Breathing Conditions Research Articles

Features of human capillary blood flow on breathing by heated helio-oxygen mixtures

The purpose of the study: to assess the features of microcirculatory blood flow.Materials and methods. A comparative assessment of microcirculation by laser Doppler flowmetry was carried out in 19 male volunteers aged 20–25 years against the background of breathing heated to 40° C oxygen-nitrogen and helium-oxygen gas mixtures.Main results. Breathing with a heated oxygen-nitrogen mixture consisted in an increase (by approximately 25–35%) of the values of the integral indicator of microcirculation against the background of a decrease in its efficiency. Switching to breathing with a heated helium-oxygen mixture «HeliOx 25/75» in all examined persons also led to an increase in the volumetric velocity of the peripheral blood flow. However, the degree of increase in the indicator (by 35–45% compared with normal breathing conditions) turned out to be significantly more pronounced than it was during breathing with a heated oxygen-nitrogen mixture. In addition, when breathing «HeliOx 25/75», starting from about the 2nd minute of breathing, an increase in the efficiency of microcirculation was observed due to an increase in the «contribution» to the blood flow reaction of its «active» (neuromyogenic) components.

Effects of nasal breathing on partial pressure of carbon dioxide in arterial blood during prolonged exercise in a hot environment

Prolonged exercise in a hot environment increases the minute ventilation (VE) and respiratory rate (RR) with an increase in core temperature. This hyperthermia-induced hyperventilation decreases the partial pressure of arterial blood carbon dioxide (PaCO2). Conversely, nasal breathing during exercise has been reported to produce low VE and RR values and high PaCO2 values; however, no studies have investigated this in hot environments. Therefore, the purpose of this study was to clarify the effect of nasal breathing on estimated partial pressure of carbon dioxide in arterial blood (PaCO2,estimate) during prolonged exercise in a hot environment. Twelve university endurance athletes participated in the study and performed a 40-minutes steady-state cycling exercise at an intensity of 55% of peak oxygen uptake in a hot environment (room temperature 35℃, relative humidity 40%). Using randomized crossover design, two experiments were performed—nasal breathing condition (NB) and mouth breathing condition (MB). Moreover, physiological indices were measured during the exercise. Rectal temperature increased in both conditions, but there was no significant difference between these conditions. PaCO2,estimate values were significantly higher in NB between 10 minutes and 40 minutes of exercise (p < 0.05) compared to MB, and decreased with time in MB. Compared to MB, the VE was significantly lower in NB between 30 minutes and 40 minutes (p < 0.05), while the RR was significantly lower in NB between 25 minutes and 40 minutes of exercise (p < 0.05). Therefore, nasal breathing during a prolonged moderate-intensity exercise in a hot environment prevented the decrease in PaCO2,estimate due to hyperthermia-induced hyperventilation.

A Minimally Interactive Method for Labeling Respiratory Phases in Free-Breathing Thoracic Dynamic MRI for Constructing 4D Images.

Determination of end-expiration (EE) and end-inspiration (EI) time points in the respiratory cycle in free-breathing slice image acquisitions of the thorax is one key step needed for 4D image construction via dynamic magnetic resonance imaging. The purpose of this paper is to realize the automation of the labeling process. The diaphragm is used as a surrogate for tracking respiratory motion and determining the state of breathing. Regions of interest (ROIs) containing the hemi-diaphragms are set by human interaction to compute the optical flow matrix between two adjacent 2D time slices. Subsequently, our approach examines the diaphragm speed and direction and by considering the change in the optical flow matrix, the EE or EI points are detected. The labeling accuracy for the lateral aspect of the left lung and the lateral aspect of the right lung (0.63±0.71) is significantly lower (P < 0.05) than the accuracy for other positions (0.42±0.44), but the error in almost all scenarios is less than 1 time point. By comparing between automatic and manual labeling in 12 scenarios, we found out that 9 scenarios showed no significant difference (P > 0.05) between two methods. Overall, our method is found to be highly agreeable with manual labeling and greatly shortens the labeling time, requiring less than 8 minutes/ study compared to 4 hours/ study for manual labeling. Our method achieves automatic labeling of EE and EI points without the need for use of patientinternal or external markers.

The Effect of Breathing Laterality on Hip Roll Kinematics in Submaximal Front Crawl Swimming.

The purpose of this study was to determine the effect of breathing laterality on hip roll kinematics in submaximal front crawl swimming. Eighteen elite competitive swimmers performed three 100 m front crawl trials at a consistent sub-maximal speed (70% of seasonal best time) in a 25 m pool. Each trial was performed with one of three different breathing conditions: (1) unilateral breathing (preferred side), (2) bilateral breathing (alternating left/right-side every 3 strokes) and (3) simulated non-breathing using a swim snorkel. A waist-mounted triaxial accelerometer was used to determine continuous hip roll angle throughout the trial, from which peak hip roll angles (Ө) and average angular velocities (ω) were calculated. Two-way repeated measures ANOVAs were used to identify significant main effects for laterality (preferred vs. non-preferred breathing sides) and condition (unilateral, bilateral and snorkel breathing) for both Ө and ω. Peak hip roll to the preferred side was significantly greater (p < 0.001) in the unilateral condition, while ω to the non-preferred side was significantly greater in the unilateral (p < 0.01) and bilateral (p < 0.04) conditions. Significant same-side differences were also found between the different breathing conditions. The results demonstrate that breathing laterality affects hip roll kinematics at submaximal speeds, and that unilateral and snorkel breathing are associated with the least and most symmetric hip roll kinematics, respectively. The findings show that a snorkel effectively balances and controls bilateral hip rotation at submaximal speeds that are consistent with training, which may help to minimize and/or correct roll asymmetries that are the result of unilateral breathing.

Complex Approach to Diagnosis of Nasal Cavity and Nasopharyngeal Pathologies in Children. Initial Results

Background. Nasal cavity and nasopharyngeal pathology are crucial and common issue in pediatric otorhinolaryngology. One of the major reasons for the nasal breathing difficulties are adenoids, allergic rhinitis, acute rhinitis, rhinosinusitis, nasal septum deviation. All these diseases can occur individually and in combination with each other, while clinical signs can be similar.Objective. The aim of the study is study and estimate the condition of nasal breathing and sense of smell in children with different nasal and nasopharyngeal pathology.Methods. The study included 128 children, all children were divided into 3 groups comparable by gender and age. Children with confirmed acute ENT organ disease were included in the 1st group, children with allergic disease exacerbation were included in the 2nd group, and clinically healthy children (control group) were included in the 3rd group. Survey methodology: rhinomanometry (RMM), rhinoresistometry (RRM), olfactometry.Results. It was revealed that nasal resistance in children with allergic diseases exacerbation is significantly higher both before and after anemisation of nasal mucosa with a solution of nasal decongestants than in children of the control group (according to the RRM). The air flow rate increases by average of 25% in children with various ENT organs diseases, and in children with allergic diseases — by average of 43% after anemisation of the nasal mucosa. The obtained data shows the role of nasal mucosal edema in patients with allergic diseases during exacerbation. Analysis of our RMM and RRM data suggests the importance of further use of these methods in children.Conclusion. The obtained results will allow us to optimize the diagnosis approach and personalize the management of patients with various nasal cavity and nasopharynx pathologies. Nowadays, the study is ongoing.

Effect of Moderate- or High-Intensity Inspiratory Muscle Strength Training on Maximal Inspiratory Mouth Pressure and Swimming Performance in Highly Trained Competitive Swimmers.

Inspiratory muscle strength training (IMST) can improve exercise performance. Increased maximal inspiratory mouth pressure (MIP) could be beneficial for swimmers to enhance their performance. This study aimed to clarify the effect of high-intensity IMST for 6weeks on MIP and swimming performance in highly trained competitive swimmers. Thirty male highly trained competitive swimmers were assigned to high-intensity IMST (HI; n = 10), moderate-intensity IMST (MOD; n = 10), and control (n = 10) groups. The 6-week IMST intervention comprised twice daily sessions for 6d/wk at inspiratory pressure threshold loads equivalent to 75% MIP (HI) and 50% MIP (MOD). Before and after the intervention, MIP and swimming performance were assessed. Swimming performance was evaluated in free and controlled frequency breathing 100-m freestyle swimming time trials in a 25-m pool. For controlled frequency breathing, participants took 1 breath every 6 strokes. The MIP values after 2 and 6 weeks of IMST in the HI and MOD groups were significantly higher than those before IMST (P = .0001). The magnitudes of the MIP increases after 6 weeks of IMST did not differ between the HI (13.4% [8.7%]) and MOD (13.1% [10.1%]) groups (P = .44). The 100-m freestyle swimming times under the controlled frequency condition were significantly shorter after IMST than those before IMST in both the HI (P = .046) and MOD (P = .042) groups. Inspiratory pressure threshold load equivalent to 50% MIP could be sufficient to improve MIP and swimming performance under the controlled frequency breathing condition in highly trained competitive swimmers.

Humidity-Based Human-Machine Interaction System for Healthcare Applications.

Human-machine interaction (HMI) systems are widely used in the healthcare field, and they play an essential role in assisting the rehabilitation of patients. Currently, a large number of HMI-related research studies focus on piezoresistive sensors, self-power sensors, visual and auditory receivers, and so forth. These sensing modalities do not possess high reliability with regard to breathing condition detection. The humidity signal conveyed by breathing provides excellent stability and a fast response; however, humidity-based HMI systems have rarely been studied. Herein, we integrate a humidity sensor and a graphene thermoacoustic device into a humidity-based HMI system (HHMIS), which is capable of monitoring respiratory signals and emitting acoustic signals. HHMIS has a practical value in healthcare to assist patients. For example, it works as a prewarning system for respiratory-related disease patients with abnormal respiratory rates, and as an artificial throat device for aphasia patients. Achieved based on a laser direct writing technology, this wearable device features low cost, high flexibility, and can be prepared on a large scale. This portable non-contact HMMIS has broad application prospects in many fields such as medical health and intelligent control.

Test–retest reliability of heart-rate variability metrics in individuals with aphasia

ABSTRACT Individuals with aphasia may have impairments in cognition, higher incidences of depression, and a variety of post-stroke functional impairments. However, evaluating these issues is challenging since most assessments require some degree of linguistic processing and task instructions are often verbal. Heart rate variability has shown to be an objective marker for cognitive functioning in neurologically healthy individuals, depression and post-stroke depression, and post-stroke functional impairments. However, before the utility of heart rate variability is established in persons with aphasia, its test–retest reliability needs to be established. The purpose of this study was to assess test–retest reliability of heart rate variability metrics in persons with aphasia. Heart rate variability was recorded at rest while in a sitting position in twenty-one persons with aphasia at two time points. Heart rate variability metrics were mostly moderately reliable. The majority of participants had resting heart rate variability parasympathetic and sympathetic indexes similar to those of neurologically healthy individuals. Further research is needed to establish the test–retest reliability of heart rate variability metrics in different postures and breathing conditions in persons with aphasia.

Prevalence of upper airway resistance syndrome in the São Paulo Epidemiologic Sleep Study

ObjectiveTo establish the prevalence of upper airway resistance syndrome (UARS) according to different diagnostic criteria and evaluate its epidemiological characteristics in a representative sample of a large urban center. MethodsThis was a single-center evaluation involving volunteers from EPISONO, an epidemiological study focused on sleep disturbances and related factors in adults from São Paulo, Brazil in 2007. ResultsConsidering the diagnostic criteria for UARS to be an apnea–hypopnea index of <5 events/h, minimum SpO2 ≥ 92%, the presence of airflow limitation during sleep for ≥5% of total sleep time, and daytime symptoms (sleepiness and/or fatigue), we observed a prevalence of the condition of 3.1% (4.4% in women and 1.5% in men). ConclusionsAlthough the diagnostic criteria for UARS, or even its existence as a syndrome, are still a subject of debate in the literature, the findings from this epidemiological study highlights UARS as a non-hypoxic sleep-disordered breathing condition with a significant prevalence in the general population, being more frequent among female young adults.

Breathing zone and exhaled air re-inhalation rate under transient conditions assessed with a computer-simulated person.

The breathing zone of an individual indoors is usually defined as a finite region steadily formed in front of a face. Assuming the steady formation of the breathing zone, we propose a procedure for quantitatively identifying a breathing zone formed in front of a human face in the transient condition. This assumption is reasonable considering that the ventilation time scale of human respiration is sufficiently short compared to the ventilation time scale of a room. We used steady-state computational fluid dynamics (CFD) and a computationally simulated person (CSP). We present the probabilistic size of the breathing zone for various postures and breathing conditions. By analyzing unsteady inhalation and exhalation airflow characteristics via a CSP with a respiratory system, we also estimated the direct re-inhalation rate of the exhaled air. The results can be used for developing methods to control the long-term and low-contaminant concentration exposures.

Smart Face Mask Based on an Ultrathin Pressure Sensor for Wireless Monitoring of Breath Conditions (Adv. Mater. 6/2022)

Wearable Healthcare Devices Convenient breath monitoring via wearable devices is helpful for personal healthcare, especially during the COVID-19 pandemic. In article number 2107758, Kenjiro Fukuda, Takao Someya, and co-workers develop a wearable smart face mask based on an ultrathin self-powered pressure sensor with high output ability, and various breath conditions from multiple testers are wirelessly detected and analyzed.

Locally tuned deformation fields combination for 2D cine-MRI-based driving of 3D motion models.

To target mobile tumors in radiotherapy with the recent MR-Linac hardware solutions, research is being conducted to drive a 3D motion model with 2D cine-MRI to reproduce the breathing motion in 4D. This work presents a method to combine several deformation fields using local measures to better drive 3D motion models. The method uses weight maps, each representing the proximity with a specific area of interest. The breathing state is evaluated on cine-MRI frames in these areas and a different deformation field is estimated for each using a 2D to 3D motion model. The different deformation fields are multiplied by their respective weight maps and combined to form the final field to apply to a reference image. A global motion model is adjusted locally on the selected areas and creates a 3DCT for each cine-MRI frame. The 13 patients on which it was tested showed on average an improvement of the accuracy of our model of 0.71mm for areas selected to drive the model and 0.5mm for other areas compared to our previous method without local adjustment. The additional computation time for each region was around 40ms on a modern laptop. The method improves the accuracy of the2D-based driving of 3D motion models. It can be used on top of existing methods relying on deformation fields. It does add some computation time but, depending on the area to deform and the number of regions of interests, offers the potential of online use.

1-hour t-piece spontaneous breathing trial vs 1-hour zero pressure support spontaneous breathing trial and reintubation at day 7: A non-inferiority approach

Physiological data suggest that T-piece and zero pressure support (PS0) ventilation both accurately reflect spontaneous breathing conditions after extubation. These two types of spontaneous breathing trials (SBTs) are used in our Intensive Care Unit to evaluate patients for extubation readiness and success but have rarely been compared in clinical studies. We performed a prospective observational study to confirm the hypothesis that 1-hour T-piece SBT and 1-h PS0 zero PEEP (ZEEP) SBT are associated with similar rates of reintubation at day 7 after extubation. A non-inferiority approach was used for sample size calculation. The cohort consisted of 529 subjects invasively ventilated for more than 24h and extubated after successful 1-hour T-piece SBT (n=303, 57%) or 1-h PS0 ZEEP SBT (n=226, 43%). The reintubation rate at day 7 was 14.6% with PS0 ZEEP and 17.5% with T-piece (difference-2.6% [95% confidence interval, -8.3% to 4.3%]; p=0.40). The reasons for reintubation did not differ significantly when compared between patients with 1-h PS0 ZEEP SBT and patients with 1-hour T-piece SBT. Our results suggest that successful 1-hour T-piece and 1-h PSO ZEEP SBTs are associated with similar reintubation rates at day 7.

Quantitative analysis of changes in lung density by dynamic chest radiography in association with CT values: a virtual imaging study and initial clinical corroboration.

Dynamic chest radiography (DCR) identifies pulmonary impairments as decreased changes in radiographic lung density during respiration (Δpixel values), but not as scaled/standardized computed tomography (CT) values. Quantitative analysis correlated with CT values is beneficial for a better understanding of Δpixel values in DCR-based assessment of pulmonary function. The present study aimed to correlate Δpixel values from DCR with changes in CT values during respiration (ΔCT values) through a computer-based phantom study. A total of 20 four-dimensional computational phantoms during forced breathing were created to simulate both CT and projection images of the same virtual patients. The Δpixel and ΔCT values of the lung fields were correlated on a regression line, and the inclination was statistically evaluated to determine whether there were significant differences among physical types, sex, and breathing methods. The resulting conversion expression was also assessed in the DCR images of 37 patients. The resulting Δpixel values for 30/37 (81%) real patients, 6/7 (86%) normal controls, and 24/30 (80%) chronic obstructive pulmonary disorder patients were within the range of ΔCT values ± standard deviation (SD) reported in a previous study. In addition, no significant differences were detected for each condition of thoracic breathing, suggesting that the same regression line inclination values measured across the entire lung can be used for the conversion of Δpixel values, providing a quantitative analysis that can be correlated with ΔCT values. The developed conversion expression may be helpful for improving the understanding of respiratory changes using radiographic lung densities from DCR-based assessments of pulmonary function.

Stretchable graded multichannel self-powered respiratory sensor inspired by shark gill

Respiratory sensing provides a simple, non-invasive, and efficient way for medical diagnosis and health monitoring, but it relies on sensors that are conformal, accurate, durable, and sustainable working. Here, a stretchable, multichannel respiratory sensor inspired by the structure of shark gill cleft is reported. The bionic shark gill structure can convert transverse elastic deformation into longitudinal elastic deformation during stretching. Combining the optimized bionic shark gill structure with the piezoelectric and the triboelectric effect, the bionic shark gill respiratory sensor (BSG-RS) can produce a graded electrical response to different tensile strains. Based on this feature, BSG-RS can simultaneously monitor the breathing rate and breathing depth of the human body accurately, and realize the effective recognition of the different human body's breathing state under the supporting software. With good stretchability, wearability, accuracy, and long-term stability (50,000 cycles), BSG-RS is expected to be applied as self-powered smart wearables for mobile medical diagnostic analysis in the future.

Evaluation of Correlation Between Surface Diaphragm Electromyography and Airflow Using Fixed Sample Entropy in Healthy Subjects.

In clinic, the acquisition of airflow with nasal prongs, masks, thermistor to monitor respiratory function is more uncomfortable and inconvenience than surface diaphragm electromyography (EMGdi) using electrode pads. The EMGdi with strong electrocardiograph (ECG) interference affect the extraction of its characteristic information. In this work, surface EMGdi and airflow signals of 20 subjects were collected under 5 incremental inspiratory threshold loading protocols from quiet breathing to maximum forced breathing. First, we filtered out the ECG interference in EMGdi based on the combination of stationary wavelet transform and the positioning of ECG to obtain pure EMGdi (EMGdip). Second, the Spearman's rank correlation coefficients between EMGdi and EMGdip quantified by time series fixed sample entropy (fSampEn), root mean square (RMS), and envelope were compared to verify the robustness of the fSampEn to ECG. A comparative analysis of correlation between fSampEn of EMGdi and inspiratory airflow and the correlation between envelope of EMGdip (EMGdie) and inspiratory airflow found that there was no significant difference between the two, indicating the feasibility of using fSampEn to predict airflow. Moreover, fSampEn of EMGdi was used as characteristic parameter to build a quantitative relationship with the airflow by polynomial regression analysis. Mean coefficient of determination of all subjects in any breathing state is greater than 0.88. Finally, nonlinear programming method was used to solve a universal fitting coefficient between fSampEn of EMGdi and airflow for each subject to further evaluate the possibility of using surface EMGdi to monitor and control respiratory activity.

Comprehensive assessment of the respiratory function of nasal packs with airway tubes

We studied packs with air tubes from two manufacturers: Medtronic and Spiggle & Theis. During the experimental part, measurements of the air tubes and their study using acoustic rhinometry were carried out. In the clinical part, there were two groups of patients with different types of tampons and control group of volunteers with normal nasal breathing, the total number of participants was 45 people. All patients of groups 1 and 2 underwent septoplasty, bilateral lower partial conchotomy. In the postoperative period, rhinomanometry, rhinoflowmetry, a study of the duration of nasal breathing, and a subjective assessment of nasal breathing were performed. According to measurements and acoustic rhinometry, the airway tubes of the tampons have a cross-sectional area that is more than 4 times smaller than the narrowest part of the nasal cavity in healthy volunteers. According to the results of a clinical study, the tampons in question are not able to provide a level of nasal breathing comparable to normal, even after clearing the lumen by a doctor. Medtronic packs provide somewhat better airway function due to the larger internal diameter of the tubes, but also do not create conditions for satisfactory nasal breathing. Improving the respiratory function of tampons in the future can be achieved by increasing the internal lumen of the breathing tubes while maintaining comfort of use.

P-OGC64 High Fidelity Patient-Reported Outcome Monitoring following Upper Gastrointestinal and Hepato-Pancreato-Biliary Cancer Surgery. Early Experience with a Novel Application

Abstract Background Patients undergoing complex upper-gastrointestinal and hepatopancreatobiliary resections experience a high incidence of post-operative symptoms. There is significant scope to expand clinicians’ understanding of longitudinal symptom progression and recognise a greater range of post-operative symptoms than those traditionally recorded. By identifying symptoms most troublesome to patients we anticipate improvement in patients’ symptom management, the surgical consent process and, ultimately, patient experience. The myICUvoice application provides patients with the opportunity to report symptoms across a wide range of domains in real-time. We report our early experience using this application with patients in the post-operative setting. Methods Following institutional governance approval, consecutive patients undergoing pancreatic, or hepatic (H) or oesophagogastric (U) resectional surgery during a four week period at a single tertiary centre were offered the opportunity to use the application. From day-1 post-op to discharge, each patient completed surveys at least twice daily, reporting their experience across a list of 34 symptoms together with pain, breathing, mood and physical state. Both individual and cohort time-series data were obtained for each symptom and stratified by resection type. A dashboard has been developed as part of the application to allow summary data to be easily displayed. Results 342 symptom surveys were completed by a total of 15 patients (5U, 10H). The median length-of-stay was 11-days and 91% of patients completed 2 surveys/day (Table-1). High frequency symptoms were tiredness (reported in H:80%;U:86% of surveys), dry mouth (14/15 patients, H:91%,U:59%) and uncomfortable position (13/15 patients, H:27%,U:43%). Whilst most patients remained happy, there were frequent reports of psychological distress; 53% reported nightmares (H:6%,U:12% of surveys), 67% felt depressed, (H:12%,U:6% of surveys) and 53% anxious (H:14%,U:6% of surveys). Pain statement analysis (Figure-1) revealed distinct profiles providing high resolution data on the efficacy of analgesic regimes/techniques. Conclusions As expected, our patient cohort experienced a wide range, and high frequency, of post-operative symptoms. Experience conducting symptom surveys demonstrated a high incidence of disconnect between clinical expectations and reported symptoms. Our data illustrate the value of detailed symptom monitoring and this application could be used routinely to measure and improve the patient experience. Further research is planned to compare the performance of these standardised symptom surveys to current methods of identifying symptoms. Furthermore, data from specific patient populations could better inform patient expectations of the post-operative symptoms they may experience, thus improving the surgical consent process.

This Month in Anesthesiology

This Month in Anesthesiology

The Effect of rGO-Doping on the Performance of SnO2/rGO Flexible Humidity Sensor.

The development of a flexible and high-performance humidity sensor is essential to expand its new applications, such as personal health monitoring and early diagnosis. In this work, SnO2/rGO nanocomposites were prepared by one-step hydrothermal method. The effect of rGO-doping on humidity sensing performance was investigated. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction and Raman spectroscopy were used to characterize the nanostructure, morphology and chemical composition of SnO2/rGO nanocomposites. The SnO2/rGO humidity sensitive film was prepared by electrospinning on a polyimide film modified with gold electrodes. The humidity test results show that different doping ratios of rGO have different effects on humidity sensing properties. Among them, the sensor with 2 wt% rGO-doping has a high sensitivity (37,491.2%) within the humidity range as well as the fast response time (80 s) and recover time (4 s). Furthermore, the sensor with 2 wt% rGO-doping remains good flexibility and stability in the case of bending (1000 times). The sensitivity of the 2 wt% rGO-doping sensor at the bending radius (8 mm and 4 mm) is 48,219% and 91,898%, respectively. More importantly, the sensor could reflect different breathing states clearly and track breathing intervals as short as 3 s. The SnO2/rGO flexible humidity sensor with accuracy, flexibility and instantaneity as well as the facile fabrication strategy is conceivable to be applied in the potential application for human health real-time monitoring.