Arterial Gas Embolism in Breath-Hold Diver.

An arterial gas embolism (AGE) is a potentially fatal complication of scuba diving that is related to insufficient exhalation during ascent. During breath-hold diving, an arterial gas embolism is unlikely because the volume of gas in the lungs generally cannot exceed the volume at the beginning of the dive. However, if a diver breathes from a gas source at any time during the dive, they are at risk for an AGE or other pulmonary overinflation syndromes (POIS). In this case report, a breath-hold diver suffered a suspected AGE due to rapidly ascending without exhalation following breathing from an air pocket at approximately 40 feet.

Growth, filtration and respiration characteristics of small single-osculum demosponge Halichondria panicea explants.

Filter-feeding demosponges are modular organisms that consist of modules each with one water-exit osculum. Once a mature module has been formed, the weight-specific filtration and respiration rates do not change. Sponge modules only grow to a certain size and for a sponge to increase in size, new modules must be formed. However, the growth characteristics of a small single-osculum module sponge are fundamentally different from those of multi-modular sponges, and a theoretically derived volume-specific filtration rate scales as F/V=V-1/3, indicating a decrease with increasing total module volume (V, cm3). Here, we studied filtration rate (F, l h-1), respiration rate (R, ml O2 h-1), volume-specific (F/V) and weight-specific (F/W) filtration rates, and the ratios F/R and F/W along with growth rates of small single-osculum demosponge Halichondria panicea explants of various sizes exposed to various concentrations of algal cells. The following relationships were found: F/V=7.08V-0.24, F=a1W1.05, and R=a2W0.68 where W is the dry weight (mg). The F/R and F/W ratios were constant and essentially independent of W, and other data indicate exponential growth. It is concluded that the experimental data support the theoretical F/V∝V-1/3.

Breathing mode assessment with thermography: a pilot study. / Avaliação do modo respiratório por meio da termografia: um estudo piloto.

PURPOSE: To present a method for analyzing breathing modes with infrared thermography. METHODS: This exploratory cross-sectional study used 38 thermal images of inspiration and expiration with nasal breathing and simulated mouth breathing in four nasal breathers without respiratory complaints. Three different data selection forms (line, rectangle, and ellipse) were used to extract the minimum, mean, and maximum temperatures of the regions of interest (nose and mouth) using the FLIR Tools® software. RESULTS: Among the three selection forms, there was greater temperature variability obtained with the line, revealing limitations in this measurement. There were no differences between the rectangle and ellipse values, showing that both selection forms present similar temperature extraction results. The comparison results between nose and mouth temperatures during inspiration and expiration indicated a statistically significant difference between all measurements, except for mean inspiration temperatures with the rectangle and ellipse. The breathing mode can be distinguished in both inspiration and expiration when using mean mouth temperatures with the rectangle and ellipse. CONCLUSION: Breathing modes should be assessed based on mean mouth temperatures during inspiration, using the ellipse.

OBJETIVO: Apresentar um método de análise do modo respiratório por meio da termografia infravermelha. MÉTODO: Estudo transversal exploratório de 38 imagens térmicas que representavam o momento da inspiração e da expiração durante a respiração nasal e durante a simulação da respiração oral de quatro voluntárias respiradoras nasais sem queixas respiratórias. Para a extração da temperatura das regiões de interesse (nariz e boca) foram utilizadas três formas de seleção distintas de dados (linha, retângulo e elipse) e três medidas de temperatura (mínima, média e máxima) por meio do software FLIR Tools®. RESULTADOS: Dentre as três formas de seleção houve maior variabilidade nas medidas obtidas pela linha, revelando limitações nessa medida. Não houve diferenças entre as medidas do retângulo e elipse, mostrando que ambas as formas de seleção apresentam resultados semelhantes para a extração das temperaturas. Na comparação entre as temperaturas do nariz e da boca na inspiração e expiração, os resultados indicaram que houve diferença com relevância estatística em todas as medidas realizadas, exceto para as medidas de temperatura média da inspiração, usando o retângulo e a elipse. Percebe-se diferenciação do modo respiratório tanto na inspiração quanto na expiração quando utilizada a temperatura média da boca com o retângulo e a elipse. CONCLUSÃO: Sugere-se para avaliação do modo respiratório a avaliação da boca, por meio da elipse, com análise da temperatura média durante a inspiração.

Improvement of Lung Function by Micronutrient Supplementation in Patients with COPD: A Systematic Review and Meta-Analysis.

BACKGROUND: A healthy, well-balanced diet plays an essential role in respiratory diseases. Since micronutrient deficiency is relatively common in patients with chronic obstructive pulmonary disease (COPD), micronutrient supplementation might have the beneficial health effects in those patients. This systematic review and meta-analysis aimed to demonstrate the impact of micronutrient supplementation on the lung function of patients with COPD. METHODS: The PubMed, Cochrane Library, and Web of Science databases were searched from their corresponding creation until February 2024. Search terms included 'chronic obstructive pulmonary disease', 'COPD', 'micronutrients', 'dietary supplements', 'vitamins', 'minerals', and 'randomized controlled trials'. Meta-analysis was performed to evaluate the effects of micronutrient supplementation alone or complex on lung function in patients with COPD. RESULTS: A total of 43 RCTs fulfilled the inclusion criteria of this study. Meta-analysis revealed that vitamin D supplementation could significantly improve FEV1% (WMDdifferences between baseline and post-intervention (de): 6.39, 95% CI: 4.59, 8.18, p < 0.01; WMDpost-intervention indicators (af): 7.55, 95% CI: 5.86, 9.24, p < 0.01) and FEV1/FVC% (WMDde: 6.88, 95%CI: 2.11, 11.65, WMDaf: 7.64, 95% CI: 3.18, 12.10, p < 0.001), decrease the odds of acute exacerbations, and improve the level of T-cell subsets, including CD3+%, CD4+%, CD8+%, and CD4+/CD8+% (all p < 0.01). The effects of compound nutrients intervention were effective in improving FEV1% (WMDde: 8.38, 95%CI: 1.89, 14.87, WMDaf: 7.07, 95%CI: -0.34, 14.48) and FEV1/FVC% (WMDde: 7.58, 95% CI: 4.86, 10.29, WMDaf: 6.00, 95% CI: 3.19, 8.81). However, vitamin C and vitamin E supplementation alone had no significant effects on lung function (p > 0.05). CONCLUSIONS: Micronutrient supplementation, such as vitamin D alone and compound nutrients, has improved effect on the lung function of patients with COPD. Therefore, proper supplementation with micronutrients would be beneficial to stabilize the condition and restore ventilation function for COPD patients.

Aluminum Nitride Thin Film Piezoelectric Pressure Sensor for Respiratory Rate Detection.

In this study, we propose a low-cost piezoelectric flexible pressure sensor fabricated on Kapton® (Kapton™ Dupont) substrate by using aluminum nitride (AlN) thin film, designed for the monitoring of the respiration rate for a fast detection of respiratory anomalies. The device was characterized in the range of 15-30 breaths per minute (bpm), to simulate moderate difficult breathing, borderline normal breathing, and normal spontaneous breathing. These three breathing typologies were artificially reproduced by setting the expiratory to inspiratory ratios (E:I) at 1:1, 2:1, 3:1. The prototype was able to accurately recognize the breath states with a low response time (~35 ms), excellent linearity (R2 = 0.997) and low hysteresis. The piezoelectric device was also characterized by placing it in an activated carbon filter mask to evaluate the pressure generated by exhaled air through breathing acts. The results indicate suitability also for the monitoring of very weak breath, exhibiting good linearity, accuracy, and reproducibility, in very low breath pressures, ranging from 0.09 to 0.16 kPa. These preliminary results are very promising for the future development of smart wearable devices able to monitor different patients breathing patterns, also related to breathing diseases, providing a suitable real-time diagnosis in a non-invasive and fast way.

Unobtrusive Sensors for Synchronous Monitoring of Different Breathing Parameters in Care Environments.

Respiratory problems are common amongst older people. The rapid increase in the ageing population has led to a need for developing technologies that can monitor such conditions unobtrusively. This paper presents a novel study that investigates Wi-Fi and ultra-wideband (UWB) antenna sensors to simultaneously monitor two different breathing parameters: respiratory rate, and exhaled breath. Experiments were carried out with two subjects undergoing three breathing cases in breaths per minute (BPM): (1) slow breathing (12 BPM), (2) moderate breathing (20 BPM), and (3) fast breathing (28 BPM). Respiratory rates were captured by Wi-Fi sensors, and the data were processed to extract the respiration rates and compared with a metronome that controlled the subjects' breathing. On the other hand, exhaled breath data were captured by a UWB antenna using a vector network analyser (VNA). Corresponding reflection coefficient data (S11) were obtained from the subjects at the time of exhalation and compared with S11 in free space. The exhaled breath data from the UWB antenna were compared with relative humidity, which was measured with a digital psychrometer during the breathing exercises to determine whether a correlation existed between the exhaled breath's water vapour content and recorded S11 data. Finally, captured respiratory rate and exhaled breath data from the antenna sensors were compared to determine whether a correlation existed between the two parameters. The results showed that the antenna sensors were capable of capturing both parameters simultaneously. However, it was found that the two parameters were uncorrelated and independent of one another.

RT-SRTS: Angle-agnostic real-time simultaneous 3D reconstruction and tumor segmentation from single X-ray projection.

Radiotherapy is one of the primary treatment methods for tumors, but the organ movement caused by respiration limits its accuracy. Recently, 3D imaging from a single X-ray projection has received extensive attention as a promising approach to address this issue. However, current methods can only reconstruct 3D images without directly locating the tumor and are only validated for fixed-angle imaging, which fails to fully meet the requirements of motion control in radiotherapy. In this study, a novel imaging method RT-SRTS is proposed which integrates 3D imaging and tumor segmentation into one network based on multi-task learning (MTL) and achieves real-time simultaneous 3D reconstruction and tumor segmentation from a single X-ray projection at any angle. Furthermore, the attention enhanced calibrator (AEC) and uncertain-region elaboration (URE) modules have been proposed to aid feature extraction and improve segmentation accuracy. The proposed method was evaluated on fifteen patient cases and compared with three state-of-the-art methods. It not only delivers superior 3D reconstruction but also demonstrates commendable tumor segmentation results. Simultaneous reconstruction and segmentation can be completed in approximately 70 ms, significantly faster than the required time threshold for real-time tumor tracking. The efficacies of both AEC and URE have also been validated in ablation studies. The code of work is available at https://github.com/ZywooSimple/RT-SRTS.

Influence of Breath-Mimicking Ventilated Incubation on Three-Dimensional Bioprinted Respiratory Tissue Scaffolds.

Development of respiratory tissue constructs is challenging due to the complex structure of native respiratory tissue and the unique biomechanical conditions induced by breathing. While studies have shown that the inclusion of biomechanical stimulus mimicking physiological conditions greatly benefits the development of engineered tissues, to our knowledge no studies investigating the influence of biomechanical stimulus on the development of respiratory tissue models produced through three-dimensional (3D) bioprinting have been reported. This paper presents a study on the utilization of a novel breath-mimicking ventilated incubator to impart biomechanical stimulus during the culture of 3D respiratory bioprinted constructs. Constructs were bioprinted using an alginate/collagen hydrogel containing human primary pulmonary fibroblasts with further seeding of human primary bronchial epithelial cells. Biomechanical stimulus was then applied via a novel ventilated incubator capable of mimicking the pressure and airflow conditions of multiple breathing conditions: standard incubation, shallow breathing, normal breathing, and heavy breathing, over a two-week time period. At time points between 1 and 14 days, constructs were characterized in terms of mechanical properties, cell proliferation, and morphology. The results illustrated that incubation conditions mimicking normal and heavy breathing led to greater and more continuous cell proliferation and further indicated a more physiologically relevant respiratory tissue model.

Sleep-stage dependence and co-existence of cardio-respiratory coordination and phase synchronization.

Interactions between the cardiac and respiratory systems play a pivotal role in physiological functioning. Nonetheless, the intricacies of cardio-respiratory couplings, such as cardio-respiratory phase synchronization (CRPS) and cardio-respiratory coordination (CRC), remain elusive, and an automated algorithm for CRC detection is lacking. This paper introduces an automated CRC detection algorithm, which allowed us to conduct a comprehensive comparison of CRPS and CRC during sleep for the first time using an extensive database. We found that CRPS is more sensitive to sleep-stage transitions, and intriguingly, there is a negative correlation between the degree of CRPS and CRC when fluctuations in breathing frequency are high. This comparative analysis holds promise in assisting researchers in gaining deeper insights into the mechanics of and distinctions between these two physiological phenomena. Additionally, the automated algorithms we devised have the potential to offer valuable insights into the clinical applications of CRC and CRPS.

PREFUL MRI for Monitoring Perfusion and Ventilation Changes after Elexacaftor-Tezacaftor-Ivacaftor Therapy for Cystic Fibrosis: A Feasibility Study.

Purpose To assess the feasibility of monitoring the effects of elexacaftor-tezacaftor-ivacaftor (ETI) therapy on lung ventilation and perfusion in people with cystic fibrosis (CF), using phase-resolved functional lung (PREFUL) MRI. Materials and Methods This secondary analysis of a multicenter prospective study was carried out between August 2020 and March 2021 and included participants 12 years or older with CF who underwent PREFUL MRI, spirometry, sweat chloride test, and lung clearance index assessment before and 8-16 weeks after ETI therapy. For PREFUL-derived ventilation and perfusion parameter extraction, two-dimensional coronal dynamic gradient-echo MR images were evaluated with an automated quantitative pipeline. T1- and T2-weighted MR images and PREFUL perfusion maps were visually assessed for semiquantitative Eichinger scores. Wilcoxon signed rank test compared clinical parameters and PREFUL values before and after ETI therapy. Correlation of parameters was calculated as Spearman ρ correlation coefficient. Results Twenty-three participants (median age, 18 years [IQR: 14-24.5 years]; 13 female) were included. Quantitative PREFUL parameters, Eichinger score, and clinical parameters (lung clearance index = 21) showed significant improvement after ETI therapy. Ventilation defect percentage of regional ventilation decreased from 18% (IQR: 14%-25%) to 9% (IQR: 6%-17%) (P = .003) and perfusion defect percentage from 26% (IQR: 18%-36%) to 19% (IQR: 13%-24%) (P = .002). Areas of matching normal (healthy) ventilation and perfusion increased from 52% (IQR: 47%-68%) to 73% (IQR: 61%-83%). Visually assessed perfusion scores did not correlate with PREFUL perfusion (P = .11) nor with ventilation-perfusion match values (P = .38). Conclusion The study demonstrates the feasibility of PREFUL MRI for semiautomated quantitative assessment of perfusion and ventilation changes in response to ETI therapy in people with CF. Keywords: Pediatrics, MR-Functional Imaging, Pulmonary, Lung, Comparative Studies, Cystic Fibrosis, Elexacaftor-Tezacaftor-Ivacaftor Therapy, Fourier Decomposition, PREFUL, Free-Breathing Proton MRI, Pulmonary MRI, Perfusion, Functional MRI, CFTR, Modulator Therapy, Kaftrio Clinical trial registration no. NCT04732910 Supplemental material is available for this article. © RSNA, 2024.

The dynamics of recovery of external breathing function in patients after laparoscopic cholecystectomy in the acute period under the influence of the rehabilitation program.

OBJECTIVE: Aim: To determine the dynamics of renewal of the function of external respiration in patients after laparoscopic cholecystectomy at the acute stage of rehabilitation under the influence of a rehabilitation program. PATIENTS AND METHODS: Materials and Methods: The study is randomized, simple with blinded assessors. The forced vital capacity (FVC, l), forced expiratory volume in the first second (FEV1, l) and peak expiratory flow rate (PEFR, l/s) were assessed. Spirometry was performed 120 patients on the first day of admission of patients to the surgical department for surgical intervention, on the second day and on the day of discharge. Methods of mathematical statistics: arithmetic mean (M) and standard error of the mean (}m), Student's t-test were calculated, differences at p<0,05 were considered statistically significant. RESULTS: Results: It has been established that laparoscopic cholecystectomy leads to a statistically significant decrease in the parameters of respiratory function in all age categories. More pronounced positive dynamics of respiratory function in the group of respiratory therapy. It was established that without respiratory therapy on the day of discharge there was no restoration (р<0.05) in groups of elderly patients of group of FVC l, FEV1 l, PEFR l/s; in middle-aged patients did no restoration FEV1, l, PEFR, l/s; in younger patients there was no recovery of FEV1, l. CONCLUSION: Conclusions: The results of the study indicate the effectiveness of the introduction of diaphragmatic breathing exercises in combination with early mobilization at the acute and subacute stages of rehabilitation in patients after laparoscopic cholecystectomy in order to restore the function of the respiratory system.

Assessment of maximal inspiratory and expiratory pressures in skeletal Class II patients with different growth patterns.

OBJECTIVES: To evaluate maximal inspiratory (MIP) and expiratory (MEP) pressures, which are reflective of respiratory muscle strength, in skeletal Class II patients with different growth patterns (horizontal, average, and vertical) and to correlate those with airway dimension. MATERIALS AND METHODS: Patients with a Class II skeletal base seeking orthodontic treatment were assigned to the following groups: average, horizontal, and vertical growth pattern. The control group (n = 14) comprised patients with a Class I skeletal base and average growth pattern. Airway dimensions were obtained using cone-beam computed tomography scans, and a spirometer with a pressure transducer was used for assessment of MIP and MEP. Routine spirometry for assessment of lung function was also performed. RESULTS: No significant differences were found in maximal inspiratory and expiratory pressures for the study groups in comparison with the control group. Class I patients had significantly greater oropharyngeal and nasopharyngeal airway volumes compared with the study groups. No significant difference in minimal cross-section area of the airway was observed among groups. A weak positive correlation between maximal inspiratory pressure and airway volume was observed. CONCLUSIONS: Although Class I patients displayed significantly greater oropharyngeal and nasopharyngeal airway volumes, there was no significant difference in respiratory muscle strength or airway function between Class II patients with different growth patterns and the Class I control group. The findings underscore the significance of exploring factors beyond craniofacial growth patterns that may contribute to sleep-related breathing disorders.

The Effects of Yoga Breathing Before Motor Speech Practice in Acquired Apraxia of Speech: An n-of-1 Trial.

A previous study discovered that two speakers with moderate apraxia of speech increased their sequential motion rates after unilateral forced-nostril breathing (UFNB) practiced as an adjunct to speech-language therapy in an AB repeated-measures design. The current study sought to: (1) delineate possible UFNB plus practice effects from practice effects alone in motor speech skills; (2) examine the relationships between UFNB integrity, participant-reported stress levels, and motor speech performance; and (3) sample a participant-led UFNB training schedule to contribute to the literature's growing understanding of UFNB dosage. A single-subject (n-of-1 trial), ABAB reversal design was used across four motor speech behaviors. A 60-year-old female with chronic, severe apraxia of speech participated. The researchers developed a breathing app to assess UFNB practice integrity and administer the Simple Aphasia Stress Scale after each UFNB session. The participant improved from overall severe to moderate apraxia of speech on the Apraxia Battery for Adults. Visual inspection of graphs confirmed robust motor speech practice effects for all variables. Articulatory-kinematic variables demonstrated sensitivity to the UFNB-plus-practice condition and correlated to stress scale scores but not UFNB integrity scores. The participant achieved 20-minute UFNB sessions 4 times per week. Removal of UFNB during A2 (UFNB withdrawal) and after a 10-day break during B2 (UFNB full dosage) revealed UFNB practice effects on stress scale scores. UFNB with motor speech practice may benefit articulatory-kinematic skills compared to motor speech practice alone. Regular, cumulative UFNB practice appeared to lower self-perceived stress levels. These findings, along with prior work, provide a foundation to further explore yoga breathing and its use with speakers who have apraxia of speech.

Comparison of weighting algorithms to mitigate respiratory motion in free-breathing neonatal pulmonary radial UTE-MRI.

Background. Thoracoabdominal MRI is limited by respiratory motion, especially in populations who cannot perform breath-holds. One approach for reducing motion blurring in radially-acquired MRI is respiratory gating. Straightforward 'hard-gating' uses only data from a specified respiratory window and suffers from reduced SNR. Proposed 'soft-gating' reconstructions may improve scan efficiency but reduce motion correction by incorporating data with nonzero weight acquired outside the specified window. However, previous studies report conflicting benefits, and importantly the choice of soft-gated weighting algorithm and effect on image quality has not previously been explored. The purpose of this study is to map how variable soft-gated weighting functions and parameters affect signal and motion blurring in respiratory-gated reconstructions of radial lung MRI, using neonates as a model population.Methods. Ten neonatal inpatients with respiratory abnormalities were imaged using a 1.5 T neonatal-sized scanner and 3D radial ultrashort echo-time (UTE) sequence. Images were reconstructed using ungated, hard-gated, and several soft-gating weighting algorithms (exponential, sigmoid, inverse, and linear weighting decay outside the period of interest), with %Nprojrepresenting the relative amount of data included. The apparent SNR (aSNR) and motion blurring (measured by the maximum derivative of image intensity at the diaphragm, MDD) were compared between reconstructions.Results. Soft-gating functions produced higher aSNR and lower MDD than hard-gated images using equivalent %Nproj, as expected. aSNR was not identical between different gating schemes for given %Nproj. While aSNR was approximately linear with %Nprojfor each algorithm, MDD performance diverged between functions as %Nprojdecreased. Algorithm performance was relatively consistent between subjects, except in images with high noise.Conclusion. The algorithm selection for soft-gating has a notable effect on image quality of respiratory-gated MRI; the timing of included data across the respiratory phase, and not simply the amount of data, plays an important role in aSNR. The specific soft-gating function and parameters should be considered for a given imaging application's requirements of signal and sharpness.

The air conditioning in the nose of mammals depends on their mass and on their maximal running speed.

The nose of the mammals is responsible for filtering, humidifying, and heating the air before entering the lower respiratory tract. This conditioning avoids, notably, dehydration of the bronchial and alveolar mucosa. However, since this conditioning is not perfect, exercising in cold air can induce lung inflammation, both for human and non-human mammals. This work aims to compare the air conditioning in the noses of various mammals during inspiration. We build our study on computational fluid dynamics simulations of the heat exchanges in the lumen of the upper respiratory tract of these mammals. These simulations show that the efficiency of the air conditioning in the nose during inspiration does not relate only to the mass m of the mammal but also to its maximal running speed v. More precisely, the results allow establishing a scaling law relating the efficiency of air conditioning in the nose of mammals to the ratio v / log 10 ( m ) . The simulations also correlate the resistance to the flow in the nose to the efficiency of this air conditioning. The obtained scaling law allows predicting the air temperature at the top of the trachea during inspiration for nasal-breathing mammals, and thus notably for humans of various ages.

Small RNA-modulated anaerobic respiration allows bacteria to survive under antibiotic stress conditions.

Despite extensive knowledge of antibiotic-targeted bacterial cell death, deeper understanding of antibiotic tolerance mechanisms is necessary to combat multi-drug resistance in the global healthcare settings. Regulatory RNAs in bacteria control important cellular processes such as cell division, cellular respiration, metabolism, and virulence. Here, we investigated how exposing Escherichia coli to the moderately effective first-generation antibiotic cephalothin alters transcriptional and post-transcriptional dynamics. Bacteria switched from active aerobic respiration to anaerobic adaptation via an FnrS and Tp2 small RNA-mediated post-transcriptional regulatory circuit. From the early hours of antibiotic exposure, FnrS was involved in regulating reactive oxygen species levels, and delayed oxygen consumption in bacteria. We demonstrated that bacteria strive to maintain cellular homeostasis via sRNA-mediated sudden respiratory changes upon sublethal antibiotic exposure.