventilation and high-frequency oscillatory ventilation are ineffective.Patient and study methods. We analyzed laboratory data, ventilatory parameters and hemodynamic parameters during ventilation in a child with birth weight of 1300 grams and respiratory failure complicated by pulmonary hypertension. Dynamic selection of parameters and modes of pulmonary ventilation with transition to Airway Pressure Release Ventilation (APRV) mode is presented. Chest radiography and echocardiography were used.Results. The use of APRV mode when traditional approaches were ineffective allowed «stabilization» of the lungs by alveolar recruitment without deep sedation and muscle relaxation. On day 20 after birth, the infant was weaned. On day 29, the infant was transferred to the neonatal pathology unit for further management, and on day 49, the infant was discharged in stable condition.Conclusion. In neonates with severe respiratory failure, the use of the APRV mode as an alternative to ineffective conventional ventilation requires further investigation and the development of guidelines for its use.

Effect of Neoadjuvant Immunotherapy Combined with Chemotherapy on Pulmonary Function and Postoperative Pulmonary Complications in Esophageal Cancer: A Retrospective Study.

Neoadjuvant immunotherapy, targeting the PD-1 or PD-L1, combined with chemotherapy (NICT), can improve the radical resection and survival rates for locally advanced EC. However, it may impair pulmonary function, and the effect of NICT on pulmonary function and postoperative pulmonary complications in EC patients remains unknown. This study aimed to investigate whether NICT can affect pulmonary functions and postoperative pulmonary complications in EC patients. The study retrospectively recruited 220 EC patients who received NICT at the Department of Esophageal Cancer in Tianjin Medical University Cancer Institute & Hospital from January 2021 to June 2022. Changes in pulmonary function before and after NICT were compared. Logistic regression analysis was performed to analyze the correlations of pulmonary functions and clinical characteristics with postoperative pulmonary complications, respectively. The FEV1% pred, FVC, FVC% pred, and FEV1/FVC% significantly increased after NICT, with a P-value of 0.018, 0.005, 0.001, and 0.036, respectively. In contrast, there was a significant decline in the DLCO (8.92 ± 2.34 L before NICT vs. 7.79 ± 2.30 L after NICT; P < 0.05) and DLCO% pred (102.97 ± 26.22% before NICT vs. 90.18 ± 25.04% after NICT; P < 0.05). High DLCO and DLCO% pred at baseline levels were risk factors for DLCO reduction in EC patients after NICT. Advanced age, smoking history, FEV1% pred after NICT, and FVC% pred baseline and after therapy were risk factors for postoperative pulmonary complications, with a P-value of 0.043, 0.038, 0.048, 0.034, and 0.004, respectively. Although the DLCO level decreased after NICT, it did not increase the incidence of postoperative pulmonary complications. NICT may improve pulmonary ventilation function but also lead to a decrease in DLCO and DLCO% pred in EC patients. Nevertheless, the decreased DLCO after NICT did not increase the risk of postoperative pulmonary complications.

Quantitative computed tomography assessment of pulmonary function and compensation after lobectomy and segmentectomy in lung cancer patients.

The effect of different surgical methods on postoperative lung function in patients with lung cancer is still inconclusive. The main objective of this study was to compare the effects of video-assisted thoracic surgery (VATS) lobectomy and segmentectomy on postoperative pulmonary function and compensatory changes in patients undergoing lung cancer surgery. A total of 120 patients (82 VATS lobectomy, 38 VATS segmentectomy) were assessed for demographic characteristics, baseline pulmonary function, tumor volume, T stage, and histological grade. Postoperative pulmonary function and compensatory changes [percentage of the well-aerated lung (WAL) total (or unilateral) lung volume (LV) (WAL%) and non-operated lung (NOL)] were measured at multiple time points up to 2 years. Logistic regression analysis identified factors associated with WAL% decline after 1 year. Both VATS lobectomy and segmentectomy led to a decrease in pulmonary function, with no significant difference in the extent of decline between the two groups (all P>0.05). Lobectomy triggered a more pronounced compensatory response, characterized by increased ipsilateral NOL volume over time. Segmentectomy induced minimal compensatory changes and had a minimal impact on pulmonary function. Factors associated with decreased pulmonary ventilation after 1 year differed between the lobectomy and segmentectomy groups. In the lobectomy group, a higher preoperative WAL% of ipsilateral NOL [odds ratio (OR) =1.073; 95% confidence interval (CI): 1.017-1.133; P=0.01] was associated with a higher risk of decline in pulmonary function, whereas in the segmentectomy group, the only influencing factor was the preoperative contralateral mean lung density (MLD) (OR =0.932; 95% CI: 0.884-0.984; P=0.01). Both lobectomy and segmentectomy after lung cancer surgery result in a decrease in WAL%, with lobectomy demonstrating a stronger pulmonary compensatory capacity. The application of quantitative computed tomography (CT) has shown significant value in predicting postoperative pulmonary function preservation and compensatory changes, providing strong support for personalized surgical decision-making.

Chronic obstructive pulmonary disease, asthma, and mechanical ventilation are risk factors for dyspnea in patients with long COVID: A Japanese nationwide cohort study

BackgroundPatients often experience multiple prolonged symptoms following acute coronavirus disease 2019 (COVID-19) recovery, defined as long coronavirus disease (COVID). Patients with long COVID may experience dyspnea during acute and post-acute phases. Therefore, this study aimed to identify specific risk factors for dyspnea in patients with long COVID. MethodsHospitalized patients with COVID-19, aged ≥18 years, were enrolled in this multicenter cohort study conducted at 26 medical institutions across Japan. Clinical data during hospitalization and patient-reported outcomes after discharge at the 3, 6, and 12-month follow-ups were retrieved from medical records and paper-based or smartphone application-based questionnaires, respectively. ResultsGeneralized linear mixed model (GLMM) analysis of prolonged dyspnea at each time point during follow-up showed that this symptom was associated with chronic obstructive pulmonary disease (COPD) (odds ratio [OR], 2.74; 95% confidence interval [CI], 1.31–5.74), asthma (OR, 2.21; 95%CI, 1.17–4.16), and ventilator management (OR, 3.10; 95%CI, 1.65–5.83). In addition, patients with COPD (44.4%) and ventilator management (25.0%) were more frequently associated with delayed dyspnea onset. The generalized estimating equations analysis results with multiple imputed datasets, conducted as a sensitivity analysis, confirmed the adjusted GLMM analysis results. ConclusionsProlonged dyspnea was associated with COPD, asthma, and severe infection that required mechanical ventilation in the Japanese population with long COVID. Further investigation is needed to clarify its mechanism and develop prophylactic and therapeutic strategies for dyspnea in patients with long COVID.

Control of hyperpnoea and pulmonary gas exchange during prolonged exercise: The role of group III/IV muscle afferent feedback.

It remains unclear whether feedback from group III/IV muscle afferents is of continuous significance for regulating the pulmonary response during prolonged (>5min), steady-state exercise. To elucidate the influence of these sensory neurons on hyperpnoea, gas exchange efficiency, arterial oxygenation and acid-base balance during prolonged locomotor exercise, 13healthy participants (4 females; 21 (3) years, : 46 (8) ml/kg/min) performed consecutive constant-load cycling bouts at ∼50% (20min), ∼75% (20min) and ∼100% (5min) of with intact (CTRL) and pharmacologically attenuated (lumbar intrathecal fentanyl; FENT) group III/IV muscle afferent feedback from the legs. Pulmonary responses were continuously recorded and arterial blood (radial catheter) periodically collected throughout the exercise. Pulmonary gas exchange efficiency was evaluated using the alveolar-arterial difference ( ). There were no differences in any of the variables of interest between conditions before the start of the exercise. Pulmonary ventilation was up to 20% lower across all intensities during FENT compared to CTRL exercise (P<0.001) and this hypoventilation was accompanied by an up to 10% lower arterial and a 2-4mmHg higher (both P<0.001). The exercise-induced widening of was up to 25% larger during FENT compared to CTRL (P<0.001). Importantly, the differences developed within the first minute of each stage and persisted, or further increased, throughout the remainder of each bout. These findings reflect a critical and time-independent significance of feedback from group III/IV leg muscle afferents for continuously regulating the ventilatory response, gas exchange efficiency, arterial oxygenation and acid-base balance during human locomotion. KEY POINTS: Feedback from group III/IV leg muscle afferents reflexly contributes to hyperpnoea during short duration (i.e. <5min) locomotor exercise. Whether continuous feedback from these sensory neurons is obligatory to ensure adequate pulmonary responses during steady-state exercise of longer duration remains unknown. Lumbar intrathecal fentanyl was used to attenuate the central projection of group III/IV leg muscle afferents during prolonged locomotor exercise (i.e. 45min) at intensities ranging from 50% to 100% of . Without affecting the metabolic rate, afferent blockade compromised pulmonary ventilation and gas exchange efficiency, consistently impairing arterial oxygenation and facilitating respiratory acidosis throughout exercise. These findings reflect the time-independent significance of feedback from group III/IV muscle afferents for regulating exercise hyperpnoea and gas exchange efficiency, and thus for optimizing arterial oxygenation and acid-base balance, during prolonged human locomotion.

Lung function in patients with asthma in the post-COVID period

Aim. To assess the lung function in patients with bronchial asthma (BA) after new-onset coronavirus infection.Materials and methods. Fifty-five patients who underwent COVID-19 participated in the study under conditions of voluntary informed consent. The main group consisted of 30 patients with mild BA, the comparison group – 25 patients without chronic respiratory diseases (CRD). According to chest computed tomography (CT) findings, the degree of lung parenchyma involvement was classified as follows: mild COVID-19 (CT 0 stage) in 14 patients; moderate COVID-19 (CT 1-2 stages) in 27 patients; and severe COVID-19 (CT 3-4 stages) in 14 patients. Lung function tests were conducted once, adhering to both Russian and international standards.Results. In patients with BA, obstructive pulmonary function impairment was predominant at CT 1-2 stages (79%), CT 0 stage (67%), and CT 3-4 stages (43%). Lung diffusion capacity (LDC) was impaired predominantly in CT 3-4 stages in both BA patients and those without CRD, occurring in 57% of cases. Analysis of lung function showed that LDC reduction was detected in 17% of BA cases and 24% of non-CRD cases. There were no statistically significant changes in pulmonary ventilation among BA patients with impaired LDC compared to patients without CRD.Conclusion. All patients with respiratory symptoms after COVID-19 should undergo comprehensive lung function assessment to identify bronchial obstruction, impaired lung diffusion capacity, and ensure timely intervention.

Breathing variability during running in athletes: The role of sex, exercise intensity and breathing reserve

Highly trained aerobic athletes progressively use most of their breathing reserve with increased exercise intensity during whole-body exercise. Additionally, females typically present proportionally smaller lungs than males. Therefore, sex, exercise intensity, and breathing reserve use likely influence the volume and time in which respiratory parameters vary between consecutive breaths during whole-body exercise. However, breath-by-breath variability has been scarcely investigated during exercise. Accordingly, we sought to investigate breath-by-breath pulmonary ventilation (V̇E), tidal volume (VT), and respiratory frequency (fR) variability during a maximal treadmill incremental exercise test in 17 females and 18 males highly trained professional endurance runners. The breath-by-breath variability was analyzed by root mean square of successive differences (RMSSD) within 1-minute windows. Females had lower absolute and percent predicted forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) than males, as well as lower height-adjusted absolute FVC than males. V̇E and VT reserve use were similar between the sexes at peak exercise. While RMSSDV̇E and RMSSDfR did not change over exercise (P > 0.05), RMSSDVT progressively decreased (P < 0.001). RMSSDVT was negatively correlated with VT reserve use only in males. Females showed lower RMSSDV̇E than males during the entire exercise test (P < 0.001). At iso-V̇E reserve use, between-sex differences in RMSSDV̇E persisted (P = 0.003). Our findings indicate that exercise intensity decreases VT variability in professional runners, which is linked to VT reserve use in males but not females. Additionally, the female sex lowers V̇E variability regardless of exercise intensity and V̇E reserve use.

Descending motor drive does not interact with muscle metaboreflex for ventilation regulation during rhythmic exercise in healthy humans.

The muscle metaboreflex effect on pulmonary ventilation (V̇E) regulation is more apparent during rhythmic exercise than rest, possibly because this reflex interacts with other mechanisms regulating V̇E during voluntary contractions, such as central command. Therefore, we tested whether one part of central command, the descending component of motor execution (i.e., descending motor drive), and the muscle metaboreflex interact synergistically to regulate V̇E. Thirteen healthy adults (9 men) completed four experiments in random order under isocapnia. The muscle metaboreflex was activated by rhythmic handgrip exercise at 60% maximal voluntary contraction (MVC) force with the dominant hand. Then, the muscle metaboreflex remained active during a 4-min recovery period via postexercise circulatory occlusion (PECO), or it was inactivated, maintaining free blood flow to the dominant upper limb. During the last 2 min of the handgrip exercise recovery, participants either performed rhythmic voluntary plantar flexion with the dominant leg at 30% MVC torque to generate descending motor drive or the dominant leg's calf muscles were involuntarily activated by electrical stimulation at a similar torque level (i.e., without descending motor drive). V̇E increased to a similar level during handgrip exercise in all conditions (≈22 L/min, P = 0.364). PECO maintained V̇E elevated above recovery with free blood flow (≈17 L/min vs. ≈13 L/min, P = 0.009). However, voluntary and involuntary plantar flexion with or without PECO evoked similar V̇E responses (Δ ≈ 4 L/min, P = 0.311). Therefore, an interaction between descending motor drive and muscle metaboreflex is not ubiquitous for V̇E regulation during rhythmic exercise.NEW & NOTEWORTHY Voluntary (i.e., with descending motor drive) and involuntary (i.e., no descending motor drive) plantar flexion elicited similar ventilatory responses when postexercise circulatory occlusion was or was not used in an upper limb. These results indicate that the descending motor drive component of the central command and the muscle metaboreflex do not interact to regulate pulmonary ventilation during rhythmic exercise, which suggests that a supposed interaction between central command-muscle metaboreflex is more complex than previously thought.

Research progress in pulmonary rehabilitation in patients who have been weaned off mechanical ventilation: A review article.

Patients who have been treated with mechanical ventilation for more than 72 hours are susceptible to symptoms such as hypoxia and respiratory muscle fatigue after weaning, which may result in weaning difficulty and delay, as well as an increased incidence of negative emotions such as anxiety and depression. Correct pulmonary rehabilitation exercise technique and timing can improve the weaning success rate, reduce the disability rate, and reduce the incidence of pulmonary infection, as well as reduce medical expenses. This article provides a review of pulmonary rehabilitation interventions for mechanically ventilated patients, searching relevant literature through databases such as CNKI and PubMed, aiming to provide guidance for the successful weaning of mechanically ventilated patients. We selected articles related to pulmonary rehabilitation interventions for mechanically ventilated patients from CNKI (China National Knowledge Infrastructure) and PubMed over the years. This article provides a comprehensive review of the research on lung rehabilitation for patients who are mechanically ventilated during the weaning process in an effort to serve as a guide for a successful transition from mechanical ventilation. Early pulmonary rehabilitation training can effectively increase the pulmonary function level and ventilation function of patients and reduce the duration of mechanical ventilation and hospitalization, and is an effective, safe, and feasible treatment method.

Pressure never sucks, pressure only pushes: a physiological exploration of the pushing power of pressure.

The movement of air into and out of the lungs is facilitated by changes in pressure within the thoracic cavity relative to atmospheric pressure, as well as the resistance encountered by airways. In this process, the movement of air into and out of the lungs is driven by pressure gradients established by changes in lung volume and intra-alveolar pressure. However, pressure never sucks! The concept that pressure never sucks, pressure only pushes encapsulates a fundamental principle in the behavior of gases. This concept challenges common misconceptions about pressure, shedding light on the dynamic forces that govern the movement of gases. In this Illumination, we explore the essence of this concept and its applications in pulmonary ventilation. Pressure is one of the most important concepts in physics and physiology. Atmospheric pressure at sea level is equal to 1 atmosphere or around 101,325 Pascal [Pa (1 Pa = 1 N/m2)]. This huge pressure is pushing down on everything all the time. However, this pressure is difficult to understand because we do not often observe the power of this incredible force. We used five readily available, simple, and inexpensive demonstrations to introduce the physics and power of pressure. This extraordinarily complex physics concept was approached in a straightforward and inexpensive manner while still providing an understanding of the fundamental concepts. These simple demonstrations introduced basic concepts and addressed common misconceptions about pressure.NEW & NOTEWORTHY The concept that pressure never sucks, pressure only pushes challenges common misconceptions about pressure, shedding light on the dynamic forces that govern the movement of gases. In this Illumination, we will explore the essence of this concept and its applications in pulmonary ventilation. Specifically, we used five readily available, simple, inexpensive demonstrations to introduce the physics and power of pressure.

Effects of preterm birth on the pattern of altitude acclimatization at rest and during moderate-intensity exercise across three days at 3,375 m.

Preterm birth elicits long-lasting physiological effects in various organ systems, potentially modulating exercise and environmental stress responses. To establish whether prematurely-born adults respond uniquely during early high-altitude acclimatization at rest and during exercise, 17 healthy adults born preterm (gestational age < 32 wk) and 17 term-born, age- and aerobic-capacity-matched, control participants completed a three-day high-altitude sojourn (3,375 m). Oxygen uptake, pulmonary ventilation, and hemodynamic responses, as well as pulse oxygen saturation, brain tissue saturation index (TSI), and skeletal muscle TSI, were measured daily at rest and during moderate-intensity steady-state exercise bouts. In general, the prematurely-born group displayed comparable acclimatization responses at rest, with similar ventilation and cardiac output observed between groups throughout. Resting brain TSI was, however, higher in the preterm group upon arrival at high altitude (72 ± 7% vs. 68 ± 3%; d = 1.20). Absolute exercising oxygen uptake was lower in the preterm participants (P = 0.047), with this group displaying lower exercising cardiac output underpinned by reduced stroke volume (both P = 0.035). Nevertheless, exercising minute ventilation (V̇e) did not differ between groups (P = 0.237) while brain TSI (70 ± 6% vs. 66 ± 3%; d = 1.35) and pulse oxygen saturation (85 ± 3% vs. 82 ± 5%; d = 1.52) were higher with prematurity upon arrival to high altitude. These findings suggest that healthy prematurely-born adults exhibit comparable early acclimatization patterns to their term-born counterparts and better maintain cerebral oxygenation at rest. Together, these data suggest that prematurely-born adults should not be discouraged from high-altitude sojourns involving physical activity.NEW & NOTEWORTHY The acclimatization pattern across three days at 3,375 m, at rest and during moderate-intensity exercise, was similar between healthy adults born prematurely and their term-born counterparts. Preterm adults free from respiratory complications were found to better maintain brain tissue and capillary oxygen saturation at high altitudes, whereas the term-born group experienced larger altitude-induced reductions. Despite apparent cardiac limitations, preterm individuals tolerated exercise similarly to their term-born peers. These findings underscore the notion that preterm birth per se does not predispose healthy adults to decreased altitude tolerance during exercise.

Post-Pulmonary Embolism Phenotypes Described by Invasive Cardiopulmonary Exercise Testing

BackgroundPost pulmonary embolism (PE) dyspnea is common. Existing non-invasive studies have demonstrated that post PE dyspnea is associated with elevations in right ventricular afterload, dead space ventilation, and deconditioning. We aimed to use invasive cardiopulmonary exercise testing (iCPET) parameters in patients with post PE dyspnea to identify unique physiologic phenotypes. Research QuestionAre there distinct post pulmonary embolism dyspnea physiologic phenotypes described with iCPET? Study Design and MethodsPatients were enrolled at the time of acute PE and through our pulmonary hypertension and dyspnea clinic. ICPET was performed if there was high suspicion for pulmonary hypertension or if there was unexplained dyspnea. A hierarchical cluster analysis was performed to identify dyspnea phenotypes. ICPET parameters assessing pulmonary hemodynamics, ventilation, and peripheral oxygen utilization were then compared within and across each cluster and with iCPET controls against peak oxygen consumption (Peak VO2). Results173 patients were enrolled. Sixty-seven patients underwent iCPET. All patients had reductions in Peak VO2 and peak cardiac index relative to controls. Three clusters were identified. Cluster one was defined by having elevated RV afterload and impaired ventilatory efficiency. Cluster two had elevated RV afterload with reductions in respiratory mechanics. Cluster three had mild derangement in RV afterload with mild reductions in peak cardiac output. InterpretationiCPET reveals significant heterogeneity in post PE dyspnea. Three phenotypes are characterized by differences in RV afterload, ventilatory efficiency, respiratory mechanics, and peripheral oxygen utilization.

The efficacy and safety of herbal formulas for adults with pulmonary hypertension combined with chronic obstructive pulmonary disease: a systematic review and meta-analysis involving 1,865 participants.

There is currently no effective treatment for the majority of patients with chronic obstructive pulmonary disease combined with pulmonary hypertension (COPD-PH). Numerous clinical trials have demonstrated the use of traditional Chinese medicine (TCM) herbal formulas in combination with routine western pharmacotherapy (WP) for the treatment of COPD-PH, with positive results. This meta-analysis was designed to evaluate the efficacy and safety of TCM herbal formulas in the treatment of COPD-PH. A systematic literature search was conducted using Web of Science, PubMed, Chinese National Knowledge Infrastructure (CNKI), WanFang, and Chinese Science and Technology Journal (VIP) from database inception until October 2023. The primary outcome was pulmonary artery pressure parameters, including pulmonary artery systolic pressure (PASP) and mean pulmonary artery pressure (mPAP). Secondary outcomes included pulmonary ventilation function parameters, such as forced expiratory volume in one second (FEV1) and the ratio of FEV1 to forced vital capacity (FEV1/FVC%), as well as functional capacity assessments measured by the six-minute walk distance (6MWD). Reviewer Manager software was used for both random-effects and fixed-effects meta-analyses. We registered the protocol for this study with the International Platform of Registered Systematic Review and Meta-analysis Protocols (INPLASY, registry number: INPLASY2022100041). Twenty randomized control trials with a total of 1,865 patients were included in the meta-analysis. The results of our meta-analysis revealed that TCM herbal formulas in combination with basic WP significantly reduced pulmonary artery pressure in patients with COPD-PH, including PASP [mean difference (MD) =-4.50 mmHg, 95% confidence interval (CI): -6.04, -2.95] and mPAP (MD =-4.47 mmHg, 95% CI: -5.07, -3.88). Additionally, pulmonary ventilation function and 6MWD (MD =48.13 m, 95% CI: 39.92, 56.34) were also improved in COPD-PH patients. Pulmonary ventilation function was reflected by FEV1 (MD =0.83 L, 95% CI: 0.35, 1.30) and FEV1/FVC% (MD =4.76, 95% CI: 3.75, 5.77). A total of six studies reported adverse events in detail, and all claimed that no adverse events were observed in COPD-PH patients using TCM herbal formulas. The combination of TCM herbal formulas and basic WP might be more effective in improving the quality of life and exercise capacity of patients with COPD-PH than basic WP alone. However, the firm conclusions of our study were hampered by the low quality of the evidence.

Landmark registration in CT for lung model approximation in EIT

Abstract For the visualization of pulmonary ventilation with Electrical Impedance Tomography (EIT), most devices rely on generalized reconstruction models. Yet, fixed thorax dimensions, predetermined electrode locations, and standard lung shapes lead to multiple sources of EIT imaging distortion. The following work compares reconstructions of a library model, a practical model based on landmark fitting, and a detailed model based on manual segmentation. CT images of five pigs were segmented into torso surface, electrode positions, and lung borders. Practical models were created with reduced data, registration, and fitting. Detailed models were created by using the complete segmentation data. After EIT reconstruction and tidal image calculation, the overlap of CT lung segmentation and ventilated voxel was calculated. Compared with the results of a standardized model, the practical model reached an average ventilation/segmentation-overlap difference of an additional 12 %, and the detailed model achieved an average difference of 10 %. In conclusion, the shift of reconstructed impedance towards the segmented lung region is similar in both models when compared to the standard model, while the practical model requires a considerably less amount of information.

The Efficacy of Budesonide-formoterol in Patients with Acute Attacks of Mild-to-moderate Bronchial Asthma: An Observational Study.

To assess the impact of budesonide-formoterol on pulmonary ventilation function and prognosis in patients with mild-to-moderate acute exacerbations of bronchial asthma. A retrospective analysis was conducted on clinical data from 232 patients with acute exacerbations of bronchial asthma. These patients were divided into 2 groups based on their treatment: a control group (n=104) receiving budesonide dry powder inhalation and an observation group (n=107) receiving budesonide-formoterol dry powder inhalation. Clinical efficacy and safety indicators were compared. The results showed that the total treatment effectiveness rate in the observation group was significantly higher than that in the control group. Following treatment, the observation group exhibited significantly higher scores in the Asthma Quality of Life Questionnaire (AQLQ), as well as improved levels of forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF), compared to the control group. Moreover, levels of tumor necrosis factor-alpha, interleukin-6, and C-reactive protein were significantly lower in the observation group. The incidence of adverse reactions between groups was comparable. Based on these findings, the application of budesonide-formoterol demonstrated significant effectiveness in patients with mild-to-moderate acute exacerbations of bronchial asthma. The combination therapy led to improved clinical outcomes, including enhanced pulmonary ventilation function and reduced inflammatory markers. Importantly, the safety profile of budesonide-formoterol was comparable to that of budesonide monotherapy. These results highlight the potential benefits of using budesonide-formoterol as an alternative treatment option for patients experiencing acute exacerbations of mild-to-moderate bronchial asthma.